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Asymmetric Hydrogenation of α,β‐Unsaturated Nitriles with Base‐Activated Iridium N,P Ligand Complexes
Author(s) -
Müller MarcAndré,
Pfaltz Andreas
Publication year - 2014
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201402053
Subject(s) - nitrile , iridium , chemistry , catalysis , conjugated system , ligand (biochemistry) , enantioselective synthesis , conjugate , reactivity (psychology) , base (topology) , combinatorial chemistry , medicinal chemistry , organic chemistry , medicine , mathematical analysis , biochemistry , receptor , mathematics , alternative medicine , pathology , polymer
Although many chiral catalysts are known that allow highly enantioselective hydrogenation of a wide range of olefins, no suitable catalysts for the asymmetric hydrogenation of α,β‐unsaturated nitriles have been reported so far. We have found that Ir N,P ligand complexes, which under normal conditions do not show any reactivity towards α,β‐unsaturated nitriles, become highly active catalysts upon addition of N , N ‐diisopropylethylamine. The base‐activated catalysts enable conjugate reduction of α,β‐unsaturated nitriles with H 2 at low catalyst loadings, affording the corresponding saturated nitriles with high conversion and excellent enantioselectivity. In contrast, alkenes lacking a conjugated cyano group do not react under these conditions, making it possible to selectively reduce the conjugated CC bond of an α,β‐unsaturated nitrile, while leaving other types of CC bonds in the molecule intact.