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Asymmetric Hydrogenation with Highly Active IndolPhos–Rh Catalysts: Kinetics and Reaction Mechanism
Author(s) -
Wassenaar Jeroen,
Kuil Mark,
Lutz Martin,
Spek Anthony L.,
Reek Joost N. H.
Publication year - 2010
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.200903476
Subject(s) - catalysis , chemistry , asymmetric hydrogenation , kinetics , denticity , substrate (aquarium) , reaction mechanism , nuclear magnetic resonance spectroscopy , spectroscopy , photochemistry , enantioselective synthesis , stereochemistry , crystallography , computational chemistry , crystal structure , organic chemistry , physics , oceanography , quantum mechanics , geology
The mechanism of the IndolPhos–Rh‐catalyzed asymmetric hydrogenation of prochiral olefins has been investigated by means of X‐ray crystal structure determination, kinetic measurements, high‐pressure NMR spectroscopy, and DFT calculations. The mechanistic study indicates that the reaction follows an unsaturate/dihydride mechanism according to Michaelis–Menten kinetics. A large value of K M ( K M =5.01±0.16 M ) is obtained, which indicates that the Rh–solvate complex is the catalyst resting state, which has been observed by high‐pressure NMR spectroscopy. DFT calculations on the substrate–catalyst complexes, which are undetectable by experimental means, suggest that the major substrate–catalyst complex leads to the product. Such a mechanism is in accordance with previous studies on the mechanism of asymmetric hydrogenation reactions with C 1 ‐symmetric heteroditopic and monodentate ligands.