Cu-β-CD-Catalyzed Csp-P Coupling of Alkynes with Dialkylphosphites and Phosphine oxides

Abstract

In this study, easily accessible Cu--CD complex has been introduced for the cross C-P coupling reaction. Cu-β-CD complex was used to catalyze C-P coupling of alkynes with both dialkylphosphites and phosphinoxides for the synthesis of alkynyl-phosphonates and -phosphineoxides. The results showed that the coupling reaction carried out with appropriate yields for both aryl and alkyl alkynes. The applicability of Cu-β-CD for oxidative decarboxylative coupling of phenylpropiolic acid with dialkyl phosphites and diphenylphosphine oxide was also studied. XPS and cyclic voltametry analysis of the catalyst confirmed the presence of both Cu(I) and Cu(II) in the complex structure. The reaction proceeded via an oxidative addition of dialkyl phosphites and alkynes to the catalyst and the final C-P cross coupling product obtained by a reductive elimination process. The presented catalytic method allows an easier and more cost-efficient cross coupling of alkynes with dialkylphosphites and phosphine oxides under mild and base free condition.