title: One-Pot N-Deprotection and Catalytic Intramolecular Asymmetric Reductive Amination for the Synthesis of Tetrahydroisoquinolines.
abstract: A one-pot N-Boc deprotection and catalytic intramolecular reductive amination protocol for the preparation of enantiomerically pure tetrahydroisoquinoline alkaloids is described. The iodine-bridged dimeric iridium complexes displayed superb stereoselectivity to give tetrahydroisoquinolines, including several key pharmaceutical drug intermediates, in excellent yields under mild reaction conditions. Three additives played important roles in this reaction: Titanium(IV) isopropoxide and molecular iodine accelerated the transformation of the intermediate imine to the tetrahydroisoquinoline product; p-toluenesulfonic acid contributed to the stereocontrol.
authors.affiliation: Department of Chemistry and Chemical Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, 712100, PR China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Chemical Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, 712100, PR China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Department of Chemistry and Chemical Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, 712100, PR China.
authors.forename: Suhua
authors.initials: S
authors.lastname: Yang
authors.affiliation: Department of Chemistry and Chemical Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, 712100, PR China.
authors.forename: Le
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Department of Chemistry and Chemical Engineering, Northwest A&F University, 22 Xinong Road, Yangling, Shaanxi, 712100, PR China.
authors.forename: Mingxin
authors.initials: M
authors.lastname: Chang
keywords: asymmetric catalysis; enantioselectivity; iridium; reductive amination; tetrahydroisoquinolines