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Arene‐Immobilized Ru(II)/TsDPEN Complexes: Synthesis and Applications to the Asymmetric Transfer Hydrogenation of Ketones
Author(s) -
Doherty Simon,
Knight Julian G.,
Alshaikh Hind,
Wilson James,
Waddell Paul G.,
Wills Corinne,
Dixon Casey M.
Publication year - 2021
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202000948
Subject(s) - chemistry , catalysis , ruthenium , transfer hydrogenation , ligand (biochemistry) , substrate (aquarium) , leaching (pedology) , electron transfer , combinatorial chemistry , organic chemistry , biochemistry , oceanography , receptor , soil science , soil water , geology , environmental science
Abstract The Noyori‐Ikariya (arene)Ru(II)/TsDPEN precatalyst has been anchored to amorphous silica and DAVISIL through the η 6 ‐coordinated arene ligand via a straightforward synthesis and the derived systems, (arene)Ru(II)/TsDPEN@silica and (arene)Ru(II)/TsDPEN@DAVISIL, form highly efficient catalysts for the asymmetric transfer hydrogenation of a range of electron‐rich and electron‐poor aromatic ketones, giving good conversion and excellent ee's under mild reaction conditions. Moreover, catalyst generated in situ immediately prior to addition of substrate and hydrogen donor, by reaction of silica‐supported [(arene)RuCl 2 ] 2 with ( S,S )‐TsDPEN, was as efficient as that generated from its preformed counterpart [(arene)Ru{( S,S )‐TsDPEN}Cl]@silica. Gratifyingly, the initial TOFs (up to 1085 h −1 ) and ee's (96–97 %) obtained with these catalysts either rivalled or outperformed those previously reported for catalysts supported by either silica or polymer immobilized through one of the nitrogen atoms of TsDPEN. While the high ee's were also maintained during recycle studies, the conversion dropped steadily over the first three runs due to gradual leaching of the ruthenium.