Catalytic, enantioselective alkylations of N,O- and N,N-acetals and hemiacetals

We report the first examples of catalytic, enantioselective alkylation of N,O-acetals to produce useful amino acid derivatives 5 in high yield (73-93%) and enantioselectivity (70-96%). We have extended the utility of our reaction to include a simple one-pot procedure from readily available starting materials. We also provide several different N-based protecting groups that greatly increase the flexibility of the reaction. In addition, we have elucidated novel mechanistic information including the discovery of unique transilylations that start off the catalytic reactions of enol silane nucleophiles with N,O-acetals. These details will guide us in further explorations of the reaction's scope and utility. (C) 1999 Elsevier Science Ltd. All rights reserved.