共查询到19条相似文献,搜索用时 109 毫秒
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不对称Henry反应的研究进展 总被引:1,自引:1,他引:1
总结了各种能有效催化不对称Henry反应的新方法、新条件和新催化剂,讨论了一类拓展的不对称催化Henry反应。对立体选择性催化Henry反应的催化剂的发展提出了作者的一些看法。参考文献26篇。 相似文献
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手性(硫)脲衍生物是各种亲核试剂对亚胺、醛、缺电子烯烃加成反应的非常有效的有机催化剂之一, 已成功应用于对映选择性催化Strecker反应、Michael加成反应、Mannich反应、Baylis-Hillman反应、Henry反应等一系列重要的有机合成反应. 手性(硫)脲衍生物具有催化活性高、对映选择性和功能基相容性好、易于制备和修饰、适用范围广等优点, 成为近年来研究较多的不对称反应有机催化剂. 对手性(硫)脲衍生物在有机催化不对称合成中的应用研究进展进行了评述. 相似文献
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三乙胺催化α-酮酰胺与硝基甲烷的Henry反应,在传统条件下该反应需要12~120 h;在超声(100 W)催化下,条件温和,反应速度快,产率提高,反应50 min得到90%的产率。研究表明超声波技术可以加速Henry反应。 相似文献
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双功能手性金属络合物催化的不对称反应是目前有机化学研究的热点之一。本文综述了氮杂半冠醚手性配体与金属有机试剂络合的双金属催化剂,在催化不对称aldol反应、不对称Henry反应、不对称Michael反应、不对称Mannich反应、不对称Friedel-Crafts烷基化反应、不对称炔基化反应、不对称硅氰化反应、共聚反应、去对称化反应以及不对称Nozaki-Hiyama烯丙基化反应体系中的应用进展,重点介绍了不同催化体系对催化剂和反应底物之间立体效应和电子效应的影响,总结了控制反应立体选择性的规律以及有关催化反应的机理。 相似文献
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研究了L-脯氨酸制得的C2-对称二胺,与醋酸铜形成新的配合物,催化各种醛与硝基烷烃间的Henry反应。 考察了反应温度、溶剂和催化剂用量对收率和反应速率的影响。 研究结果表明,在室温下,以乙醇作为反应溶剂时,摩尔分数10%的二胺醋酸铜配合物能够有效地催化醛与硝基甲烷反应,生成相应的β-硝基醇,收率为60%~92%。 醛与硝基乙烷的Henry反应产物具有非对映立体选择性。 芳香醛参与Henry反应产物的非对映选择性高达24∶1,但脂肪醛为底物时,此催化剂对Henry反应的非对映选择性不明显。 相似文献
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《Tetrahedron: Asymmetry》2014,25(3):278-283
A series of chiral N,N′-dialkyl-1,2-cyclohexanediamine derivatives were designed, synthesized, and applied as ligands in asymmetric copper(II)-catalyzed Henry reactions. The catalysts based on such ligands and copper(II) acetate were found to promote asymmetric Henry reactions between aromatic/aliphatic aldehydes and nitromethane efficiently, and could provide the corresponding β-nitroalcohols in very good yields and with enantioselectivities of up to 93.6%. 相似文献
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Four new copper(II)/diamine complexes comprising some (+)-sparteine surrogates and a cyclohexane-derived diamine were prepared and evaluated as chiral catalysts in desymmetrisation of meso-diols and asymmetric Henry reactions. Mono-benzoylation reactions generated two products with high enantioselectivity (90:10 to 97:3 er). Asymmetric Henry reactions gave nitro alcohols in 90:10 to 98:2 er. Notably, the sense of induction with the (+)-sparteine surrogates was opposite to that obtained using the copper(II)/(−)-sparteine complex. One of the nitro alcohol products was utilised in a concise synthesis of a chiral morpholine. 相似文献
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Tao Jiang Guoying Zhao Yanhong Chang Weize Wu Liang Gao Guanying Yang 《Tetrahedron letters》2004,45(12):2699-2701
The 1,1,3,3-tetramethyl guanidine (TMG)-based ionic liquid was used as a recyclable catalyst for Henry reactions to produce 2-nitroalcohols. Good yields were obtained even after 15 reactions. 相似文献
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Wen-juan Wang Wen-ping Cheng Li-li Shao Cai-Hua Liu Jian-guo Yang 《Kinetics and Catalysis》2009,50(2):186-191
Henry reactions and Knoevenagel reactions, used to prepare substituted olefins, have been limited by complex catalyst separation.
In this article, methoxyl propylamine acetate ionic liquid was used as an environmentally benign catalyst for these reactions
under solvent-free condition for the first time. This ionic liquid was shown to effectively catalyze Henry reactions and Knoevenagel
reaction of active nitromethane compounds with various aldehydes. Yields from the catalyzed reactions were over 99% under
solvent free condition. The process is highly effective, environmentally benign, and very selective. Furthermore, methoxyl
propylamine acetate ionic liquid was conveniently separated with the products and easily recycled to catalyze Knoevenagel
reaction again with excellent yields.
Published in Russian in Kinetika i Kataliz, 2009, Vol. 50, No. 2, pp. 199–204.
The article is published in the original. 相似文献
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The preparation of a new series of 2-(pyridine-2-yl)imidazolidine-4-thione derivatives is described. Their corresponding copper(II) complexes were found to be highly enantioselective catalysts for asymmetric Henry reactions (up to 98% ee). Immobilization of these complexes by anchoring onto Merrifield? resin with respect to their use as recyclable catalysts was subsequently performed. The heterogeneous catalysts prepared in this way were tested in the asymmetric Henry reactions and showed high catalytic activity; they can be easily recycled, although their enantioselectivities were only moderate (~50% ee). 相似文献
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A new series of Schiff bases derived from Cinchona alkaloids were developed as chiral ligands for the copper(II)-catalyzed asymmetric Henry reaction. The optimized catalyst can promote the Henry reaction of both aromatic and aliphatic aldehydes with nitromethane or nitroethane. Those reactions can afford the chiral β-nitro alcohol adducts with high enantioselectivities. 相似文献
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Henry reaction is one of the most classical reactions to construct synthetically useful product nitro alcohol, which as a privileged skeleton is widely distributed in various pharmaceuticals. This review summarizes the recent progress of copper-catalyzed asymmetric Henry reaction from 2011 to 2016. The significant progress that has been made in this area will be highlighted and some of challenges that the author believes may be hindering further progress will be revealed. 相似文献
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Sakkani Nagaraju Kota Sathish Neeli Satyanarayana Banoth Paplal Dhurke Kashinath 《Journal of heterocyclic chemistry》2020,57(1):469-476
Catalyst-free synthesis of the isoxazole-spirooxindole-tetrahydrothiophene hybrids is reported. Formation of 1,4-thia-Michael and intramolecular aldol reactions were observed (instead of 1,6-thia-Michael followed by vinylogous Henry reactions) in a regioselective fashion to give new isoxazole-spirooxindole-tetrahydrothiophene hybrids with excellent yields. 相似文献
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Shi-Guang Li 《Tetrahedron》2010,66(44):8557-8561
A novel synthetic method for polysubstituted naphthalene derivatives via a pyrrolidine-mediated cascade Michael/Henry reaction was developed, in which easily prepared 2-(2-oxoethyl)benzaldehydes and nitroalkenes were employed as the starting materials. The reaction consists of four consecutive reactions that include a cascade Michael/Henry reaction, a dehydration reaction, and an aromatization reaction in one pot to afford synthetically important naphthalene derivatives with moderate yields. 相似文献