Palladium‐Catalyzed Directing‐Group‐Mediated γ‐C(sp3)−H Glycosylation for Synthesis of C‐Alkyl Glycosides

Abstract

AbstractC‐alkyl glycosides play a crucial role in various bioactive compounds. However, the synthesis of C‐alkyl glycosides poses significant challenges, particularly through C(sp3)−H glycosylation. Here, we report a set of reactions for constructing C‐alkyl glycosides through directing‐group‐mediated functionalization of unactivated γ‐C(sp3)−H bonds under mild conditions. These reactions not only achieve high regioselectivity and stereoselectivity in glycosylation, but also exhibit a wide substrate scope. They are compatible with both arene and alkane substrates, as well as natural and unnatural amino acid substrates. Mechanistic studies have shown that the directing‐group 8‐aminoquinoline (AQ) and picolinamide (PA) may affect the chirality of the β‐carbon of L‐valine through a sterically favorable trans‐palladacycle intermediate, resulting in (R) or (S) configuration of glycosylated amino acid, respectively. These reactions are promising to provide a convenient and powerful tool for constructing C‐alkyl glycosides and carbohydrate‐based drugs in the future.