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《Tetrahedron letters》1987,28(33):3815-3816
Isocyanates react with isopropyl or sec-butylmagnesium bromide in the presence of a small amount of Cp2TiCl2 to afford amides with normal alkyl group. A possibl mechanism for this reaction is proposed. 相似文献
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A novel coupling reaction of diaryl methanols with ketones or aldehydes has been developed under the catalysis of AlCl3. Various ketones and aldehydes could couple with 9H-xanthen-9-ol smoothly, affording coupling products in 48% –88% yields. A plausible mechanism using AlCl3 to activate both diaryl methanol and ketone or aldehyde is proposed. 相似文献
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《Tetrahedron letters》1988,29(6):651-652
Phenylisocyanate and phenylthioisocyanate react with Grignard reagents in the presence of a small amount of Cp2TiCl2 at room temperature to afford reduction-coupling products, N-methyl-N, N′-diphenylurea and N-methyl-N, N′-diphenylthiourea. 相似文献
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Reductive coupling of aldimines into vicinal diamines mediated with samarium catalyzed by Cp2TiCl2 proceeds in refluxing THF with good yields. 相似文献
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在一般情况下,格氏试剂与酰卤偶合反应难以控制在酮阶段,往往得到叔醇。在较低温度下有机铜试剂与酰卤偶合可高产率地得到酮,所以用固体铜盐CuX(X=Cl、Br、I)作为格氏试剂与酰卤偶合的催化剂,可以提高反应的选择性,从而提高酮的产率。但固体铜盐的催化反应仅适合于空间位阻较大的脂肪酮和某些芳香酮的制备,对于直链脂肪酮的制备则产率很低。我们采用可溶性铜络合物Li_2Cucl_4(四氯合铜酸锂)等作催化剂,在均相溶液中反应,有效地提高了催化效果及反应的选择性,从而使格氏试剂与酰卤的偶合反应成功地用于直链脂肪酮的制备,产率良好。 相似文献
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Meunier 等曾研究了 Cp_2TiCl_2催化下,格氏试剂对卤代烷和羰基化合物的还原反应,并报道了与芳环或碳-碳双键或碳-碳三键共轭的羰基化合物不被格氏试剂还原。我们却发现,在较低温度下,这些芳醛或与碳-碳重键共轭的羰基化合物也会被还原,特别是在芳环上有吸电子取代基时,还原产物的产率很高。 相似文献
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The pinacolic coupling of aromatic aldehydes and ketone was performed with cerium trichloride and samarium in THF at room temperature to afford the corresponding 1,2‐diols in good yields. 相似文献
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The reaction of 2-alkyl-l, 3-dimethylbenzimidazolinm salts with Grignard reagents gave addition products which were hy-drelyzed to give ketones. A new method for the preparation of cyclohexyl ketones and isopropyl ketones is provided. 相似文献
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Dr. Takanori Iwasaki Ryo Akimoto Prof. Dr. Hitoshi Kuniyasu Prof. Dr. Nobuaki Kambe 《化学:亚洲杂志》2016,11(20):2834-2837
Iron‐catalyzed cross‐coupling reaction of vinylic ethers with aryl Grignard reagents is described. The reaction proceeded at room temperature with catalytic amounts of an iron salt without the aid of costly ligands and additives. In this catalytic system, vinylic C?O bonds were preferentially cleaved over aromatic C?O bonds of aryl ethers or aryl sulfonates. 相似文献
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Continuous Flow Synthesis of Ketones from Carbon Dioxide and Organolithium or Grignard Reagents
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Dr. Jie Wu Dr. Xiaoqing Yang Dr. Zhi He Dr. Xianwen Mao Prof. Dr. T. Alan Hatton Prof. Dr. Timothy F. Jamison 《Angewandte Chemie (International ed. in English)》2014,53(32):8416-8420
We describe an efficient continuous flow synthesis of ketones from CO2 and organolithium or Grignard reagents that exhibits significant advantages over conventional batch conditions in suppressing undesired symmetric ketone and tertiary alcohol byproducts. We observed an unprecedented solvent‐dependence of the organolithium reactivity, the key factor in governing selectivity during the flow process. A facile, telescoped three‐step–one‐flow process for the preparation of ketones in a modular fashion through the in‐line generation of organometallic reagents is also established. 相似文献
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The pinacolic coupling of aromatic aldehydes and ketones was performed with samarium/mercury amalgam in THF at room temperature to afford the corresponding 1,2-diols in good yields. 相似文献
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Dzhemilev U. M. Ibragimov A. G. Khafizova L. O. Khalilov L. M. Vasil"ev Yu. V. Tomilov Yu. V. 《Russian Chemical Bulletin》2001,50(2):297-299
1-Ethyl-2,3-fullerenoaluminacyclopropanes (EtAl)n(2-C60) were synthesized by the reaction of fullerene C60 with an excess of EtAlCl2 in the presence of Mg and using Cp2TiCl2 as the catalyst in a THF--toluene solution at 20 °C. Deuterolysis of fullerenoaluminacyclopropanes afforded a mixture of deuteriofullerenes C60Dm, where m = 6--12. 相似文献
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Melissa Moss Xinping Han Prof. Joseph M. Ready 《Angewandte Chemie (International ed. in English)》2016,55(34):10017-10021
Organozirconocenes are versatile synthetic intermediates that can undergo carbonylation to yield acyl anion equivalents. Zirconocene hydrochloride ([Cp2ZrHCl]) is often the reagent of choice for accessing these intermediates but generates organozirconocenes only from alkenes and alkynes. This requirement eliminates a broad range of substrates. For example, organozirconocenes in which the zirconium center is bonded to an aromatic ring, a benzylic group, or an alkyl group that possesses a tertiary or quaternary carbon atom α to the carbon–zirconium bond can not be formed in this way. To provide more generalized access to acyl zirconium reagents, we explored the transmetalation of Grignard reagents with zirconocene dichloride under a CO atmosphere. This protocol generates acyl zirconium(IV) complexes that are inaccessible with the Schwartz reagent, including those derived from secondary and tertiary alkyl and aryl Grignard reagents. 相似文献
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《Journal of organometallic chemistry》1986,302(2):181-191
Stoichiometric reactions of Cp2TiCl2 or CpTiCl3 with Li3N in various molar ratios result in reduction to (Cp2TiCl)2, (CpTiCl2)n and (CpTiCl)4 and provide useful synthetic routes. Further reduction produces hexanuclear nitrido titanium clusters, Cp8Ti6N and Cp8Ti6N3, characterised from mass spectral evidence. The nitrido clusters react with HCl to form (Cp2TiCl)2 and Cp2TiCl2. (Cp2TiCl2 is also obtained by reaction with Me3SiCl. Cp2Ti(CO)2 is formed by the reaction between Cp2TiCl2 and Li3 N in THF in the presence of CO. 相似文献
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The effect of reflected sunlight on the formation of Grignard reagents has been reported1. In the present work irradiation of mixtures of magnesium turnings and organic halides in dry diethyl ether by the method of Evans et al.2 gave elevated yields of Grignard reagents as compared to those achieved in control experiments carried out in the absence of light. Four organic halides: 2-bromofluorene, 2-bromothiophene, chlorobenzene and chlorodiphenylmethane were selected for study in the light of their reputed poor performance in the Grignard reaction3. A quantitative estimate of the amount of Grignard reagent formed in each reaction was carried out by the method of Gorog and Szepesi4. The experimental results are shown in the table. 相似文献