Regioselective radical arylation: silver-mediated synthesis of 3-phosphorylated coumarins, quinolin-2(1H)-one and benzophosphole oxides

Abstract

A silver-mediated domino radical addition/cyclization reaction of diarylphosphine oxides with propynoic acid derivatives is described in this article. The reaction of diarylphosphine oxides with alkynoates or propynoic amide was regioselective, producing 3-phosphorylated coumarins and benzophosphole oxides in moderate to good isolated yield, respectively. The hydrogen bond between PO and N–H was proposed to assist the vinyl radical regioselective arylation process. The reaction conditions were also compatible with the conversion of dialkylphosphine oxides to 3-phosphorylated-coumarins and quinolin-2(1H)-one in good yields.