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1.
Matthias Schuster Siegfried Blechert 《Angewandte Chemie (International ed. in English)》1997,36(19):2036-2056
Transition metal catalyzed C? C bond formations belong to the most important reactions in organic synthesis. One particularly interesting reaction is olefin metathesis, a metal-catalyzed exchange of alkylidene moieties between alkenes. Olefin metathesis can induce both cleavage and formation of C? C double bonds. Special functional groups are not necessary. Although this reaction—which can be catalyzed by numerous transition metals—is used in industry, its potential in organic synthesis was not recognized for many years. The recent abrupt end to this Sleeping-Beauty slumber has several reasons. Novel catalysts can effect the conversion of highly fictionalized and sterically demanding olefins under mild reaction conditions and in high yields. Improved understanding of substrate–catalyst interaction has greatly contributed to the recent establishment of olefin metathesis as a synthetic method. In addition to the preparation of polymers with fine-tuned characteristics, the metathesis today also provides new routes to compounds of low molecular weight. The highly developed ring-closing metathesis has been proven to be key step in the synthesis of a growing number of natural products. At the same time interesting applications can be envisioned for newly developed variants of bimolecular metathesis. Improvements in the selective cross-metathesis of acyclic olefins as well as promising attempts to include alkynes as viable substrates provide for a vivid development of the metathesis chemistry. 相似文献
2.
Dr. Benedikt W. Grau Alexander Neuhauser Dr. Sadig Aghazada Prof. Dr. Karsten Meyer Prof. Dr. Svetlana B. Tsogoeva 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(62):e202201414
The “metathesis reaction” is a straightforward and often metal-catalyzed chemical reaction that transforms two hydrocarbon molecules to two new hydrocarbons by exchange of molecular fragments. Alkane, alkene and alkyne metathesis have become an important tool in synthetic chemistry and have provided access to complex organic structures. Since the discovery of industrial olefin metathesis in the 1960s, many modifications have been reported; thus, increasing scope and improving reaction selectivity. Olefin metathesis catalysts based on high-valent group six elements or Ru(IV) have been developed and improved through ligand modifications. In addition, significant effort was invested to realize olefin metathesis with a non-toxic, bio-compatible and one of the most abundant elements in the earth′s crust; namely, iron. First evidences suggest that low-valent Fe(II) complexes are active in olefin metathesis. Although the latter has not been unambiguously established, this review summarizes the key advances in the field and aims to guide through the challenges. 相似文献
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4.
[reaction: see text] Enyne metathesis has been used to prepare bridged azabicycles and applied in a short asymmetric synthesis of the tropane ferruginine. A Grubbs first generation catalyst proved to be superior to the second generation catalyst in the enyne metathesis reaction. 相似文献
5.
Prof. Dr. Rui Wang Yi Chen Mao Shu Wenwen Zhao Maoling Tao Chao Du Xiaoya Fu Prof. Dr. Ao Li Prof. Dr. Zhihua Lin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(9):1941-1946
Compared with the ripeness of olefin metathesis, exploration of the construction of carbon–carbon double bonds through the catalytic carbonyl–olefin metathesis reaction remains stagnant and has received scant attention. Herein, a highly efficient AuCl3-catalyzed intramolecular ring-closing carbonyl–olefin metathesis reaction is described. This method features easily accessible starting materials, simple operation, good functional-group tolerance and short reaction times, and provides the target cyclopentenes, polycycles, benzocarbocycles, and N-heterocycle derivatives in good to excellent yields. 相似文献
6.
Vougioukalakis GC 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(29):8868-8880
Olefin metathesis has revolutionized the way chemists design and synthesize molecules, mostly due to the development of well-defined ruthenium catalysts with high oxygen-, moisture-, and functional-group tolerance. However, the complete removal of residual ruthenium after the end of a metathesis reaction often imposes significant challenges. This Minireview summarizes the strategies for the sequestration of ruthenium impurities from olefin metathesis post-reaction mixtures, thus comprising a practical guide for synthetic chemists employing ruthenium-catalyzed metathesis reactions in the synthesis of organic or polymeric materials. 相似文献
7.
