共查询到20条相似文献,搜索用时 441 毫秒
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芳基硼酸(酯)不仅是有机合成中的重要中间体,而且在生物学、医学及材料科学中有着广泛的应用.综述了近年来其合成方法学的研究进展,着重说明钯催化剂在氯代芳杂环及大位阻底物结构中硼基化的应用,并介绍了镍、铜、锌、铁、铑、钴等金属催化剂和非金属催化的芳基硼基化,以及光诱导合成芳基硼酸的反应. 相似文献
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自从Kagan将二碘化钐应用于有机合成以来,钐试剂在有机合成中的应用的研究引起了人们的很大兴趣.随着研究的深入,金属钐、二碘化钐、三碘化钐、有机钐等钐试剂在有机合成中的应用越来越广泛[1].我们课题组也研究了三碘化钐促进的一些有机合成反应[2,3].Friedel-Crafts酰基化反应是合成芳酮的重要反应,但在传统的Lewis酸催化的芳烃酰基化反应中,由于络合作用等的影响,存在着催化剂的用量过大、副反应多、选择性差等不足[4].高效、催化量的催化剂的采用是人们期待的目标.本文报道用催化量的(10 mol%)SmI3促进的芳烃酰基化反应,反应方程式如下,产物的结构经IR和1HNMR所确证. 相似文献
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手性有机分子催化剂在不对称催化中的应用 总被引:2,自引:0,他引:2
近三十年来,不对称催化研究获得了迅猛发展[1].按手性催化剂的种类分,一般可分为手性有机金属配合物催化以及路易斯酸、碱等手性有机分子催化.手性有机金属配合物催化剂在不对称还原、不对称氧化等官能团转化反应中的应用,已达到实用阶段;不使用金属的有机分子催化剂由于其对环境友好,也日益被重视,有机合成化学中十分重要的碳-碳键形成反应,如Aldol反应、Diels-Alder反应等,近年来发表了很多使用手性有机分子催化剂的成功的实例.早在1971年Wiechert[2]等人曾以脯氨酸为催化剂,用于分子内不对称醇醛缩合(Aldol)反应,1974年Hajos[3]等… 相似文献
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Yamamoto Y 《The Journal of organic chemistry》2007,72(21):7817-7831
Computed enthalpies of formation for various Lewis acid complexes with representative unsaturated compounds (aldehydes, imines, alkynes, and alkenes) provide a means to evaluate the applicability of a particular catalyst in a catalytic reaction. As expected, main group Lewis acids such as BX3 show much stronger complexes with heteroatoms than with carbon-carbon multiple bonds (sigma-electrophilic Lewis acids). Gold(I) and copper(I) salts with non-nucleophilic anions increase the relative strength of coordination to the carbon-carbon multiple bonds (pi-electrophilic Lewis acids). As representative examples for the use of sigma-electrophilic Lewis acids in organic synthesis, the Lewis acid mediated allylation reactions of aldehydes and imines with allylic organometallic reagents which give the corresponding homoallyl alcohols and amines, respectively, are mentioned. The allylation method is applied for the synthesis of polycyclic ether marine natural products, such as hemibrevetoxin B, gambierol, and brevetoxin B. As representative examples for the use of pi-electrophilic Lewis acids in organic synthesis, the Zr-, Hf-, or Al-catalyzed trans-stereoselective hydro- and carbosilylation/stannylation of alkynes is mentioned. This method is extended to sigma-pi chelation controlled reduction and allylation of certain alkynylaldehydes. Gold- and copper-catalyzed benzannulation of ortho-alkynylaldehydes (and ketones) with alkynes (and alkenes) is discovered, which proceeds through the reverse electron demand Diels-Alder type [4+2] cycloaddition catalyzed by the pi-electrophilic Lewis acids. This reaction is applied for the short synthesis of (+)-ochromycinone. Palladium and platinum catalysts act as a sigma- and/or pi-electrophilic catalyst depending on substrates and reaction conditions. 相似文献
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M. A. Nasseri S. A. Alavi B. Zakeri Nasab 《Journal of the Iranian Chemical Society》2013,10(2):213-219
A versatile, alternative and environmentally benign strategy for the synthesis of a series of pyrazoles has been successfully performed in water using PEG–SO3H as an acidic catalyst. The products are obtained in high yield from the one-pot reaction procedure involving dicarbonyl compounds and hydrazines/hydrazides. This new method totally avoids the use of organic acids and toxic or expensive solvents in this reaction. The catalyst is waste-free, easily prepared, and efficiently re-used. 相似文献
