Synthesis of Polysubstituted Thiophenes via Base-Induced [2+2+1] Cycloaddition Reaction of Alkynes and Elemental Sulfur

Abstract

A simple approach to polysubstituted thiophene derivatives is demonstrated. The synthesis is highlighted by the direct [2+2+1] cycloaddition reaction to construct carbon-sulfur and carbon-carbon bonds, without adding oxidizing, reducing and noble metal agents. All tested substrates provided their corresponding thiophene products in high isolated yields under the optimized conditions.