A General Photooxidation Platform for Alcohols via Transient Excited-State α-Keto Esters

Transient excited-state auxiliaries provide a powerful strategy for enabling difficult bond activations under mild conditions. Here we report a general alcohol oxidation platform in which phenylglyoxalate α-keto esters act as visible-light-activated, traceless oxidation devices, converting primary and secondary alcohols to aldehydes and ketones without external photocatalysts, metals, or stoichiometric oxidants. The protocol shows broad functionalgroup tolerance and supports late-stage oxidation of complex scaffolds, including pharmacophores, carbohydrates, steroids and a peptide. Practicality is further demonstrated through in situ alcohol activation and efficient continuous-flow scale-up. Mechanistic experiments and DFT studies support a photoinduced fragmentation pathway consistent with a 1,5-HAT-initiated biradical process, underscoring the utility of excitedstate α-keto esters as transient, traceless auxiliaries for preparative oxidation chemistry.