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In this report, we try to show the importance of incorporation of name reactions in the sequential cascade reaction in which significantly decreasing the number of steps towards an ideal and practical multi-step synthesis of natural products as well showing virtually all the advantages already mentioned for “Click Chemistry”. In addition, since the chiral inductions are desired for most of these sequential name reactions, their asymmetric catalyzed reactions were also described. 相似文献
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《Green Chemistry Letters and Reviews》2013,6(4):311-320
Abstract In the second part of our paper, further recent developments of ionic liquids in selected name reactions of carbonyl chemistry such as Mannich, Reformatsky, Cannizaro, Streacker, Barbier, Pechmann, etc. are described. 相似文献
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Thermal reaction of 2-[N-(alk-2-enyl)benzylamino]-3-(2-substituted and 2,2-disubstituted)vinylpyrido[1,2-a]pyrimidin-4(4H)-ones gave azepine, the desired ene products, and/or pyran derivatives. The formation of the latter was responsible for the [4+2] cycloaddition reaction between the α,β-unsaturated ester carbonyl moiety as a diene part and the alkenylamino moiety as an ene one. The reaction features depended upon the kinds of substituents both on the vinyl and alkenyl counterparts; strongly electron-withdrawing substituents on the vinyl moiety or an electron-donating substituent on the alkenyl one changed the reaction feature from the ene reaction to the hetero Diels-Alder reaction. 相似文献
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Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate) catalyzed Suzuki, Heck, Sonogashira, and cyanation reactions 总被引:1,自引:0,他引:1
Nitin S. Nandurkar 《Tetrahedron》2008,64(17):3655-3660
Palladium bis(2,2,6,6-tetramethyl-3,5-heptanedionate): a structurally well-defined O-containing transition metal complex is reported as an efficient catalyst for Suzuki, Heck, and Sonogashira cross-coupling reactions. The protocol was also applied successfully for cyanation of aryl halides under milder operating conditions. The system tolerated the coupling of various aryl halides with alkenes, alkynes, and organoboronic acid along with the cyanation of aryl halides providing good to excellent yields of desired products. 相似文献
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Arash Ghorbani‐Choghamarani Masoud Mohammadi Robert H.E. Hudson Taiebeh Tamoradi 《应用有机金属化学》2019,33(8)
A boehmite@tryptophan‐Pd nanoparticulate catalyst was prepared by a simple, fast and convenient route. The nanomaterial was characterized using various techniques and employed as a thermally stable catalyst for Heck, Stille and Suzuki cross‐coupling reactions. Optimized conditions for these reactions are described. The catalyst could be isolated, post‐reaction, by simple filtration and recycled for several consecutive cycles without a notable change in its activity. 相似文献
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Thomas A. Klein 《Tetrahedron letters》2005,46(27):4535-4538
Dimethylnitro alcohols are constructed in a one-pot process from benzylic halides and 2-nitropropane. The use of tetrabutylammonium fluoride (TBAF) as the promoter is essential for this tandem Hass-Bender/Henry reaction to proceed. 相似文献
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温度和时间对有机合成反应影响的探讨 总被引:1,自引:0,他引:1
根据物理化学和有机合成原理,从动力学、热力学、反应机理及溶解度等各方面详细分析了反应温度和反应时间对有机合成反应的影响。通过这些分析,可以让同学们更好地在合成反应课程的学习中掌握和分析反应温度和反应时间对反应的影响。 相似文献
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钯催化的交叉偶联反应是非常实用的合成新方法.文章给出了Heck反应、Negishi反应和Suzuki反应的概念,对其反应机理作了详细的说明,并对其在复杂化合物和天然产物全合成中的应用作了评价. 相似文献
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Shaomin Chen Rongxian Bai Minghao Li Ping Liu Yanlong Gu 《Chemical record (New York, N.Y.)》2021,21(1):87-115
Acid‐catalyzed tandem reactions with auto‐tandem catalysis are effective for simplifying organic synthesis. However, some of the reported reactions were established based on the use of well‐designed substrate with complex structure. In some cases, owing to the existence of a big gap between each catalytic cycle, it is hard to bind all the individual reaction steps to be a peaceful sequence. To enrich the diversity and also to strengthen the practical usefulness of the methodology developed by auto‐tandem catalysis, an additive‐like component was added to induce acid‐acid‐catalyzed tandem reaction. During the reaction, the additive‐like component acted either as an activator to increase the reactivity of the starting material or a hided reagent to enable successful transformation of the intermediate. Many novel tandem reactions were established in