Tricationic Xanthylium-Catalyzed Oxyamination of Activated Alkenes Using O-Benzoylhydroxylamines As Bifunctional Reagents.

1,2-Amino alcohols are essential scaffolds in organic synthesis and pharmaceutical development, yet the direct catalytic synthesis of secondary alkylamino alcohol derivatives from alkene precursors remains a significant challenge. Although O-benzoylhydroxylamines are effective aminating reagents, the direct use of primary alkyl amino groups (RNH-X) in amination is still rare. Moreover, existing methods often suffer from poor atom economy due to the generation of stoichiometric byproducts. Herein, we report a tricationic xanthylium-based organophotoredox catalyst that enables primary O-benzoylhydroxylamines to act as bifunctional reagents in the oxyamination of alkenes. This strategy provides direct and regioselective access to 1,2-amino alcohols bearing secondary alkylamine motifs under mild conditions, offering regiocomplementarity to the Sharpless aminohydroxylation. The reaction exhibits broad substrate scope and functional group tolerance, and has been successfully applied to the concise synthesis of natural products. Mechanistic investigations, including control experiments and isotope-labeling studies, support a radical cation pathway involving key alkene oxidation and concerted carbon to nitrogen 1,3-radical acyloxy migration steps. This study establishes tricationic xanthylium salts as powerful organophotoredox catalysts for challenging synthetic transformations.