17480-69-2Relevant articles and documents
Horner,Skaletz
, p. 3679 (1970)
Application of phosphine-oxazoline ligands in Ir-catalyzed asymmetric hydrogenation of acyclic aromatic N-arylimines
Triforiova, Anna,Diesen, Jarle S.,Chapman, Christopher J.,Andersson, Pher G.
, p. 3825 - 3827 (2004)
(Chemical Equation Presented) A new class of chiral phosphine-oxazoline ligands have been developed. Chiral Ir complexes prepared from these ligands induced high enantioselectivities (66-90% ee) when applied to the asymmetric hydrogenation of acyclic aromatic N-arylimines.
Phosphines versus phosphinites as ligands in the rhodium catalyzed asymmetric hydrogenation of imines: A systematic study
Tararov, Vitali I.,Kadyrov, Renat,Riermeier, Thomas H.,Holz, Jens,Boerner, Armin
, p. 4009 - 4015 (1999)
The asymmetric hydrogenation of N-(1-phenylethylidene)benzylamine with a range of rhodium(I)-diphosphine and diphosphinite catalysts is studied. The reaction is strongly sensitive to the size of the metal chelate. Complexes based on five- and six-membered chelates or electron-rich alkylphosphines gave poor or moderate conversions. The reactivity of diphosphine catalysts could be increased by the addition of p-toluenesulfonic acid. Unexpectedly, Rh-complexes based on chiral diphosphinites and a diphosphite also rapidly converted the substrate to the desired amine. Highest efficiency was observed with a rhodium(I) complex with (R,R)-1,2-cyclohexanol-bisdiphenylphosphinite [(R,R)-bdpch] as chiral ligand. Without any additive complete hydrogenation of the imine was achieved within 5 h. The product was produced in an enantioselectivity of 71%.
Asymmetric thermal transformation, a new way to enantiopure biphenyl- bridged titanocene and zirconocene complexes: Efficient catalysts for asymmetric imine hydrogenation
Ringwald, Markus,Stürmer, Rainer,Brintzinger, Hans H.
, p. 1524 - 1527 (1999)
Enantiopure biphenyl-bridged titanocene and zirconocene complexes were obtained, by an asymmetric thermal transformation of the binaphthol complexes formed from the metallocene racemates and subsequent transformation to the corresponding dichlorides, in practically quantitative yields. Increased rates of this transformation in the presence of O2 gas or TEMPO indicate a radical reaction mechanism. The biphenyl-bridged titanocene enantiomers give rise to an efficient asymmetric catalysis for the hydrogenation of cyclic and noncyclic imines.
Application of Transmetalation to the Synthesis of Planar Chiral and Chiral-at-Metal Iridacycles
Arthurs, Ross A.,Hughes, David L.,Horton, Peter N.,Coles, Simon J.,Richards, Christopher J.
, p. 1099 - 1107 (2019)
Diastereoselective lithiation of (S)-2-ferrocenyl-4-(1-methylethyl)oxazoline, followed by addition of HgCl2, resulted in the formation by transmetalation of an (S,Sp)-configured mercury substituted complex. Addition to this of [Cp?IrCl2]2 and tetrabutylammonium chloride resulted in a second transmetalation reaction and formation of an (S,Sp,RIr)-configured chloride-substituted half-sandwich iridacycle as exclusively a single diastereoisomer. By reversing the lithiation diastereoselectivity by use of a deuterium blocking group, an alternative (S,Rp,SIr)-configured iridacycle was synthesized similarly. Use of (R)-Ugi's amine as substrate in the lithiation/double transmetalation sequence gave an (R,Sp,SIr)-configured half-sandwich iridacycle, complexes of this type being previously unavailable by direct cycloiridation. Lithium to gold transmetalation was also demonstrated with the synthesis of an (S,Sp)-configured Au(I) ferrocenyloxazoline derivative. Use of the (S,Rp,SIr)-iridacycle as a catalyst for the formation of a chiral product by reductive amination with azeotropic HCO2H/NEt3 resulted in a racemate.
Mechanistic investigation on the hydrogenation of imines by [p-(Me 2CH)C6H4Me]RuH(NH2CHPhCHPhNSO 2C6H4-p-CH3). Experimental support for an ionic pathway
Aberg, Jenny B.,Samec, Joseph S. M.,Baeckvall, Jan-E.
