Enantioselective Synthesis of α-Trifluoromethyl Arylmethylamines by Ruthenium-Catalyzed Transfer Hydrogenation Reaction
作者:Xiaoyang Dai、Dominique Cahard
DOI:10.1002/adsc.201301115
日期:2014.4.14
A simple combination of dichloro(para‐cymene)ruthenium(II) dimer, a chiral amino alcohol and isopropyl alcohol allowed for in‐situ generation of the bifunctional catalyst responsible for the transfer hydrogenation reaction of trifluoromethyl ketimines in excellent yields with high enantioselectivities (up to 93% ee). Herein, we describe the optimization, scope, limitations, and applications of the
The enantioselective organocatalytic reduction of trifluoromethyl aryl and alkyl ketoimines afforded the corresponding fluorinated amines with high chemical and stereochemical efficiency. The Lewis base catalyzed reaction with trichlorosilane led to chiral products with a trifluoromethyl group directly linked to the newly generated stereocenter typically in >90% yield and up to 98% e.e.
Amines to an end: Highly opticallyactive α‐CF3‐functionalized amines can be obtained using metal‐free reaction conditions. The method involves the transfer hydrogenation of CF3‐substituted ketimines catalyzed by 1 and reductive amination of CF3‐substituted ketones. The synthetic utility of this method was demonstrated by the synthesis of a CF3 analogue of NPS R‐568. PMP=para‐methoxyphenyl.