Investigation on the One-Step Preparation of 2-Substituted Benzo[B]Thiophenes

Abstract

A convenient and efficient synthesis of 2-substituted benzo[b]thiophenes is described. This one-step reaction of alkylthiobenzaldehyde and activated electrophiles proceeded smoothly in toluene at 120 °C with magnesium oxide as a catalyst. The target 2-substituted benzo[b]thiophenes are obtained in moderate yields and the side reaction is inhibited via azeotropic distillation. According to the experiments, a plausible mechanism is presented.

GRAPHICAL ABSTRACT

Keywords:

• 2-Substituted benzo[b]thiophenes
• aldol condensation
• mechanism

Acknowledgments

This work was supported by the Natural Science Foundation of Zhejiang Province (Y4100147, R4090358).