β-Amino alcohols as ligands for asymmetric transfer hydrogenation of ketones in water

Half-sandwich iridium complexes—Synthesis and applications in catalysis

“…The resulting complexes show varying activities and enantioselectivities in asymmetric transfer hydrogenations of ketones [5]. The complexes 88a-c were believed to be Scheme 20. formed as catalyst precursors under the catalytic conditions (Scheme 19).…”

“…Half-sandwich iridium chloro, aminocarboxylate, amino alcohol, and diamine complexes are excellent catalysts for a range of hydrogen transfer reactions, including asymmetric transfer hydrogenation (ATH) in organic media or in water [5,69,70,[87][88][89][90][91][92][93]. Described below are selected recent examples of alcohol oxidation, ATH of ketones, and dynamic kinetic resolution of imines and alcohols.…”

“…For example, a Cp*-Ir(III) catalyst containing a diamine ligand gave a higher activity in transfer hydrogenation of aldehydes than its ruthenium and rhodium analogues [4]. Similarly, higher catalytic activities and enantioselectivities were obtained in the asymmetric transfer hydrogenation of ketones with an iridium catalyst containing a ␤-amino alcohol ligand than the corresponding Ru(II) and Rh(III) catalysts [5], highlighting the great potential of half-sandwich iridium complexes in catalysis [6]. Herein we focus attention on half-sandwich iridium complexes containing the Cp* and Cp ligands, especially on those with chirality at the metal and on the advances made from 2000 onwards.…”

Enantioselective Transfer Hydrogenation of Aliphatic Ketones Catalyzed by Ruthenium Complexes Linked to the Secondary Face of β‐Cyclodextrin

“…77% [11] 14 99% [11] 85% [11] 15 40% [11] 82% [12] [a] Reaction conditions: 8/substrate/HCOONa = 1:10:100 in water/DMF = 3:1; 50 8C, 12 h; same conditions for 11 except T = 25 8C . ordinating to ruthenium is included into the cavity of b-cyclodextrin.…”

“…[13,22,23] Unfortunately, the metal complexes 8 and 11 refused to gave crystals suitable for X-ray analysis, accordingly we have no precise information on the structure of these pre-catalysts, the substrate inclusion complexes and the corresponding catalytically active hydride-ruthenium complexes. The NMR spectra of 8 and 11 provided no evidence that the phenyl ring co- 89% [8] 99% [11] 86% [11] 2 98% [8] 92% [8] 99% [11] 93% [11] 3 98% [11] 96% [11] 4 35% [8] 98% [8] 76% [11] 93% [11] 5 95% [8] 90% [8] 99% [11] 86% [11] 6 60% [8] 89% [8] 7 72% [8] 70% [8] 98% [11] 74% [11] 8 80% [8] 89% [8] 99% [11] 89% [11] 9 55% [8] 91% [8] 99% [11] 93% [11] 10 56% [8] 91% [8] 80% [11] 93% [11] 11 37% [11] 93% [11] 12 55%…”