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Use of the Trost Ligand in the Ruthenium‐Catalyzed Asymmetric Hydrogenation of Ketones
Author(s) -
Cettolin Mattia,
Puylaert Pim,
Pignataro Luca,
Hinze Sandra,
Gennari Cesare,
de Vries Johannes G.
Publication year - 2017
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201700545
Subject(s) - ruthenium , chemistry , ligand (biochemistry) , catalysis , ketone , medicinal chemistry , yield (engineering) , hydrogen , metal , organic chemistry , materials science , biochemistry , receptor , metallurgy
The Trost ligand, (1 S ,2 S )‐1,2‐diaminocyclohexane‐ N , N′ ‐bis(2′‐diphenylphosphinobenzoyl) ( L ), is reported for the first time as a ligand for the asymmetric hydrogenation (AH) of ketones. Ligand ( S , S )‐ L was screened in the presence of several metal salts and was found to form active catalysts if combined with ruthenium sources in the presence of hydrogen and a base. Reaction optimization was performed by screening different Ru sources, solvents, and bases. Under the optimized conditions, the complex formed by the combination of ( S , S )‐ L with RuCl 3 (H 2 O) x in the presence of Na 2 CO 3 was able to promote the AH of several ketones at room temperature in good yields with up to 96 % ee . The reaction kinetics measured under the optimized conditions revealed the presence of a long induction period, during which the initially formed Ru species was transformed into the catalytically active complex by reaction with hydrogen. Remarkably, a ketone that is a precursor of the antiemetic drug aprepitant was hydrogenated in excellent yield with a good ee value.