A Simplified Wittig Synthesis of Substituted Styrenes

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).