4493
1992
deu
article
1
2010-12-13
--
--
Organometall-Imide - höhervalente Derivate der d-Metall-Säuren, 3. Synthese ond Reaktionen von (Pentamethylcyclopentadienyl)(imido)-Komplexen des Molybdäns und Wolframs und eine effiziente Strategie zur Synthese der Organometallate NBu\(_4\)[Cp*MO\(_3\)] (M = Mo, W)
Organometallic imido complexes - higher valent derivatives of the d-metal acids. 3. Synthesis and reactions of pentamethylcyclopentadienyl imido complexes of molybdenum and tungsten and an efficient strategy for the synthesis of the organometallates
A convenient and new entry into the chemistry of highvalent pentamethylcyclopentadienyl halfsandwich complexes of molybdenum and tungsten is described. The reaction of Mo-(NtBu)\(_2\)Cl\(_2\) or W(NtBu)\(_2\)Cl\(_2\)(py)\(_2\) with Cp*Li (Cp* = \(\eta^5\)-C\(_5\)Me\(_5\)) provides a high-yield route to new complexes Cp*Mo-(NtBu)\(_2\)CI (la) and Cp*W(NtBu)\(_2\)Cl (1 b) which are converted into a variety of diimido, monoimido, and oxo derivatives. Treatment of 1 a, b with MeLi yields the highly volatile methyl derivatives Cp*Mo(NtBu)\(_2\)Me (2a) and Cp*W(NtBu)\(_2\)Me (2b), while protolysis of 1 a, b with an excess of HCI gas leads to selective cleavage of only one imido function with formation of Cp*Mo(NtBu)Cl\(_3\) (3a) and Cp*W(NtBu)Cl\(_3\) (3b). In contrast, protolysis of 1 a, b with aqueous HCI provides a high-yield route to the well-known organometallic oxides [Cp*MoO\(_2\)](μ-0) (4a) and [Cp*WO\(_2\)](\(\mu\)-0) (4b). These two key compounds are easily converted into the organomolybdate and organotungstate salts NBu\(_4\)[Cp*MoO\(_3\)] (5a) and NBu\(_4\)[Cp*WO\(_3\)] (Sb) by cleavage of the M - 0 - M bridge with NBu\(_4\)[OH]. The Xray structure of 3a is reported.
urn:nbn:de:bvb:20-opus-31884
3188
Chemische Berichte (1992) 25, 11, S. 2379 - 2384
Deutsches Urheberrecht
Joerg Sundermeyer
Udo Radius
Christian Burschka
deu
swd
Pentamethylcyclopentadienderivate
eng
uncontrolled
Imido ligands
eng
uncontrolled
Oxo ligands
eng
uncontrolled
Pentamethylcyclopentadienylligand
eng
uncontrolled
Molybdenum complexes
eng
uncontrolled
Tungsten complexes
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/4493/Burschka_Synthese.pdf
31192
2023
eng
3
29
article
1
--
--
--
Activation of Ge−H and Sn−H Bonds with N‐Heterocyclic Carbenes and a Cyclic (Alkyl)(amino)carbene
A study of the reactivity of several N‐heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene 1‐(2,6‐di‐iso‐propylphenyl)‐3,3,5,5‐tetramethyl‐pyrrolidin‐2‐ylidene (cAAC\(^{Me}\)) with the group 14 hydrides GeH2Mes2 and SnH2Me2 (Me=CH\(_{3}\), Mes=1,3,5‐(CH\(_{3}\))\(_{3}\)C\(_{6}\)H\(_{2}\)) is presented. The reaction of GeH\(_{2}\)Mes\(_{2}\) with cAAC\(^{Me}\) led to the insertion of cAAC\(^{Me}\) into one Ge−H bond to give cAAC\(^{Me}\)H−GeHMes\(_{2}\) (1). If 1,3,4,5‐tetramethyl‐imidazolin‐2‐ylidene (Me\(_{2}\)Im\(^{Me}\)) was used as the carbene, NHC‐mediated dehydrogenative coupling occurred, which led to the NHC‐stabilized germylene Me\(_{2}\)Im\(^{Me}\)⋅GeMes\(_{2}\) (2). The reaction of SnH\(_{2}\)Me\(_{2}\) with cAAC\(^{Me}\) also afforded the insertion product cAAC\(^{Me}\)H−SnHMe\(_{2}\) (3), and reaction of two equivalents Me\(_{2}\)Im\(^{Me}\) with SnH\(_{2}\)Me\(_{2}\) gave the NHC‐stabilized stannylene Me\(_{2}\)Im\(^{Me}\)⋅SnMe\(_{2}\) (4). If the sterically more demanding NHCs Me\(_{2}\)Im\(^{Me}\), 1,3‐di‐isopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene (iPr\(_{2}\)Im\(^{Me}\)) and 1,3‐bis‐(2,6‐di‐isopropylphenyl)‐imidazolin‐2‐ylidene (Dipp\(_{2}\)Im) were employed, selective formation of cyclic oligomers (SnMe\(_{2}\))\(_{n}\) (5; n=5–8) in high yield was observed. These cyclic oligomers were also obtained from the controlled decomposition of cAAC\(^{Me}\)H−SnHMe\(_{2}\) (3).
Chemistry – A European Journal
10.1002/chem.202202493
urn:nbn:de:bvb:20-opus-311929
2023-04-19T14:01:56+00:00
sword
swordwue
attachment; filename=deposit.zip
77d374cea6d52e0b907593969a25dbed
Chemistry – A European Journal 2023, 29(3):e202202493. DOI: 10.1002/chem.202202493
false
true
CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International
Michael S. M. Philipp
Rüdiger Bertermann
Udo Radius
eng
uncontrolled
cyclic alkyl(amino)carbenes
eng
uncontrolled
germanium
eng
uncontrolled
hydrides
eng
uncontrolled
N-heterocyclic carbenes
eng
uncontrolled
tin
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/31192/Philipp_Chemistry.pdf
25666
2021
eng
3504–3516
10
27
article
1
2022-02-13
--
--
Tris(pentafluoroethyl)difluorophosphorane: a versatile fluoride acceptor for transition metal chemistry
Fluoride abstraction from different types of transition metal fluoride complexes [L\(_n\)MF] (M=Ti, Ni, Cu) by the Lewis acid tris(pentafluoroethyl)difluorophosphorane (C\(_2\)F\(_5\))\(_3\)PF\(_2\) to yield cationic transition metal complexes with the tris(pentafluoroethyl)trifluorophosphate counterion (FAP anion, [(C\(_2\)F\(_5\))\(_3\)PF\(_3\)]\(^-\)) is reported. (C\(_2\)F\(_5\))\(_3\)PF\(_2\) reacted with trans-[Ni(iPr\(_2\)Im)\(_2\)(Ar\(^F\))F] (iPr2Im=1,3-diisopropylimidazolin-2-ylidene; Ar\(^F\)=C\(_6\)F\(_5\), 1 a; 4-CF\(_3\)-C\(_6\)F\(_4\), 1 b; 4-C\(_6\)F\(_5\)-C\(_6\)F\(_4\), 1 c) through fluoride transfer to form the complex salts trans-[Ni(iPr\(_2\)Im)\(_2\)(solv)(Ar\(^F\))]FAP (2 a-c[solv]; solv=Et\(_2\)O, CH\(_2\)Cl\(_2\), THF) depending on the reaction medium. In the presence of stronger Lewis bases such as carbenes or PPh\(_3\), solvent coordination was suppressed and the complexes trans-[Ni(iPr\(_2\)Im)\(_2\)(PPh\(_3\))(C\(_6\)F\(_5\))]FAP (trans-2 a[PPh\(_3\)]) and cis-[Ni(iPr\(_2\)Im)\(_2\)(Dipp\(_2\)Im)(C\(_6\)F\(_5\))]FAP (cis-2 a[Dipp\(_2\)Im]) (Dipp\(_2\)Im=1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) were isolated. Fluoride abstraction from [(Dipp\(_2\)Im)CuF] (3) in CH\(_2\)Cl\(_2\) or 1,2-difluorobenzene led to the isolation of [{(Dipp\(_2\)Im)Cu}\(_2\)]\(^2\)\(^+\)2 FAP\(^-\) (4). Subsequent reaction of 4 with PPh\(_3\) and different carbenes resulted in the complexes [(Dipp\(_2\)Im)Cu(LB)]FAP (5 a–e, LB=Lewis base). In the presence of C6Me6, fluoride transfer afforded [(Dipp\(_2\)Im)Cu(C\(_6\)Me\(_6\))]FAP (5 f), which serves as a source of [(Dipp\(_2\)Im)Cu)]\(^+\). Fluoride abstraction of [Cp\(_2\)TiF\(_2\)] (7) resulted in the formation of dinuclear [FCp\(_2\)Ti(μ-F)TiCp\(_2\)F]FAP (8) (Cp=η\(^5\)-C\(_5\)H\(_5\)) with one terminal fluoride ligand at each titanium atom and an additional bridging fluoride ligand.
