Facile generation of alpha-silyl carbanion of trimethylsilyl group assisted by intramolecular pyridyl group coordination

Novel methodology for the generation of alpha-silyl carbanion by the deprot onation of trimethylsilyl group with tert-butyllithium or LDA has been deve loped. This newly developed alpha-lithiation protocol is based on the intra molecular pyridyl group coordination to stabilize the alpha-silyl carbanion , together with the inherent silicon alpha effect. The importance of the us e of the 2-pyridyl group in 'pyridyl'- and 'silyl'-directed alpha-lithiatio n has been confirmed by the control experiments utilizing phenyltrimethylsi lane and (3-pyridyl)trimethylsilane. (C) 1999 Elsevier Science Ltd. All rig hts reserved.