The Chemistry of Small Ring Compounds. Part 24¹An Improved Synthesis of Aminals of Bicyclo[3.1.0]Hexan-6-One and Bicyclo[4.1.0]Heptan-7-One

Abstract

Abstract Bicyclic aminals 4a-d have been prepared by Szmuszkovicz3,4 and by Cantacuzène 5 in moderate yields (15–40%) from α-haloketones 1a, b, d and secondary amines. In these reactions α-halo-enamines 2a-d and iminium ions 3a-d have been suggested as likely intermediates. Bordwell6 has found that similar species are probably involved in the formation of “Favorskii amides” in the reaction of α-halo-α'-arylketones with secondary amines6.