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Asymmetric Activation/Deactivation of Racemic Ru Catalysts for Highly Enantioselective Hydrogenation Irrespective of Ketonic Substrates: Molecular Design of Dimethylbinaphthylamine for Enantiomeric Catalysts Discrimination
Author(s) -
Mikami Koichi,
Korenaga Toshinobu,
Yusa Yukinori,
Yamanaka Masahiro
Publication year - 2003
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.200390019
Subject(s) - chemistry , enantioselective synthesis , binap , catalysis , enantiomeric excess , enantiomer , kinetic resolution , moiety , asymmetric hydrogenation , stereochemistry , medicinal chemistry , combinatorial chemistry , organic chemistry
Asymmetric activation and deactivation of racemic catalysts are two extremes in asymmetric catalysis. In a combination of these two protocols, higher enantioselectivity can be achieved by maximizing the difference in catalytic activity between the enantiomers of racemic catalysts through selective activation and deactivation of enantiomeric catalysts. 3,3′‐Dimethyl‐2,2′‐diamino‐1,1′‐binaphthyl (DM‐DABN) is thus designed as a chiral poison (deactivator) for complete enantiomer resolution of racemic BINAP‐Ru(II) catalysts. The catalyst system of DM‐DABN, 1,2‐diphenylethylenediamine (DPEN), and racemic BINAP‐Ru(II) led to great success in highly enantioselective hydrogenation irrespective of the ketonic substrates. The lower catalytic activity of the BINAP‐Ru(II)/DM‐DABN complex stems from the electron delocalization from the Ru center to the diamine moiety in contrast to the BINAP‐Ru(II)/DPEN complex where the highest electron densities are localized on the Ru‐N region. The present ‘asymmetric activation/deactivation protocol' can provide a guiding principle for the rational design of a molecule for enantiomeric discrimination between racemic catalysts.