Conjugate Addition Reactions of α-Aminoalkylcuprates Prepared from Organostannyl tert-Butylcarbamates

Abstract

α-Aminoalkylcyanocuprates, readily available from α-aminoalkylstannanes via the organolithium reagents, undergo efficient conjugate addition to both simple and sterically hindered enones. Effective conjugate addition with cuprates prepared via direct deprotonation of tert-butylcarbamates is substrate and carbamate dependent but can be enhanced by use of sparteine instead of TMEDA in the deprotonation step. The method provides the first synthetically viable procedure for introduction of α-aminoalkyl groups via conjugate addition chemistry.