Efficient Construction of 3‐Fluoroalkylated Oxindoles Enabled by Zwitterion Catalysis

Abstract

Abstract3,3‐Disusbtituted oxindoles are important compounds in organic synthesis, and methods to access this class of compounds have always been sought after. Herein, we have identified a new method where a zwitterion generated using a combination of phosphine and para‐quinone methide could efficiently catalyze the 1,6‐conjugate addition of α‐fluoro‐β‐ketoamides to isatin‐derived para‐quinone methides to access 3‐fluoroalkylated oxindoles. It was further shown that the methodology could be extended to arylaldehyde‐derived p‐QMs. Moreover, one of the conjugate addition products was efficiently transformed into oxoindolinyl fluoroacetamide derivative through a K2CO3 mediated deacylation reaction.