A Convenient Synthesis of Tetrasubstituted Furans from Propargylic Dithioacetals

Abstract

A convenient procedure for the regioselective synthesis of tetrasubstituted furans from the corresponding propargylic dithioacetals is described. Treatment of propargylic dithioacetals with n-BuLi and an aldehyde followed by mercuric acetate promoted annulation and desulfurization affords the corresponding mercurio-substituted furans. Subsequent replacement of the mercury moiety with iodine yields the corresponding 2,4,5-trisubstituted 3-iodofurans. Transition-metal-catalyzed cross-coupling reactions of the iodofurans furnish a variety of tetrasubstituted furans.