Visible Light‐Induced Salan‐Copper(II)‐Catalyzed Enantioselective Aerobic α‐Hydroxylation of β‐Keto Esters

Abstract A strategy of visible light‐induced salan‐copper(II)‐catalyzed asymmetric α‐hydroxylation of β‐keto ester with utilization of sustainable air as the oxidant was developed. This protocol allows convenient access to a number of enantioenriched α‐hydroxyl β‐keto esters (up to 95% yield, 96% ee), especially for β‐keto methyl esters that are valuable architectures in pharmaceuticals, including the key intermediate of the sodium‐channel blocker ( S )‐indoxacarb. Experimental studies suggest that reactive singlet oxygen may participate in this reaction. magnified image