Selective hydrophosphorylation of alkynes for the synthesis of (E)-vinylphosphonates

Abstract

Hydrophosphorylation of alkynes with dialkylphosphites in the various copper catalysts was investigated. The reactions provided the regio- and stereoselective E-vinylphosphonates under commercially available copper chloride catalyst in the presence of ethylene diamine as an efficient ligand. The impact of solvents, temperature, and diamine ligands are included in this report. In addition, the DFT calculations provided insight into the regio- and stereoselectivity of the reaction. It is suggested that the reaction proceeded via an in situ generated Cu(AN)₄⁺ complex. The reaction of phenylacetylene with diethyl phosphite in the presence of EDA and the (CH₃CN)₄CuBF₄ complex as a catalyst also gave the corresponding E-vinylphosphonates in good yield.