共查询到19条相似文献,搜索用时 890 毫秒
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铱(Ⅲ)卟啉β-羟乙基,IrⅢ(ttp)CH2CH2OH(ttp=5,10,15,20-二价阴离子tetratolylporphyrinato),发现选择性裂解芳醛的醛的碳-氢键和给铱酰基配合物。酰基铱配合物对羰基化和脱羰反应以及潜在的功能化研究的很好的候选材料。这碳-氢键的建议活化机理:通过初始的β-羟基消除IrⅢ(ttp)CH2CH2OH生成IrⅢ(ttp)OH,然后进行与醛的CH键的σ-键复分解发生。 相似文献
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在鹰爪碱诱导下,2-氯甲基-4,4-二甲基噁唑啉与叔丁基苯基膦硼烷经络合反应,以43%的收率合成了光学纯度大于99%,手性中心在P上的新型手性噁唑啉氮膦配体(3); 3和铱配合物([Ir(cod)Cl]2)经络合反应以55%的收率制得两个新型手性膦噁唑啉铱络合物催化剂(1和2),其结构经1H NMR, 13C NMR, 31P NMR和元素分析表征。考察了1和2对烯烃的不对称氢化反应的催化性能。结果表明:1具有较好的催化能力,收率>92%,但催化剂的手性诱导能力较差(ee≤36%)。 相似文献
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金属催化的不对称氢化反应研究进展与展望 总被引:1,自引:0,他引:1
手性过渡金属络合物催化的不对称氢化反应是合成光学活性化合物的重要方法. 本文从手性配体及手性催化剂、不对称催化新反应、新方法和新策略三个方面简要评述新世纪以来过渡金属催化的不对称氢化反应研究领域的新进展. 从新世纪初至今, 手性单磷配体得到了复兴, 出现了如MonoPhos、SiPhos、DpenPhos等高效单齿亚磷酰胺酯配体; 磷原子手性(P-手性)配体也得到了快速发展, 如BenzP*、ZhanPhos、TriFer等已成为新的高效手性双膦配体; 螺环骨架手性配体成为新世纪手性配体设计合成的亮点, 除了SiPhos、SIPHOX、SpinPHOX等高效手性螺环配体外, 手性螺环吡啶胺基磷配体SpiroPAP的铱催化剂成为目前最高效的分子催化剂. 不对称催化氢化新反应研究也取得了突破, 如非保护烯胺、杂芳环化合物及N-H亚胺的氢化等反应都实现了高对映选择性. 自组装手性催化剂、树枝状手性催化剂、铁磁性纳米负载的可回收手性催化剂, 以及“混合”配体手性催化剂等新方法和新策略也在不对称催化氢化反应中得到了应用. 然而, 手性过渡金属络合物催化的不对称氢化研究仍然充满挑战, 也期待新的突破. 相似文献
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过渡金属催化高选择性膦氢化反应 总被引:1,自引:1,他引:0
本文总结了过去几十年特别是近15年来过渡金属催化下各种含磷-氢键的膦氢化合物对炔烃的高选择性膦氢化反应,详尽叙述了其发现、发展和现状.自1996年来,过渡金属催化高选择性膦氢化反应研究工作发展迅速,各种高选择性膦氢化反应不断开发,目前已具有底物适用范围广、过渡金属催化剂活性高、反应选择性高、原子经济性高、以及能满足不同合成需求等优点,并逐步向反应条件温和化、金属催化剂简单化、无配体化、合成步骤简易化以及原料催化剂成本低价化方向发展.虽然如此,至今仍缺乏关于本研究全面的综述和介绍,希望本文可以弥补文献缺陷,对过渡金属催化高选择性膦氢化反应研究有个客观全面的介绍.过渡金属催化烯烃的不对称膦氢化反应合成碳手性或磷手性的光学活性有机磷化合物作为相关研究中的起步最晚的分支,本文也将作阶段小结. 相似文献
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Javier Mazuela Alexander Paptchikhine Oscar Pàmies Pher G. Andersson Montserrat Diéguez 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(15):4567-4576
A library of readily available phosphite–oxazole/thiazole ligands ( L1 a – g – L7 a – g ) was applied in the Ir‐catalyzed asymmetric hydrogenation of several largely unfunctionalized E‐ and Z‐trisubstituted and 1,1‐disubstituted terminal alkenes. The ability of the catalysts to transfer chiral information to the product could be tuned by choosing suitable ligand components (bridge length, the substituents in the heterocyclic ring and the alkyl backbone chain, the configuration of the ligand backbone, and the substituents/configurations in the biaryl phosphite moiety), so that enantioselectivities could be maximized for each substrate as required. Enantioselectivities were therefore excellent (enantiomeric excess (ee) values up to >99 %) for a wide range of E‐ and Z‐trisubstituted and 1,1‐disubstituted terminal alkenes. The biaryl phosphite moiety was a very advantageous ligand component in terms of substrate versatility. 相似文献
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手性醇和胺是重要的精细化学品,不对称转移氢化是获得这类手性化合物有效、实用的途径之一。在众多的催化剂中,Noyori等发展的手性二胺与过渡金属钌TsDPEN-Ru(TsDPEN = 1,2-二苯基乙二胺)络合物是最有效的催化剂。近年来,随着化学家对绿色化学的日益重视,水作为绿色溶剂被广泛地用作为不对称催化转移氢化的反应介质,具有很高的反应活性、对映选择性和化学选择性。本文综述近年来应用未经修饰和修饰的手性二胺配体与过渡金属钌[(cymene)RuCl2]2、铑[(Cp*)RhCl2]2和铱[(Cp*)IrCl2]2的络合物催化的水相中酮、亚胺和活化烯烃的不对称转移氢化的研究进展。 相似文献
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正手性过渡金属配合物催化的不对称氢化是合成手性药物、农药和精细化工中间体的重要方法.到目前为止,已经有一些过渡金属/配体配合物催化的不对称氢化反应得到工业化应用,典型的实例如孟山都公司采用手性双齿膦配体DIPAMP生产L 相似文献
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Linlong Dai Yuheng Liu Qing Xu Meifang Wang Dr. Qiaohong Zhu Prof. Dr. Peiyuan Yu Prof. Dr. Guofu Zhong Prof. Dr. Xiaofei Zeng 《Angewandte Chemie (International ed. in English)》2023,62(7):e202216534
