101402-04-4Relevant articles and documents
Application of a Heterogeneous Chiral Titanium Catalyst Derived from Silica-Supported 3-Aryl H8-BINOL to Enantioselective Alkylation and Arylation of Aldehydes
Akai, Junichiro,Watanabe, Satoshi,Michikawa, Kumiko,Harada, Toshiro
, p. 3632 - 3635 (2017)
A 3-aryl H8-BINOL was grafted on the surface of silica gel using a hydrosilane derivative as a precursor, and the resulting silica-supported ligand (6 mol %) was employed in the enantioselective alkylation and arylation of aldehydes in the pres
Hydroxyalkyl thiazolines, a new class of highly efficient ligands for carbonyl additions
Bauer, Michael,Maurer, Frauke,Hoffmann, Svenja M.,Kazmaier, Uli
, p. 3202 - 3207 (2008)
Hydroxyalkyl thiazoline ligands can easily be obtained in an isonitrile-based multicomponent reaction. These ligands are significantly more stable than the comparable oxazoline ligands, and give excellent enantiomeric excess in carbonyl additions of alkyl- and arylzinc compounds. Georg Thieme Verlag Stuttgart.
Enantioselective additions of diphenylzinc to aldehydes using chiral pyrrolidinylmethanol derivatives as catalysts
Zhao, Gang,Li, Xiang-Guo,Wang, Xiu-Ran
, p. 399 - 403 (2001)
The enantioselective addition of diphenylzinc to aldehydes using a series of chiral ligands derived from (S)-proline afforded secondary alcohols in high yields and with high enantiomeric excesses of up to 92.6%. The configuration of the secondary alcohol enantiomer obtained was found to be dependent on the catalyst used.
Synthesis and electrochemical characterization of iminophosphine-based ruthenium(II) complexes and application in asymmetric transfer hydrogenation reaction as catalysts
Kele?, Mustafa,Kele?, Hülya,Y?lmaz, Mustafa Kemal
, p. 945 - 951 (2019)
A range of Ru(II) complexes have been prepared with chiral iminophosphine ligands ([(2-PPh2)C6H4CH=NCH(CH3)C6H5(4-R)]; R = –H, p-CH3, p-NO2) and characterized by 1H, 13C, 31P{1H} NMR and FTIR spectroscopy. The electrochemical properties of the [Ru(PN)2Cl2] complexes were investigated in ACN/TBAP solution with cyclic voltammetry and square wave voltammetry techniques. The use of chiral [Ru(PN)2Cl2] complexes as catalysts for the asymmetric transfer hydrogenation of aromatic and aliphatic ketones was studied in 2-propanol in an attempt to demonstrate the effect of substituents, which attached to the phenyl ring bonded to the nitrogen donor, on the catalytic activity and enantioselectivity. It was seen that the electronic effects of these substituents did not contribute to the catalytic efficiency of the ruthenium(II) catalysts.
Catalytic enantioselective aryl transfer to aldehydes using chiral 2,2'-bispyrrolidine-based salan ligands
Jia, Xuefeng,Lin, Aijun,Mao, Zhijie,Zhu, Chengjian,Cheng, Yixiang
, p. 2971 - 2981 (2011)
Chiral C2-symmetric diamines have emerged as versatile auxiliaries or ligands in numerous asymmetric transformations. Chiral 2,2'-bispyrrolidine-based salan ligands were prepared and applied to the asymmetric aryl transfer to aldehydes with arylboronic acids as the source of transferable aryl groups. The corresponding diarylmethanols were obtained in high yields with moderate to good enantioselectivitives of up to 83% ee.
Synthesis of rhodium(I) and iridium(I) complexes of chiral N-heterocyclic carbenes and their application to asymmetric transfer hydrogenation
Dyson, Gavin,Frison, Jean-Cedric,Whitwood, Adrian C.,Douthwaite, Richard E.
