A Simplified Wittig Synthesis of Substituted Styrenes

Abstract

The Wittig reaction has been used originally by Hauser¹ e.a. for the preparation of styrene using formaldehyde in non-aquous solutions and butyl lithium as the base. Aquous formaldehyde solutions, that are preparatively more attractive, have recently been introduced by Butcher² e.a. during the preparation of para nitrostyrene. The method consisted in a previous isolation of p-nitrobenzyl triphenylphosphorane obtained by treatment of the onium salt with 10% aquous sodium carbonate after which it was condensed as a suspension with 40% aquous formaldehyde. Frequently however phosphoranes are not stable enough in alkaline solutions (giving rapidly rise to substituted toluenes) as to generalize this procedure (cfr. ref. 3).