Aerobic Photoredox Catalyzed Oxamate Ester Synthesis from Bromodifluoroacetate Esters

Here we report an aerobic photoredox catalysis approach to oxamate ester synthesis using bromodifluoroacetate esters and amines under open-air conditions. Oxamate ester is an important skeleton found in bioactive molecules and used as a synthetic building block. However, previous synthetic methods require the use of moisture- and air-sensitive precursors and/or harsh conditions, limiting accessible oxamate esters. The present method uses bench-stable bromodifluoroacetate esters and amines under mild photoredox catalytic conditions to furnish a wide variety of oxamate esters. Combining photoredox catalysis with aerobic oxygenation enables the use of bromodifluoroacetate ester as a precursor for the synthesis of oxamate esters via fluoroglyoxylate esters.