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E. V. Tret’yakova E. V. Salimova E. R. Shakurova L. V. Parfenova V. N. Odinokov 《Russian Journal of Organic Chemistry》2017,53(11):1701-1704
Effective one-pot synthesis of 1,2,3-triazole derivatives of maleopimaric and dihydroquinopimaric acids consists in the reaction of diterpene propargyl esters with organic azides generated in situ in the presence of СuI catalyst. 相似文献
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A Facile Synthesis of Novel Cyclic Esters of γ‐Keto Acid Derivatives by Heck Coupling Reaction 下载免费PDF全文
Nellisara D. Shashikumar G. Krishnamurthy Halehatti S. Bhojyanaik 《Journal of heterocyclic chemistry》2014,51(Z1):E354-E357
γ‐Keto acids and esters are highly useful compounds in organic synthesis, because a number of five‐membered carbocycles and various other heterocycles can be readily obtained from them. A number of γ‐keto acids derivatives have been synthesized with high yield by Heck coupling reaction with different alkenes using Pd(OAc)2 as catalyst in dioxane solvent. The obtained products were characterized by elemental analysis, IR, proton NMR, and mass spectral studies. 相似文献
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Room-temperature Ni0-catalyzed cross-coupling reactions of aryl arenesulfonates with arylboronic acids 总被引:1,自引:0,他引:1
Room-temperature Ni(0)-catalyzed cross-coupling reactions of aryl arenesulfonates with arylboronic acids are described. The Ni(0) catalyst, derived from Ni(COD)2 and PCy3, proved to be a general one for the Suzuki-Miyaura cross-coupling of a variety of aryl arenesulfonates. The mild reaction condition, the readily availability of the catalyst, and excellent coupling yields make aryl arenesulfonates potentially useful substrates in organic synthesis. 相似文献
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研究了不饱和烯酸在有机高价碘催化剂和间氯过氧苯甲酸作用下与氯化锂的反应. 通过该反应, 4-戊烯酸等可在常温下短时间内得到良好产率的氯代γ-丁内酯化合物, 提供了简单快速合成氯代γ-丁内酯的新方法. 考察了反应条件的影响, 并提出了可能的反应机理. 相似文献
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Sadula Sunitha 《Tetrahedron letters》2007,48(39):6962-6965
The first liquid-liquid biphasic synthesis of wax esters in a Lewis acidic ionic liquid, choline chloride·2ZnCl2 by the esterification of long chain carboxylic acids with long chain alcohols is described. The reported reaction system has the advantages of both homogeneous and heterogeneous catalysis with high product yield and the ease of product as well as catalyst separation without the use of an organic solvent. The ionic liquid studied plays the dual role of solvent as well as catalyst and is recycled up to six times without any significant loss of activity. 相似文献
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The instability of carbamate-protected alkyl imines has greatly hampered the development of catalytic asymmetric Mannich reactions suitable for the synthesis of optically active carbamate-protected chiral alkyl amines. A highly enantioselective Mannich reaction with in situ generation of carbamate-protected imines from stable alpha-amido sulfones catalyzed by an organic catalyst was developed. This reaction provides a concise and highly enantioselective route converting aromatic and aliphatic aldehydes into optically active aryl and alkyl beta-amino acids. [reaction: see text]. 相似文献