Chemistry Europe
10.1002/chem.202004885
urn:nbn:de:bvb:20-opus-256665
publish
Chemistry Europe (2021) 27:10, 3504–3516. DOI: 10.1002/chem.202004885
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Steffen A. Föhrenbacher
Mirjam J. Krahfuss
Ludwig Zapf
Alexandra Friedrich
Nikolai V. Ignat'ev
Maik Finze
Udo Radius
eng
uncontrolled
inorganic chemistry
deu
uncontrolled
copper
deu
uncontrolled
nickel
deu
uncontrolled
phosphoranes
deu
uncontrolled
titanium
deu
uncontrolled
weakly coordinating anions
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25666/Chemistry_A_European_J_2020_Fhrenbacher.pdf
29386
2022
eng
32
2022
article
1
--
--
--
N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Germanium(IV) and Tin(IV) Chlorides and Organyl Chlorides
A study on the reactivity of N‐heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAAC\(^{Me}\) with selected germanium(IV) and tin(IV) chlorides and organyl chlorides is presented. The reactions of the NHCs Me\(_{2}\)Im\(^{Me}\), iPr\(_{2}\)Im\(^{Me}\) and Dipp2Im with the methyl chlorides ECl\(_{2}\)Me\(_{2}\) afforded the adducts NHC ⋅ ECl\(_{2}\)Me\(_{2}\) (E=Ge (1), Sn (2)), NHC=Me\(_{2}\)Im\(^{Me}\) (a), iPr\(_{2}\)Im\(^{Me}\) (b), Dipp\(_{2}\)Im (c)). The reaction of Me2Im\(^{Me}\) with GeCl\(_{4}\) led to isolation of Me\(_{2}\)Im\(^{Me}\) ⋅ GeCl\(_{4}\) (3), the reaction of iPr\(_{2}\)Im\(^{Me}\) with SnCl\(_{4}\) in THF afforded the THF adduct iPr\(_{2}\)Im\(^{Me}\) ⋅ SnCl\(_{4}\) ⋅ THF (4). Dipp\(_{2}\)Im ⋅ GeCl\(_{2}\)Me\(_{2}\) (1 c) isomerized into the backbone coordinated imidazolium salt [aDipp\(_{2}\)Im ⋅ GeClMe\(_{2}\)][Cl] (5) upon thermal treatment. The reactions of cAAC\(^{Me}\) with (i) ECl\(_{2}\)R\(_{2}\) (E=Ge, Sn) gave the adducts cAAC\(^{Me}\) ⋅ ECl\(_{2}\)R\(_{2}\) (R=Me: E=Ge (6); Sn (7); Ph: E=Ge (8)), with (ii) GeClMe\(_{3}\) and GeCl\(_{4}\) the salts [cAAC\(^{Me}\) ⋅ GeMe\(_{3}\)][Cl] (9) and [cAACMeCl][GeCl\(_{3}\)] (10), and (iii) with SnCl\(_{4}\) the salt [cAACMeCl][SnCl\(_{3}\)] (11) and the adduct cAAC\(^{Me}\) ⋅ SnCl\(_{4}\) (12). Reduction of 2 a with KC\(_{8}\) afforded the NHC‐stabilized stannylene Me\(_{2}\)Im\(^{Me}\) ⋅ SnMe\(_{2}\) 13, reduction of 7 with either KC8 or 1,4‐bis‐(trimethylsilyl)‐1,4‐dihydropyrazin in the presence of SnCl\(_{2}\)Me\(_{2}\) yielded cAAC\(^{Me}\) ⋅ SnMe\(_{2}\) ⋅ SnMe\(_{2}\)Cl\(_{2}\) (14).
European Journal of Inorganic Chemistry
10.1002/ejic.202200429
urn:nbn:de:bvb:20-opus-293865
2022-12-05T10:01:56+00:00
sword
swordwue
attachment; filename=deposit.zip
9ae91020790eec3b0949bd78ab4ba978
European Journal of Inorganic Chemistry 2022, Vol. 2022(32):e202200429. DOI: 10.1002/ejic.202200429
false
true
CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International
Michael S. M. Philipp
Rüdiger Bertermann
Udo Radius
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/29386/Philipp_Chemistry.pdf
29370
2022
eng
31
2022
article
1
--
--
--
Cationic Nickel d\(^{9}\)‐Metalloradicals [Ni(NHC)\(_{2}\)]\(^{+}\)
A series of five new homoleptic, linear nickel d\(^{9}\)‐complexes of the type [Ni\(^{I}\)(NHC)\(_{2}\)]\(^{+}\) is reported. Starting from the literature known Ni(0) complexes [Ni(Mes\(_{2}\)Im)\(_{2}\)] 1, [Ni(Mes\(_{2}\)Im\(^{H2}\))2] 2, [Ni(Dipp\(_{2}\)Im)\(_{2}\)] 3, [Ni(Dipp\(_{2}\)Im\(^{H2}\))\(_{2}\)] 4 and [Ni(cAAC\(^{Me}\))\(_{2}\)] 5 (Mes\(_{2}\)Im=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazolin‐2‐ylidene, Mes\(_{2}\)Im\(^{H2}\)=1,3‐bis(2,4,6‐trimethylphenyl)‐imidazolidin‐2‐ylidene, Dipp\(_{2}\)Im=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolin‐2‐ylidene, Dipp\(_{2}\)Im\(^{H2}\)=1,3‐bis(2,6‐diisopropylphenyl)‐imidazolidin‐2‐ylidene, cAAC\(^{Me}\)=1‐(2,6‐diisopropylphenyl)‐3,3,5,5‐tetramethylpyrrolidin‐2‐yliden), their oxidized Ni(I) analogues [Ni\(^{I}\)(Mes\(_{2}\)Im)\(_{2}\)][BPh\(_{4}\)] 1\(^{+}\), [Ni\(^{I}\)(Mes\(_{2}\)Im\(^{H2}\))\(_{2}\)][BPh\(_{4}\)] 2\(^{+}\), [Ni\(^{I}\)(Dipp\(_{2}\)Im)\(_{2}\)][BPh\(_{4}\)] 3\(^{+}\), [Ni\(^{I}\)(Dipp\(_{2}\)Im\(^{H2}\))\(_{2}\)][BPh\(_{4}\)] 4\(^{+}\) and [Ni\(^{I}\)(cAAC\(^{Me}\))\(_{2}\)][BPh\(_{4}\)] 5\(^{+}\) were synthesized by one‐electron oxidation with ferrocenium tetraphenyl‐borate. The complexes 1\(^{+}\)–5\(^{+}\) were fully characterized including X‐ray structure analysis. The complex cations reveal linear geometries in the solid state and NMR spectra with extremely broad, paramagnetically shifted resonances. DFT calculations predicted an orbitally degenerate ground state leading to large magnetic anisotropy, which was verified by EPR measurements in solution and on solid samples. The magnetic anisotropy of the complexes is highly dependent from the steric protection of the metal atom, which results in a noticeable decrease of the g‐tensor anisotropy for the N‐Mes substituted complexes 1\(^{+}\) and 2\(^{+}\) in solution due to the formation of T‐shaped THF adducts.
European Journal of Inorganic Chemistry
10.1002/ejic.202200416
urn:nbn:de:bvb:20-opus-293702
2022-12-05T10:00:07+00:00
sword
swordwue
attachment; filename=deposit.zip
1719bc453d81b3863d03a6c58c2724b2
European Journal of Inorganic Chemistry 2022, Vol. 2022(31):e202200416. DOI: 10.1002/ejic.202200416
false
true
CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International
Lukas Tendera
Martin S. Luff
Ivo Krummenacher
Udo Radius
eng
uncontrolled
Alkyl(amino)carbene
eng
uncontrolled
EPR spectroscopy
eng
uncontrolled
Metalloradicals
eng
uncontrolled
Nickel ComplexCyclic
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/29370/Tendera_Chemistry.pdf
31826
2022
eng
24
28
article
1
--
--
--
Selective, Transition Metal-free 1,2-Diboration of Alkyl Halides, Tosylates, and Alcohols
Defunctionalization of readily available feedstocks to provide alkenes for the synthesis of multifunctional molecules represents an extremely useful process in organic synthesis. Herein, we describe a transition metal-free, simple and efficient strategy to access alkyl 1,2-bis(boronate esters) via regio- and diastereoselective diboration of secondary and tertiary alkyl halides (Br, Cl, I), tosylates, and alcohols. Control experiments demonstrated that the key to this high reactivity and selectivity is the addition of a combination of potassium iodide and N,N-dimethylacetamide (DMA). The practicality and industrial potential of this transformation are demonstrated by its operational simplicity, wide functional group tolerance, and the late-stage modification of complex molecules. From a drug discovery perspective, this synthetic method offers control of the position of diversification and diastereoselectivity in complex ring scaffolds, which would be especially useful in a lead optimization program.
Chemistry-A European Journal
10.1002/chem.202200480
urn:nbn:de:bvb:20-opus-318262
@articleHuang.2022, author = Huang, Mingming and Hu, Jiefeng and Shi, Shasha and Friedrich, Alexandra and Krebs, Johannes and Westcott, Stephen A. and Radius, Udo and Marder, Todd B., year = 2022, title = Selective, Transition Metal-free 1,2-Diboration of Alkyl Halides, Tosylates, and Alcohols, pages = e202200480, volume = 28, number = 24, journal = Chemistry (Weinheim an der Bergstrasse, Germany), doi = 10.1002/chem.202200480,
md5:2629f24a4c73bc7b8b520514b9c8a9e1
2023-06-06T13:32:14+00:00
/tmp/phpjvxiOw
bibtex
647f355e90edf6.33363317
Chemistry-A European Journal 2022, 28(24):e202200480. DOI: 10.1002/chem.202200480
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Mingming Huang
Jiefeng Hu
Shasha Shi
Alexandra Friedrich
Johannes Krebs
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
organic synthesis
eng
uncontrolled
boronate esters
eng
uncontrolled
alkyl halides
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/31826/Huang_Chemistry.pdf
31827
2022
eng
17
648
article
1
--
--
--
A Versatile Route To Cyclic (Alkyl)(Amino)Carbene–Stabilized Stibinidenes
A convenient route for the synthesis of the cAAC\(^{Me}\) (cAAC=cyclic (alkyl)(amino)carbene, cAAC\(^{Me}\)=1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) and cAAC\(^{Cy}\) (cAAC\(^{Cy}\)=2-azaspiro[4.5]dec-2-(2,6-diisopropylphenyl)-3,3-dimethyl-1-ylidene) stabilized stibinidenes cAAC\(^{Me}\)⋅SbMes (2a) (Mes=2,4,6-trimethylphenyl) and cAAC\(^{Cy}\)⋅SbMes (2b) is reported. A mechanism for the formation of [cAAC\(^{R}\)Cl][SbCl\(_{3}\)Mes] 1 and cAAC\(^{R}\)⋅SbMes 2 from the reaction of cAAC with the antimony(III) precursor SbCl\(_{2}\)Mes, which proceeds via the isolable intermediate [cAAC\(^{R}\)SbClMes][SbCl\(_{3}\)Mes] (3), is proposed.
