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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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Albert Moyano Prof. Niama El‐Hamdouni Ahmed Atlamsani Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(18):5260-5273
Rearrangement reactions often lead to the regio‐ and stereoselective formation of carbon–carbon or carbon–heteroatom bonds, and allow the construction of otherwise hard‐to‐access molecular frameworks. Research disclosed in the present decade, especially in the last two years, has shown that organocatalytic modes of activation can be successfully applied to a variety of rearrangements. In this Minireview we discuss the advances achieved so far in asymmetric organocatalytic rearrangement reactions. 相似文献
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Łukasz Albrecht Dr. Anna Albrecht Dr. Henryk Krawczyk Prof. Dr. Karl Anker Jørgensen Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(1):28-48
240 Years have passed since the discovery of elemental phosphorus. During that time organophosphorus chemistry has emerged as an interesting and exciting field of research. Recently organophosphorus chemistry has been raised to a new level. Organophosphorus compounds have found applications in asymmetric organocatalysis for the synthesis of optically active compounds of synthetic or biological importance. The aim of this review article is to present recent contributions to this developing field of chemistry and to point out synthetic advantages of methodologies developed so far. 相似文献
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硫酯在生物合成和有机合成中扮演着十分重要的角色. 硫酯的羰基C(2p)轨道和S(3p)轨道重叠度较小, 其α质子具有较强的酸性, 能在温和的条件下烯醇化并进行亲核反应. 同时, 硫酯还是高效的酰基化试剂, 可用于酯键和酰胺键的构建. 有机小分子催化是不对称催化的重要研究领域. 近十几年来有机催化硫酯底物的不对称反应取得了大量重要成果, 极大拓宽了有机催化酯类底物的反应类型, 并实现了一些其氧酯类似物无法实现的反应. 本综述按照硫酯底物的类型(可烯醇化硫酯和α,β-不饱和硫酯)、有机催化剂类型和反应类型对硫酯底物参与的有机催化不对称反应进行梳理和总结, 同时对代表性反应的机理以及该领域的未来发展进行了简单阐述. 相似文献
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Xiu-Ning Hu Dong-Ping Wu Ye-Peng Xu Prof. Dr. Pei-Qiang Huang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):609-613
The first organocatalytic asymmetric synthesis of an advanced intermediate of (+)-sarain A was achieved. This approach featured the employment of an organocatalytic asymmetric Michael addition reaction and a nitrogen-to-carbon chirality transfer to forge three chiral centers, as well as a catalytic hydrosilylation for the chemoselective reduction of a key lactam intermediate. The tricyclic intermediate contained all the required functionalities for elaborating into (+)-sarain A. 相似文献
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Prof. Claudio Curti Dr. Gloria Rassu Prof. Dr. Marco Lombardo Dr. Vincenzo Zambrano Prof. Dr. Luigi Pinna Prof. Dr. Lucia Battistini Prof. Dr. Andrea Sartori Prof. Dr. Giorgio Pelosi Prof. Dr. Franca Zanardi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(45):20230-20239
The discovery of chemical methods enabling the construction of carbocycle-fused uracils which embody a three-dimensional and functional-group-rich architecture is a useful tool in medicinal chemistry oriented synthesis. In this work, an unprecedented amine-catalyzed [4+2] cross-cycloaddition is documented; it involves remotely enolizable 6-methyluracil-5-carbaldehydes and β-aryl enals, and chemoselectively produces two novel bicyclic and tricyclic fused uracil chemotypes in good yields with a maximum level of enantiocontrol. In-depth mechanistic investigations and control experiments support an intriguing homo-synergistic organocatalytic approach, where the same amine organocatalyst concomitantly engages both aldehyde partners in a stepwise eliminative [4+2] cycloaddition, whose vinylogous iminium ion intermediate product may diverge—depending upon conditions—to either bicyclic targets by hydrolysis or tricyclic products by a second homo-synergistic trienamine-mediated stepwise [4+2] cycloaddition. 相似文献
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手性磷酸催化的有机催化不对称反应 总被引:1,自引:0,他引:1
手性磷酸是近年来发展起来的一类新型高效、高对映选择性的Brønsted酸类有机催化剂, 已成功应用于催化不对称Mannich反应、还原胺化反应、Pictet-Spengler反应、aza-Diels-Alder反应和aza-Ene反应等许多重要的有机合成反应. 手性磷酸催化剂分子内同时含有Lewis碱性位点和Brønsted酸性位点, 可同时活化亲电与亲核底物. 作为一种新型双功能有机催化剂, 手性磷酸具有较高的催化活性和对映选择性, 催化剂最低用量可达0.05 mol%. 对各类手性磷酸催化剂在有机催化不对称合成反应中的应用研究进展, 以及不对称诱导反应的机理、手性磷酸的分子结构及反应条件对其催化活性和不对称诱导活性的影响进行了评述. 相似文献
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Organocatalytic Asymmetric Conjugate Additions to Cyclopent‐1‐enecarbaldehyde: A Critical Assessment of Organocatalytic Approaches towards the Telaprevir Bicyclic Core 下载免费PDF全文
Dr. Luca Bernardi Dr. Mariafrancesca Fochi Riccardo Carbone Ada Martinelli Dr. Martin E. Fox Dr. Christopher J. Cobley Bhaskar Kandagatla Dr. Srinivas Oruganti Dr. Vilas H. Dahanukar Dr. Armando Carlone 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(52):19208-19222
In the context of a programme directed at the manufacture of telaprevir, eight possible approaches to its bicyclic α‐amino acid core, based on organocatalytic enantioselective conjugate additions to cyclopent‐1‐enecarbaldehyde, were identified and preliminarily explored. Four reactions, delivering advanced intermediates en route to the target amino acid, were selected for a thorough optimisation. Three of this reactions involved iminium ion catalysis with a prolinol catalyst (addition of nitromethane, nitroacetate and acetamidomalonate) and one was based on a Cinchona‐derived phase‐transfer catalyst (addition of glycine imines). A careful choice of additives allowed lowering of the catalyst loading to 0.5 mol % in some cases. The preparation of intermediates that would give access to the core of telaprevir in good yields and enantioselectivities by exploiting readily available substrates and catalysts, highlights the potential of organocatalytic technology for a cost‐effective preparation of pharmaceuticals. 相似文献
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Asymmetric Organocatalytic Stepwise [2+2] Entry to Tetra‐Substituted Heterodimeric and Homochiral Cyclobutanes 下载免费PDF全文
Alex J. Nielsen Dr. Hilary A. Jenkins Dr. James McNulty 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(27):9111-9115
An asymmetric synthesis of tetra‐substituted cyclobutanes involving an organocatalytic, stepwise [2+2]‐cycloaddition is described. The secondary‐amine‐catalyzed method allows for the hetero‐dimerization of two different cinnamic‐acid‐derived sub‐units, opening a novel one‐step assembly to densely functionalized, head‐to‐tail coupled dimeric cyclobutanes in high enantiomeric excess. A series of selective synthetic interconversions in these sensitive cycloadducts is also described. 相似文献