共查询到19条相似文献,搜索用时 93 毫秒
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1,6-烯炔底物在过渡金属催化剂作用下的化学行为得到了广泛的研究,重点是关于过渡金属催化的1,6-烯炔环异构化反应.从反应机理角度入手,把1,6-烯炔环异构化反应按启动方式总结为三类,并对这三种方式启动的1,6-烯炔环异构化反应进行了详细地总结和阐述. 相似文献
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过渡金属催化是现代有机合成化学中精准构建化学键最重要的工具之一.有机小分子催化是21世纪初开始蓬勃发展的一个新兴研究领域.两者在不对称烯丙基化反应中的完美结合有意义地解决了该领域亲核试剂的普适性、立体选择性控制等挑战性问题.本文综述了过渡金属与有机小分子协同催化的不对称烯丙基化反应研究进展.按照不同的手性控制方式(过渡金属催化剂控制手性、有机小分子催化剂控制手性以及两者共同控制手性)对这些反应进行了梳理和总结,同时对代表性反应的机理以及该领域仍然存在的问题与未来发展进行了简单阐述. 相似文献
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Baeyer-Villiger反应是有机化学基本反应之一,但是催化不对称Baeyer-Villiger反应的研究尚处于起步阶段。本文按手性配体的不同,评述了手性金属络合物催化不对称Baeyer-Villiger反应的研究,特别是由外消旋或前手性酮制备光学活性内酯的研究进展。 相似文献
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综述了近年来过渡金属不对称催化氧杂苯并降冰片烯开环反应的研究进展, 包括钯催化、镍催化、铜催化和铑催化四部分内容, 并对部分反应的机理进行了介绍. 相似文献
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综述了Schiffbase过渡金属配合物在不对称催化烯烃环氧化、氮杂环丙烷化、环丙烷化和其它催化反应中的应用研究进展,参考文献39篇。 相似文献
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Dr. Christian Schmitz Prof. Walter Leitner Dr. Giancarlo Franciò 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(30):10696-10702
A library of α,α,α,α‐tetraaryl‐1,3‐dioxolane‐4,5‐dimethanol (TADDOL)‐based phosphoramidites has been synthesized and applied in the Ni‐catalyzed cycloisomerization of different dienes. Through the systematic variation of the three structural motifs of the lead structure, that is, the amine moiety, the protecting group, and the aryl substituents, the ligand features could be optimized for the asymmetric cycloisomerization of the model substrate diethyl diallylmalonate. The substrate scope of the new catalytic system was extended to other diallylic substrates, including unsymmetrical dienes. Overall remarkably high activities of up to approximately 13 500 h?1, very high selectivities toward five‐membered exo‐methylenecyclopentanes, and enantioselectivities of up to 92 % ee have been achieved. 相似文献
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Rhodium‐Catalyzed Asymmetric Cycloisomerization and Parallel Kinetic Resolution of Racemic Oxabicycles 下载免费PDF全文
Dr. Charles C. J. Loh Matthias Schmid Dr. Robert Webster Andy Yen Shabnam K. Yazdi Dr. Patrick T. Franke Prof. Dr. Mark Lautens 《Angewandte Chemie (International ed. in English)》2016,55(34):10074-10078
While desymmetrizations by intermolecular asymmetric ring‐opening reactions of oxabicyclic alkenes with various nucleophiles have been reported over the past two decades, the demonstration of an intramolecular variant is unknown. Reported herein is the first rhodium‐catalyzed asymmetric cycloisomerization of meso‐oxabicyclic alkenes tethered to bridgehead nucleophiles, thus providing access to tricyclic scaffolds through a myriad of enantioselective C?O, C?N, and C?C bond formations. Moreover, we also demonstrate a unique parallel kinetic resolution, whereby racemic oxabicycles bearing two different bridgehead nucleophiles can be resolved enantioselectively. 相似文献
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廉价过渡金属催化烯烃异构反应研究进展 总被引:2,自引:0,他引:2
过渡金属催化的烯烃异构反应在有机化合物合成、日用化学品合成、原料油应用和天然产物合成中都有着举足轻重的作用。廉价过渡金属由于其在资源、价格、后处理等方面的优势,日益受到研究者的重视。本文主要综述了近几十年来廉价过渡金属铁、钴、镍在催化烯烃异构反应方面的研究进展,详细阐述了不同的催化体系在催化活性、反应选择性、底物适用性及反应机理方面的特点。虽然目前的催化体系已经表现出优异的性能与应用价值,但在烯烃异构的立体选择性、区域选择性机制等方面,仍然需要更深入的研究。 相似文献
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Ignat'ev R. A. Maslennikov S. V. Spirina I. V. Artemov A. N. Maslennikov V. P. Lineva A. N. 《Russian Journal of General Chemistry》2002,72(6):882-885
Chlorides of Ti(IV), V(III), Nb(V), and Mo(VI), in contrast to Cr(III) and Zr(IV) chlorides, catalyze oxidation of magnesium with cyclopentadiene to magnesium cyclopentadienide. The kinetic features of the process were revealed, and the composition and yield of reaction products were determined. Certain details of the reaction mechanism were discussed. 相似文献