Mercuric acetate-mediated annulation of homopropargylic alcohols having thioether substituent. A general route for the synthesis of tetrasubstituted furans from propargylic dithioacetals

Treatment of an alkyl-substituted propargylic dithioacetal with nBuLi followed by an aldehyde furnishes thio-substituted homopropargylic alcohol 7 which undergoes annulation in the presence of two equivalents of mercury acetate to give the corresponding mercurio-substituted furan 12. Reaction of 12 with iodine gives iodofuran in moderate to good yield.