Furan-fused 3-sulfolene as a novel building block: intermolecular Diels–Alder reactions of 4H,6H-thieno[3,4-c]furan 5,5-dioxide

Abstract

A furan-fused 3-sulfolene 4H,6H-thieno[3,4-c]furan 5,5-dioxide 1, can be used as a bis-diene, reacting sequentially with a variety of dienophiles to construct four types of skeleton, depending on the dienophile and the reaction conditions. The 3-sulfolene moiety of the furansulfolene not only functions as the s-cis-diene part in Diels–Alder reactions, but also extends the range of the Diels–Alder reactions of the furan moiety with various dienophiles through its desulfonylation to form the s-cis-diene.