Construction of C2-Quaternary-indol-3-ones via Rh-Catalyzed [3+2] Spirocyclization from Indole Ketones and Nitroolefins.

Novel complex C2-quaternary-indol-3-one units bearing versatile nitro groups have been successfully developed from pseudo-indolones and α,β-unsaturated nitroolefins through rhodium-catalyzed C-H activation/[3 + 2] spirocyclization. Notably, four diastereomers could be selectively obtained in the reaction by condition control.