Efficient Synthesis of Tetrahydrobenzo[b]pyrans under Solvent‐Free Conditions at Room Temperature

Abstract

A range of tetrahydrobenzo[b]pyrans have been synthesized in very good yields under solvent‐free conditions by grinding α‐cyanocinnamonitrils or β‐cyano‐β‐carbethoxy styrene and 5,5‐dimethyl‐1,3‐cyclohexanedione in the presence of TEBA as catalyst. The short reaction time, cleaner reaction, and easy workup make this protocol practical and economically attractive.

Keywords:

• α‐Cyanocinnamonitrils
• β‐cyano‐β‐carbethoxy styrene
• solvent‐free conditions
• tetrahydrobenzo[b]pyrans

Acknowledgment

We are grateful to Natural Science Foundation (04XLB14) of Xuzhou Normal University and the Foundation of the Key Laboratory of Biotechnology on Medical Plants of Jiangsu Province for financial support.