Nickel-catalyzed arylation, alkenylation, and alkynylation of unprotected thioglycosides at room temperature

Unprotected thioglycosides were effective nucleophiles for Ni ⁰-catalyzed C-S bond-forming reaction with functionalized (hetero)aryl, alkenyl, and alkynyl halides. The functional-group tolerance on the electrophilic partner was typically high and the anomeric selectivities of the thioglycosides were high in all cases. The efficiency of this general procedure was well-demonstrated by the synthesis of 4-methyl-7-thioumbelliferyl- β-D-cellobioside (MUS-CB). Ni on impossible: Unprotected thioglycosides were effective nucleophiles for Ni⁰-catalyzed C-S bond-forming reactions with functionalized (hetero)aryl, alkenyl, and alkynyl halides. The functional-group tolerance on the electrophilic partner was typically high and the anomeric selectivities were high in all cases. The efficiency of this method was well-demonstrated by the synthesis of 4-methyl-7-thioumbelliferyl-β-D- cellobioside (MUS-CB; see scheme).