共查询到20条相似文献,搜索用时 15 毫秒
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近年来,用聚合物负载的手性催化剂和手性试剂完成的不对称合成反应主要集中在潜手性酮的不对称还原反应;烯烃的不对称双羟基化反应;烯烃的不对称环氧化反应;不对称Diels-Alder反应和饱和碳原子上的不对称取代反应。就近十年来聚合物负载手性催化剂和手性试剂的合成及应用进行了讨论。 相似文献
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本文介绍了手性铁催化体系在酮及亚胺的不对称还原、烯烃及硫醚的不对称氧化、不对称环加成、不对称环丙烷化以及不对称Friedel-Crafts烷基化等反应中的应用. 相似文献
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Xiu-Shuai Chen 《合成通讯》2016,46(11):917-941
Chiral phosphine-phosphoramidite ligands, featuring ready availability, easy modification, and stability towards air and moisture, have recently emerged as a new kind of robust ligands for asymmetric catalysis. They have been found to display wide utilities in various catalytic asymmetric reactions, giving excellent enantioselectivities in the Rh-, Ru-, and Ir-catalyzed asymmetric hydrogenation of C?C, C?O, and C?N double bonds; Rh-catalyzed asymmetric hydroformylation; Pd-catalyzed asymmetric hydrophosphorylation; Pd-catalyzed asymmetric allylic alkylation; Ag-catalyzed asymmetric [3 + 2] cycloaddition; and Cu-catalyzed conjugate addition and reduction. In this review, the progress on the development of chiral phosphine-phosphoramidite ligands in asymmetric catalysis has been summarized. 相似文献
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综述了钯-手性膦配体催化剂在烯烃的不对称氢氰化、不对称羰基化、不对称交叉偶联、不对称氢化硅氢化等方面的研究进展。参考文献36篇。 相似文献
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本文综述了近年来在无溶剂条件下进行的一些不对称催化反应的进展, 着重介绍了无溶剂条件下的不对称Aldol反应、环氧化合物不对称开环反应、外消旋环氧化合物的拆分、不对称Diels-Alder反应、金属有机试剂对醛酮的不对称加成反应、不对称氢化反应、不对称氢甲酰化反应、不对称烯烃复分解反应、不对称Michael加成反应、不对称氧化反应、不对称Friedel-Crafts反应等, 同时展望了无溶剂不对称催化反应的研究前景。 相似文献
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N-芳基氮氧方酸的活性羟基能够被芳伯胺取代。利用这一特性,可在方酸四碳环上引入另一不同的芳胺基,即可获得不对称芳基取代的方酰胺或异方酰胺。以乙醇等为介质,芳伯胺与7种N-芳基氮方酸反应,制得25个不对称的方酰胺和24个不对称的异方酰胺。该合成方法优点突出,反应简便有效,通用性强。 相似文献
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Recent progress in asymmetric organocatalysis has led to the development of several asymmetric transformations that employ various substrates. Among these substrates, maleimides have emerged as excellent Michael acceptors, dienophiles, and dipolarophiles. In this Focus Review we highlight the advances in the asymmetric synthesis of succinimide derivatives through asymmetric organocatalytic addition reactions of maleimides. 相似文献
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We discovered asymmetric autocatalysis in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde, where the product 5-pyrimidyl alkanol acts as a highly efficient asymmetric autocatalyst to afford more of itself (Soai reaction). Asymmetric autocatalysis proceeded quantitatively (>99% yield), affording itself as a near enantiomerically pure (>99.5% ee) product. An extremely low enantiomeric excess (ca. 0.00005% ee) can automultiply during three rounds of consecutive asymmetric autocatalysis to >99.5% ee by asymmetric amplification. Circularly polarized light, and inorganic and organic crystals, act as the origin of chirality to trigger asymmetric autocatalysis. Asymmetric autocatalysis has enormous power to recognize and amplify the chirality of hydrogen, carbon, oxygen, and nitrogen isotopomers. Moreover, absolute asymmetric synthesis, i.e., the formation of enantioenriched compounds without the intervention of any chiral factor, is realized by asymmetric autocatalysis. By using designed molecules based on 5-pyrimidyl alkanol, the intramolecular asymmetric control, self-replication, and improvement of chiral multifunctionalized large molecules has been developed by applying asymmetric autocatalysis. 相似文献
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Keiko Takahashi Kenjiro Hattori 《Journal of inclusion phenomena and macrocyclic chemistry》1994,17(1):1-24
Cyclodextrins have great potential for exploitation as a useful tool for asymmetric induction. Many kinds of asymmetric reaction have been achieved in the presence of cyclodextrin under various conditions such as the solid phase, heterogeneous suspension or homogeneous aqueous or organic solution. Complexation is essential for asymmetric induction. What is necessary to improve CDs for greater asymmetric induction? 相似文献
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The potential of the t-Bu-QuinoxP* ligand (1) as a chiral ligand in asymmetric synthesis was examined. The ligand exhibited good to excellent asymmetric induction in Pd-catalyzed asymmetric allylic substitution of 1,3-diphenyl-2-propenyl acetate (up to 98.7% ee) and in Ru-catalyzed asymmetric hydrogenation of ketones (up to 99.9% ee). 相似文献
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介绍了“碳中心”手性有机硅化合物的合成,以及在烯丙基硅烷与醛的Hosomi-Sakurai反应和α-烯丙基硅碳负离子与醛的反应中的应用。提出并实践了两条提高对映选择性的途径。烯基硅醇的不对称环氧化反应扩展了Sharpless反应的适用范围,为合成光活性的具简单结构的环氧化合物提供了一条简易的途径。 相似文献
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Aetheramides A and B are very potent anti-HIV agents. An enantioselective synthesis of a MEM-protected aetheramide A derivative is described. The synthesis was accomplished in a convergent and stereoselective manner. The key reactions involved asymmetric dihydroxylation, asymmetric allylation, asymmetric syn-aldol reactions, and asymmetric hydrogenation. 相似文献
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手性钛配合物催化不对称反应研究 总被引:4,自引:0,他引:4
手性钛配合物是一类很有用的手性催化剂,在许多反应中显示出了良好的催化活性和高的对映选择性。在我们研究的系列反应中,发现手性钛配合物是一类优良的手性催化剂,其中不对称催化杂Diels-Alder反应制备二氢吡喃酮(99%ee),不对称催化硫醚氧化成亚砜反应(96%ee)和不对称催化硅腈化反应(87%ee),都获得了好的催化活性和高的对映选择性。我们对以上反应中其催化剂的用量、溶剂、催化剂浓度和抗衡离子的Lewis酸碱性、底物的结构与对映选择性的关系、催化循环机理等进行了较系统、深入的研究,发现非共价相互作用和分子识别现象在不对称催化反应中显示出重要的作用,为进一步设计新的手性催化剂,发展不对称催化反应提供了基础数据。 相似文献
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Joshodeep Boruwa 《Tetrahedron》2006,62(6):1193-1198
A seteroselective total synthesis of (+)-boronolide is described. The key steps are Sharpless asymmetric dihydroxylation, Shibasaki's asymmetric Henry reaction, asymmetric allylation and ring closing metathesis. 相似文献