High diastereoselective synthesis of spiro-barbituratechromans via domino oxa-Michael/1,6-addition reactions of ortho-hydroxyphenylsubstituted para-quinone methides with barbiturate-based olefins

A novel Et3N-catalyzed domino oxa-Michael/1,6-addition reaction of ortho-hydroxyphenylsubstituted p-QMs with barbiturate-based olefins is achieved under mild conditions. Various new spiro-barbituratechromans were obtained in excellent yields and diastereoselectivities (90–99% yield, >99:1 dr). The structure of the new compound 3a was determined by single crystal X-ray analysis.