共查询到20条相似文献,搜索用时 15 毫秒
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Zhi-Zhou Pan Jia-Heng Li Hu Tian Prof. Liang Yin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(1):e202315293
Catalytic asymmetric allylation of ketones under proton-transfer conditions is a challenging issue due to the limited pronucleophiles and the electrophilic inertness of ketones. Herein, a copper(I)-catalyzed asymmetric allylation of ketones with 2-aza-1,4-dienes (N-allyl-1,1-diphenylmethanimines) is disclosed, which affords a series of functionalized homoallyl tertiary alcohols in high to excellent enantioselectivity. Interestingly, N-allyl-1,1-diphenylmethanimines work as synthetic equivalents of propanals. Upon the acidic workup, a formal asymmetric β-addition of propanals to ketones is achieved. An investigation on KIE effect indicates that the deprotonation of N-allyl-1,1-diphenylmethanimines is the rate-determining step, which generates nucleophilic allyl copper(I) species. Finally, the synthetic utility of the present method is demonstrated by the asymmetric synthesis of (R)-boivinianin A and (R)-gossonorol. 相似文献
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对D-(-)-酒石酸异丙酯修饰的烯丙基硼试剂与苯甲醛的不对称烯丙基化反应机理进行了研究. 反应中间体和过渡态进行B3LYP/6-31G(d,p)全优化, 发现主要经六元环椅式过渡态生成手性烯丙基羟基化合物. 由相对反应速率理论,预测的主产物构型与实验的R-手性醇相吻合. 相似文献
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Gavrilov K. N. Tsarev V. N. Lubimov S. E. Zheglov S. V. Davankov V. A. 《Russian Journal of Coordination Chemistry》2004,30(10):685-691
Chiral ferrocene-containing iminoarylphosphite ligands based on 4,4-dimethoxy-6,6-di-tert-butyl-biphenyldiol-2,2 and their chelate complexes with Rh(I) and Pd(II) were synthesized for the first time. They were shown to be perspective reagents in the reactions of asymmetric allyl substitution. The Pd-catalyzed alkylation of 1,3-diphenylallylacetate with dimethyl malonate results in a 87% enantiomer excess (ee), while in sulfonylation of 1,3-diphenylallylacetate with sodium para-toluenesulfinite, this figure amounts to 67%. The results obtained were compared with coordination and catalytic efficiency of a less sterically hindered ferro-cenyliminophosphite based on pyrocatechol. The compositions and structures of new compounds were determined by the 1H, 13C, 31P NMR, IR, mass spectrometry (EI, FAB, and electrospray techniques), and elemental analysis. 相似文献
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非对称双(均三唑席夫碱)衍生物的合成及抗肿瘤活性 总被引:2,自引:0,他引:2
为寻找新结构的水溶性抗癌先导化合物, 采用氨基均三唑硫代苯丙酮(1)与氨基均三唑硫醇(2a~2e)缩合得双均三唑单席夫碱化物3a~3e, 接着依次与氨基氯乙烷和水杨醛进行亲核取代和缩合反应, 分别得到含碱性侧链的单席夫碱4a~4e和非对称双席夫碱5a~5e. 所合成新化合物的结构经元素分析和光谱数据表征, 用甲基四噻唑蓝比色法(MTT)对新化合物进行了对于CHO, HL60和L1210 3种癌细胞株的体外活性试验. 在合成的15个新化合物中, 双席夫碱结构的抗癌活性最强, 其IC50值在20.0 μmol•L-1以下, 尤其是均三唑环连有双供电子取代基时(如化合物5c), 表现出潜在的活性, 其抗癌活性与上市药物比生群相当, 具有侯选药物研究的价值. 相似文献
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D. P. Kiryukhin 《High Energy Chemistry》2005,39(5):291-294
Non-steady-state kinetic measurements on the radiation-initiated polymerization of diethylene glycol bis(methacryloyloxyethyl carbonate) (OKM-2) were made over a wide range of conversions at various reaction temperatures. The polymer-chain propagation and termination rate constants were determined and compared with those for other monomers and oligomers.__________Translated from Khimiya Vysokikh Energii, Vol. 39, No. 5, 2005, pp. 339–342.Original Russian Text Copyright © 2005 by Kiryukhin. 相似文献
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Introduction.Poly(N-vinylcarbazole)(PVCZ)hasreceivedmuchattentionasarepresentativephotoconductivepolymerandextensivestudiesonmechanical,physical,chemicalandelectricalpropertieshavebeenreported"'.Ingeneral,thePVCZobtainedbyradicalandordinarycanonpolym... 相似文献
