@phdthesis{Lindl2023, author = {Lindl, Felix}, title = {Synthese und Reaktivit{\"a}t spezieller Borheterocyclen}, doi = {10.25972/OPUS-24692}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-246929}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2023}, abstract = {Die Dissertationsschrift befasst sich mit der Synthese, Charakterisierung sowie Reaktivit{\"a}t spezieller Borheterocyclen und l{\"a}sst sich in drei Themengebiete gliedern. Der erste Teil behandelt die Reaktivit{\"a}t des elektronisch stabilisierten 1-Ferrocenyl-2,3,4,5-tetraphenylborols gegen{\"u}ber klassischen Substraten f{\"u}r Ringerweiterungsreaktionen von Borolen. Der zweite Abschnitt beschreibt post-synthetische Funktionalisierungen von 1,2-Azaborininen. Dargestellte Boryl-substituierte 1,2-Azaborinine konnten in BN-analoge Verbindungen von Borafluorenen {\"u}berf{\"u}hrt werden. Ferner gelang die Isolierung eines zweifach BN-substituierten Phenanthrenderivats. Im dritten Teil erfolgt eine kritische Auseinandersetzung mit anerkannten Zusammenh{\"a}ngen der Reaktionen von B-funktionalisierten 2,3,4,5-Tetraphenylborolen gegen{\"u}ber Diphenylacetylen.}, subject = {Borheterocyclen}, language = {de} } @article{LindlLamprechtArrowsmithetal.2023, author = {Lindl, Felix and Lamprecht, Anna and Arrowsmith, Merle and Khitro, Eugen and Rempel, Anna and Dietz, Maximilian and Wellnitz, Tim and B{\´e}langer-Chabot, Guillaume and Stoy, Andreas and Paprocki, Valerie and Prieschl, Dominik and Lenczyk, Carsten and Ramler, Jacqueline and Lichtenberg, Crispin and Braunschweig, Holger}, title = {Aromatic 1,2-Azaborinin-1-yls as Electron-Withdrawing Anionic Nitrogen Ligands for Main Group Elements}, series = {Chemistry - A European Journal}, volume = {29}, journal = {Chemistry - A European Journal}, number = {11}, doi = {10.1002/chem.202203345}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312222}, year = {2023}, abstract = {The 2-aryl-3,4,5,6-tetraphenyl-1,2-azaborinines 1-EMe\(_{3}\) and 2-EMe\(_{3}\) (E=Si, Sn; aryl=Ph (1), Mes (=2,4,6-trimethylphenyl, 2)) were synthesized by ring-expansion of borole precursors with N\(_{3}\)EMe\(_{3}\)-derived nitrenes. Desilylative hydrolysis of 1- and 2-SiMe\(_{3}\) yielded the corresponding N-protonated azaborinines, which were deprotonated with nBuLi or MN(SiMe\(_{3}\))\(_{2}\) (M=Na, K) to the corresponding group 1 salts, 1-M and 2-M. While the lithium salts crystallized as monomeric Lewis base adducts, the potassium salts formed coordination polymers or oligomers via intramolecular K⋅⋅⋅aryl π interactions. The reaction of 1-M or 2-M with CO\(_{2}\) yielded N-carboxylate salts, which were derivatized by salt metathesis to methyl and silyl esters. Salt metathesis of 1-M or 2-M with methyl triflate, [Cp*BeCl] (Cp*=C\(_{5}\)Me\(_{5}\)), BBr\(_{2}\)Ar (Ar=Ph, Mes, 2-thienyl), ECl\(_{3}\) (E=B, Al, Ga) and PX\(_{3}\) (X=Cl, Br) afforded the respective group 2, 13 and 15 1,2-azaborinin-2-yl complexes. Salt metathesis of 1-K with BBr\(_{3}\) resulted not only in N-borylation but also Ph-Br exchange between the endocyclic and exocyclic boron atoms. Solution \(^{11}\)B NMR data suggest that the 1,2-azaborinin-2-yl ligand is similarly electron-withdrawing to a bromide. In the solid state the endocyclic bond length alternation and the twisting of the C\(_{4}\)BN ring increase with the sterics of the substituents at the boron and nitrogen atoms, respectively. Regression analyses revealed that the downfield shift of the endocyclic \(^{11}\)B NMR resonances is linearly correlated to both the degree of twisting of the C\(_{4}\)BN ring and the tilt angle of the N-substituent. Calculations indicate that the 1,2-azaborinin-1-yl ligand has no sizeable π-donor ability and that the aromaticity of the ring can be subtly tuned by the electronics of the N-substituent.