Zeitschrift für Anorganische und Allgemeine Chemie
0044-2313
10.1002/zaac.202200085
urn:nbn:de:bvb:20-opus-318272
@articlePhilipp.2022, author = Philipp, Michael S. M. and Radius, Udo, year = 2022, title = A Versatile Route To Cyclic (Alkyl)(Amino)Carbene–Stabilized Stibinidenes, volume = 648, number = 17, issn = 0044-2313, journal = Zeitschrift für anorganische und allgemeine Chemie, doi = 10.1002/zaac.202200085
md5:4199d97abf2923299b651c1f2bd1b929
2023-06-06T13:32:14+00:00
/tmp/phpjvxiOw
bibtex
647f355e90edf6.33363317
Zeitschrift für Anorganische und Allgemeine Chemie 2022, 648(17):e202200085. DOI: 10.1002/zaac.202200085
false
true
CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International
Michael S. M. Philipp
Udo Radius
eng
uncontrolled
stibinidenes
eng
uncontrolled
antimony
eng
uncontrolled
cyclic (alkyl)(amino)carbenes
eng
uncontrolled
lewis acid/base adducts
eng
uncontrolled
main group element halides
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/31827/Philipp_JIGC.pdf
22436
2020
eng
17267
17274
71
26
article
1
--
--
--
Copper‐Catalyzed Oxidative Cross‐Coupling of Electron‐Deficient Polyfluorophenylboronate Esters with Terminal Alkynes
We report herein a mild procedure for the copper‐catalyzed oxidative cross‐coupling of electron‐deficient polyfluorophenylboronate esters with terminal alkynes. This method displays good functional group tolerance and broad substrate scope, generating cross‐coupled alkynyl(fluoro)arene products in moderate to excellent yields. Thus, it represents a simple alternative to the conventional Sonogashira reaction.
Chemistry – A European Journal
10.1002/chem.202002888
urn:nbn:de:bvb:20-opus-224362
2021-02-15T10:01:37+00:00
sword
swordwue
attachment; filename=deposit.zip
7351df393e24ccd7237deaa615849707
Chemistry – A European Journal 2020, 26(71):17267-17274. DOI: 10.1002/chem.202002888
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Zhiqiang Liu
Yudha P. Budiman
Ya‐Ming Tian
Alexandra Friedrich
Mingming Huang
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
boronate esters
eng
uncontrolled
coupling reactions
eng
uncontrolled
fluorine
eng
uncontrolled
fluoroarenes
eng
uncontrolled
Sonogashira reaction
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/22436/CHEM_CHEM202002888.pdf
20872
2020
eng
281-291
3
2020
article
1
2020-07-20
--
--
N-Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Complexes of Titanium(IV) and Titanium(III)
The reaction of one and two equivalents of the N ‐heterocyclic carbene IMes [IMes = 1,3‐bis(2,4,6‐trimethyl‐phenyl)imidazolin‐2‐ylidene] or the cyclic (alkyl)(amino)carbene cAAC\(^{Me}\) [cAAC\(^{Me}\) = 1‐(2,6‐diisopropyl‐phenyl)‐3,3,5,5‐tetra‐methylpyrrolidin‐2‐ylidene] with [TiCl\(_{4}\)] in n ‐hexane results in the formation of mono‐ and bis‐carbene complexes [TiCl\(_{4}\)(IMes)] 1 , [TiCl\(_{4}\)(IMes)2] 2 , [TiCl\(_{4}\)(cAAC\(^{Me}\))] 3 , and [TiCl\(_{4}\)(cAAC\(^{Me}\))\(_{2}\)] 4 , respectively. For comparison, the titanium(IV) NHC complex [TiCl\(_{4}\)(Ii Pr\(^{Me}\))] 5 (Ii Pr\(^{Me}\) = 1,3‐diisopropyl‐4,5‐dimethyl‐imidazolin‐2‐ylidene) has been synthesized and structurally characterized. The reaction of [TiCl\(_{4}\)(IMes)] 1 with PMe\(_{3}\) affords the mixed substituted complex [TiCl\(_{4}\)(IMes)(PMe\(_{3}\))] 6 . The reactions of [TiCl\(_{3}\)(THF)\(_{3}\)] with two equivalents of the carbenes IMes and cAAC\(^{Me}\) in n ‐hexane lead to the clean formation of the titanium(III) complexes [TiCl\(_{3}\)(IMes)\(_{2}\)] 7 and [TiCl\(_{3}\)(cAAC\(^{Me}\))\(_{2}\)] 8 . Compounds 1 –8 have been completely characterized by elemental analysis, IR and multinuclear NMR spectroscopy and for 2 –5 , 7 and 8 by X‐ray diffraction. Magnetometry in solution, EPR and UV/Vis spectroscopy and DFT calculations performed on 7 and 8 are indicative of a predominantly metal‐centered d\(^{1}\)‐radical in both cases.
European Journal of Inorganic Chemistry
10.1002/ejic.201901207
urn:nbn:de:bvb:20-opus-208725
European Journal of Inorganic Chemistry 2020(3), 281–291. DOI: 10.1002/ejic.201901207
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Günther Horrer
Mirjam J. Krahfuß
Katharina Lubitz
Ivo Krummenacher
Holger Braunschweig
Udo Radius
eng
uncontrolled
N-heterocyclic carbenes
eng
uncontrolled
carbene ligands
eng
uncontrolled
Titanium
eng
uncontrolled
structure elucidation
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/20872/Horrer_European_Journal_of_Inorganic_Chemistry.pdf
25649
2021
eng
17974–17980
33
60
article
1
2022-02-12
--
--
1,3-bis(tricyanoborane)imidazoline-2-ylidenate anion - a ditopic dianionic N-heterocyclic carbene ligand
The 1,3-bis(tricyanoborane)imidazolate anion 1 was obtained in high yield from lithium imidazolate and B(CN)\(_3\)−pyridine adduct. Anion 1 is chemically very robust and thus allowed the isolation of the corresponding H\(_5\)O\(_2\)\(^+\) salt. Furthermore, monoanion 1 served as starting species for the novel dianionic N-heterocyclic carbene (NHC), 1,3-bis(tricyanoborane)imidazoline-2-ylidenate anion 3 that acts as ditopic ligand via the carbene center and the cyano groups at boron. First reactions of this new NHC 3 with methyl iodide, elemental selenium, and [Ni(CO)\(_4\)] led to the methylated imidazolate ion 4, the dianionic selenium adduct 5, and the dianionic nickel tricarbonyl complex 6. These NHC derivatives provide a first insight into the electronic and steric properties of the dianionic NHC 3. Especially the combination of properties, such as double negative charge, different coordination sites, large buried volume and good σ-donor and π-acceptor ability, make NHC 3 a unique and promising ligand and building block.
Angewandte Chemie International Edition
10.1002/anie.202105529
urn:nbn:de:bvb:20-opus-256498
publish
Angewandte Chemie International Edition (2021) 60:33, 17974–17980. DOI: 10.1002/anie.202105529
false
true
CC BY-NC-ND: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell, Keine Bearbeitungen 4.0 International
Ludwig Zapf
Udo Radius
Maik Finze
eng
uncontrolled
inorganic chemistry
eng
uncontrolled
N-heterocyclic carbene
eng
uncontrolled
anioniccarbene
eng
uncontrolled
boron
eng
uncontrolled
cyanoborate
eng
uncontrolled
imidazolate
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25649/Angew_Chem_Int_Ed_2021_Zapf.pdf
21249
2019
eng
11365
11374
48
25
article
1
--
--
--
Intramolecular Ring‐Expansion Reaction (RER) and Intermolecular Coordination of In Situ Generated Cyclic (Amino)(aryl)carbenes (cAArCs)
Cyclic (amino)(aryl)carbenes (cAArCs) based on the isoindoline core were successfully generated in situ by α‐elimination of 3‐alkoxyisoindolines at high temperatures or by deprotonation of isoindol‐2‐ium chlorides with sodium or copper(I) acetates at low temperatures. 3‐Alkoxy‐isoindolines 2 a,b‐OR (R=Me, Et, iPr) have been prepared in high yields by the addition of a solution of 2‐aryl‐1,1‐diphenylisoindol‐2‐ium triflate (1 a,b‐OTf; a: aryl=Dipp=2,6‐diisopropylphenyl; b: Mesityl‐, Mes=2,4,6‐trimethylphenyl) to the corresponding alcohol (ROH) with NEt3 at room temperature. Furthermore, the reaction of 2 a,b‐OMe in diethyl ether with a tenfold excess of hydrochloric acid led to the isolation of the isoindol‐2‐ium chlorides 1 a,b‐Cl in high yields. The thermally generated cAArC reacts with sulfur to form the thioamide 3 a. Without any additional trapping reagent, in situ generation of 1,1‐diphenylisoidolin‐3‐ylidenes does not lead to the isolation of these compounds, but to the reaction products of the insertion of the carbene carbon atom into an ortho C−H bond of a phenyl substituent, followed by ring‐expansion reaction; namely, anthracene derivatives 9‐N(H)aryl‐10‐Ph‐C14H8 4 a,b (a: Dipp; b: Mes). These compounds are conveniently synthesized by deprotonation of the isoindol‐2‐ium chlorides with sodium acetate in high yields. Deprotonation of 1 a‐Cl with copper(I) acetate at low temperatures afforded a mixture of 4 a and the corresponding cAArC copper(I) chloride 5 a, and allowed the isolation and structural characterization of the first example of a cAArC copper complex of general formula [(cAArC)CuCl].
