HIGHLY EFFICIENT DIASTEREOSELECTIVE MICHAEL ADDITION OF VARIOUS THIOLS TO (-BREFELDIN-A())

The Michael addition of thiols to brefeldin A occurs with high diaster eoselectivity, affording ratios of major to minor diastereomers of at least 30:1. On the basis of the X-ray structure of a crystalline diben zoyl derivative, the major diastereomers are assigned the 3R configura tion, while the minor diastereomers have the 3S configuration.