, p. 2771 - 2773 (2006)
The need for acidic activation in the stoichiometric hydrogenation of benzyl-[1-phenyl-ethylidene]-amine (6a) or [1-(4-methoxy-phenyl)-ethylidene]- methyl-amine (6b) by Noyori's catalyst [p-(Me2CH)C6H 4Me]RuH(NH2CHPhCHPhNSO2C6H 4-p-CH3) (2) is inconsistent with the proposed concerted mechanism and supports an ionic mechanism. The Royal Society of Chemistry 2006.
Synthesis of polymer microspheres functionalized with chiral ligand by precipitation polymerization and their application to asymmetric transfer hydrogenation
Haraguchi, Naoki,Nishiyama, Akihiro,Itsuno, Shinichi
, p. 3340 - 3349 (2010)
Monodisperse, crosslinked poly(divinylbenzene) and poly(methacrylic acid-co-ethylene glycol dimethacrylate) microspheres with (1R,2R)-N 1-toluenesulfonyl-1,2-diphenylethylene-1,2-diamine ((R,R)-TsDPEN) moiety were successfully prepared by precipitation polymerization. Introduction site of the (R,R)-TsDPEN moiety into the polymer microspheres could be controlled by changing the order of addition of the corresponding monomers. The functionalized polymer microspheres were applied to asymmetric transfer hydrogenation of ketone and imine. Polymer microsphere-supported chiral catalysts showed good reactivity and enantioselectivity in the catalytic asymmetrie transfer hydrogenations. Chiral secondary alcohol was quantitatively obtained with 94% ee in the asymmetric transfer hydrogenation of acetophenone in water. We also found that introduction site of the chiral catalyst and hydrophobiclty of the microspheres, as well as degree of the crosslinking, affected the yield and enantioselectivity of chiral product in this reaction.
Switching Selectivity in Copper-Catalyzed Transfer Hydrogenation of Nitriles to Primary Amine-Boranes and Secondary Amines under Mild Conditions
Song, Hao,Xiao, Yao,Zhang, Zhuohua,Xiong, Wanjin,Wang, Ren,Guo, Liangcheng,Zhou, Taigang
, p. 790 - 800 (2022/01/11)
A simple and efficient copper-catalyzed selective transfer hydrogenation of nitriles to primary amine-boranes and secondary amines with an oxazaborolidine-BH3 complex is reported. The selectivity control was achieved under mild conditions by switching the solvent and the copper catalysts. More than 30 primary amine-boranes and 40 secondary amines were synthesized via this strategy in high selectivity and yields of up to 95%. The strategy was applied to the synthesis of 15N labeled in 89% yield.
Chiral cyclometalated iridium complexes for asymmetric reduction reactions
Smith, Jennifer,Kacmaz, Aysecik,Wang, Chao,Villa-Marcos, Barbara,Xiao, Jianliang
supporting information, p. 279 - 284 (2021/01/18)
A series of chiral cyclometalated iridium complexes have been synthesised by cyclometalating chiral 2-aryl-oxazoline and imidazoline ligands with [Cp?IrCl2]2. These iridacycles were studied for asymmetric transfer hydrogenation reactions with formic acid as the hydrogen source and were found to display various activities and enantioselectivities, with the most effective ones affording up to 63% ee in the asymmetric reductive amination of ketones and 77% ee in the reduction of pyridinium ions. This journal is
Copper-catalyzed enantioselective carbonylation toward α-chiral secondary amides
Wu, Xiao-Feng,Yuan, Yang,Zhao, Fengqian
, p. 12676 - 12681 (2021/10/19)
Secondary amides are omnipresent structural motifs in peptides, natural products, pharmaceuticals, and agrochemicals. The copper-catalyzed enantioselective hydroaminocarbonylation of alkenes described in this study provides a direct and practical approach for the construction of α-chiral secondary amides. An electrophilic amine transfer reagent possessing a 4-(dimethylamino)benzoate group was the key to the success. This method also features broad functional group tolerance and proceeds under very mild conditions, affording a set of α-chiral secondary amides in high yields (up to 96% yield) with unprecedented levels of enantioselectivity (up to >99% ee). α,β-Unsaturated secondary amides can also be produced though the method by using alkynes as the substrate.