}, language = {en} } @article{LindlGuoKrummenacheretal.2021, author = {Lindl, Felix and Guo, Xueying and Krummenacher, Ivo and Rauch, Florian and Rempel, Anna and Paprocki, Valerie and Dellermann, Theresa and Stennett, Tom E. and Lamprecht, Anna and Br{\"u}ckner, Tobias and Radacki, Krzysztof and B{\´e}langer-Chabot, Guillaume and Marder, Todd B. and Lin, Zhenyang and Braunschweig, Holger}, title = {Rethinking Borole Cycloaddition Reactivity}, series = {Chemistry—A European Journal}, volume = {27}, journal = {Chemistry—A European Journal}, number = {43}, doi = {10.1002/chem.202101290}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256888}, pages = {11226-11233}, year = {2021}, abstract = {Boroles are attracting broad interest for their myriad and diverse applications, including in synthesis, small molecule activation and functional materials. Their properties and reactivity are closely linked to the cyclic conjugated diene system, which has been shown to participate in cycloaddition reactions, such as the Diels-Alder reaction with alkynes. The reaction steps leading to boranorbornadienes, borepins and tricyclic boracyclohexenes from the thermal reaction of boroles with alkynes are seemingly well understood as judged from the literature. Herein, we question the long-established mechanistic picture of pericyclic rearrangements by demonstrating that seven-membered borepins (i. e., heptaphenylborepin and two derivatives substituted with a thienyl and chloride substituent on boron) exist in a dynamic equilibrium with the corresponding bicyclic boranorbornadienes, the direct Diels-Alder products, but are not isolable products from the reactions. Heating gradually converts the isomeric mixtures into fluorescent tricyclic boracyclohexenes, the most stable isomers in the series. Results from mechanistic DFT calculations reveal that the tricyclic compounds derive from the boranorbornadienes and not the borepins, which were previously believed to be intermediates in purely pericyclic processes.}, language = {en} } @article{HagspielFantuzziDewhurstetal.2021, author = {Hagspiel, Stephan and Fantuzzi, Felipe and Dewhurst, Rian D. and G{\"a}rtner, Annalena and Lindl, Felix and Lamprecht, Anna and Braunschweig, Holger}, title = {Adducts of the parent boraphosphaketene H\(_2\)BPCO and their decarbonylative insertion chemistry}, series = {Angewandte Chemie International Edition}, volume = {60}, journal = {Angewandte Chemie International Edition}, number = {24}, doi = {10.1002/anie.202103521}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256470}, pages = {13666-13670}, year = {2021}, abstract = {The first examples of Lewis base adducts of the parent boraphosphaketene (H\(_2\)B-PCO) and their cyclodimers are prepared. One of these adducts is shown to undergo mild decarbonylation and phosphinidene insertion into a B-C bond of a borole, forming very rare examples of 1,2-phosphaborinines, B/P isosteres of benzene. The strong donor properties of these 1,2-phosphaborinines are confirmed by the synthesis of their π complexes with the Group 6 metals.}, language = {en} } @article{HagspielFantuzziDewhurstetal.2021, author = {Hagspiel, Stephan and Fantuzzi, Felipe and Dewhurst, Rian D. and G{\"a}rtner, Annalena and Lindl, Felix and Lamprecht, Anna and Braunschweig, Holger}, title = {Addukte des Stammboraphosphaketens H\(_{2}\)BPCO und deren Insertionsreaktionen mittels Decarbonylierung}, series = {Angewandte Chemie}, volume = {133}, journal = {Angewandte Chemie}, number = {24}, doi = {10.1002/ange.202103521}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244803}, pages = {13780 -- 13784}, year = {2021}, abstract = {Die ersten Beispiele f{\"u}r Lewis-Basen-Addukte des Stammboraphosphaketens H\(_{2}\)B-PCO und ihre cyclischen Dimere wurden hergestellt. Eines dieser Addukte zeigt unter milden Bedingungen eine Decarbonylierung und anschließende Insertion des Phosphinidens in die B-C-Bindung eines Borols, was in der Bildung sehr seltener Beispiele f{\"u}r 1,2-Phosphaborinine, B,P-Isostere von Benzol, resultiert. Die starken Donoreigenschaften dieser 1,2-Phosphaborinine wurden durch die Synthese ihrer π-Komplexe mit Metallen der Gruppe 6 best{\"a}tigt.}, language = {de} }