is described using the Diels-Alder reaction of benzoquinone 1,8-dihydroxynaphthalene acetal (10) with 1-methoxy-1,3-butadiene under neat reaction conditions. The stereochemistry of adduct 15 was confirmed by single-crystal X-rayanalysis. The transformation of 15 into target products 4, 5, and 17 involved dehydrogenation, methyl ether cleavage, and reduction and oxidation steps.