Oxidative Decyanation of Secondary Nitriles to Ketones

Procedures for the oxidative decyanation of secondary nitriles to ketones involve (1) iodination of lV-(trialkylsilyl)ketenimines derived from secondary nitriles and subsequent hydrolysis of the α-iodo nitriles with silver oxide, (2) addition of nitrosobenzene to N-(trialkylsilyl)ketenimines, (3) conversion of secondary nitriles to α-(phenylthio) nitriles and subsequent hydrolysis with N-bromosuccinimide in aqueous acetonitrile, and (4) preparation of α-hydroperoxy nitriles by direct oxygenation of anions of secondary nitriles and subsequent reductive hydrolysis with stannous chloride followed by sodium hydroxide. The latter general procedure was applied to various secondary nitriles bearing dialkyl, aryl and alkyl, and diaryl substituents to provide ketones in good yield and was extended to the oxidative decyanation of α,β-unsaturated nitrlles to furnish α,β-unsaturated ketones.