, p. 7141 - 7151 (2009)
Rhodium and iridium complexes of chiral NHC-phenolimine and NHC-amine ligands have been prepared and studied for asymmetric transfer hydrogenation. X-ray and NMR spectroscopy show that for NHC-phenolimine complexes abstraction of chloride results in a change in ligand coordination from NHC only to chelating NHC-imine. Complexes of NHC-amines are inactive for transfer hydrogenation, whereas complexes of NHC-phenolimines are active at room temperature for a range of aryl containing ketones. Enantioselectivity is very sensitive to the NHC N-substituent resulting in a switch in the predominant enantiomer.
Structural Insight into Enantioselective Inversion of an Alcohol Dehydrogenase Reveals a "polar Gate" in Stereorecognition of Diaryl Ketones
Zhou, Jieyu,Wang, Yue,Xu, Guochao,Wu, Lian,Han, Ruizhi,Schwaneberg, Ulrich,Rao, Yijian,Zhao, Yi-Lei,Zhou, Jiahai,Ni, Ye
, p. 12645 - 12654 (2018)
Diaryl ketones are important building blocks for synthesizing pharmaceuticals and are generally regarded as "difficult-to-reduce" ketones due to the large steric hindrance of their two bulky aromatic side chains. Alcohol dehydrogenase from Kluyveromyces polyspora (KpADH) has been identified as a robust biocatalyst due to its high conversion of diaryl ketone substrate (4-chlorophenyl)(pyridine-2-yl)ketone (CPMK) with a moderate R-selectivity of 82% ee. To modulate the stereoselectivity of KpADH, a "polarity scanning" strategy was proposed, in which six key residues inside and at the entrance of the substrate binding pocket were identified. After iterative combinatorial mutagenesis, variants Mu-R2 and Mu-S5 with enhanced (99.2% ee, R) and inverted (97.8% ee, S) stereoselectivity were obtained. The crystal structures of KpADH and two mutants in complex with NADPH were resolved to elucidate the evolution of enantioselective inversion. Based on MD simulation, Mu-R2-CPMKProR and Mu-S5-CPMKProS were more favorable in the formation of prereaction states. Interestingly, a quadrilateral plane formed by α-carbons of four residues (N136, V161, C237, and G214) was identified at the entrance of the substrate binding pocket of Mu-S5; this plane acts as a "polar gate" for substrates. Due to the discrepancy in charge characteristics between chlorophenyl and pyridine substituents, the pro-S orientation of CPMK is defined when it passes through the "polar gate" in Mu-S5, whereas the similar plane in wild-type is blocked by several aromatic residues. Our result paves the way for engineering stereocomplementary ADH toward bulky diaryl ketones and provides structural insight into the mechanism of stereoselective inversion.
Catalytic enantioselective aryl transfer: Asymmetric addition of diphenylzine to aldehydes
Bolm, Carsten,Muniz, Kilian
, p. 1295 - 1296 (1999)
The asymmetric addition of diphenylzinc to aldehydes in the presence of catalytic amounts of a planar chiral ferrocene-based hydroxy oxazoline affords products with enantiomeric excesses of up to 96%.
Chiral zinc amidate catalyzed additions of diethylzinc to aldehydes
Zhang, Jinxia,Li, Shasha,Zheng, Xinxin,Li, Hongjie,Jiao, Peng
, p. 1913 - 1917 (2019)
A series of bifunctional spiro ligands bearing “carboxamide–phosphine oxide” groups and ethylzinc carboxamidates from these ligands as catalysts for Et2Zn additions to aldehydes were reported. Excellent yields were obtained with moderate ee′s in Et2Zn additions to benzaldehyde derivatives, implying effectiveness of our newly designed catalytic structures as well as mediocre stereocontrol by these chiral ligands. Possible transition states were suggested based on the crystal structures of two ligands.
Continuous flow enantioselective arylation of aldehydes with ArZnEt using triarylboroxins as the ultimate source of aryl groups
Rolland, Julien,Cambeiro, Xacobe C.,Rodriguez-Escrich, Carles,Pericas, Miquel A.
, (2009)
A continuous flow system for the synthesis of enantioenriched diarylmethanols from aldehydes is described. The system uses an amino alcohol-functionalized polystyrene resin as the catalyst, and the arylating agent is conveniently prepared by transmetallation of triarylboroxins with diethylzinc.
