PREPARATION OF OPTICALLY-ACTIVE ALPHA-SILYLCARBONYL COMPOUNDS USING ASYMMETRIC ALKYLATION OF ALPHA-SILYLACETIC ESTERS AND ASYMMETRIC METAL-CARBENE INSERTION INTO THE SI-H BOND

Substituted alpha-silylacetic esters have been prepared in good yields and with reasonable diastereoselectivities by three different routes. The first two involved alkylation of the parent alpha-silylacetic est er enolates, with the chiral auxiliaries being present either on silic on or on the ester function. The third route involving asymmetric inse rtion of metal-carbenoids into the Si-H bond was found to afford bette r diastereoselectivities, using pantolactone as chiral auxiliary. (C) 1997 Elsevier Science Ltd.