The use of phosphite-type ligands in the Ir-catalyzed asymmetric hydrogenation of heterocyclic compounds

Abstract

A series of chiral phosphite-type ligands was tested in asymmetric Ir-catalyzed hydrogenation of quinolines and 2,4,5,6-tetrahydro-1H-pyrazino(3,2, 1-j,k)carbazole. Hydrogenation of quinaldine hydrochloride provided superior enantioselectivity up to 65% ee compared to quinaldine free base. The ligands were tested for the first time in the asymmetric Ir-Ircatalyzed hydrogenation of 2,4,5,6-tetrahydro-1H-pyrazino(3,2,1-j,k)carbazole yielding the antidepressant drug, pirlindole. Chirality 26:56-60, 2013. © 2013 Wiley Periodicals, Inc. © 2013 Wiley Periodicals, Inc.