Reaction of dimethylphosphorous acid with 2,5-bis(carbomethoxy)-3,4-diphenylcyclopentadienone

Abstract

The reaction of 2,5-bis(carbomethoxy)-3,4-diphenylcyclopentadienone with dimethyl phosphite, both in the presence of Et3N and in the absence of catalysts, goes with the formation of the dimethyl esters of 2-oxo-4,5-diphenyl-1,3-dicarbomethoxy-4-cyclopentene- and 2-oxo-4,5-diphenyl-1,3-dicarbomethoxy-3-cyclopentene-1-phosphonic acids. In contrast to alcohols and primary amines, dimethyl phosphite does not form the 1,4-addition products with this acceptor. © 1980 Plenum Publishing Corporation.