<i>O</i> ‐ <i>p</i> ‐Methoxyphenyl α‐Hydroxycarboxylic Acids as Versatile Hydroxyalkylation Agents for Photocatalysis

Reliable radical precursors are crucial for photocatalytic processes. In particular, heteroatom-stabilized radicals have attracted considerable research interest in photocatalysis. Among them, α-amino radicals have received the most attention, while the research on α-hydroxy radicals is much less developed. Herein, we present O-PMP α-hydroxycarboxylic acids as novel precursors for the formation of oxygen-stabilized radicals. These radicals have been successfully used as building blocks in Pd-catalyzed allylation reactions, Ni-catalyzed arylation and alkenylation reactions, and Giese reactions. A subsequent deprotection step liberates the corresponding hydroxyalkylation products.