Visible-light-catalyzed cascade carboxylation/cyclization of o-cyano(bi)arylacrylamides with formate for the synthesis of carboxylated quinolinones and ester-containing phenanthridines

Described here is a visible-light-catalyzed cascade carboxylation/cyclization of o -cyano(bi)arylacrylamides with formate to access various carboxylated quinolinones and ester-containing phenanthridines. The reaction commences with the addition of a CO 2 radical anion across the alkene, generating an alkyl radical. This intermediate adds to the cyano group, and the resulting adduct undergoes hydrolysis or rearomatization to yield the final products. This reaction provides a facile and sustainable protocol for the construction of carboxylated quinolinones and ester-containing phenanthridines using formates as the carboxylic source. Described here is a visible-light-catalyzed cascade carboxylation/cyclization of o -cyano(bi)arylacrylamides with formate to access various carboxylated quinolinones and ester-containing phenanthridines.