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Novel chiral bisformamides have been prepared from (R,R)-1,2-cyclohexanediamine and utilized as Lewis bases in the asymmetric allylation of benzaldehyde with allyltrichlorosilane. The reaction in the presence of Lewis base 1i gave an 83:17 enantiomeric ratio (R/S) of the products in 90% isolated yield. 相似文献
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Laura E. N. Allan Jarret P. MacDonald Amy M. Reckling Christopher M. Kozak Michael P. Shaver 《Macromolecular rapid communications》2012,33(5):414-418
Tetradentate amine–bis(phenolate) iron(III) halide complexes containing chloro substituents on the aromatic ring are extremely efficient catalysts for controlled radical polymerization. Molecular weights are in good agreement with theoretical values and polydispersity indexes (PDIs) are as low as 1.11 for styrene and methyl methacrylate polymerizations. Complexes containing alkyl substituents on the aromatic ring are less efficient. Kinetic data reveal activity for styrene polymerization among the fastest reported to date and initial studies implicate a multimechanism system. Despite the highly colored polymerization media, simple work‐up procedures yield pure white polymers. 相似文献
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New Bis(arylimino)pyridyl Complexes as Components of Catalysts for Ethylene Polymerization 总被引:1,自引:0,他引:1
Ivanchev S. S. Tolstikov G. A. Badaev V. K. Oleinik I. I. Ivancheva N. I. Rogozin D. G. Oleinik I. V. Myakin S. V. 《Kinetics and Catalysis》2004,45(2):176-182
A new series of 2,6-bis(arylimino)pyridineiron(II) complexes with cycloaliphatic (cyclopentyl, cyclohexyl, cyclooctyl, and cyclododecyl) substituents in the ortho position of the aryl ring are synthesized and studied as components for ethylene polymerization catalysts. Methylaluminoxane is used as an activator for the complexes. The resulting catalytic systems are more active in polymerization at elevated temperatures (60–80°C) than previously described systems based on substituted 2,6-bis(arylimino)pyridines. The influence of the number of CH2 groups in a cycloaliphatic substituent on the efficiency of the catalytic system is studied. Polymers formed are characterized by an increased molecular weight, high density, and high crystallinity. 相似文献
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Nan Jiang Pei-Zhi Liu Zhi-Zhou Pan Si-Qing Wang Prof. Dr. Qian Peng Prof. Dr. Liang Yin 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(21):e202402195
Chiral trisubstituted vicinal diols are a type of important organic compounds, serving as both common structure units in bioactive natural products and chiral auxiliaries in asymmetric synthesis. Herein, by using siloxypropadienes as the precursors of allyl copper(I) species, a copper(I)-catalyzed diastereoselective and enantioselective reductive allylation of ketones was achieved, providing both syn-diols and anti-diols in good to excellent enantioselectivity. DFT calculations show that cis-γ-siloxy-allyl copper species are generated favorably with either 1-TBSO-propadiene or 1-TIPSO-propadiene. Moreover, the steric difference of TBS group and TIPS group distinguishes the face selectivity of acetophenone, leading to syn-selectivity for 1-TBSO-propadiene and anti-selectivity for 1-TIPSO-propadiene. Easy transformations of the products were performed, demonstrating the synthetic utility of the present method. Moreover, one chiral diol prepared in the above transformations was used as a suitable organocatalyst for the catalytic asymmetric reductive self-coupling of aldimines generated in situ with B2(neo)2. 相似文献