Silver(I)-Catalyzed Dearomatization of Alkyne-Tethered Indoles: Divergent Synthesis of Spirocyclic Indolenines and Carbazoles.

A high-yielding, divergent approach to generate either spirocyclic indolenines or carbazoles from a common indole-tethered propargyl alcohol precursor is described, with mechanistic insight provided. Either product can be obtained upon treatment with different Ag(I) catalysts at rt. An unexpected hydration reaction to afford (±)-actinopolymorphol B is also reported.