Three-Component Synthesis of Dialkyl 2-(Dicyanomethyl)- 3-(triphenyl-?5)phosphoranylidene)succinates from Triphenylphosphine, Acetylenic Esters and Malononitrile in Solvent-Free Conditions

Abstract

Protonation of the highly reactive 1:1 intermediates, produced by the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by malononitrile under microwave irradiation in solvent-free conditions leads to vinyltriphenylphosphonium salts. These salts undergo Michael addition reaction with conjugate base to produce dialkyl 2-(dicyanomethyl)- 3-(triphenyl-λ⁵-phosphoranylidene)succinates in fairly good yields. The structures of these compounds were confirmed by IR, ¹H, ³¹P and ¹³C NMR spectroscopy.