Abstract
A variety of Lewis bases were combined with 9-BBN-NTf(2) to establish the requirements for the generation of borenium cations. Five different types of behavior were found, but the most interesting was the combination of Et(3)N, DABCO, 2,6-lutidine, or Ph(3)P=S which formed borenium ions exclusively even in sub- or superstoichiometric quantities. The 9-BBN borenium ion complex of 2,6-lutidine was found to rapidly catalyze the hydrosilylation of a variety of ketones in the presence of Et(3)SiH. Preliminary mechanistic experiments suggest that the reduction involves borenium ion activation of Et(3)SiH and not the ketone.