ENDOPEROXIDES OF NAPHTHALENES - SYNTHESIS AND REACTIONS OF SUBSTITUTED 2,3-EPOXYNAPHTHALENE 1,4-ENDOPEROXIDES

Oxidation of the 1, 4-endoperoxides of 1, 2, 3, 4-tetramethyl- or octamethylnaphthalene with m-chloroperbenzoic acid gave the stable, crystalline epoxy endoperoxides 8 and 9. Epoxidation occurred predominantly syn to the peroxide bridge. The syn-epoxy peroxides underwent acid-catalyzed solvolytic rearrangement to the stable peroxy ac-etais 14 and 24, respectively, but the anti-epoxy endoperoxide 8a was recovered under similar conditions. The rearrangement involves a 1, 2-aryl migration. Catalytic hydrogenolysis of 14 gave cis-1-acetyl-l, 2, 3-trimethylindan-2, 3-diol (16), which was obtained independently from the acid-catalyzed methanolysis of the syn-epoxide of 1, 2, 3, 4-tetramethylnaphthalene 1, 4-endoxide (19). Deuterium labeling studies support the proposed mechanism for these rearrangements (Scheme II). Thermolysis of the epoxy endoperoxide 8s occurs with O-O bond cleavage, as established by trapping the intermediate diradical with good hydrogen donors (diglyme, benzhydrol) to give the epoxydiol 10s, synthesized independently by hydrogenolysis of 8s. In the absence of trapping agent, thermolysis of 8s occurs with loss of a methyl group to give the ketone 33. © 1979, American Chemical Society. All rights reserved.