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Nicolai Stuhr-Hansen 《Tetrahedron letters》2005,46(33):5491-5494
Microwave heating was applied in high-yield syntheses of alkenes by McMurry coupling of aldehydes and ketones with low-valent titanium. All aldehydes and ketones including sulfur end-capped analogues gave alkenes in isolated yields above 80% without detectable amounts of pinacols. 相似文献
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Prunet J 《Angewandte Chemie (International ed. in English)》2003,42(25):2826-2830
(E)-Alkene units are frequently found in macrocyclic natural products. Among the reactions that form the double bond during the cyclization, the classical Horner-Emmons coupling is still frequently used with success. During the last decade, ring-closing metathesis has emerged as a very powerful tool for the synthesis of large rings, but the E/Z selectivity, which is rarely predictable, depends on many factors which will be discussed in this review. The best solution might be a two-step procedure involving ring-closing alkyne metathesis (RCAM) followed by stereoselective reduction of the macrocyclic alkyne unit to the corresponding E double bond. 相似文献
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Laura H. S. Smith Susannah C. Coote Dr. Helen F. Sneddon Dr. David J. Procter Prof. 《Angewandte Chemie (International ed. in English)》2010,49(34):5832-5844
Since the early 1960s the Pummerer reaction has evolved to become an indispensable tool for synthesis, and continues to serve as a source of inspiration for organic chemists. In recent years, many exciting advances have demonstrated the broad scope and synthetic utility of Pummerer methodology and the versatility of thionium ion intermediates. 相似文献
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Jang YJ Shih YK Liu JY Kuo WY Yao CF 《Chemistry (Weinheim an der Bergstrasse, Germany)》2003,9(9):2123-2128
Stereoselective styryl derivatives have been prepared based on radical substitution (addition-elimination) of heterocycles or cyclohydrocarbons units to (E)-beta-nitrostyrenes 1 using a common radical initiator benzoyl peroxide. High reactivity and selectivity with wide substrate scope were attained by using this easy methodology. The reactions using easily obtained and one-pot potential starting materials gave excellent trans-selectivity with medium to high yields in all cases. Synthetic utility of this approach has been demonstrated by the preparation of various trans-styryl derivatives. 相似文献
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Prof. Dr. John E. Ellis Garry F. Warnock Mikhail V. Barybin Marie K. Pomije 《Chemistry (Weinheim an der Bergstrasse, Germany)》1995,1(8):521-527
Reduction of [TaCl5] by six equivalents of alkali metal naphthalenide in 1,2-dimethoxyethane at −60°C followed by treatment with gaseous PF3 provides the first homoleptic phosphane complex containing tantalum in the −1 oxidation state, [Ta(PF3)6]−. This can be protonated by concentrated sulfuric acid to yield the previously unknown highly acidic and volatile hydride [HTa(PF3)6]. An improved normal-pressure synthesis of [Ta(CO)6]− is described. Reduction of the latter species by sodium in liquid ammonia gives the carbonyl trianion [Ta(CO)5]3− which undergoes monoprotonation and stannylation to form [HTa(CO)5]2− and [Ph3SnTa(CO)5]2−, respectively. The hydride is a useful precursor to [(Ph3PAu)3Ta(CO)5], the only known gold cluster of tantalum. 相似文献
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This review article is a survey of the literature on aminoisoxazoles. It describes the methods of synthesis and chemical reactions of aminoisoxazoles as building blocks for the synthesis of polyfunctionalized heterocyclic compounds. 相似文献
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本文对二环戊二烯基二羰基钛(1),的化学作了较详细的评述。第一部分叙述了合成1的多种不同方法及其结构和性质。第二部分详述了1的各种反应,包括铁金属价态变化的反应和钛价不变的反应。同时也涉及近年来1和其他类型金属有机化合物生成多核金属有机化合物或簇合物的反应。最后还讨论了1对无机小分子的活化反应。 相似文献
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Efficient Synthesis of 2-Arylbenzothiazole Derivatives with the Aid of a Low-Valent Titanium Reagent
A novel and facile synthesis of 2-arylbenzothiazole derivatives was accomplished in good yields via the novel reductive cyclization of bis-(2-benzalaminophenyl)disulfide promoted by the TiCl4/Sm system. The advantages of this new method are the easily accessible starting materials, short reaction time, and moderate to good yields. 相似文献
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Guysolladi 《中国化学会会志》1990,37(6):525-533
The total synthesis of lasiodiplodin via optically active sulfoxides and the preparation of polyenes through low valent titanium reagents are described. 相似文献
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The focus of our review is on the methods of synthesis and chemical reactivity of 2-pyridone and some derivatives as 2-chloro-3-nicotinonitrile in addition to the biological activity of the 2-pyridone moiety. 相似文献
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Influence of Catalyst Structure and Reaction Conditions on anti‐ versus syn‐Aminopalladation Pathways in Pd‐Catalyzed Alkene Carboamination Reactions of N‐Allylsulfamides 下载免费PDF全文
Ryan M. Fornwald Prof. Dr. Jonathan A. Fritz Prof. Dr. John P. Wolfe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(28):8782-8790
The Pd‐catalyzed coupling of N‐allylsulfamides with aryl and alkenyl triflates to afford cyclic sulfamide products is described. In contrast to other known Pd‐catalyzed alkene carboamination reactions, these transformations may be selectively induced to occur by way of either anti‐ or syn‐aminopalladation mechanistic pathways by modifying the catalyst structure and reaction conditions. 相似文献