Diastereocontrolled Construction of Spiroindolenines via Hexafluoroisopropanol-Promoted Dearomative Epoxide-Indole Cyclization.

Herein, we report the discovery of the ipso -selective, dearomatizing spirocyclization of indole-tethered epoxides as a fundamentally new approach for constructing spiroindolenines equipped with three contiguous stereogenic centers under complete diastereocontrol (dr >99:1) and in high yields. Promoted by hexafluoroisopropanol, the protocol features a broad substrate scope, easy scale-up, and versatile transformations of the synthesized spiroindolenines.