Visible-light-driven photocatalyst-free deoxygenative homologation of alcohols to access tertiary alcohols

A general and effective deoxygenation process for the homologation of alcohols has been developed, driven by visible light without the need for any external photocatalysts or EDA complex formation. Using xanthate anions as intermediates, the present protocol facilitates the C-O bond homolysis of a variety of primary, secondary and tertiary alcohols to couple with diverse α-ketoesters, providing facile and practical access to diverse sterically hindered α-hydroxy esters under mild conditions. Mechanistic studies demonstrate that SET from xanthate anions to α-ketoesters triggered by direct photoexcitation is pivotal in initiating the transformation.