Carbene-Catalyzed the Synthesis of 2-Oxindole from Sulfonates and Isatin Derivatives

A novel N-heterocyclic carbene (NHC) catalyzed reaction between sulfonate and isatin derivatives has been successfully developed, enabling the efficient synthesis of a series of 2-oxindole derivatives. This catalytic system demonstrated remarkable efficiency, affording the desired products in excellent yields of up to 96%. Notably, the reaction exhibited significant stereoselectivity, with the ratio of cis-trans configurations reaching Z:E  = 1:10. Mechanistically, this methodology represents a significant advancement in NHC mediated activation of sulfonyl compounds, providing a new strategic approach for the construction of biologically important 2-oxindole scaffolds. The developed protocol features mild reaction conditions, broad substrate scope, and high functional group tolerance, making it a valuable addition to the NHC catalyzed synthetic toolbox.