Silylcupration of (R)-2,2-dimethyl-3-(tert-butoxycarbonyl)-4-ethynyloxazolidine: A stereoselective approach to the synthesis of gamma-silylated saturated and unsaturated alpha-amino acids

Enantioselective synthesis of gamma-silylated amino acids is reported, usin g 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 a nd highlighted as useful intermediates to yield the final-compounds after r eduction, opening of the oxazolidine ring, and oxidation. Moreover, beta,ga mma-unsaturated amino acids are obtained as very interesting vinylglycine d erivatives. The capability of silicon-containing amino acids to be incorpor ated into dipeptides is also shown.