- Dynamic Kinetic Asymmetric Reductive Amination: Synthesis of Chiral Primary β-Amino Lactams
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A highly efficient ruthenium-catalyzed asymmetric reductive amination (ARA) of racemic β-keto lactams with molecular hydrogen and ammonium salts is disclosed for the synthesis of enantiomerically pure primary amino lactams through dynamic kinetic resolution (DKR). By this approach, a range of syn primary β-amino lactams were obtained in high yields with high chemo-, enantio-, and diastereoselectivity (up to 98 % yield, 99 % ee, >20:1 d.r., syn products). The utility of the products has been demonstrated by rapid access to a key synthetic intermediate towards biologically active drug molecules. Meanwhile, mechanistic studies and control experiments indicate that the reaction may proceed through the hydrogenation of an iminium intermediate.
- Lou, Yazhou,Hu, Yutao,Lu, Jiaxiang,Guan, Fanfu,Gong, Gelin,Yin, Qin,Zhang, Xumu
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supporting information
p. 14193 - 14197
(2018/10/15)
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- METHOD FOR PRODUCING A RUTHENIUM COMPLEX
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Provided is a method for producing a ruthenium complex comprises the step of reacting a ruthenium compound represented by general formula (1): [in-line-formulae][RuX(L)(PP)]X ??(1),[/in-line-formulae] wherein Ru represents a ruthenium atom; X represents a halogen atom; L represents an arene; and PP represents an optically active bisphosphine, with a carboxylate salt represented by general formula (2): [in-line-formulae]R1CO2M ??(2),[/in-line-formulae] wherein M represents a monovalent cation; and R1 represents a group selected from the group consisting of alkyl groups, haloalkyl groups, phenyl groups optionally having a substituent(s), 1-aminoalkyl groups and 1-amino-1-phenylalkyl groups, to produce a ruthenium complex represented by general formula (3): [in-line-formulae]Ru(OCOR1)2(PP) ??(3),[/in-line-formulae] wherein R1 represents the group selected from the group consisting of alkyl groups, haloalkyl groups, phenyl groups optionally having a substituent(s), 1-aminoalkyl groups and 1-amino-1-phenylalkyl groups; and PP represents the optically active bisphosphine.
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Page/Page column 6
(2010/04/23)
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- Enantioselective hydrogenation of tiglic acid in methanol and in dense carbon dioxide catalyzed by a ruthenium-BINAP complex substituted with OCF 3 groups
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A fluorinated analog of the 2,2′-bis(diphenylphosphino)-1,1′- binaphthyl (BINAP) ligand was synthesized with OCF3-substitution of the aryl groups in BINAP skeleton (p-OCF3-BINAP). Ruthenium complexes of both BINAP (Ru-BINAP) and (p-OCF3)-BINAP (Ru-[(p-OCF3)-BINAP]) were also synthesized and investigated as catalysts for hydrogenation of tiglic acid in methanol. Typically, Ru-[(p-OCF3)-BINAP] had lower activity but had higher enantioselectivity at high hydrogen pressures than Ru-BINAP at the same condition. The effect of OCF3 groups on the catalytic properties was discussed on the basis of NMR spectra and kinetic data. Ru-[(p-OCF 3)-BINAP] was found to have sufficiently high solubility in dense CO2 for homogeneous catalytic reactions and was investigated for hydrogenation of tiglic acid in CO2. The results showed that CO 2 had a great influence on both activity and enantioselectivity. Addition of methanol to CO2 was found to increase the enantioselectivity.
- Dong, Xing,Erkey, Can
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- Asymmetrische Katalysen. LXXXII. Enantioselektive Hydrierung von 4-Oxoisophoron
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Enantioselective hydrogenation of 4-oxoisophorone 1, catalysed by BINAP-RuII complexes, gives the corresponding saturated diketone 2 in 80percent chemical yield and 50percent enantiomeric excess.By repeated crystallisation from petroleum ether/
- Brunner, Henri,Fisch, Konrad
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