Electrochemical Oxidation of Homocaniphenilone Enol Acetate Derivatives

Comparison of the Reaction Products with those of the Lead Tetraacetate Oxidation of d-Longifolene

Abstract

The electrochemical oxidation of l-R-homocamphenilone enol acetate in glacial acetic acid using triethylamine as a supporting electrolyte afforded a mixture of exo and endo 3-acetoxy-R-homocamphenilone in good yields. That of d-longihomocamphenilone enol acetate (4) gave a mixture of the corresponding exo and endo α-acetoxy ketones, d-7-acetoxylongihomocamphenilone (7) in good yields. The mixture of 7 was subjected to base-catalyzed hydrolysis that proceeded quantitatively, to give a mixture of exo and endo d-7-hydroxylongihomocamphenilone (8) and d-longidione (9). The oxidation of d-longifolene with lead tetraacetate also gave the two minor products, 8 and 9, which were independently produced by the electrochemical oxidation of 4, in addition to six previously known products.