Silver-Catalyzed [3+2] Cycloaddition for the Diastereoselective Synthesis of anti-3-Substituted Hydroindolin-2-Imines

We describe a silver catalyzed [3+2] diastereoselective annulation of p-quinamines and ketenimine zwitterionic salts, leading to anti-3-substituted hydroindolin-2-imines under mild conditions. Ketenimine zwitterionic salts participate in the [3+2] cycloadditions as a monoolefin (2 pi-system). The relative stereoselectivity of the reaction was regulated by the tert-butyl ester. This protocol is complementary to the synthesis of functionalized hydroindoles moiety and expands the application of ketenimine zwitterionic salts.

Automated summary

In this study, a silver-catalyzed [3+2] diastereoselective annulation of p-quinamines and ketenimine zwitterionic salts was successfully carried out, leading to the synthesis of new compounds with specific stereochemical configurations. The relative stereoselectivity of the reaction can be controlled by specific functional groups. This method is significant for expanding the application of ketenimine zwitterionic salts.