The O2-Mediated Cross-Dehydrogenative Coupling: Rose Bengal-Catalyzed Direct Oxidative α-Acyloxylation of Ketones.

A general and facile approach for the direct oxidative α-acyloxylation of ketones using molecular oxygen as the oxidant is developed. This method avoids the use of excessive peroxides and expensive metal catalysts, affording a variety of α-acyloxylated ketones in satisfactory yields. Experimental studies indicate that the reaction proceeds via a radical pathway. Additionally, α-hydroxy ketones could be obtained by changing the solvent.