Excited-State Palladium-CatalyzedRadical AllylicAlkylation: Rapid Access to C2-Allyl Carbohydrates

Glycomimetics have emerged as a promising strategy to mimic the biological activities of carbohydrates while enhancing drug-like properties. Yet, their efficient synthesis and modifications remain a major challenge. Herein, we report an excited-state Pd-catalyzed, rapid synthesis of C2-allylated carbohydrates, useful synthons for preparing glycomimetics, from readily available α-bromosugars. The transformation features a high level of atom economy, broad functional group tolerance, and suitability for the late-stage modification of complex molecules. Preliminary experimental and computational studies suggest a radical mechanism involving excited Pd species, 1,2-radical migration (RaM), and kinetically controlled β-H elimination processes. We anticipate that our findings will broaden the reaction profile of excited-state Pd catalysis and enable rapid access to valuable glycomimetics.