Chemistry – A European Journal
10.1002/chem.201902630
urn:nbn:de:bvb:20-opus-212496
swordwue
2020-10-03T02:02:24+00:00
attachment; filename=deposit.zip
2657dd8b27f0ce3c24409c506e28cf97
Chemistry – A European Journal 2019, 25(48):11365–11374. DOI: 10.1002/chem.201902630
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Jan Lorkowski
Mirjam Krahfuß
Maciej Kubicki
Udo Radius
Cezary Pietraszuk
eng
uncontrolled
cAArC
eng
uncontrolled
complexes
eng
uncontrolled
copper
eng
uncontrolled
NHC
eng
uncontrolled
ring-expansion reaction
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/21249/CHEM_CHEM201902630.pdf
26258
2021
eng
3591
3600
35
2021
article
1
--
--
--
NON‐Ligated N‐Heterocyclic Tetrylenes
We report on the synthesis of N‐heterocyclic tetrylenes ligated by the NON‐donor framework 4,5‐bis(2,6‐diisopropylphenyl‐amino)‐2,7‐di‐tert‐butyl‐9,9‐dimethylxanthene. The molecular structures of the germylene (3), stannylene (4) and plumbylene (5) where determined by X‐ray diffraction studies. Furthermore, we present quantum chemical studies on the σ‐donor and π‐acceptor properties of 3–5. Additionally, we report on the reactivity of the tetrylenes towards the transition metal carbonyls [Rh(CO)\(_{2}\)Cl]\(_{2}\), [W(CO)\(_{6}\)] and [Ni(CO)\(_{4}\)]. The isolated complexes (6 and 7) show the differing reactivity of NHTs compared to NHCs. Instead of just forming the anticipated complex [(NON)Sn−Rh(CO)\(_{2}\)Cl], 4 inserts into the Rh−Cl bond to afford [(NON)Sn(Cl)Rh(CO)(C\(_{6}\)H\(_{6}\))] (6, additional CO/C6H6 exchange) and [(NON)Sn(Cl)Rh\(_{2}\)(CO)\(_{4}\)Cl] (7). By avoiding halogenated transition metal precursors in order to prevent insertion reactions, germylene 3 shows “classical” coordination chemistry towards {Ni(CO)3} forming the complex [(NON)Ge−Ni(CO)\(_{3}\)] (8).
European Journal of Inorganic Chemistry
10.1002/ejic.202100446
urn:nbn:de:bvb:20-opus-262586
2022-03-28T07:44:19+00:00
sword
swordwue
attachment; filename=deposit.zip
6460c72378a81a9df599a9aab1dbde18
European Journal of Inorganic Chemistry 2021, 2021(35):3591–3600. DOI: 10.1002/ejic.202100446
CC BY-NC: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell 4.0 International
Felix Krämer
Martin S. Luff
Udo Radius
Florian Weigend
Frank Breher
eng
uncontrolled
Germylenes
eng
uncontrolled
heterocyclic tetrylenes
eng
uncontrolled
hetrocyclic tetrylene complexes
eng
uncontrolled
Plumbylenes
eng
uncontrolled
Stannylenes
Chemie und zugeordnete Wissenschaften
open_access
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/26258/EJIC_EJIC202100446.pdf
29378
2022
eng
63
28
article
1
--
--
--
Transition Metal‐Free Regio‐ and Stereo‐Selective trans Hydroboration of 1,3‐Diynes: A Phosphine‐Catalyzed Access to (E)‐1‐Boryl‐1,3‐Enynes
We report a transition metal‐free, regio‐ and stereo‐selective, phosphine‐catalyzed method for the trans hydroboration of 1,3‐diynes with pinacolborane that affords (E)‐1‐boryl‐1,3‐enynes. The reaction proceeds with excellent selectivity for boron addition to the external carbon of the 1,3‐diyne framework as unambiguously established by NMR and X‐ray crystallographic studies. The reaction displays a broad substrate scope including unsymmetrical diynes to generate products in high yield (up to 95 %). Experimental and theoretical studies suggest that phosphine attack on the alkyne is a key process in the catalytic cycle.
Chemistry – A European Journal
10.1002/chem.202202349
urn:nbn:de:bvb:20-opus-293784
2022-12-05T10:01:04+00:00
sword
swordwue
attachment; filename=deposit.zip
fb722fba0f17498d30ddc454cbd97b87
Chemistry – A European Journal 2022, 28(63):e202202349. DOI: 10.1002/chem.202202349
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Swetha Jos
Connor Szwetkowski
Carla Slebodnick
Robert Ricker
Ka Lok Chan
Wing Chun Chan
Udo Radius
Zhenyang Lin
Todd B. Marder
Webster L. Santos
eng
uncontrolled
enediyne
eng
uncontrolled
enyne
eng
uncontrolled
hydroboration
eng
uncontrolled
organocatalytic
eng
uncontrolled
stereoselective
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/29378/Jos_Chemistry.pdf
25713
2021
eng
17849–17861
71
27
article
1
2022-02-17
--
--
Case Study of N-\(^{i}\)Pr versus N-Mes Substituted NHC Ligands in Nickel Chemistry: The Coordination and Cyclotrimerization of Alkynes at [Ni(NHC)\(_{2}\)]
A case study on the effect of the employment of two different NHC ligands in complexes [Ni(NHC)\(_{2}\)] (NHC=\(^{i}\)Pr\(_{2}\)Im\(^{Me}\) 1\(^{Me}\), Mes\(_{2}\)Im 2) and their behavior towards alkynes is reported. The reaction of a mixture of [Ni\(_{2}\)(\(^{i}\)Pr\(_{2}\)Im\(^{Me}\))\(_{4}\)(μ-(η\(^{2}\) : η\(^{2}\))-COD)] B/ [Ni(\(^{i}\)Pr\(_{2}\)Im\(^{Me}\))\(_{2}\)(η\(^{4}\)-COD)] B’ or [Ni(Mes\(_{2}\)Im)\(_{2}\)] 2, respectively, with alkynes afforded complexes [Ni(NHC)\(_{2}\)(η\(^{2}\)-alkyne)] (NHC=\(^{i}\)Pr\(_{2}\)Im\(^{Me}\): alkyne=MeC≡CMe 3, H\(_{7}\)C\(_{3}\)C≡CC\(_{3}\)H\(_{7}\) 4, PhC≡CPh 5, MeOOCC≡CCOOMe 6, Me\(_{3}\)SiC≡CSiMe\(_{3}\) 7, PhC≡CMe 8, HC≡CC\(_{3}\)H\(_{7}\) 9, HC≡CPh 10, HC≡C(p-Tol) 11, HC≡C(4-\(^{t}\)Bu-C\(_{6}\)H\(_{4}\)) 12, HC≡CCOOMe 13; NHC=Mes\(_{2}\)Im: alkyne=MeC≡CMe 14, MeOOCC≡CCOOMe 15, PhC≡CMe 16, HC≡C(4-\(^{t}\)Bu-C\(_{6}\)H\(_{4}\)) 17, HC≡CCOOMe 18). Unusual rearrangement products 11 a and 12 a were identified for the complexes of the terminal alkynes HC≡C(p-Tol) and HC≡C(4-\(^{t}\)Bu-C\(_{6}\)H\(_{4}\)), 11 and 12, which were formed by addition of a C−H bond of one of the NHC N-\(^{i}\)Pr methyl groups to the C≡C triple bond of the coordinated alkyne. Complex 2 catalyzes the cyclotrimerization of 2-butyne, 4-octyne, diphenylacetylene, dimethyl acetylendicarboxylate, 1-pentyne, phenylacetylene and methyl propiolate at ambient conditions, whereas 1\(^{Me}\) is not a good catalyst. The reaction of 2 with 2-butyne was monitored in some detail, which led to a mechanistic proposal for the cyclotrimerization at [Ni(NHC)\(_{2}\)]. DFT calculations reveal that the differences between 1\(^{Me}\) and 2 for alkyne cyclotrimerization lie in the energy profile of the initiation steps, which is very shallow for 2, and each step is associated with only a moderate energy change. The higher stability of 3 compared to 14 is attributed to a better electron transfer from the NHC to the metal to the alkyne ligand for the N-alkyl substituted NHC, to enhanced Ni-alkyne backbonding due to a smaller C\(_{NHC}\)−Ni−C\(_{NHC}\) bite angle, and to less steric repulsion of the smaller NHC \(^{i}\)Pr\(_{2}\)Im\(^{Me}\).
