Merging Reductive Ring-Rearrangement with Oxidative Alkyl–Alkyl Coupling via Copper Catalysis: Conversion of Bridged Benzoxocin-4-ones to Bridged Benzoxocin-2-ols

A Cu-catalyzed reductive skeletal rearrangement of bridged benzoxocin-4-ones into bridged benzoxocin-2-ols is reported. Various alkyl Grignard reagents, including methylmagnesium bromide, can promote the reaction with high selectivity. Mechanistic studies indicate the generation of an organocopper(III) species that favors β-methoxyl elimination over C-C bond-forming reductive elimination.