Enantioselective Borylative Dearomatization of Indoles through Copper(I) Catalysis.

The enantioselective borylative dearomatization of a heteroaromatic compound has been achieved using a copper(I) catalyst and a diboron reagent. This reaction involves the regio- and enantioselective addition of active borylcopper(I) species to indole-2-carboxylates, followed by the diastereoselective protonation of the resulting copper(I) enolate to give the corresponding chiral indolines, which bear consecutive stereogenic centers.