Chemistry—A European Journal
10.1002/chem.202103093
urn:nbn:de:bvb:20-opus-257137
publish
Chemistry—A European Journal 2021, 27(71):17849–17861. DOI: 10.1002/chem.202103093
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Lukas Tendera
Moritz Helm
Mirjam Krahfuss
Maximilian W. Kuntze-Fechner
Udo Radius
eng
uncontrolled
nickel complexes
eng
uncontrolled
cyclooligomerization
eng
uncontrolled
cyclotrimerization
eng
uncontrolled
alkyne complexes
eng
uncontrolled
N-heterocyclic carbenes
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25713/Tendera_Chemistry.pdf
28720
2022
eng
39
28
article
1
--
--
--
Tricyanoborane‐Functionalized Anionic N‐Heterocyclic Carbenes: Adjustment of Charge and Stereo‐Electronic Properties
The 1‐methyl‐3‐(tricyanoborane)imidazolin‐2‐ylidenate anion (2) was obtained in high yield by deprotonation of the B(CN)3‐methylimidazole adduct 1. Regarding charge and stereo‐electronic properties, anion 2 closes the gap between well‐known neutral NHCs and the ditopic dianionic NHC, the 1,3‐bis(tricyanoborane)imidazolin‐2‐ylidenate dianion (IIb). The influence of the number of N‐bonded tricyanoborane moieties on the σ‐donating and π‐accepting properties of NHCs was assessed by quantum chemical calculations and verified by experimental data on 2, IIb, and 1,3‐dimethylimidazolin‐2‐ylidene (IMe, IIa). Therefore NHC 2, which acts as a ditopic ligand via the carbene center and the cyano groups, was reacted with alkyl iodides, selenium, and [Ni(CO)\(_{4}\)] yielding alkylated imidazoles 3 and 4, the anionic selenium adduct 5, and the anionic nickel tricarbonyl complex 8, respectively. The results of this study prove that charge, number of coordination sites, buried volume (%V\(_{bur}\)) and σ‐donor and π‐acceptor abilities of NHCs can be effectively fine‐tuned via the number of tricyanoborane substituents.
Chemistry – A European Journal
10.1002/chem.202200275
urn:nbn:de:bvb:20-opus-287200
2022-09-21T21:40:10+00:00
sword
swordwue
attachment; filename=deposit.zip
9fb769b41e1f3e11aeb834f4b988f1b3
Chemistry – A European Journal 2022, 28(39):e202200275. DOI: 10.1002/chem.202200275
false
true
CC BY-NC-ND: Creative-Commons-Lizenz: Namensnennung, Nicht kommerziell, Keine Bearbeitungen 4.0 International
Ludwig Zapf
Sven Peters
Rüdiger Bertermann
Udo Radius
Maik Finze
eng
uncontrolled
N-heterocyclic carbene
eng
uncontrolled
anionic carbene
eng
uncontrolled
boron
eng
uncontrolled
cyanoborate
eng
uncontrolled
imidazolate
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/28720/CHEM_CHEM202200275.pdf
25677
2021
eng
8149–8158
31
27
article
1
2022-02-14
--
--
Ni-Catalyzed Borylation of Aryl Sulfoxides
A nickel/N-heterocyclic carbene (NHC) catalytic system has been developed for the borylation of aryl sulfoxides with B\(_{2}\)(neop)\(_{2}\) (neop=neopentyl glycolato). A wide range of aryl sulfoxides with different electronic and steric properties were converted into the corresponding arylboronic esters in good yields. The regioselective borylation of unsymmetric diaryl sulfoxides was also feasible leading to borylation of the sterically less encumbered aryl substituent. Competition experiments demonstrated that an electron-deficient aryl moiety reacts preferentially. The origin of the selectivity in the Ni-catalyzed borylation of electronically biased unsymmetrical diaryl sulfoxide lies in the oxidative addition step of the catalytic cycle, as oxidative addition of methoxyphenyl 4-(trifluoromethyl)phenyl sulfoxide to the Ni(0) complex occurs selectively to give the structurally characterized complex trans-[Ni(ICy)\(_{2}\)(4-CF\(_{3}\)-C\(_{6}\)H\(_{4}\)){(SO)-4-MeO-C\(_{6}\)H\(_{4}\)}] 4. For complex 5, the isomer trans-[Ni(ICy)\(_{2}\)(C\(_{6}\)H\(_{5}\))(OSC\(_{6}\)H\(_{5}\))] 5-I was structurally characterized in which the phenyl sulfinyl ligand is bound via the oxygen atom to nickel. In solution, the complex trans-[Ni(ICy)\(_{2}\)(C\(_{6}\)H\(_{5}\))(OSC\(_{6}\)H\(_{5}\))] 5-I is in equilibrium with the S-bonded isomer trans-[Ni(ICy)\(_{2}\)(C\(_{6}\)H\(_{5}\))(SOC\(_{6}\)H\(_{5}\))] 5, as shown by NMR spectroscopy. DFT calculations reveal that these isomers are separated by a mere 0.3 kJ/mol (M06/def2-TZVP-level of theory) and connected via a transition state trans-[Ni(ICy)\(_{2}\)(C\(_{6}\)H\(_{5}\))(η\(^{2}\)-{SO}-C\(_{6}\)H\(_{5}\))], which lies only 10.8 kcal/mol above 5.
Chemistry—A European Journal
10.1002/chem.202100342
urn:nbn:de:bvb:20-opus-256778
publish
Chemistry—A European Journal 2021, 27(31):8149–8158. DOI: 10.1002/chem.202100342
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Mingming Huang
Zhu Wu
Johannes Krebs
Alexandra Friedrich
Xiaoling Luo
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
Boron
eng
uncontrolled
cross-coupling
eng
uncontrolled
N-heterocyclic carbenes
eng
uncontrolled
nickel
eng
uncontrolled
borylation
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25677/Huang_Chemistry.pdf
25648
2021
eng
16529–16538
30
60
article
1
2022-02-12
--
--
Transition metal catalyst-free, base-promoted 1,2-additions of polyfluorophenylboronates to aldehydes and ketones
A novel protocol for the transition metal-free 1,2-addition of polyfluoroaryl boronate esters to aldehydes and ketones is reported, which provides secondary alcohols, tertiary alcohols, and ketones. Control experiments and DFT calculations indicate that both the ortho-F substituents on the polyfluorophenyl boronates and the counterion K\(^+\) in the carbonate base are critical. The distinguishing features of this procedure include the employment of commercially available starting materials and the broad scope of the reaction with a wide variety of carbonyl compounds giving moderate to excellent yields. Intriguing structural features involving O−H⋅⋅⋅O and O−H⋅⋅⋅N hydrogen bonding, as well as arene-perfluoroarene interactions, in this series of racemic polyfluoroaryl carbinols have also been addressed.
Angewandte Chemie International Edition
10.1002/anie.202103686
urn:nbn:de:bvb:20-opus-256487
publish
Angewandte Chemie International Edition (2021) 60:30, 16529–16538. DOI: 10.1002/anie.202103686
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Zhiqiang Liu
Goutam Kumar Kole
Yudha P. Budiman
Ya-Ming Tian
Alexandra Friedrich
Xiaoling Luo
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
inorganic chemistry
eng
uncontrolled
transition metal-free
eng
uncontrolled
alcohol
eng
uncontrolled
1,2-additionreaction
eng
uncontrolled
boronateesters
eng
uncontrolled
fluoroarene
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25648/Angew_Chem_Int_Ed_2021_Liu.pdf
22590
2021
eng
2224
2255
9
363
article
1
--
--
--
Fluorinated Aryl Boronates as Building Blocks in Organic Synthesis
Organoboron compounds are well known building blocks for many organic reactions. However, under basic conditions, polyfluorinated aryl boronic acid derivatives suffer from instability issues that are accelerated in compounds containing an ortho‐fluorine group, which result in the formation of the corresponding protodeboronation products. Therefore, a considerable amount of research has focused on novel methodologies to synthesize these valuable compounds while avoiding the protodeboronation issue. This review summarizes the latest developments in the synthesis of fluorinated aryl boronic acid derivatives and their applications in cross‐coupling reactions and other transformations.
image
Advanced Synthesis & Catalysis
10.1002/adsc.202001291
urn:nbn:de:bvb:20-opus-225908
2021-02-22T15:25:31+00:00
sword
swordwue
attachment; filename=deposit.zip
132eb8922daad97d4c5e463f22f52381
Advanced Synthesis & Catalysis 2021, 363(9):2224–2255. DOI: 10.1002/adsc.202001291
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Yudha P. Budiman
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
homogeneous catalysis
eng
uncontrolled
boron reagents
eng
uncontrolled
boronates
eng
uncontrolled
fluorine
eng
uncontrolled
fluoroarene
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/22590/adsc.202001291.pdf
25740
2021
eng
4007–4019
38
2021
article
1
--
--
--
N‐Heterocyclic Carbene and Cyclic (Alkyl)(amino)carbene Adducts of Antimony(III)
A systematic study on Lewis-acid/base adducts of N-heterocyclic carbenes (NHCs) and the cyclic (alkyl)(amino)carbene cAAC\(^{Me}\) (1-(2,6-di-iso-propylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) with antimony(III) chlorides of the general formula SbCl\(_{2}\)R (R=Cl, Ph, Mes) is presented. The reaction of the NHCs Me\(_{2}\)Im\(^{Me}\) (1,3,4,5-tetra-methyl-imidazolin-2-ylidene), iPr\(_{2}\)Im\(^{Me}\) (1,3-di-isopropyl-4,5-dimethyl-imidazolin-2-ylidene), Mes\(_{2}\)Im, Dipp\(_{2}\)Im (R\(_{2}\)Im=1,3-di-organyl-imidazolin-2-ylidene; Mes=2,4,6-trimethylphenyl, Dipp=2,6-di-isopropylphenyl) and cAAC\(^{Me}\) with antimony(III) compounds SbCl\(_{2}\)R (R=Cl (1), Ph (2) and Mes (3)) yields the adducts NHC ⋅ SbCl\(_{2}\)R (R=Cl (4), Ph (5) and Mes (6); NHC=Me\(_{2}\)Im\(^{Me}\) (a), iPr\(_{2}\)Im\(^{Me}\) (b), Dipp\(_{2}\)Im (c) and Mes\(_{2}\)Im (d)) and cAAC\(^{Me}\) ⋅ SbCl\(_{2}\)R (R=Cl (4 e) and Ph (5 e)). Thermal treatment of (Dipp\(_{2}\)Im) ⋅ SbCl\(_{2}\)Ar (Ar=Ph (5 c) and Mes (6 c)) in benzene leads to isomerization to the backbone coordinated \(^{a}\)NHC-adduct \(^{a}\)Dipp\(_{2}\)Im ⋅ SbCl\(_{2}\)Ar (Ar=Mes (7) and Ph (8)) (\(^{"a"}\) denotes “abnormal” coordination mode of the NHC) in high yields. One of the chloride substituents at antimony of 7 can be abstracted by GaCl3 or Ag[BF\(_{4}\)] to obtain the imidazolium salts [\(^{a}\)Dipp\(_{2}\)Im ⋅ SbClMes][BF\(_{4}\)] (9) and [\(^{a}\)Dipp\(_{2}\)Im ⋅ SbClMes][GaCl\(_{4}\)] (10).
