Base-induced rearrangement of dihydropyran oxides: A novel synthesis of cyclic enol ethers with a hydroxy-function in the allylic position

Abstract

A sequence of ring closing metathesis of allyl-homoallyl ethers, epoxidation of the resulting dihydropyrans, and rearrangement of the dihydropyran oxides with LDA provides convenient access to 2,3-dihydropyrans with a hydroxy group in the 4-position. The products may serve as starting materials for e.g. the Carbon-Ferrier rearrangement.