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Asymmetric transfer hydrogenation of ketones catalyzed by rhodium and iridium complexes with chiral bidentate Schiff's bases 总被引:1,自引:0,他引:1
Pavlov V. A. Vinogradov M. G. Starodubtseva E. V. Chel"tsova G. V. Ferapontov V. A. Malyshev O. R. Heise G. L. 《Russian Chemical Bulletin》2001,50(4):734-735
Rhodium and iridium complexes of Schiff's bases derived from (1R,2R)- and (1S,2S)-diaminocyclohexane catalyze asymmetric transfer hydrogenation of alkyl aryl ketones in PriOH at room temperature to give chiral secondary alcohols (up to 65% ee). 相似文献
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Kochetkov K. A. Harutyunyan S. R. Kuz"mina N. A. Savel"eva T. F. Maleev V. I. Peregudov A. S. Vyskočil S. Sagiyan A. S. 《Russian Chemical Bulletin》2001,50(9):1620-1624
Alkali metal salts of substituted (S)-prolines, alkali metal alkoxides of (S)-prolinol, and Na salts of chiral substituted 2-amino-2"-hydroxy-1,1"-binaphthyls can catalyze the asymmetric Michael reaction of diethyl malonate with crotonaldehyde to give adducts in >90% yields with ee up to 40%. The influences of the catalyst structure, the nature of the alkali metal cation, temperature, the solvent, and salt additives on the reaction outcome were studied. 相似文献
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I. M. Lyapkalo S. L. Ioffe Yu. A. Strelenko V. A. Tartakovsky 《Russian Chemical Bulletin》1996,45(9):2245-2247
N,N-Bis(nitroacetyl)diamines were synthesized for the first time by the reaction of methyl nitroacetate with aliphatic diamines in H2O or EtOH in the presence of pyridine or imidazole. In the case of 1,2-ethylenediamine, theN-mononitroacetyl derivative was isolated as an intermediate product.Translated fromIzvestiva Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2363–2366, September, 1996 相似文献
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Hong-Wei Sun Yu-Hua Liao Zhi-Jun WuHao-Yu Wang Xiao-Mei ZhangWei-Cheng Yuan 《Tetrahedron》2011,67(22):3991-3996
A simple and efficient method for the enantioselective 1,6-Michael addition reaction of anthrone to a series of 3-methyl-4-nitro-5-alkenyl-isoxazoles with a bifunctional thiourea-tertiary amine as catalyst is described. This transformation proceeds smoothly with 10 mol % catalyst and provides a series of Michael adducts bearing 3-methyl-4-nitro-isoxazole and anthrone units with good to high enantioselectivities (up to 96% ee) and in very high yields (up to 99%). 相似文献
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The stereoselective addition of phenyl acetylene and alkyl acetylenes to imines, catalyzed by chiral bis-imines-Cu(I) complexes was studied. A very simple experimental procedure allowed to obtain at room temperature optically active propargyl amines in very good yields and enantioselectivity up to 81%. 相似文献
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Linglin Wu 《Tetrahedron》2008,64(11):2651-2657
A chiral polymer ligand was synthesized by the polymerization of (S)-5,5′-dibromo-6,6′-dibutyl-2,2′-binaphthol (S-M-1) with (S)-2,2′-bishexyloxy-1,1′-binaphthyl-6,6′-boronic acid (S-M-2) via Pd-catalyzed Suzuki reaction. The application of the chiral polymer ligand to the asymmetric addition of phenylethynyl zinc to various aldehydes has been studied. The results show that the soluble chiral polybinaphthols ligand in combination with Et2Zn and Ti(OiPr)4 can exhibit excellent enantioselectivity for phenylacetylene addition to both aromatic and aliphatic aldehydes. The catalytically active center of the repeating unit S-1 used as a catalyst produced the opposite configuration of the propargylic alcohols to that of S-1, on the contrary, the chiral polymer gave the same configuration as the optically active binaphthol moiety of the polybinaphthols ligand. Moreover, the chiral polymer ligand can be easily recovered and reused without loss of catalytic activity as well as enantioselectivity. 相似文献
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Wang J Li H Lou B Zu L Guo H Wang W 《Chemistry (Weinheim an der Bergstrasse, Germany)》2006,12(16):4321-4332
Chiral (S)-pyrrolidine trifluoromethanesulfonamide has been shown to serve as an effective catalyst for direct Michael addition reactions of aldehydes and ketones with nitroolefins. A wide range of aldehydes and ketones as Michael donors and nitroolefins as acceptors participate in the process, which proceeds with high levels of enantioselectivity (up to 99 % ee) and diastereoselectivity (up to 50:1 d.r.). The methodology has been employed successfully in an efficient synthesis of the potent H(3) agonist Sch 50917. In addition, a practical three-step procedure for the preparation of (S)-pyrrolidine trifluoromethanesulfonamide has been developed. The high levels of stereochemical control attending Michael addition reactions catalyzed by this pyrrolidine sulfonamide, have been investigated by using ab initio and density functional methods. Transition state structures for the rate-limiting C--C bond-forming step, corresponding to re- and si-face addition to the reactive conformation of the key enamine intermediates have been calculated. Analysis of these structures indicates that hydrogen bonding plays an important role in catalysis and that the energy barrier for si-face attack in reactions of aldehydes to form 2R,3S products is lower than that for the re-face attack leading to 2S,3R products. In contrast, the energy barrier for re-face addition is lower than that for si-face addition in reactions of ketones. The computational results, which are in good agreement with the experimental observations, are discussed in the context of the stereochemical course of these Michael addition reactions. 相似文献