European Journal of Inorganic Chemistry
10.1002/ejic.202100632
urn:nbn:de:bvb:20-opus-257408
publish
European Journal of Inorganic Chemistry 2021, Volume 2021(38):4007–4019. DOI: 10.1002/ejic.202100632
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Michael S. M. Philipp
Mirjam J. Krahfuss
Krzysztof Radacki
Udo Radius
eng
uncontrolled
N-Heterocyclic carbenes
eng
uncontrolled
antimony
eng
uncontrolled
cyclic (alkyl)(amino)carbenes
eng
uncontrolled
Lewis acid/base adducts
eng
uncontrolled
main group element halides
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25740/Philipp_EurJIC.pdf
20483
2019
eng
5387-5396
21
11
article
1
2020-05-26
--
--
Copper-catalysed Suzuki-Miyaura cross-coupling of highly fluorinated aryl boronate esters with aryl iodides and bromides and fluoroarene-arene π-stacking interactions in the products
A combination of copper iodide and phenanthroline as the ligand is an efficient catalyst for Suzuki‐Miyaura cross‐coupling of highly fluorinated boronate esters (aryl−Bpin) with aryl iodides and bromides to generate fluorinated biaryls in good to excellent yields. This method represents a nice alternative to traditional cross‐coupling methods which require palladium catalysts and stoichiometric amounts of silver oxide. We note that π⋅⋅⋅π stacking interactions dominate the molecular packing in the partly fluorinated biaryl crystals investigated herein. They are present either between the arene and perfluoroarene, or solely between arenes or perfluoroarenes, respectively.
ChemCatChem
10.1002/cctc.201901220
urn:nbn:de:bvb:20-opus-204839
ChemCatChem (2019) 11:21, 5387-5396. https://doi.org/10.1002/cctc.201901220
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Yudha P. Budiman
Alexandra Friedrich
Udo Radius
Todd B. Marder
eng
uncontrolled
homogeneous catalysis
eng
uncontrolled
boron
eng
uncontrolled
boronate
eng
uncontrolled
fluorine
eng
uncontrolled
fluoroarene
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/20483/budiman_chemcatchem_2019.pdf
20484
2019
eng
11365-11374
48
25
article
1
2020-05-26
--
--
Intramolecular ring expansion reaction (RER) and intermolecular coordination of in situ generated Cyclic (Amino)(Aryl)Carbenes (cAArCs)
Cyclic (amino)(aryl)carbenes (cAArCs) based on the isoindoline core were successfully generated in situ by α‐elimination of 3‐alkoxyisoindolines at high temperatures or by deprotonation of isoindol‐2‐ium chlorides with sodium or copper(I) acetates at low temperatures. 3‐Alkoxy‐isoindolines 2 a ,b‐OR (R=Me, Et, i Pr) have been prepared in high yields by the addition of a solution of 2‐aryl‐1,1‐diphenylisoindol‐2‐ium triflate (1 a ,b‐OTf ; a : aryl=Dipp=2,6‐diisopropylphenyl; b : Mesityl‐, Mes=2,4,6‐trimethylphenyl) to the corresponding alcohol (ROH) with NEt3 at room temperature. Furthermore, the reaction of 2 a ,b‐OMe in diethyl ether with a tenfold excess of hydrochloric acid led to the isolation of the isoindol‐2‐ium chlorides 1 a ,b‐Cl in high yields. The thermally generated cAArC reacts with sulfur to form the thioamide 3 a . Without any additional trapping reagent, in situ generation of 1,1‐diphenylisoidolin‐3‐ylidenes does not lead to the isolation of these compounds, but to the reaction products of the insertion of the carbene carbon atom into an ortho C−H bond of a phenyl substituent, followed by ring‐expansion reaction; namely, anthracene derivatives 9‐N(H)aryl‐10‐Ph‐C14H8 4 a ,b (a : Dipp; b : Mes). These compounds are conveniently synthesized by deprotonation of the isoindol‐2‐ium chlorides with sodium acetate in high yields. Deprotonation of 1 a‐Cl with copper(I) acetate at low temperatures afforded a mixture of 4 a and the corresponding cAArC copper(I) chloride 5 a , and allowed the isolation and structural characterization of the first example of a cAArC copper complex of general formula [(cAArC)CuCl].
Chemistry - A European Journal
10.1002/chem.201902630
urn:nbn:de:bvb:20-opus-204847
Chemistry - A European Journal (2019) 25:48, 11365-11374. https://doi.org/10.1002/chem.201902630
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Jan Lorkowski
Mirjam Krahfuss
Maciej Kubicki
Udo Radius
Cezary Pietraszuk
eng
uncontrolled
cAArC
eng
uncontrolled
complexes
eng
uncontrolled
copper
eng
uncontrolled
NHC
eng
uncontrolled
ring-expansion reaction
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/20484/lorkowski_chempubsoc_2019.pdf
22568
2021
eng
3869
3874
11
27
article
1
--
--
--
Base‐Free Pd‐Catalyzed C−Cl Borylation of Fluorinated Aryl Chlorides
Catalytic C−X borylation of aryl halides containing two ortho‐fluorines has been found to be challenging, as most previous methods require stoichiometric amounts of base and the polyfluorinated aryl boronates suffer from protodeboronation, which is accelerated by ortho‐fluorine substituents. Herein, we report that a combination of Pd(dba)2 (dba=dibenzylideneacetone) with SPhos (2‐dicyclohexylphosphino‐2’,6’‐dimethoxybiphenyl) as a ligand is efficient to catalyze the C‐Cl borylation of aryl chlorides containing two ortho‐fluorine substituents. This method, conducted under base‐free conditions, is compatible with the resulting di‐ortho‐fluorinated aryl boronate products which are sensitive to base.
Chemistry – A European Journal
10.1002/chem.202004648
urn:nbn:de:bvb:20-opus-225687
2021-02-22T11:47:39+00:00
sword
swordwue
attachment; filename=deposit.zip
c5a1fd4b65e4cfd335630c899894b487
Chemistry – A European Journal 2021, 27(11):3869-3874. DOI: 10.1002/chem.202004648
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Yudha P. Budiman
Sabine Lorenzen
Zhiqiang Liu
Udo Radius
Todd B. Marder
eng
uncontrolled
boronate ester
eng
uncontrolled
borylation
eng
uncontrolled
cross-coupling
eng
uncontrolled
fluoroarene
eng
uncontrolled
palladium-catalyzed
Chemie und zugeordnete Wissenschaften
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/22568/CHEM_CHEM202004648.pdf
21605
2020
eng
3194
3207
33
2020
article
1
--
--
--
Large vs. Small NHC Ligands in Nickel(0) Complexes: The Coordination of Olefins, Ketones and Aldehydes at [Ni(NHC)\(_{2}\)]
Investigations concerning the reactivity of Ni(0) complexes [Ni(NHC)\(_{2}\)] of NHCs (N‐heterocyclic carbene) of different steric demand, Mes\(_{2}\)Im (= 1,3‐dimesitylimidazoline‐2‐ylidene) and iPr\(_{2}\)Im (= 1,3‐diisopropyl‐imidazoline‐2‐ylidene), with olefins, ketones and aldehydes are reported. The reaction of [Ni(Mes\(_{2}\)Im)\(_{2}\)] 1 with ethylene or methyl acrylate afforded the complexes [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐C\(_{2}\)H\(_{4}\))] 3 and [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐(C,C)‐H\(_{2}\)C=CHCOOMe)] 4, as it was previously reported for [Ni\(_{2}\)(iPr\(_{2}\)Im)\(_{4}\)(µ‐(η\(^{2}\):η\(^{2}\))‐COD)] 2 as a source for [Ni(iPr\(_{2}\)Im)\(_{2}\)]. In contrast to 2, complex 1 does not react with sterically more demanding olefins such as tetramethylethylene, 1,1‐diphenylethylene and cyclohexene. The reaction of [Ni(NHC)\(_{2}\)] with more π‐acidic ketones or aldehydes led to formation of complexes with side‐on η\(^{2}\)‐(C,O)‐coordinating ligands: [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CH\(^{t}\)Bu)] 5, [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CHPh)] 6, [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CMePh)] 7, [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CPh\(_{2}\))] 8, [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=C(4‐F‐C\(_{6}\)H\(_{4}\))\(_{2}\))] 9, [Ni(iPr\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=C(OMe)(CF\(_{3}\)))] 10 and [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CHPh)] 11, [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CH(CH(CH\(_{3}\))\(_{2}\)))] 12, [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CH(4‐NMe\(_{2}\)‐C\(_{6}\)H\(_{4}\)))] 13, [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CH(4‐OMe‐C\(_{6}\)H\(_{4}\)))] 14, [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=CPh\(_{2}\))] 15 and [Ni(Mes\(_{2}\)Im)\(_{2}\)(η\(^{2}\)‐O=C(4‐F‐C\(_{6}\)H\(_{4}\))\(_{2}\))] 16. The reaction of 1 and 2 with these simple aldehydes and ketones does not lead to a significantly different outcome, but NHC ligand rotation is hindered for the Mes\(_{2}\)Im complexes 3, 4 and 11–16 according to NMR spectroscopy. The solid‐state structures of 3, 4, 11 and 12 reveal significantly larger C\(_{NHC}\)‐Ni‐C\(_{NHC}\) angles in the Mes\(_{2}\)Im complexes compared to the iPr\(_{2}\)Im complexes. As electron transfer in d\(^{8}\)‐ (or d\(^{10}\)‐) ML\(_{2}\) complexes to π‐acidic ligands depends on the L–M–L bite angle, the different NHCs lead thus to a different degree of electron transfer and activation of the olefin, aldehyde or ketone ligand, i.e., [Ni(iPr\(_{2}\)Im)\(_{2}\)] is the better donor to these π‐acidic ligands. Furthermore, we identified two different side products from the reaction of 1 with benzaldehyde, trans‐[Ni(Mes\(_{2}\)Im)\(_{2}\)H(OOCPh)] 17 and [Ni\(_{2}\)(Mes\(_{2}\)Im)\(_{2}\)(µ\(_{2}\)‐CO)(µ\(_{2}\)‐η\(^{2}\)‐C,O‐PhCOCOPh)] 18, which indicate that radical intermediates and electron transfer processes might be of importance in the reaction of 1 with aldehydes and ketones.
