Contraction of the cyclohexene ring in the Diels–Alder adduct of levoglucosenone with piperylene

Resumo

Diels–Alder adducts of levoglucosenone with piperylene were subjected to allylic oxidation–epoxidation, followed by successive functionalization of the α- and β-positions, and transformations of the resulting 1,2-epoxy derivatives under the action of boron trifluoride–diethyl ether complex and bases were studied. The most efficient was the Wagner–Meerwein rearrangement of the α-hydroxy derivative with formation of a fused cyclopentane in 39% yield.