Manganese(III) Acetate-mediated Oxidative Cyclization of a-Methylstyrene and trans-Stilbene with b-Ketosulfones

A convenient microwave irradiation protocol was utilized for the synthesis of b-ketosulfones 1– 5 in good yields. These sulfones reacted with alkenes through a radical oxidative cyclization mediated by Mn(OAc) 3. Dihydrofurans 6– 10 were obtained in moderate to good yields starting from 1,1-disubstituted alkenes. Dihydrofurans 11– 15 were synthesized in moderate yields and unexpected cyclopropanes 16– 19 were obtained in low yields starting from 1,2-disubstituted alkenes. This protocol offers access to various dihydrofurans which could be tested for their antiparasitic potential.