a one‐pot manner with the aid of this strategy. Importantly, this strategy not only allows the use of simple and commercially available chemicals as substrates, but also possesses multiple merits, such as simplifying operation, lowering waste generation and enhancing synthetic efficiency and atom‐economy. A summarization of the additive‐like component‐induced auto‐tandem catalysis with an acid catalyst was given in this review, in which many acid‐acid‐catalyzed tandem reactions were discussed. The reported additive‐like components were classified as three types: oxidative type, reductive type and neutral type depending on their mechanisms in assisting the establishment of acid‐acid‐catalyzed tandem reactions. Many examples were collected and analyzed from the viewpoints of simplifying the synthesis and manifesting their superior and distinct functionalities of the additives. A perspective of this concept was also given at the end of this review. 相似文献
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Yoshishige Okuno 《International journal of quantum chemistry》2000,77(4):791-796
A microscopic method to examine a nonequilibrium solvation effect is reported. The solution reaction is simplified as a barrier‐crossing reaction within a solution reaction surface that corresponds to a two‐dimensional space determined by solute and solvent reactive coordinates. For this simplification, the motions within the space spanned by nonreactive coordinates are frozen. We derive three rate constant expressions: (1) in the nonadiabatic solvation limit, (2) in the equilibrium solvation limit, and (3) of the transition‐state theory. This method was applied to the examination of the contact‐ion‐pair formation of t‐BuCl in four waters. We found that the nonadiabatic solvation picture overestimates the nonequilibrium solvation effect. © 2000 John Wiley & Sons, Inc. Int J Quant Chem 77: 791–796, 2000 相似文献
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In Howa Jeong Young Sam Park Myong Sang Kim Yong Sup Song 《Journal of fluorine chemistry》2003,120(2):195-209
α- or β-Trifluoromethylated vinylstannanes 1, 2a, 3 and 4 were prepared form 1,1-bis(phenylthio)-2,2,3,3,3-pentafluoropropylbenzene (5) via several steps. The cross-coupling arylation reactions of 1–4 with aryl iodides bearing a bromo, methoxy, methyl, nitro or trifluoromethyl group on para- or meta-position of benzene ring afforded the corresponding coupling products in good yields. Compounds 1, 2a and 4 underwent the acylation reaction with various types of acyl chlorides to give the corresponding trifluoromethylated enone derivatives in good yields. Reduction of trifluoromethylated enone derivatives with LiAlH4, followed by Fridel-Craft’s type of cyclization with AlCl3 provided trifluoromethylated indene derivatives in good yields. 相似文献
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An efficient one-pot and regioselective synthesis of 3,4-dihydroquinazolines and 4,5-dihydro-3H-1,4-benzodiazepin-3-ones by Ugi/Staudinger/aza-Wittig sequence has been developed. The Ugi reactions of 2-azidobenzylamines, aldehydes, acids (or α-keto acids) and isocyanides produced the azide intermediates, which were then treated with tributylphosphine or triphenylphosphine to give polysubstituted 3,4-dihydroquinazolines or 4,5-dihydro-3H-1,4-benzodiazepin-3-ones in moderate to good yields by tandem Standinger/aza-Wittig reactions. 相似文献
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《Green Chemistry Letters and Reviews》2013,6(4):289-310
Abstract The present overview describes ionic liquids as alternate, attractive solvents of today and tomorrow in organic synthesis. Since this subject is too wide and developments have been too fast, only a recent account is presented on indispensable carbon-carbon bond forming named reactions such as Knoevenagel, Michael Aldol, Biginelli Reaction, and so on, which has never been done before exclusively. 相似文献
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《Mendeleev Communications》2021,31(6):769-780
The synthesis of the desired chemical compound is the main task of synthetic organic chemistry. The predictions of reaction conditions and some important quantitative characteristics of chemical reactions as yield and reaction rate can substantially help in the development of optimal synthetic routes and assessment of synthesis cost. Theoretical assessment of these parameters can be performed with the help of modern machine-learning approaches, which use available experimental data to develop predictive models called quantitative or qualitative structure–reactivity relationship (QSRR) modelling. In the article, we review the state-of-the-art in the QSRR area and give our opinion on emerging trends in this field. 相似文献