European Journal of Inorganic Chemistry
10.1002/ejic.202000493
urn:nbn:de:bvb:20-opus-216058
2020-11-09T14:38:56+00:00
sword
swordwue
attachment; filename=deposit.zip
d4bdff97fcebec136e5ee7e9551ed0a4
European Journal of Inorganic Chemistry 2020, 33, 3194-3207. DOI: 10.1002/ejic.202000493
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Lukas Tendera
Thomas Schaub
Mirjam J. Krahfuss
Maximilian W. Kuntze‐Fechner
Udo Radius
eng
uncontrolled
Nickel Complexes
eng
uncontrolled
N‐Heterocyclic Carbenes
eng
uncontrolled
NHC Complexes
eng
uncontrolled
Olefin Complexes
eng
uncontrolled
Aldehyde Complexes
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/21605/EJIC_EJIC202000493.pdf
22450
2021
eng
548
561
6
2021
article
1
--
--
--
N‐Heterocyclic Silylene Main Group Element Chemistry: Adduct Formation, Insertion into E−X Bonds and Cyclization of Organoazides
Investigations concerning the reactivity of the N‐heterocyclic silylene Dipp\(_{2}\)NHSi (1, 1,3‐bis(2,6‐diisopropylphenyl)‐1,3‐diaza‐2‐silacyclopent‐4‐en‐2‐ylidene) towards selected alanes and boranes, elemental halides X\(_{2}\) (X=Br, I), selected halide containing substrates such as tin chlorides and halocarbons, as well as organoazides are presented. The NHSi adducts Dipp\(_{2}\)NHSi⋅AlI\(_{3}\) (2), Dipp\(_{2}\)NHSi⋅Al(C\(_{6}\)F\(_{5}\))\(_{3}\) (3), and Dipp\(_{2}\)NHSi⋅B(C\(_{6}\)F\(_{5}\))\(_{3}\) (4) were formed by the reaction of Dipp\(_{2}\)NHSi with the corresponding Lewis acids AlI\(_{3}\), Al(C\(_{6}\)F\(_{6}\))\(_{3}\) and B(C\(_{6}\)F\(_{5}\))\(_{3}\). Adducts 3 and 4 were tested with respect to their ability to activate small organic molecules, but no frustrated Lewis pair reactivity was observed. Reactions of Dipp\(_{2}\)NHSi with Br\(_{2}\), I\(_{2}\), Ph\(_{2}\)SnCl\(_{2}\) and Me\(_{3}\)SnCl led to formation of Dipp\(_{2}\)NHSiBr\(_{2}\) (5), Dipp\(_{2}\)NHSiI\(_{2}\) (6), Dipp\(_{2}\)NHSiCl\(_{2}\) (7) and {(Me\(_{3}\)Sn)N(Dipp)CH}\(_{2}\) (8), respectively. The reaction with the halocarbons methyl iodide, benzyl chloride, and benzyl bromide afforded the insertion products Dipp\(_{2}\)NHSi(I)(CH\(_{3}\)) (9), Dipp\(_{2}\)NHSi(Cl)(CH\(_{2}\)Ph) (10) and Dipp\(_{2}\)NHSi(Br)(CH\(_{2}\)Ph) (11). Reaction of Dipp\(_{2}\)NHSi with the organoazides Ad‐N\(_{3}\) (Ad=adamantyl) and TMS‐N\(_{3}\) (TMS=trimethylsilyl) led to the formation of 1‐Dipp\(_{2}\)NHSi‐2,5‐bis(adamantyl)‐tetrazoline (12) and bis(trimethylsilyl)amido azido silane (13), respectively. For 2,6‐(diphenyl)phenyl‐N\(_{3}\) C−H activation occurs and a cyclosilamine 14 was isolated.
European Journal of Inorganic Chemistry
10.1002/ejic.202000942
urn:nbn:de:bvb:20-opus-224507
2021-02-15T12:34:13+00:00
sword
swordwue
attachment; filename=deposit.zip
0259d657801fae7a5dc2a5ebc23a03e0
European Journal of Inorganic Chemistry 2021, 6, 548-561. DOI: 10.1002/ejic.202000942
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Mirjam J. Krahfuss
Udo Radius
eng
uncontrolled
arbenes
eng
uncontrolled
E−X bond activation
eng
uncontrolled
acid/base adducts
eng
uncontrolled
Organoazides
eng
uncontrolled
Silylenes
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/22450/EJIC_EJIC202000942.pdf
21792
2020
eng
4015
4023
42
2020
article
1
--
--
--
Bis‐NHC Aluminium and Gallium Dihydride Cations [(NHC)\(_{2}\)EH\(_{2}\)]\(^{+}\) (E = Al, Ga)
The NHC alane and gallane adducts (NHC)·AlH\(_{2}\)I (NHC = Me\(_{2}\)Im\(^{Me}\) 7, iPr\(_{2}\)Im 8, iPr\(_{2}\)Im\(^{Me}\) 9) and (NHC)·GaH\(_{2}\)I (NHC = Me\(_{2}\)Im\(^{Me}\) 10, iPr\(_{2}\)Im\(^{Me}\) 11, Dipp\(_{2}\)Im 12; R\(_{2}\)Im = 1,3‐di‐organyl‐imidazolin‐2‐ylidene; Dipp = 2,6‐diisopropylphenyl; iPr = isopropyl; Me\(_{2}\)Im\(^{Me}\) = 1,3,4,5‐tetra‐methyl‐imidazolin‐2‐ylidene) were prepared either by the simple yet efficient reaction of the NHC adduct (NHC)·AlH\(_{3}\) with elemental iodine or by the treatment of (NHC)·GaH\(_{3}\) with an excess of methyl iodide at room temperature. The reaction of one equivalent of the group 13 NHC complexes with an additional equivalent of the corresponding NHC afforded cationic aluminium and gallium hydrides [(NHC)\(_{2}\)·AlH\(_{2}\)]\(^{+}\)I− (NHC = Me\(_{2}\)Im\(^{Me}\) 13, iPr\(_{2}\)Im 14, iPr\(_{2}\)Im\(^{Me}\) 15) and [(NHC)\(_{2}\)·GaH\(_{2}\)]\(^{+}\)I− (NHC = Me\(_{2}\)Im\(^{Me}\) 16, iPr\(_{2}\)Im\(^{Me}\) 17) and the normal and abnormal NHC coordinated compound [(Dipp\(_{2}\)Im)·GaH\(_{2}\)(aDipp\(_{2}\)Im)]+I− 18. Compounds 7–18 were isolated and characterized by means of elemental analysis, IR and multinuclear NMR spectroscopy and by X‐ray diffraction of the compounds 7, 9, 10, 15, 16 and 18.
European Journal of Inorganic Chemistry
10.1002/ejic.202000720
urn:nbn:de:bvb:20-opus-217928
2020-12-07T10:29:59+00:00
sword
swordwue
attachment; filename=deposit.zip
b640dc6c7a89709db31422602b1bfdf1
European Journal of Inorganic Chemistry 2020, 42, 4015–4023. DOI: 10.1002/ejic.202000720
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Andreas Hock
Luis Werner
Melanie Riethmann
Udo Radius
eng
uncontrolled
aluminium
eng
uncontrolled
cations
eng
uncontrolled
Gallium
eng
uncontrolled
main group elements
eng
uncontrolled
heterocyclic carbenes
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/21792/EJIC_EJIC202000720.pdf
21472
2020
eng
1941
1946
13
2020
article
1
--
--
--
Regio‐ and Stereoselective Synthesis of 1,1‐Diborylalkenes via Brønsted Base‐Catalyzed Mixed Diboration of Alkynyl Esters and Amides with BpinBdan
The NaOtBu‐catalyzed mixed 1,1‐diboration of terminal alkynes using the unsymmetrical diboron reagent BpinBdan (pin = pinacolato; dan = 1,8‐diaminonaphthalene) proceeds in a regio‐ and stereoselective fashion affording moderate to high yields of 1,1‐diborylalkenes bearing orthogonal boron protecting groups. It is applicable to gram‐scale synthesis without loss of yield or selectivity. The mixed 1,1‐diborylalkene products can be utilized in Suzuki–Miyaura cross‐coupling reactions which take place selectivly at the C–B site. DFT calculations suggest the NaOtBu‐catalyzed mixed 1,1‐diboration of alkynes occurs through deprotonation of the terminal alkyne, stepwise addition of BpinBdan to the terminal carbon followed by protonation with tBuOH. Experimentally observed selective formation of (Z)‐diborylalkenes is supported by our theoretical studies.
