Synthesis of dihydrooxepinobenzofuranone derivatives via Claisen rearrangement and ring closing metathesis

Abstract

A simple and effective protocol for synthesizing dihydrooxepinobenzofuranone derivatives was developed using Claisen Rearrangement (CR) and Ring Closing Metathesis (RCM). This protocol requires low catalyst loading and moderate heating to construct the 7-membered and 9-membered ring fused aurone derivatives in very short reaction times. Various substrates including biphenyl and hetero aryl aldehydes were well tolerated. The scope and limitations of the reactions were established. The structures of the representative compounds were established by Single Crystal X-ray Diffraction. Similarly, ene–yne RCM products were also synthesized by the same protocol.