Reactions of cyclohexadienes. Part VII. A Diels–Alder adduct of a tetrahydropyranyloxycyclohexadiene

Abstract

p-Cresol tetrahydropyranyl ether is converted into 4-methyl-1-(tetrahydropyran-2-yloxy)cyclohexa-1,4-diene and thence by reaction with methyl acrylate into methyl 1-methyl-4-(tetrahydropyran-2-yloxy)bicyclo[2,2,2]oct-2-ene-5-carboxylate. After removal of the protecting group, both this carboxylate and its reduction product 5-hydroxy-1-methyl-4-(tetrahydropyran-2-yloxy)bicyclo[2,2,2]oct-1-ene can undergo reverse-aldol or 1,3-glycol-type fissions to monocyclic cyclohexenones.