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

A convenient microwave irradiation protocol was utilized for the synthesis of beta-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.