Just Published in Angewandte Chemie, International Edition

Authors: Tobias Brückner, Benedikt Ritschel, J. Oscar C. Jiménez-Halla, Felipe Fantuzzi, Dario Duwe, Christian Markl, Rian D. Dewhurst, Maximilian Dietz, and Holger Braunschweig

Abstract: 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.

Link: https://onlinelibrary.wiley.com/doi/10.1002/anie.202213284