TY  - JOUR
A1  - Witte, Robert
A1  - Arrowsmith, Merle
A1  - Lamprecht, Anna
A1  - Schorr, Fabian
A1  - Krummenacher, Ivo
A1  - Braunschweig, Holger
T1  - C−C and C−N Bond Activation, Lewis‐Base Coordination and One‐ and Two‐Electron Oxidation at a Linear Aminoborylene
JF  - Chemistry – A European Journal
N2  - A cyclic alkyl(amino)carbene (CAAC)‐stabilized dicoordinate aminoborylene is synthesized by the twofold reduction of a [(CAAC)BCl\(_{2}\)(TMP)] (TMP=2,6‐tetramethylpiperidyl) precursor. NMR‐spectroscopic, X‐ray crystallographic and computational analyses confirm the cumulenic nature of the central C=B=N moiety. Irradiation of [(CAAC)B(TMP)] (2) resulted in an intramolecular C−C bond activation, leading to a doubly‐fused C\(_{10}\)BN heterocycle, while the reaction with acetonitrile resulted in an aryl migration from the CAAC to the acetonitrile nitrogen atom, concomitant with tautomerization of the latter to a boron‐bound allylamino ligand. One‐electron oxidation of 2 with CuX (X=Cl, Br) afforded the corresponding amino(halo)boryl radicals, which were characterized by EPR spectroscopy and DFT calculations. Placing 2 under an atmosphere of CO afforded the tricoordinate (CAAC,CO)‐stabilized aminoborylene. Finally, the twofold oxidation of 2 with chalcogens led, in the case of N\(_{2}\)O and sulfur, to the splitting of the B−C\(_{CAAC}\) bond and formation of the 2,4‐diamino‐1,3,2,4‐dichalcogenadiboretanes and CAAC‐chalcogen adducts, whereas with selenium a monomeric boraselenone was isolated, which showed some degree of B−Se multiple bonding.
KW  - bond activation
KW  - boraselenone
KW  - dicoordinate borylene
KW  - one-electron oxidation
KW  - push-pull stabilization
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312491
VL  - 29
IS  - 16
ER  - 
TY  - JOUR
A1  - Brückner, Tobias
A1  - Ritschel, Benedikt
A1  - Jiménez‐Halla, J. Oscar C.
A1  - Fantuzzi, Felipe
A1  - Duwe, Dario
A1  - Markl, Christian
A1  - Dewhurst, Rian D.
A1  - Dietz, Maximilian
A1  - Braunschweig, Holger
T1  - Metal‐Free Intermolecular C−H Borylation of N‐Heterocycles at B−B Multiple Bonds
JF  - Angewandte Chemie International Edition
N2  - Carbene‐stabilized diborynes of the form LBBL (L=N‐heterocyclic carbene (NHC) or cyclic alkyl(amino)carbene (CAAC)) induce rapid, high yielding, intermolecular ortho‐C−H borylation at N‐heterocycles at room temperature. A simple pyridyldiborene is formed when an NHC‐stabilized diboryne is combined with pyridine, while a CAAC‐stabilized diboryne leads to activation of two pyridine molecules to give a tricyclic alkylideneborane, which can be forced to undergo a further H‐shift resulting in a zwitterionic, doubly benzo‐fused 1,3,2,5‐diazadiborinine by heating. Use of the extended N‐heteroaromatic quinoline leads to a borylmethyleneborane under mild conditions via an unprecedented boron‐carbon exchange process.
KW  - Boron
KW  - Borylation
KW  - Carbene
KW  - Diboryne
KW  - Hydroarylation
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312385
VL  - 62
IS  - 5
ER  - 
TY  - JOUR
A1  - Härterich, Marcel
A1  - Matler, Alexander
A1  - Dewhurst, Rian D.
A1  - Sachs, Andreas
A1  - Oppel, Kai
A1  - Stoy, Andreas
A1  - Braunschweig, Holger
T1  - A step-for-step main-group replica of the Fischer carbene synthesis at a borylene carbonyl
JF  - Nature Communications
N2  - The Fischer carbene synthesis, involving the conversion of a transition metal (TM)-bound CO ligand to a carbene ligand of the form [=C(OR’)R] (R, R’ = organyl groups), is one of the seminal reactions in the history of organometallic chemistry. Carbonyl complexes of p-block elements, of the form [E(CO)n] (E = main-group fragment), are much less abundant than their TM cousins; this scarcity and the general instability of low-valent p-block species means that replicating the historical reactions of TM carbonyls is often very difficult. Here we present a step-for-step replica of the Fischer carbene synthesis at a borylene carbonyl involving nucleophilic attack at the carbonyl carbon followed by electrophilic quenching at the resultant acylate oxygen atom. These reactions provide borylene acylates and alkoxy-/silyloxy-substituted alkylideneboranes, main-group analogues of the archetypal transition metal acylate and Fischer carbene families, respectively. When either the incoming electrophile or the boron center has a modest steric profile, the electrophile instead attacks at the boron atom, leading to carbene-stabilized acylboranes – boron analogues of the well-known transition metal acyl complexes. These results constitute faithful main-group replicas of a number of historical organometallic processes and pave the way to further advances in the field of main-group metallomimetics.
KW  - chemical bonding
KW  - ligands
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357270
VL  - 14
ER  -