Synthesis of New Stable Phosphorus Ylides and 1,4-Diionic Organophosphorus Compound from a Reaction between Hexamethyl Phosphorous Triamide and Dimethyl Acetylenedicarboxylate in the Presence of CH-Acids

A simple and efficient one-pot three-component reaction between hexamethyl phosphorous triamide and dimethyl acetylenedicarboxylate (DMAD) in the presence of CH-acids, such as acetylacetone, 1,3-indandione, dibenzoylmethane, anthrone, and N,N-dimethylbarbituric acid, has been studied. In all cases, new and stable phosphorus ylides are obtained in excellent yields. These stable ylides exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carboncarbon partial double bond, resulting from conjugation of the ylide moiety with the adjacent carbonyl group. From the reaction of N,N-dimethylbarbituric acid with DMAD in the presence of hexamethyl phosphorous triamide, a 1,4-diionic organophosphorus compound is obtained. (c) 2012 Wiley Periodicals, Inc. Heteroatom Chem 24:8489, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.21067