Weena Phongsawat Benjamas Netivorruksa Kongkiat Suriye Siraprapha Dokjampa Piyasan Praserthdam Joongjai Panpranot 《天然气化学杂志》2012,(1):83-90
An unconventional metathesis of ethylene and 2-pentene over Re2O7/SiO2-Al2O3 catalysts has been studied as an alternative route for the production of propylene. Complete conversion of 2-pentene and propylene yield as high as 88 wt% were obtained under mild reaction conditions at 35°C and atmospheric pressure. Unlike the conventional metathesis of ethylene and 2-butenes in which isomerization is a competing side reaction, the isomerization of 1-butene product from the unconventional metathesis of ethylene and 2-pentene to 2-butenes can further react with excess ethylene in the feed, resulting in additional increase in propylene yield. The secondary metathesis reaction was found to be favored under ethylene/2-pentene (E/2P) molar ratio 3 and gas hourly space velocity (GHSV) 1000 h-1 at the reaction temperature of 35°C. No catalyst deactivation was observed during the 455 min time-on-stream under the selected reaction conditions. 相似文献
8.
[reaction: see text] The first total synthesis of the novel sesquiterpene lactone (+)-8-epi-xanthatin (1) has been achieved starting from the commercially available ester 8. The synthesis features an asymmetric aldol reaction and palladium-catalyzed carbonylation/lactonization sequence leading to 4 and a domino ring-closing enyne metathesis/cross metathesis reaction to afford 1. 相似文献
9.
Among the many types of transition-metal-catalyzed C-C bond-forming reactions, olefin metathesis has come to the fore in recent years owing to the wide range of transformations that are possible with commercially available and easily handled catalysts. Consequently, olefin metathesis is now widely considered as one of the most powerful synthetic tools in organic chemistry. Until recently the intermolecular variant of this reaction, cross-metathesis, had been neglected despite its potential. With the evolution of new catalysts, the selectivity, efficiency, and functional-group compatibility of this reaction have improved to a level that was unimaginable just a few years ago. These advances, together with a better understanding of the mechanism and catalyst-substrate interactions, have brought us to a stage where more and more researchers are employing cross-metathesis reactions in multistep procedures and in the synthesis of natural products. The recent inclusion of alkynes and hindered bicyclic olefins as viable substrates for bimolecular metathesis coupling, the discovery of enantioselective cross-metathesis and cross-metathesis in water, and the successful marriage of metathesis and solid-phase organic synthesis has further widened the scope of this versatile reaction. 相似文献
10.
Density functional and second-order Moller–Plesset theory were used to model W(0) carbene mediated homogeneous metathesis reaction of propylene. The calculations show that the rate determining step of the metathesis is the initiation. After the initiation has been completed the rate determining step becomes dissociation of olefin–metallocarbene complex. The low stereoselectivity of the olefin metathesis reaction is due to the close matching of activation energies for cis and trans isomer formation and the fast cis–trans isomerization caused by the catalysts. The non-productive olefin metathesis reaction always dominates the reaction mixture owing to its very low activation energy. The electronic structure of metal carbene olefin complexes can be described as a combination of donor–acceptor interactions between HOMO of the olefin and LUMO of metal carbene located at carbene carbon on the one hand, and the Dewar, Chatt and Duncanson back donation scheme on the other. 相似文献
11.
Yu Xie Ye Yuan Bibimaryam Mousavi Yuan Cai Cheng Kai Yin Lu Mehman Yusubov Francis Verpoort 《应用有机金属化学》2015,29(9):573-579
Olefin metathesis is a transition metal‐mediated transformation that rearranges the carbon atoms of the carbon–carbon double bond of olefins. This reaction has become one of the most important and powerful reactions. Therefore development of new, well‐defined, highly active and selective catalysts is very desirable and a valuable goal. This mini‐review mainly introduces the development of ruthenium catalysts in olefin metathesis highlighting oxygen‐chelated indenylidene ruthenium catalysts. Applying an alkoxyl group on the indenylidene ligand fragment can generate the Ru ? O chelating bond. Additionally, various modifications of the ligand as well as the catalytic activity for ring‐closing metathesis reaction and selectivity of cross metathesis reaction are overviewed. Finally, the perspectives on the development of new catalysts are summarized. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
12.
Tatsushi Imahori 《Tetrahedron letters》2008,49(2):265-268
An interesting allylic substituent effect on ring-closing enyne metathesis has been found. An allylic hydroxy group on enyne substrates accelerates ring-closing enyne metathesis of terminal alkynes. The reaction proceeds smoothly without ethylene atmosphere and/or more reactive newer generation Ru-carbene catalysts, which are generally necessary to promote the reaction. This efficient reaction was applied to the synthesis of isofagomine. 相似文献
13.
