Reaction of Bis(alkynyl)silanes with Tris(pentafluorophenyl)borane: Synthesis of Bulky Silole Derivatives by Means of 1,1‐Carboboration under Mild Reaction Conditions

The strong Lewis acid tris(pentafluorophenyl)borane [B(C 6 F 5 ) 3 ] reacts rapidly with dimethylbis(phenylethynyl)silane ( 1c ) at room temperature in toluene by shift of a pentafluorophenyl (C 6 F 5 ) group and formation of a new carbon‐bis(pentafluorophenyl)boron linkage [CB(C 6 F 5 ) 2 ] in a sequence of 1,1‐carboboration reactions to yield the 4‐bis(pentafluorophenyl)boryl/3‐pentafluorophenyl‐substituted 1,1‐dimethyl‐2,5‐diphenylsilole derivative 7c . The analogous reaction of bis(trimethylsilylethynyl)diphenylsilane ( 1d ) with tris(pentafluorophenyl)borane gave the corresponding boryl‐substituted silole derivative ( 7d ) featuring six bulky substituents attached at the central heterocyclic framework. Both the starting materials ( 1c , 1d ) and the products ( 7c , 7d ) were characterized by X‐ray crystal structure analyses.