Diaryl ethers are widespread in biologically active compounds, ligands and catalysts. It is known that the diaryl ether skeleton may exhibit atropisomerism when both aryl rings are unsymmetrically substituted with bulky groups. Despite recent advances, only very few catalytic asymmetric methods have been developed to construct such axially chiral compounds. We describe herein a dynamic kinetic resolution approach to axially chiral diaryl ethers via a Brønsted acid catalyzed atroposelective transfer hydrogenation (ATH) reaction of dicarbaldehydes with anilines. The desired diaryl ethers could be obtained in moderate to good chemical yields (up to 79 %) and high enantioselectivities (up to 95 % ee) under standard reaction conditions. Such structural motifs are interesting precursors for further transformations and may have potential applications in the synthesis of chiral ligands or catalysts. 相似文献
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J.W. Faller Suzanna C. Milheiro Jonathan Parr 《Journal of organometallic chemistry》2006,691(23):4945-4955
The relatively inexpensive chiral monodentate phosphoramidite (S)-MONOPHOS may be used in combination with pyridines to prepare iridium complexes effective for catalysis of asymmetric imine hydrogenation with comparable enantioselectivity to some of those containing more costly chiral bidentate phosphines. [Ir(cod)((S)-MONOPHOS)(L)]BArF (cod = 1,5-cyclooctadiene; L = 3-methylisoquinoline, acridine, 2,6-lutidine, acetonitrile, or 2,3,3-trimethylindolenine; BArF = tetrakis[3,5-bis(trifluoromethyl)phenyl]borate) are efficient catalysts for the asymmetric hydrogenation of 2,3,3-trimethylindolenine. An important observation is that the catalyst containing acridine is more enantioselective than the catalyst derived from 2,3,3-trimethylindolenine which suggests that the other N-donor ligands are not readily displaced by the substrate during the catalytic cycle. 相似文献
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Two new chiral unsymmetrical (non-C2-symmetric) Schiff-base ligands containing salicylaldehyde and 1-(2-hydroxyphenyl)ketone units were synthesized from (R,R)-1,2-diphenylethylenediamine as the chiral diamine using a stepwise approach. The Mn(III) complexes of the ligands were subsequently used as catalysts in asymmetric epoxidation of unfunctionalized alkenes and the results were compared with those obtained using typical C2-symmetric Mn(III)–salen complexes. Possible reasons for the differences in reactivity and selectivity between the two types of catalysts are briefly discussed. 相似文献
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各种手性三齿席夫碱与金属(钛, 铬, 钒, 铁, 铜, 铝)形成的络合物,在催化醛的硅腈化、Diels-Alder、Aldol、杂ene、硫化物的氧化等不对称反应中具有良好的催化活性和对映选择性;其中一些催化体系已成功的应用于天然产物的全合成中,该研究取得了系统性的研究成果。本文综述了手性三齿席夫碱金属络合物在不对称催化反应中的研究进展,同时,探讨了催化剂结构和反应条件对其催化活性和对映选择性的影响。 相似文献
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A Mild Dihydrobenzooxaphosphole Oxazoline/Iridium Catalytic System for Asymmetric Hydrogenation of Unfunctionalized Dialins 下载免费PDF全文
Dr. Bo Qu Dr. Lalith P. Samankumara Dr. Shengli Ma Dr. Keith R. Fandrick Dr. Jean‐Nicolas Desrosiers Dr. Sonia Rodriguez Dr. Zhibin Li Dr. Nizar Haddad Dr. Zhengxu S. Han Keith McKellop Scott Pennino Dr. Nelu Grinberg Dr. Nina C. Gonnella Dr. Jinhua J. Song Dr. Chris H. Senanayake 《Angewandte Chemie (International ed. in English)》2014,53(52):14428-14432
Air‐stable P‐chiral dihydrobenzooxaphosphole oxazoline ligands were designed and synthesized. When they were used in the iridium‐catalyzed asymmetric hydrogenation of unfunctionalized 1‐aryl‐3,4‐dihydronaphthalenes under one atmosphere pressure of H2, up to 99:1 e.r. was obtained. High enantioselectivities were also observed in the reduction of the exocyclic imine derivatives of 1‐tetralones. 相似文献