European Journal of Organic Chemistry
10.1002/ejoc.202000128
urn:nbn:de:bvb:20-opus-214728
swordwue
2020-10-26T16:11:06+00:00
attachment; filename=deposit.zip
af39a133e36d5d416be4e42a6e760294
European Journal of Organic Chemistry 2020, 13, 1941-1946. DOI: 10.1002/ejoc.202000128
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Xiaocui Liu
Wenbo Ming
Xiaoling Luo
Alexandra Friedrich
Jan Maier
Udo Radius
Webster L. Santos
Todd B. Marder
eng
uncontrolled
boronate esters
eng
uncontrolled
borylation
eng
uncontrolled
cross‐coupling
eng
uncontrolled
synthesis design
eng
uncontrolled
structure elucidation
Organische Chemie
open_access
Institut für Anorganische Chemie
Import
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/21472/EJOC_EJOC202000128.pdf
25728
2022
eng
e202103866
3
28
article
1
2022-02-19
--
--
Base-Mediated Radical Borylation of Alkyl Sulfones
A practical and direct method was developed for the production of versatile alkyl boronate esters via transition metal-free borylation of primary and secondary alkyl sulfones. The key to the success of the strategy is the use of bis(neopentyl glycolato) diboron (B\(_{2}\)neop\(_{2}\)), with a stoichiometric amount of base as a promoter. The practicality and industrial potential of this protocol are highlighted by its wide functional group tolerance, the late-stage modification of complex compounds, no need for further transesterification, and operational simplicity. Radical clock, radical trap experiments, and EPR studies were conducted which show that the borylation process involves radical intermediates.
Chemistry—A European Journal
10.1002/chem.202103866
urn:nbn:de:bvb:20-opus-257281
publish
Chemistry—A European Journal 2022, 28(3):e202103866. DOI: 10.1002/chem.202103866
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Mingming Huang
Jiefeng Hu
Ivo Krummenacher
Alexandra Friedrich
Holger Braunschweig
Stephen A. Westcott
Udo Radius
Todd B. Marder
eng
uncontrolled
boron
eng
uncontrolled
boronate
eng
uncontrolled
boronic acid
eng
uncontrolled
metal-free
eng
uncontrolled
radical
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25728/Huang_Chemistry.pdf
25801
2021
eng
881–895
8
647
article
1
--
--
--
A General Synthetic Route to NHC‐Phosphinidenes: NHC‐mediated Dehydrogenation of Primary Phosphines
The dehydrocoupling of primary phosphines with N-heterocyclic carbenes (NHCs) to yield NHC-phosphinidenes is reported. The reaction of two equivalents of the NHCs Me\(_2\)Im (1,3-dimethylimidazolin-2-ylidene), Me\(_4\)Im (1,3,4,5-tetramethylimidazolin-2-ylidene), iPr\(_2\)Im (1,3-di-iso-propylimidazolin-2-ylidene) and Mes\(_2\)Im (2,4,6-trimethylphenylimidazolin-2-ylidene) with PhPH\(_2\) and MesPH\(_2\) led to the NHC stabilized phosphinidenes (NHC)PAr: (iPr\(_2\)Im)PPh (1), (Mes\(_2\)Im)PPh (2), (Me\(_4\)Im)PPh (3), (Mes\(_2\)Im)PMes (4), (Me\(_2\)Im)PMes (5), (Me\(_4\)Im)PMes (6) and (iPr\(_2\)Im)PMes (7). The reaction of tBuPH\(_2\) with two equivalents of the NHCs afforded the corresponding NHC stabilized parent phosphinidenes (NHC)PH: (iPr\(_2\)Im)PH (8), (Mes\(_2\)Im)PH (9) and (Me\(_4\)Im)PH (10). Reaction of 1 with oxygen and sulfur led to isolation of iPr\(_2\)Im-P(O)\(_2\)Ph (11) and iPr\(_2\)Im-P(S)\(_2\)Ph (12), whereas the reaction with elemental selenium and tellurium gave (NHC)PPh cleavage with formation of (iPr\(_2\)Im)Se (13), iPr\(_2\)ImTe (14) and different cyclo-oligophosphines. Furthermore, the complexes [{(iPr\(_2\)Im)PPh}W(CO)\(_5\)] (15), [Co(CO)\(_2\)(NO){(iPr\(_2\)Im)PPh}] (16) and [(η\(^5\)-C\(_5\)Me\(_2\))Co(η\(^2\)-C\(_2\)H\(_4\)){(iPr\(_2\)Im)PPh}] (17) have been prepared starting from 1 and a suitable transition metal complex precursor. The complexes 16 and 17 decompose in solution upon heating to ca. 80 °C to yield the NHC complexes [Co(iPr\(_2\)Im)(CO)\(_2\)(NO)] and [(η\(^5\)-C\(_5\)Me\(_5\))Co(iPr\(_2\)Im)(η\(^2\)-C\(_2\)H\(_4\))] with formation of cyclo-oligophosphines. The reaction of 1 with [Ni(COD)\(_2\)] afforded the diphosphene complex [Ni(iPr\(_2\)Im)\(_2\)(trans-PhP=PPh)] 18.
Zeitschrift für anorganische und allgemeine Chemie
10.1002/zaac.202000405
urn:nbn:de:bvb:20-opus-258016
publish
Zeitschrift für anorganische und allgemeine Chemie 2021, 647(8):881–895. DOI: 10.1002/zaac.202000405
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Werner Luis
Günther Horrer
Michael Philipp
Katharina Lubitz
Maximilian W. Kuntze‐Fechner
Udo Radius
eng
uncontrolled
transition metal complexes
eng
uncontrolled
N-heterocyclic carbenes
eng
uncontrolled
phosphinidenes
eng
uncontrolled
dehydrocoupling
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25801/Werner_Inorganic.pdf
25738
2021
eng
1941–1960
20
2021
article
1
--
--
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Tris(pentafluoroethyl)difluorophosphorane and N‐Heterocyclic Carbenes: Adduct Formation and Frustrated Lewis Pair Reactivity
The synthesis and characterization of Lewis acid/base adducts between tris(pentafluoroethyl)difluorophosphorane PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) and selected N-heterocyclic carbenes (NHCs) R\(_{2}\)Im (1,3-di-organyl-imidazolin-2-ylidene) and phosphines are reported. For NHCs with small alkyl substituents at nitrogen (R=Me, nPr, iPr) the adducts NHC ⋅ PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) (2 a–h) were isolated. The reaction with the sterically more demanding NHCs Dipp\(_{2}\)Im (1,3-bis-(2,6-di-iso-propylphenyl)-imidazolin-2-ylidene) (1 i) and tBu\(_{2}\)Im (1,3-di-tert-butyl-imidazolin-2-ylidene) (1 j) afforded the aNHC adducts 3 i and 3 j (a denotes “abnormal” NHC coordination via a backbone carbon atom). The use of tBuMeIm (1-tert-butyl-3-methyl-imidazolin-2-ylidene) (1 m) led to partial decomposition of the NHC and formation of the salt [tBuMeIm−H][MeIm ⋅ PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\)] (4 m). The phosphorane PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) forms adducts with PMe\(_{3}\) but does not react with PPh\(_{3}\) or PCy\(_{3}\). The mer-cis isomer of literature-known Me\(_{3}\)P ⋅ PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) (5 a) was structurally characterized. Mixtures of the phosphorane PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) and the sterically encumbered NHCs tBu\(_{2}\)Im, Dipp\(_{2}\)Im, and Dipp\(_{2}\)Im\(^{H2}\) (1,3-bis-(2,6-di-iso-propylphenyl)-imidazolidin-2-ylidene) (1 k) showed properties of FLPs (Frustrated Lewis Pairs) as these mixtures were able to open the ring of THF (tetrahydrofuran) to yield NHC−(CH\(_{2}\))\(_{4}\)O−PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\) 6 i–k. Furthermore, the deprotonation of the weak C−H acids CH\(_{3}\)CN, acetone, and ethyl acetate was achieved, which led to the formation of the corresponding imidazolium salts and the phosphates [PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\)(CH\(_{2}\)CN)]\(^{-}\) (7), [PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\)(OC(=CH\(_{2}\))CH\(_{3}\))]\(^{-}\) (8) and [PF\(_{2}\)(C\(_{2}\)F\(_{5}\))\(_{3}\)(CH\(_{2}\)CO\(_{2}\)Et)]\(^{-}\) (9).
European Journal of Inorganic Chemistry
10.1002/ejic.202100183
urn:nbn:de:bvb:20-opus-257386
publish
European Journal of Inorganic Chemistry 2021, Volume 2021(20):1941–1960. DOI: 10.1002/ejic.202100183
false
true
CC BY: Creative-Commons-Lizenz: Namensnennung 4.0 International
Steffen A. Föhrenbacher
Vivien Zeh
Mirjam J. Krahfuss
Nikolai V. Ignat'ev
Maik Finze
Udo Radius
eng
uncontrolled
C-H activation
eng
uncontrolled
N-Heterocyclic Carbene Adducts
eng
uncontrolled
N-Heterocyclic Carbenes
eng
uncontrolled
Frustrated Lewis Pairs
eng
uncontrolled
Fluoro(perfluoroalkyl) phosphoranes
Anorganische Chemie
open_access
Institut für Anorganische Chemie
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/opus4-wuerzburg/files/25738/Foehrenbacher_EurJIC.pdf