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.
Prolinol as a Chiral Auxiliary in Organophosphorus Chemistry
Kozio?, Anna E.,W?odarczyk, Adam
, p. 1931 - 1941 (2021/04/06)
Several strategies for the development of the synthesis of P-chiral organophosphorus compounds with (L)-prolinol as a source of chirality have been examined. A reaction of L-prolinol with a set of different alkyl/arylphosphonous acid diamides led in most of the cases to the quantitative formation of the appropriate bicyclic oxazaphospholidines with complete diastereo and enantioselectivity. The latter were reacted with BH3 complex and the formed borane analogues were submitted to structural modifications leading to tertiary phosphine-boranes. Additionally, the effectiveness of oxazaphospholidines as ligands in transition metal asymmetric catalysis has been tested in hydrogenation of dehydroaminoacid esters and imine.
Zirconium Catalyzed Hydroaminoalkylation for the Synthesis of α-Arylated Amines and N-Heterocycles
Koperniku, Ana,Schafer, Laurel L.
supporting information, p. 6334 - 6339 (2021/03/08)
The zirconium catalyzed hydroaminoalkylation of alkenes with N-aryl- and sterically demanding N-alkyl-α-arylated secondary amines by using commercially available Zr(NMe2)4 is reported. N-phenyl- and N-isopropylbenzylamine are used as amine substrates to establish the alkene substrate scope. Exclusively linear products are obtained in the presence of bulky vinylsilanes. Challenging α-heteroarylated amines and functionalized alkene substrates are compatible with this easy to use catalyst, affording a new disconnection strategy for the atom- and step-economic preparation of selectively substituted saturated α-arylated heterocycles.
