Stereoselective synthesis of 3-sulfone sugars via cobalt catalysis

We report herein the stereoselective synthesis of 3-sulfone sugars in good yields from glycals and sodium arylsulfinates. Various 3,4-O-carbonate glycals were sulfonylated directly by a range of benzene- and naphthalene-sulfinic acid sodium salts catalyzed by cobalt species, demonstrating a broad substrate scope. The mechanism of cobalt-catalyzed decarboxylative allylation from the bottom face of the sugar ring due to the steric effect from the C3 group of glycals was proposed. Moroever, cobalt catalysis tends to favor branched allylation, resulting in excellent regioselectivity. This synthetic strategy features the green sulfone source, good functional group tolerance, exclusive regioselectivity, and excellent stereoselectivity.