Gold-Catalyzed “Back-to-Front” Synthesis of 4‑Silyloxyindoles

A series of pyrrol-yn-glycol
derivatives were easily prepared from
simple pyrroles through a three-step sequence involving hydroxyalkylation-alkynylation-O-silylation. Their reaction with IPrAuNTf2 triggers
a C2-pyrrole attack onto the activated alkyne and subsequent highly
selective 1,2-migration of the oxyalkyl group in the intermediate
spirocycle. This approach enables the efficient synthesis of a wide
selection of regioselectively functionalized 4-hydroxyindoles, which
represent important yet challenging indole scaffolds, in high yields.