Et3N mediated synthesis of polysubstituted thiophenes from α-oxo ketene dithioacetals

Abstract In this Letter, an efficient synthetic route to prepare polysubstituted thiophene derivatives was achieved via the Et 3 N-mediated (Claisen) rearrangement reaction from α-oxo S -methyl- S -propargyl ketenes, which were obtained through alkylation of β-oxodithioesters with propargylic bromides, followed by regioselective intramolecular cyclization.