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Iridium‐Catalyzed Asymmetric Hydrogenation of Tosylamido‐Substituted Pyrazines for Constructing Chiral Tetrahydropyrazines with an Amidine Skelton
Author(s) -
Higashida Kosuke,
Nagae Haruki,
Mashima Kazushi
Publication year - 2016
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201600852
Subject(s) - chemistry , amidine , iridium , catalysis , bromide , yield (engineering) , asymmetric hydrogenation , amine gas treating , enantioselective synthesis , medicinal chemistry , racemization , organic chemistry , combinatorial chemistry , materials science , metallurgy
Dinuclear triply chloro‐bridged iridium(III) complexes bearing chiral diphosphine ligands catalyze the asymmetric hydrogenation of tosylamido‐substituted pyrazines to give the corresponding chiral tetrahydropyrazines with an amidine skeleton in high yield and with high enantioselectivity. Addition of N , N ‐dimethylanilinium bromide enhanced the catalytic activity of the iridium complexes and also increased the enantioselectivity of the products by trapping the hydrogenated amine products with HBr from N , N ‐dimethylanilinium bromide. The amidine skeleton of the products could be transformed to give chiral piperazinones and piperazines without loss of enantioselectivity.