An Unexpected Inversion of Enantioselectivity in a Copper-Catalyzed Intramolecular­ Desymmetric Aryl C–N Coupling Reaction

Abstract

Enantioselective formation of indolines was achieved through desymmetrization of α,α-bis(2-iodobenzyl)glycines under the catalysis of copper(I) iodide and (2<i>S</i>,3a<i>S</i>,7a<i>S</i>)-octahydro-1<i>H</i>-­indole-2-carboxylic acid. An unexpected inversion of enantioselectivity was observed when achiral additives such as 4-(<i>N</i>,<i>N</i>-dimethylamino)pyridine were added which work together with the ligand. The configuration-reversed products were obtained in moderate yields as well as moderate ee values.