scholarly journals Ruthenium(II)‐Chitosan, an Enantioselective Catalyst for the Transfer Hydrogenation of N ‐Heterocyclic Ketones

ChemCatChem ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2725-2731 ◽  
Author(s):  
Vanessza Judit Kolcsár ◽  
Ferenc Fülöp ◽  
György Szőllősi
Keyword(s):  
Transfer Hydrogenation ◽  
Enantioselective Catalyst

Mild and Selective Rhodium-Catalyzed Transfer Hydrogenation of Functionalized Arenes

2021 ◽  
Vol 23 (5) ◽  
pp. 1910-1914
Author(s):  
Yuhan Wang ◽  
Zhiqian Chang ◽  
Yan Hu ◽  
Xiao Lin ◽  
Xiaowei Dou
Keyword(s):  
Transfer Hydrogenation

scholarly journals New Bifunctional Bis(azairidacycle) with Axial Chirality via Double Cyclometalation of 2,2′-Bis(aminomethyl)-1,1′-binaphthyl

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1165
Author(s):  
Yasuhiro Sato ◽  
Yuichi Kawata ◽  
Shungo Yasui ◽  
Yoshihito Kayaki ◽  
Takao Ikariya
Keyword(s):  
Hydrogen Transfer ◽  
Bond Cleavage ◽  
Enantiomeric Excess ◽  
Transfer Hydrogenation ◽  
Catalyst Precursor ◽  
Asymmetric Catalysts ◽  
Axially Chiral ◽  
Diastereomeric Mixture ◽  
Raney Ni ◽  
Half Sandwich

As a candidate for bifunctional asymmetric catalysts containing a half-sandwich C–N chelating Ir(III) framework (azairidacycle), a dinuclear Ir complex with an axially chiral linkage is newly designed. An expedient synthesis of chiral 2,2′-bis(aminomethyl)-1,1′-binaphthyl (1) from 1,1-bi-2-naphthol (BINOL) was accomplished by a three-step process involving nickel-catalyzed cyanation and subsequent reduction with Raney-Ni and KBH4. The reaction of (S)-1 with an equimolar amount of [IrCl2Cp*]2 (Cp* = η5–C5(CH3)5) in the presence of sodium acetate in acetonitrile at 80 °C gave a diastereomeric mixture of new dinuclear dichloridodiiridium complexes (5) through the double C–H bond cleavage, as confirmed by 1H NMR spectroscopy. A loss of the central chirality on the Ir centers of 5 was demonstrated by treatment with KOC(CH3)3 to generate the corresponding 16e amidoiridium complex 6. The following hydrogen transfer from 2-propanol to 6 provided diastereomers of hydrido(amine)iridium retaining the bis(azairidacycle) architecture. The dinuclear chlorido(amine)iridium 5 can serve as a catalyst precursor for the asymmetric transfer hydrogenation of acetophenone with a substrate to a catalyst ratio of 200 in the presence of KOC(CH3)3 in 2-propanol, leading to (S)-1-phenylethanol with up to an enantiomeric excess (ee) of 67%.

scholarly journals Design of Iridium N-Heterocyclic Carbene Amino Acid Catalysts for Asymmetric Transfer Hydrogenation of Aryl Ketones

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 671
Author(s):  
Chad M. Bernier ◽  
Joseph S. Merola
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Enantiomeric Excess ◽  
Transfer Hydrogenation ◽  
Acid Catalysts ◽  
Asymmetric Transfer Hydrogenation ◽  
Reaction Conditions ◽  
Chiral Complexes ◽  
Acetophenone Derivatives ◽  
Aryl Ketones

A series of chiral complexes of the form Ir(NHC)2(aa)(H)(X) (NHC = N-heterocyclic carbene, aa = chelated amino acid, X = halide) was synthesized by oxidative addition of -amino acids to iridium(I) bis-NHC compounds and screened for asymmetric transfer hydrogenation of ketones. Following optimization of the reaction conditions, NHC, and amino acid ligands, high enantioselectivity was achieved when employing the Ir(IMe)2(l-Pro)(H)(I) catalyst (IMe = 1,3-dimethylimidazol-2-ylidene), which asymmetrically reduces a range of acetophenone derivatives in up to 95% enantiomeric excess.

Ruthenium (ii) complexes with c- and c-symmetric bis-(+)-camphopyrazole ligands and their evaluation in catalytic transfer hydrogenation of aldehydes

2021 ◽  
pp. 120429
Author(s):  
Christian O. Blanco ◽  
Ligia Llovera ◽  
Alberto Herrera ◽  
Romano Dorta ◽  
Giuseppe Agrifoglio ◽  
...  
Keyword(s):  
Transfer Hydrogenation ◽  
Catalytic Transfer Hydrogenation ◽  
Catalytic Transfer

Photocatalytic Transfer Hydrogenation in Water: Insight into Mechanism and Catalyst Speciation

2021 ◽  
Author(s):  
David M. Kaphan ◽  
Kelsey R. Brereton ◽  
Rachel C. Klet ◽  
Ryan J. Witzke ◽  
Alexander J. M. Miller ◽  
...  
Keyword(s):  
Transfer Hydrogenation ◽  
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