Optimized catalysts for the asymmetric addition of trimethylsilyl cyanide to aldehydes and ketones

A bimetallic titanium(IV)salen complex has been developed as an exceptionally active catalyst for the asymmetric addition of trimethylsilyl cyanide to ketones. For the corresponding addition to aldehydes, a vanadium(IV)salen complex was found to give higher levels of asymmetric induction. In both cases, additional evidence in support of the proposed catalytic cycle is presented. (C) 2001 Elsevier Science Ltd. All rights reserved.