[reaction: see text] Bivalent carbohydrate substrates for metathesis were synthesized from glucuronic acid and phenylene-1,4-diamine. The substrate secondary structure depends on whether secondary or tertiary amides are present, and this influences the course of the metathesis reaction leading to novel multivalent scaffolding. Molecular modeling suggests that a very rigid macrocyclic scaffold has potential for the development of alpha-helix peptidomimetics. 相似文献
14.
Asymmetric total synthesis of small ring macrolide stagonolide-E has been described in this communication. The main highlight of our synthetic strategy is the application of ME-DKR (metal enzyme combo dynamic kinetic resolution) reaction, asymmetric reduction with Noyori’s BINAL-H reagent system, stereoselective cross metathesis, and RCM (ring closing metathesis) reaction at a late stage enables us to achieve the synthesis of the target molecule in an efficient way. 相似文献
15.
Jennifer M. StorvickEvgenia Ankoudinova Brianne R. KingHeather Van Epps Gregory W. O’Neil 《Tetrahedron letters》2011,52(44):5858-5861
The total synthesis of haminol A has been completed featuring a masked-alkene metathesis reaction followed by bis-acyloxysulfone elimination to install the 1,3,8-triene subunit. During the course of our synthesis, the metathesis reactivity of 3-vinylpyridine was evaluated and our data suggest the rapid formation of a ruthenium pyridylalkylidene that no longer participates in productive metathesis. A chemotaxis assay using Caenorhabditis elegans demonstrated that haminol A produced an avoidance response from this organism. 相似文献
16.
A unique example of sequential ring-closing metathesis and cross-enyne metathesis is reported. Here, the in situ generated ethylene by product from ring-closing metathesis is trapped by alkyne moiety. No metathesis product formation was observed with more reactive second generation catalyst in the absence of ethylene. Differential chemoselectivity with the first and second generation Grubbs’ catalyst has been observed when the reaction was performed in presence of the external source of ethylene. 相似文献
17.
An efficient two-step strategy has been developed to access diversely functionalized benzylic sulfonamides. Execution of this strategy required the development of two reaction methods: the palladium-catalyzed cross-coupling of aryl halides with CH-acidic methanesulfonamides and a metathesis reaction between the resulting alpha-arylated sulfonamides and diverse amines. The broad scope of the cross-coupling process combined with a versatile sulfonamide metathesis constitutes an efficient strategy for the synthesis of various benzylic sulfonamides. 相似文献
18.
Miguel ngel Rivero‐Crespo María Tejeda‐Serrano Horacio Prez‐Snchez Jos Pedro Cern‐Carrasco Antonio Leyva‐Prez 《Angewandte Chemie (International ed. in English)》2020,59(10):3846-3849
The carbonyl–olefin metathesis reaction has experienced significant advances in the last seven years with new catalysts and reaction protocols. However, most of these procedures involve soluble catalysts for intramolecular reactions in batch. Herein, we show that recoverable, inexpensive, easy to handle, non‐toxic, and widely available simple solid acids, such as the aluminosilicate montmorillonite, can catalyze the intermolecular carbonyl–olefin metathesis of aromatic ketones and aldehydes with vinyl ethers in‐flow, to give alkenes with complete trans stereoselectivity on multi‐gram scale and high yields. Experimental and computational data support a mechanism based on a carbocation‐induced Grob fragmentation. These results open the way for the industrial implementation of carbonyl–olefin metathesis over solid catalysts in continuous mode, which is still the origin and main application of the parent alkene–alkene cross‐metathesis. 相似文献
19.
Olefin metathesis has recently emerged as a viable reaction for chemical protein modification. The scope and limitations of olefin metathesis in bioconjugation, however, remain unclear. Herein we report an assessment of various factors that contribute to productive cross-metathesis on protein substrates. Sterics, substrate scope, and linker selection are all considered. It was discovered during this investigation that allyl chalcogenides generally enhance the rate of alkene metathesis reactions. Allyl selenides were found to be exceptionally reactive olefin metathesis substrates, enabling a broad range of protein modifications not previously possible. The principles considered in this report are important not only for expanding the repertoire of bioconjugation but also for the application of olefin metathesis in general synthetic endeavors. 相似文献
20.
The reactivity for metathesis reaction of some polyunsaturated cyclopentanols, and of a polyunsaturated ketone bearing vinyl groups or vinyl and propenyl groups has been examined. In the presence of two of these reactants, depending on the ruthenium catalyst employed, either the ring closing metathesis or the cross‐coupling metathesis was observed. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献