SYNTHESIS OF ACETYLENEDICARBOXYLIC ACID-ESTERS AND ASYMMETRIC DIELS-ALDER REACTIONS OF THE BIS(METHYL (S)-LACTYL) ESTER

A general method has been developed for the preparation of acetylenedi carboxylic acid esters and applied to the synthesis of both achiral an d chiral esters. Diels-Alder reactions of one of the chiral esters, th e bis(methyl (S)-lactyl) ester, with various types of dienes, such as phenylbutadiene, orthoquinodimethanes, and isobenzofuran, have been in vestigated. Moderate asymmetric induction was observed in reactions wi th dienes bearing an alpha-hydroxyl group. In one case, an unusual sol vent-induced reversal of asymmetric induction was observed.