Enantioselective Synthesis of 3‑Alkynyl-3-hydroxyindolin-2-ones by Copper-Catalyzed Asymmetric Addition of Terminal Alkynes to Isatins

A highly
efficient copper-catalyzed asymmetric addition of terminal
alkynes to isatins has been developed. In the presence of a catalytic
amount of copper iodide and a chiral phosphine ligand, the reaction
gave the corresponding chiral 3-alkynyl-3-hydroxyindolin-2-ones in
high yields with high enantioselectivity. This methodology has a broad
substrate scope, and the synthetic utility of the present protocol
was further demonstrated by the transformation of chiral alkynylation
products.