Evidence for a methylenethioxophosphorane (thiophosphene) intermediate in nucleophilic substitution at a benzylthiophosphonyl centre

Abstract

The remarkably high rate of the reaction of p-NO₂C₆H₄CH₂P(S)(NMe₂)Cl with Et₂NH, the presence of deuterium in the benzylic methylene group of the product formed with Et₂ND, and the relative lack of discrimination between competing Me₂NH and Et₂NH, suggest an elimination–addition mechanism for substitution, with a three-coordinate P^V methylenethioxophosphorane (thiophosphene) intermediate 6.