Stable phosphorus ylides and heterocyclic phosphonate esters derivatives synthesised from stereoselective reactions between triphenyl phosphite and activated acetylenic esters

Abstract

One-pot synthesis of stable heterocyclic phosphorus ylides 4a–j is reported in fairly good yields by the reaction between dialkyl acetylenedicarboxylates and triphenyl phosphite in the presence of strong NH-acids such as 2-benzoxazolinone, 2-indolinone and 2-mercaptobenzoxazole in aqueous media as an environmentally friendly solvent. The hydrolysis of compounds 4a–f led to stable phosphonate ester derivatives 5h–l. The configuration of compounds 5h–l (2S^*,3R^*) was determined on the basis of coupling constant predicted from the Karplus equation.