Visible‐Light Photoredox‐Catalyzed Ring‐Opening Carboxylation of Cyclic Oxime Esters with CO2

Abstract The carboxylation of cyclic oxime esters with carbon dioxide via visible‐light photoredox catalysis is demonstrated for the first time. A variety of cyclic oxime esters undergo ring‐opening C−C bond cleavage and carboxylation to give cyanoalkyl‐containing carboxylic acids in moderate to good yields. Moreover, this methodology features mild reaction conditions (room temperature, 1 atm), wide substrate scope, good functional group tolerance as well as facile derivations of products. Mechanistic studies indicate that the benzylic radicals and anions might be the key intermediates.