Stereoselective Synthesis of Glycosides via Tsuji–Trost Type Glycosylation Using 3,4‐Carbonate Galactals

Abstract

Pd‐catalyzed stereoselective glycosylations using unsaturated sugar derivatives, glycals, have been successfully achieved in recent years. This review focuses on approaches to control the stereoselectivities of glycosides via π‐allyl intermediates that mimic the Tsuji–Trost asymmetric allylic alkylation reactions, enabling stereoselectivity control through rational design. In the reaction process, zwitterionic Pd‐π‐allyl complexes, formed after the oxidative addition and decarboxylation, play a crucial role in increasing reactivities and enhancing the stereoselectivities of α‐ and β‐glycosides. We summarized recently developed Tsuji–Trost type glycosylations using 3,4‐carbonate galactals, featuring high efficiency, exclusive stereoselectivities, and a broad reaction scope including O‐, N‐, S‐, and C‐glycosylations.