Preparation and Baeyer-Villiger Reaction of certain 2-carbalkoxycyclopropyl methyl ketones

Treatment of mixed anhydrides derived from cis- and trans-2-carbobenzyloxycyclopropanecarboxylic acids and ethyl chloroformate with ethoxymagnesio di-tert-butyl malonate and subsequent treatment of the resulting adducts with p-toluenesulfonic acid afforded cis- and trans-benzyl-2-acetylcyclopropanecarboxylates in good to excellent yields, with retention of the original stereochemistry of the systems. These methyl ketones and an open chain congener, benzyl levulinate, were inert toward m-chloroperbenzoic acid. The cis-isomer and benzyl levulinate underwent normal Baeyer-Villiger reactions mediated by trifluoroperacetic acid, forming moderate yields of the acetate ester insertion products.