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Unprecedented Halide Dependence on Catalytic Asymmetric Hydrogenation of 2‐Aryl‐ and 2‐Alkyl‐Substituted Quinolinium Salts by Using Ir Complexes with Difluorphos and Halide Ligands
Author(s) -
Tadaoka Hiroshi,
Cartigny Damien,
Nagano Takuto,
Gosavi Tushar,
Ayad Tahar,
Genêt JeanPierre,
Ohshima Takashi,
RatovelomananaVidal Virginie,
Mashima Kazushi
Publication year - 2009
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200901477
Subject(s) - halide , alkyl , aryl , catalysis , chemistry , aryl halide , medicinal chemistry , polymer chemistry , organic chemistry
A better way : Halide ligands bound to an iridium atom are the key to achieving high catalytic activity and enantioselectivity on asymmetric hydrogenation of 2‐aryl‐ and 2‐alkyl‐substituted quinolinium salts. The reaction was catalyzed by a cationic dinuclear iridium(III) complex with difluorphos and chloride or bromide ligands and gave the corresponding 2‐substituted 1,2,3,4‐tetrahydroquinolines in high enantioselectivities (up to 95 % ee ; see scheme, difluorphos=[(4,4′‐bi‐2,2‐difluoro‐1,3‐benzodioxole)‐5,5′‐diyl]bis(diphenylphosphine)).