Selective formation of phosphonium ylide or iminophosphorane by electroreduction of alkylaminophosphonium salt

Electroreduction of alkylaminophosphonium salt has been utilized for the si mple and safe preparation of the iminophosphorane without the use of the or ganic azide or dihalophosphorus compounds. An equimolar amount of electrici ty was applied to give one electron reduction products, from which hydrogen atom at alpha position was cleaved giving iminophosphorane and phosphonium ylide. Under the presence of aldehyde in this system, the reaction product s were isolated and identified to elucidate the reaction paths involved. Th e onium salt with electron donating methyl group it gave only iminophosphor ane quantitatively, On the other hand, the onium salt with electron withdra wing groups such as carbonyl groups yielded only phosphonium ylide quantita tively. In case of the onium salt with benzyl group, the mixed products fro m both Wittig and Aza-Wittig reactions were obtained.