Iodobenzene catalysed synthesis of spirofurans and benzopyrans by oxidative cyclisation of vinylogous esters

Abstract

Vinylogous esters bearing para or meta methoxy benzyl groups undergo oxidative cyclisation with 5-20 mol% iodobenzene and m-CPBA to give spirofuran or benzopyran containing heterocycles. The reaction allows rapid generation of skeletal complexity in good to excellent yields via a novel oxidative cyclisation.