Thermally Induced Intramolecular Benzannulation of Diazoacetoacetate Enones Tethered with Unactivated Alkynes: Synthesis of Substituted 6H-Benzo[c]chromenes

Abstract

A facile and efficient intramolecular benzannulation strategy for the synthesis of substituted 6H-benzo[c]chromenes from diazoaceto­acetate enones tethered with unactivated alkynes has been developed. The reaction proceeds in moderate to good yields under operationally simple conditions with thermally induced [4+2]-annulation of intermediate vinyl ketenes as the key step.