Sulfur-Promoted Oxidative Cyclization of Pentan-1-ones: Direct Access to Tetrasubstituted Furans from Deoxybenzoins and Chalcones.

Furan is an important heterocyclic scaffold in natural product, bioorganic, and medicinal chemistry as well as in materials science. The system S ₈ /DABCO/DMSO was found to efficiently mediate the oxidative cyclization of 1,2,3,5-tetraarylpentan-1-ones A , which were obtained in situ as the Michael adducts of chalcones 1 and deoxybenzoins 2 , to furan 3 . The strategy provided convenient and direct access to tetrasubstituted furans 3 from readily available starting materials with high functional group tolerance.