Asymmetric Synthesis of Spiro[Azetidine-3,3'-Indoline]-2,2'-Diones via Copper(I)-Catalyzed Kinugasa/C-C Coupling Cascade Reaction.

Spiro[azetidine-indolines] are important scaffolds in diverse bioactive compounds. Current efforts to synthesize spiro[azetidine-indolines] are limited to chiral spiro[azetidine-2,3'-indolines]. Asymmetric synthesis of structurally similar chiral spiro[azetidine-3,3'-indolines] remains unexplored. In this work, the first copper(I)-catalyzed asymmetric Kinugasa/aryl C-C coupling cascade reaction is described. This provides a straightforward access to densely functionalized chiral spiro[azetidine-3,3'-indoline]-2,2'-diones in good yields and with high enantioselectivity.