Diels–Alder reactions of long-chain unsaturated fatty acids

Abstract

Methyl 9,12-dioxo-octadeca-trans-10-enoate undergoes Diels-Alder reaction with isoprene, with 2,3-dimethylbutadiene, and with methyl octadeca-trans-9,trans-11-dienoate to give substituted cyclohexenes. Clemmensen reduction of the cycloaddition product from the last-mentioned compound does not proceed normally, but yields a dihydroisobenzofuran compound by cyclodehydration. Diels–Alder reaction of 12-oxo-octadec-trans-10-enoic acid and octadeca-trans-9,trans-11-dienoic acid does not proceed to completion, but Clemmensen reduction of the cycloaddition product occurs normally to give the C₃₆ cyclic di-acid.