An Unsymmetrical, Cyclic Diborene Based on a Chelating CAAC Ligand and its Small‐Molecule Activation and Rearrangement Chemistry
Wei Lu, Arumugam Jayaraman, Felipe Fantuzzi, Rian D. Dewhurst, Marcel Härterich, Maximilian Dietz, Stephan Hagspiel, Ivo Krummenacher, Kai Hammond, Jingjing Cui, Holger Braunschweig
Abstract
Abstract A one‐pot synthesis of a CAAC‐stabilized, unsymmetrical, cyclic diborene was achieved via consecutive two‐electron reduction steps from an adduct of CAAC and B 2 Br 4 (SMe 2 ) 2 . Theoretical studies revealed that this diborene has a considerably smaller HOMO–LUMO gap than those of reported NHC‐ and phosphine‐supported diborenes. Complexation of the diborene with [AuCl(PCy 3 )] afforded two diborene–Au I π complexes, while reaction with DurBH 2 , P 4 and a terminal acetylene led to the cleavage of B−H, P−P, and C−C π bonds, respectively. Thermal rearrangement of the diborene gave an electron‐rich cyclic alkylideneborane, which readily coordinated to Ag I via its B=C double bond.