37439-99-9Relevant articles and documents
The Enantioselective Dakin-West Reaction
Wende, Raffael C.,Seitz, Alexander,Niedek, Dominik,Schuler, S?ren M. M.,Hofmann, Christine,Becker, Jonathan,Schreiner, Peter R.
, p. 2719 - 2723 (2016/02/27)
Here we report the development of the first enantioselective Dakin-West reaction, yielding α-acetamido methylketones with up to 58 % ee with good yields. Two of the obtained products were recrystallized once to achieve up to 84 % ee. The employed methylimidazole-containing oligopeptides catalyze both the acetylation of the azlactone intermediate and the terminal enantioselective decarboxylative protonation. We propose a dispersion-controlled reaction path that determines the asymmetric reprotonation of the intermediate enolate after the decarboxylation.
Convenient method for reduction of C-N double bonds in oximes, imines, and hydrazones using sodium Borohydride-Raney ni system
Yang, Yihua,Liu, Shouxin,Li, Junzhang,Tian, Xia,Zhen, Xiaoli,Han, Jianrong
experimental part, p. 2540 - 2554 (2012/07/27)
(Chemical Equation Presented) A practical method has been developed for reduction of C-N double bond in oximes, imines, and hydrazones with sodium borohydride catalyzed by Raney Ni. The reactions were carried out in basic aqueous solution, and the desired products were obtained in moderate yields after a simple procedure. This method can be applied to synthesize simpler aliphatic or aromatic amines and its analogs. Copyright Taylor & Francis Group, LLC.
Electron-donating and rigid p-stereogenic bisphospholane ligands for highly enantioselective rhodium-catalyzed asymmetric hydrogenations
Zhang, Xiaowei,Huang, Kexuan,Hou, Guohua,Cao, Bonan,Zhang, Xumu
supporting information; experimental part, p. 6421 - 6424 (2010/12/19)
More electron donating, more rigid: A new highly electron-donating P-stereogenic bisphospholane ligand (ZhangPhos) was synthesized in a practical and highly enantioselective manner from a commercially available chiral source. Better or comparable enantioselectivities and reactivities than TangPhos were achieved in rhodium-catalyzed hydrogenation of various functionalized olefins (see scheme; nbd=3,5-norbornadiene). Copyright
CHIRAL PHOSPHORUS COMPOUNDS
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Page/Page column 37-39, (2008/12/04)
The present invention provides P-chiral compounds of general formula (II) and (III): wherein at least one of R21, R25, R26 and R30 is independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; at least one of R22, R24, R27 and R29 are independently selected from C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy and the remaining substituents selected from R22, R24, R27 and R29 are hydrogen; and R23 and R28 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy; Formula (III): wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.wherein at least one of R21, R25, R26 and R30 is independently selected from phenyl and benzyloxy and the remaining substituents selected from R21, R25, R26 and R30 are hydrogen; and R22, R23, R24, R27, R28 and R29 are independently selected from hydrogen, C1-4 alkyl, CF3, C1-4 alkoxy, phenyl and benzyloxy.
ASYMMETRIC SYNTHESIS CATALYZED BY TRANSITION METAL COMPLEXES WITH CYCLIC CHIRAL PHOSPHINE LIGANDS
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Page 9, (2010/02/05)
The present invention relates to rigid chiral ligands usefull in making catalysts for asymmetric synthesis. More particularly, the present invention relates to new monodentate and bidentate cyclic chiral phosphine ligands which are formed into catalysts to provide high selectivity of the enantiomeric structure of the end-product.
Novel phosphine-phosphite and phosphine-phosphinite ligands for highly enantioselective asymmetric hydrogenation
Yan, Yongjun,Chi, Yongxiang,Zhang, Xumu
, p. 2173 - 2175 (2007/10/03)
Two novel phosphine-phosphite (S,R)-o-BINAPHOS and phosphine-phosphinite (S)-o-BIPNITE ligands based on ortho phenyl substituted (S)-BINOL have been synthesized. Extremely high enantioselectivity (over 99% ee in most cases) has been achieved for the Rh-catalyzed asymmetric hydrogenation of α-dehydroamino acid derivatives.
Synthesis of ortho-phenyl substituted MeO-BIPHEP ligand and its application in Rh-catalyzed asymmetric hydrogenation
Wu, Shulin,He, Minsheng,Zhang, Xumu
, p. 2177 - 2180 (2007/10/03)
A new BIPHEP-type ligand with phenyl groups at the 3,3′-positions, o-Ph-MeO-BIPHEP 3 was prepared. This ligand afforded excellent enantioselectivities when used in the Rh-catalyzed asymmetric hydrogenation of α-dehydroamino acid derivatives. The strong influence of o-phenyl groups of the ligand on the enantioselectivities of the reaction has been demonstrated by a comparison with its parent ligand MeO-BIPHEP.
Asymmetric catalysis based on chiral phospholanes and hydroxyl phospholanes
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Page column 22, (2010/02/06)
Chiral phosphine ligands derived from chiral natural products including D-mannitol and tartaric acid. The ligands contain one or more 5-membered phospholane rings with multiple chiral centers, and provide high stereoselectivity in asymmetric reactions.
A Novel Chiral Ferrocenyl Phosphine Ligand from Sugar: Applications in Rh-Catalyzed Asymmetric Hydrogenation Reactions
Liu, Duan,Li, Wenge,Zhang, Xumu
, p. 4471 - 4474 (2007/10/03)
(Matrix Presented) A new chiral ferrocenyl diphosphine ligand 3 was synthesized from readily available D-mannitol. Rh-complex with this ligand showed high enantioselectivity and reactivity in the asymmetric hydrogenation of dehydroamino acid derivatives and itaconic acid derivatives. Up to over 99% ee and 10 000 TON were achieved with this catalytic system.
Asymmetric catalysis based on chiral phospholanes and hydroxyl phospholanes
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Page column 22, (2010/01/30)
Chiral phosphine ligands derived from chiral natural products including D-mannitol and tartaric acid. The ligands contain one or more 5-membered phospholane rings with multiple chiral centers, and provide high stereoselectivity in asymmetric reactions.