Silylcupration of (<i>R</i>)-2,2-Dimethyl-3-(<i>tert</i>-butoxycarbonyl)-4-ethynyloxazolidine:  A Stereoselective Approach to the Synthesis of γ-Silylated Saturated and Unsaturated α-Amino Acids

Abstract

Enantioselective synthesis of γ-silylated amino acids is reported, using a four-step procedure based on the silylcupration of ethynyloxazolidine 2 . Silylcuprates 6a − c are highlighted as useful reagents to be employed with enantiomerically enriched substrates. Vinylsilanes 5 are easily prepared and highlighted as useful intermediates to yield the final compounds after reduction, opening of the oxazolidine ring, and oxidation. Moreover, β,γ-unsaturated amino acids are obtained as very interesting vinylglycine derivatives. The capability of silicon-containing amino acids to be incorporated into dipeptides is also shown.