Regioselective Synthesis of 3-(Methylthio)phenols by Formal [3 + 3]-Cyclocondensations of 3-Oxo-bis(methylthio)ketenacetals with 1,3-Bis(trimethylsilyloxy)-1,3-butadienes and 1,3-Dicarbonyl Dianions.

Abstract The cyclization of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-oxo-bis(methylthio)ketenacetals afforded 3-(methylthio)phenols containing an acyl or ester substituent located at position 2. The cyclization of free 1,3-dicarbonyl dianions with 3-oxo-bis(methylthio)ketenacetals resulted in the formation of regioisomeric products containing an acyl group located at position 6.