Evolution of Regioselective Oxidation of Unprotected Carbohydrates: From Microbial Dehydrogenation to Site‐Selective Photocatalysis and Electrosynthesis

This review focuses on the latest advances in site‐selective generation of ketoses from carbohydrates, with an emphasis on methods for distinguishing multiple hydroxyl groups. Emphasis is placed on the oxidation of secondary hydroxyl groups, while discussing key influencing factors such as catalyst design, substrate scope, and reaction mechanisms. Advances in enzymatic, transition‐metal‐catalyzed, electrochemical, photocatalytic, and chemoenzymatic strategies are systematically summarized, illustrating their synthetic utility in accessing rare sugars and functionalized glycoconjugates without protecting‐group manipulations.