Unique β‐Turn Peptoid Structures and Their Application as Asymmetric Catalysts

2020 ◽  
Vol 26 (43) ◽  
pp. 9573-9579 ◽  
Author(s):  
Chandra Mohan Darapaneni ◽  
Pritam Ghosh ◽  
Totan Ghosh ◽  
Galia Maayan
Keyword(s):  
Asymmetric Catalysts

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%.

Polymer-Supported BisBINOL Ligands for the Immobilization of Multicomponent Asymmetric Catalysts

2003 ◽  
Vol 5 (15) ◽  
pp. 2647-2650 ◽  
Author(s):  
Tetuya Sekiguti ◽  
Yoshimasa Iizuka ◽  
Shinobu Takizawa ◽  
Doss Jayaprakash ◽  
Takayoshi Arai ◽  
...  
Keyword(s):  
Asymmetric Catalysts ◽  
Polymer Supported

Optimization of Asymmetric Catalysts Using Achiral Ligands:  Metal Geometry-Induced Ligand Asymmetry†

2001 ◽  
Vol 3 (14) ◽  
pp. 2161-2164 ◽  
Author(s):  
Timothy J. Davis ◽  
Jaume Balsells ◽  
Patrick J. Carroll ◽  
Patrick J. Walsh
Keyword(s):  
Asymmetric Catalysts

Recent progress in Lewis acid-Lewis base bifunctional asymmetric catalysis

2005 ◽  
Vol 77 (12) ◽  
pp. 2047-2052 ◽  
Author(s):  
Motomu Kanai ◽  
Nobuki Kato ◽  
Eiko Ichikawa ◽  
Masakatsu Shibasaki
Keyword(s):  
Asymmetric Catalysis ◽  
Lewis Acid ◽  
Recent Progress ◽  
Lewis Base ◽  
Pyridine Derivatives ◽  
Asymmetric Catalysts ◽  
Strecker Reaction

Two enantioselective cyanation reactions, the Strecker reaction of ketoimines and the Reissert reaction of pyridine derivatives, promoted by Lewis acid-Lewis base bifunctional asymmetric catalysts are described.

Self-Supported Asymmetric Catalysts

2009 ◽  
pp. 155-177
Author(s):  
Wenbin Lin ◽  
David J. Mihalcik
Keyword(s):  
Asymmetric Catalysts
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