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51.
Palladium‐Catalyzed C−H Arylation of α,β‐Unsaturated Imines: Catalyst‐Controlled Synthesis of Enamine and Allylic Amine Derivatives
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Minyan Li Dr. María González‐Esguevillas Dr. Simon Berritt Prof. Xiaodong Yang Dr. Ana Bellomo Prof. Dr. Patrick J. Walsh 《Angewandte Chemie (International ed. in English)》2016,55(8):2825-2829
A unique chemo‐ and regioselective α‐ and γ‐arylation of palladium azapentadienyl intermediates is presented. Two distinct catalysts and sets of conditions successfully controlled the regioselectivity of the arylation. These methods provide the first umpolung C?H functionalization of azapentadienyl palladium intermediates and enable the divergent synthesis of allylic amine and enamine derivatives, which are of significant interest in the pharmaceutical industry. 相似文献
52.
Enantioselective Total Syntheses of (−)‐Rhazinilam, (−)‐Leucomidine B,and (+)‐Leuconodine F
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Dylan Dagoneau Dr. Zhengren Xu Dr. Qian Wang Prof. Dr. Jieping Zhu 《Angewandte Chemie (International ed. in English)》2016,55(2):760-763
A divergent total synthesis of three structurally distinct natural products from imine 9 was accomplished through an approach featuring: 1) a Pd‐catalyzed decarboxylative cross‐coupling, and 2) heteroannulation of 9 with bromoacetaldehyde and oxalyl chloride to give tetrahydroindolizine 6 and dioxopyrrole 7 , respectively. The former was converted into (?)‐rhazinilam, while the latter was converted into (?)‐leucomidine B and (+)‐leuconodine F. A substrate‐directed highly diastereoselective reduction of a sterically unbiased double bond by using a homogeneous palladium catalyst was developed. A self‐induced diastereomeric anisochronism (SIDA) phenomenon was observed for leucomidine B. 相似文献
53.
M. Sc. Yen‐Chun Lee Dr. Kamal Kumar Prof. Dr. Herbert Waldmann 《Angewandte Chemie (International ed. in English)》2018,57(19):5212-5226
Chemical tools that enable a catalytic reaction to selectively and efficiently yield different products will allow charting of wider chemical space. In ligand‐directed divergent synthesis, a common mode of catalysis is modulated by employing different ligands for catalytic organometallic complexes to transform either common substrates or common reactive intermediates into distinct molecular scaffolds. The strategy has the potential to create important and diverse scaffolds and to unveil novel modes of catalytic transformations for wider synthetic applications. This strategy is described and recent efforts in this emerging field of catalysis, focusing on transition‐metal catalysis for the synthesis of carbo‐ and heterocyclic ring systems, are reviewed. 相似文献
54.
Yuesen Shi Tianle Huang Ting Wang Jian Chen Xuexin Liu Zhouping Wu Xiaofang Huang Yao Zheng Zhongzhen Yang Prof. Yong Wu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(53):13346-13351
A transition-metal-catalyzed C−H activation cascade strategy to rapidly construct diverse quinazolinone derivatives in a one-pot manner is reported. The catalysts play an important role in the different transformations. Additionally, the procedure is scalable, proceeds with high efficiency and good chemo-/regio-selectivity, and tolerates a range of functional groups. 相似文献
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Almost everywhere strong exponential summability of Fourier series in Walsh and trigonometric systems was established by Rodin in 1990. We prove, that if the growth of a function Φ(t):[0,∞)→[0,∞) is bigger than the exponent, then the strong Φ-summability of a Walsh–Fourier series can fail everywhere. The analogous theorem for trigonometric system was proved before by one of the authors of this paper. 相似文献
58.
Facile synthesis of second-generation dendrons with an aldehyde, epoxy, or t-Boc group at the focal point and nine carboxylic acid groups at the periphery is reported. The scheme includes a coupling of the first-generation dendrons and a two-step, one-pot reaction that proceeds through a Boc deprotection and in situ conjugation at the focal point. 相似文献
59.
Najah Cheriaa Mouna Mahouachi Amel Ben Othman Lassaad Baklouti Yang Kim Rym Abidi 《Supramolecular chemistry》2013,25(3):265-271
A new family of hyperbranched molecules and dendrimers has been constructed from a diamide–dicalix derivative prepared from monocarbomethoxymethyl p-tert-butyl calix[4]arene and tris(2-aminoethyl)amine (‘tren’) via amide-formation reactions. The selective 1,3-di-O-functionalization of p-tert-butyl calix[4]arene moieties allows the synthesis of first- (G1) and second-generation (G2) calix-dendrimers. Replacement of the quadridentate amine by a trithia-ether-triamine-mono-ol, ’hyten’, again results in acylation of the amino groups, but with the generation of a central cavity with different complexing properties. A new family of hyperbranched molecules and dendrimers has been constructed from a diamide–dicalix derivative prepared from monocarbomethoxymethyl p-tert-butyl calix[4]arene and tris(2-aminoethyl)amine (‘tren’) via amide-formation reactions. The selective 1,3-di-O-functionalization of p-tert-butyl calix[4]arene moieties allows the synthesis of first- (G1) and second-generation (G2) calix-dendrimers 相似文献
60.
在具体物理问题情境中设计发散思维测试题,通过取样、测试,制定初步的评分标淮,并根据所得测试分数,应用软件SPSS5.0对学生发散思维进行统计分析,得出发散思维和学生物理考试成绩的相关程度不高(r=0.414),t检验表明男女生发散思维没有显著差异(P>0.05)。 相似文献