Glycosyl thiosulfonate: a stable electrophilic reagent for the synthesis of thioglycosylated indoles and total synthesis of isatindigotindolosides

We disclose a copper-catalyzed C2- or C3-thioglycosylation of indole with a shelf-stable and odorless glycosyl thiosulfonate to assemble indole alkaloid glucoside frameworks. This straightforward catalytic system exhibits the features of broad substrate scope, good functional group tolerance, and high yields. Also, the reported protocol is suitable for performing thioglycosylation of pyrroles. Furthermore, this approach renders access to the total syntheses of isatindigotindolosides I and II.