Abstract

Protonation of the highly reactive 1:1 intermediates, produced in the reaction between triphenylphosphine and dialkyl acetylenedicarboxylates, by CH-acids (nitromethane, acetylacetone, dibenzoylmethane and diethyl malonate) leads to vinyl triphenylphosphonium salts, which undergo Michael addition reaction with conjugate base to produce corresponding highly stabilized phosphorus ylides in the mixture of acetone-water (2:1).