Reaction of Olefins with α-Cyanoacetamide in the Presence of Manganese(III) Acetate

Abstract

Abstract 2-Butenamides and 2-buten-4-olides are formed by the reaction of phenyl or 4-chlorophenyl-substituted olefins with α-cyanoacetamide in the presence of manganese(III) acetate. On the other hand, aryl substituted olefins having electron-donating groups are oxidized under similar reaction conditions to give 1,5-dihydro-2H-pyrrol-2-ones and 3-ethenyl-2-pyrrolidones. All these reactions also produce glycols or ketones which are given by the direct oxidation of these olefins with manganese(III) acetate. The question whether an intermediate carbocation in the oxidation process cyclized on an oxygen or a nitrogen atom can be explained by the hard and soft acids and bases (HSAB) concept. A possible mechanism for the formation of 2-butenamides and 2-buten-4-olides is proposed.