TY  - INPR
A1  - Légaré, Marc-André
A1  - Pranckevicius, Conor
A1  - Braunschweig, Holger
T1  - Metallomimetic Chemistry of Boron
T2  - Chemical Reviews
N2  - The study of main-group molecules that behave and react similarly to transition-metal (TM) complexes has attracted significant interest in recent decades. Most notably, the attractive idea of replacing the all-too-often rare and costly metals from catalysis has motivated efforts to develop main-group-element-mediated reactions. Main-group elements, however, lack the electronic flexibility of TM complexes that arises from combinations of empty and filled d orbitals and that seem ideally suited to bind and activate many substrates. In this review, we look at boron, an element that despite its nonmetal nature, low atomic weight, and relative redox staticity has achieved great milestones in terms of TM-like reactivity. We show how in interelement cooperative systems, diboron molecules, and hypovalent complexes the fifth element can acquire a truly metallomimetic character. As we discuss, this character is powerfully demonstrated by the reactivity of boron-based molecules with H2, CO, alkynes, alkenes and even with N2.
KW  - boron
KW  - small-molecule activation
KW  - catalysis
KW  - low-valent main group chemistry
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-186317
N1  - This document is the unedited Author’sv ersion of a Submitted Work that was subsequently accepted for publication in Chemical Reviews,copyright ©American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/acs.chemrev.8b00561.
ER  - 
TY  - INPR
A1  - Böhnke, Julian
A1  - Arrowsmith, Merle
A1  - Braunschweig, Holger
T1  - Activation of a Zerovalent Diboron Compound by Desymmetrization
T2  - Journal of the American Chemical Society
N2  - The desymmetrization of the cyclic (alkyl)(amino)carbene-supported diboracumulene, B\(_2\)(cAAC\(^{Me}\))\(_2\) (cAAC\(^{Me}\) = 1- (2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) by mono-adduct formation with IMe\(^{Me}\) (1,3-dimethylimidazol-2-ylidene) yields the zerovalent sp-sp\(^2\) diboron compound B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)), which provides a versatile platform for the synthesis of novel symmetrical and unsymmetrical zerovalent sp\(^2\)-sp\(^2\) diboron compounds by adduct formation with IMe\(^{Me}\) and CO, respectively. Furthermore, B\(_2\)(cAAC\(^{Me}\))\(_2\)(IMe\(^{Me}\)) displays enhanced reactivity compared to its symmetrical precursor, undergoing spontaneous intramolecular C-H activation and facile twofold hydrogenation, the latter resulting in B-B bond cleavage and the formation of the mixed-base parent borylene, (cAAC\(^{Me}\))(IMe\(^{Me}\))BH.
KW  - diboryne
KW  - boron
KW  - carbenes
KW  - low-valent main group chemistry
KW  - erovalent diboron compounds
KW  - desymmetrization
KW  - bond activation
KW  - hydrogenation
KW  - borylene
Y1  - 2018
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-167983
N1  - This document is the unedited Author’s version of a Submitted Work that was subsequently accepted for publication in Journal of the American Chemical Society, copyright © American Chemical Society after peer review. To access the final edited and published work see https://doi.org/10.1021/jacs.8b06930
(Julian Böhnke, Merle Arrowsmith, and Holger Braunschweig: Reactivity Enhancement of a Zerovalent Diboron Compound by Desymmetrization, Journal of the American Chemical Society 2018, 140, (32), 10368-10373. DOI: 10.1021/jacs.8b06930)
ER  -