Cobalt-Catalyzed\nHighly α‑Stereoselective\nGlycosylation of Glycals

Following the satisfactory catalytic performance of cobalt\nin the <i>C</i>-glycosylation of glycals, further study\nof cobalt’s\napplication values was performed under mild conditions, leading to\na range of highly α-stereoselective 2,3-unsaturated <i>O-</i>, <i>S-</i>, and <i>N-</i>glycosides.\nThe synthetic potential of the developed protocol was underscored\nby the late-stage functionalization of pharmaceutically relevant molecules\nincluding the canagliflozin derivative (a potential candidate for\ntreating type 2 diabetes and alleviating pathological aging). Furthermore,\ncontrol experiments were conducted to elucidate a reasonable mechanism\nand rule out the pathway involving the configuration conversion between <i>α-</i> and <i>β-</i>anomers.