New method for the synthesis of phosphonic and phosphinic esters and their thio analogs Communication 12. Addition of dialkylphosphorous acids to unsaturated, dibasic acids and their esters

Summary

• 1. It has been shown that, in presence of alkali-metal alkoxides, dialkylphosphorous acids readily add to maleic acid and to maleic and fumaric esters. The addition products, have been obtained ,in good. yield (dialk-oxyphosphinylsuccinic acids and their eskers).

• 2. It As been shown that under the same conditions, dialkylphosphorous acids add to diethyl acetylenedicarboxylate, and the products formed by addition of two molecules of dialkylphosphorous acid [bis(dialkoxyphos-phinyl)succinic esters] have been isolated.