A Modular Design of Ruthenium Catalysts with Diamine and BINOL‐Derived Phosphinite Ligands that Are Enantiomerically‐Matched for the Effective Asymmetric Transfer Hydrogenation of Simple Ketones.

Abstract

An effective, modular catalytic system for the asymmetric transfer hydrogenation of acetophenone derivatives is developed. -(GUO, R.; ELPELT, C.; CHEN, X.; SONG, D.; MORRIS*, R. H.; Chem. Commun. (Cambridge) 2005, 24, 3050-3052; Dep. Chem., Univ. Toronto, Toronto, Ont. M5S 1A1, Can.; Eng.) -R. Staver 43-036

Bifunctional Homogeneous Catalysts Based on Ruthenium, Rhodium and Iridium in Asymmetric Hydrogenation

“…The Ru II (diphosphane)(diamine) complexes in which the ruthenium centre is coordinated by a nonchiral diphosphine and a chiral diamine drew special attention because of the easy variation of their chiral ligands. [43][44][45] In 2015, Karabuga and co-workers reported on ruthenium complexes that combine quinazoline based chiral diamines (Scheme 4a) and dppb (diphenylphosphinobutane). These complexes catalysed the ATH of aryl methyl ketones with good conversions and variable enantioselectivities (9-91% ee).…”

“…[39][40][41][42] Furthermore, the Noyori's ruthenium/diamine/diphosphine catalysts initially applied in AH have inspired the design of tetradentate analogues (Scheme 3, left) for the ATH of aryl-alkyl ketones, 43 as well as many other variants such as the phosphinite complexes reported by Morris (Scheme 3, right). [44][45] Scheme 3. Ruthenium/P2N2 ATH catalysts developed by Noyori and co-workers (left) and Morris and coworkers (right).…”

“…Ruthenium/P2N2 ATH catalysts developed by Noyori and co-workers (left) and Morris and coworkers (right). [43][44][45] Since the 90's and to date, bifunctional catalysts for ATH and AH have aroused high interest. This long-term interest for innovative catalyses is due to a lack of general solutions for the catalytic asymmetric hydrogenations and has led to the development of a number of metal catalysts exhibiting new functionalities.…”

Asymmetric transfer hydrogenation of prochiral ketones in aqueous media with chiral water‐soluble and heterogenized bifunctional catalysts of the RhCp*‐type ligand

“…Since this discovery, a significant number of new ligands have been reported for the ATH with ruthenium(II), iridium(III), and rhodium(III) complexes as catalysts in the ATH of ketones 18–35. More importantly, the hydride source for the reaction has been changed from isopropanol/KOH or HCOOH/NEt 3 to a “greener” hydride source using sodium formate/water, a solvent system that is readily available, benign, and environmentally acceptable 36–51.…”