Taming of Thioketones: The First Asymmetric Thia-Diels-Alder Reaction with Thioketones as Heterodienophiles

An efficient application of aryl and hetaryl thioketones as dienophiles in the enantioselective thia-Diels-Alder reaction was explored for the first time. It was found that thioketones could serve as useful heterodienophiles in aminocatalytic, trienamine-mediated [4+2] cycloadditions with 2,4-dienals. This enantioselective approach (up to 99: 1 er) was efficiently promoted by diarylprolinol silyl ethers and led to new types of potentially relevant 5,6-dihydro-2H-thiopyrans. lytic, trienamine-mediated [4+2] cycloadditions with 2,4-dienals. This enantioselective approach (up to 99:1 er) was efficiently promoted by diarylprolinol silyl ethers and led to new types of potentially relevant 5,6-dihydro-2H-thiopyrans.