We here report glycosyl sulfoxides appended with an aryl iodide moiety as readily available,air and moisture stable precursors to glycosyl radicals.These glycosyl sulfoxides could be converted to glycosyl radicals by way of arapid and efficient intramolecular radical substitution event. The use of this type of precursors enabled the synthesis of various complex Clinked glycoconjugates under mild conditions.T his reaction could be performed in aqueous media and is amenable to the synthesis of glycopeptidomimetics and carbohydrate-DNA conjugates. Scheme 1. a) Glycosyl radicals as valuable intermediates in C-glycoside synthesis. b) Our strategy to generate glycosyl radicals.

Direct and site-selective O-arylation of carbohydrates has been a challenge in synthesis. Herein we report a method based on copper-catalyzed O-arylation to address this challenge. Proper choice of the ancillary ligand on copper is critical for the efficiency and site selectivity of this transformation. This method features mild conditions, tolerates various functional groups, and demonstrates broad substrate scope.

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