共查询到18条相似文献,搜索用时 78 毫秒
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重点从立体选择性和催化机理方面,总结了不同的有机小分子催化剂在烯酮的[2+2]和[4+2]不对称环加成反应中的应用. 相似文献
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对手性钛衍生物作为路易斯酸催化的几种有机金属试剂与羰基化合物的不对称加成反应进行了综述。 相似文献
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配体参与的有机金属化合物对亚胺的不对称加成反应 总被引:1,自引:0,他引:1
手性胺类化合物是一类重要的有机化合物,在生物化学及药物合成中有广泛应用.有机金属化合物对亚胺的不对称加成反应是合成手性胺类化合物的重要方法之一.本文对近年来外加配体参与的有机金属化合物对亚胺的不对称加成反应,特别是催化合成手性胺类化合物的研究进展作一概述. 相似文献
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Susanne Olsson Dr. Anders Lennartson Prof. Mikael Håkansson 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12415-12423
We report the absolute asymmetric synthesis (AAS) of indenylzinc reagents by using total spontaneous resolution followed by enantiospecific conversion into 1‐chloroindene. The chiral complex [Zn(dcp)(ind)(tmeda)] (dcp=2,6‐dichlorophenoxy and tmeda=N,N,N′,N′‐tetramethylethylenediamine) ( 3 ) was prepared from the achiral starting materials indene, potassium, zinc chloride, TMEDA, and 2,6‐dichlorophenol. The reagent resolved spontaneously on crystallization, and single crystals of 3 react with N‐chlorosuccinimide in the presence of benzoquinone in 2‐propanol to give 1‐chloroindene in >98 % enantiomeric excess. It was found that (R)‐ 3 gave (R)‐1‐chloroindene upon reaction, indicating an SE2′‐mechanism. Since bulk samples of 3 gave optically active product upon chlorination, total spontaneous resolution must have occurred. This demonstrates that enantiopure products can be obtained through the absolute asymmetric synthesis of organometallic reagents starting from achiral materials. The general absolute asymmetric synthesis (AAS) method offers easy access to both enantiomers and an almost limitless variation in the design of the product. 相似文献
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手性α-氰醇类化合物在有机合成领域中的应用非常广泛,分子中α-碳原子上连接的羟基和氰基两个官能团很容易控制、转化为大量极其重要的合成中间体,包括:α-羟基酸、α-羟基酯,α-羟基醛、α-羟基酮、α-胺基酸和β-胺基醇等.这些化合物都是工业上合成医药、农化产品、 相似文献
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Philippe Klein Vivien Denise Lechner Tanja Schimmel Prof. Dr. Lukas Hintermann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(1):176-180
The generation of arylzinc reagents (ArZnX) by direct insertion of zinc into the C−X bond of ArX electrophiles has typically been restricted to iodides and bromides. The insertions of zinc dust into the C−O bonds of various aryl sulfonates (tosylates, mesylates, triflates, sulfamates), or into the C−X bonds of other moderate electrophiles (X=Cl, SMe) are catalyzed by a simple NiCl2–1,4-diazadiene catalyst system, in which 1,4-diazadiene (DAD) stands for diacetyl diimines, phenanthroline, bipyridine and related ligands. Catalytic zincation in DMF or NMP solution at room temperature now provides arylzinc sulfonates, which undergo typical catalytic cross-coupling or electrophilic substitution reactions. 相似文献