Zn-Catalyzed Enantio- and Diastereoselective Formal [4 + 2] Cycloaddition Involving Two Electron-Deficient Partners: Asymmetric Synthesis of Piperidines from 1-Azadienes and Nitro-Alkenes
作者:John C. K. Chu、Derek M. Dalton、Tomislav Rovis
DOI:10.1021/jacs.5b00033
日期:2015.4.8
We report a catalytic asymmetricsynthesis of piperidines through [4 + 2] cycloaddition of 1-azadienes and nitro-alkenes. The reaction uses earth abundant Zn as catalyst and is highly diastereo- and regioselective. A novel BOPA ligand (F-BOPA) confers high reactivity and enantioselectivity in the process. The presence of ortho substitution on the arenes adjacent to the bis(oxazolines) was found to
Modular Synthesis of Stereodefined Benzocyclobutene Derivatives via Sequential Cu- and Pd-Catalysis
作者:Fabien J. T. Talbot、Shibo Zhang、Bishnupada Satpathi、Gareth P. Howell、Gregory J. P. Perry、Giacomo E. M. Crisenza、David J. Procter
DOI:10.1021/acscatal.1c04496
日期:2021.12.3
materials and medicinal chemistry, although general routes for their provision remain underexplored. A modular, divergent, and stereoselective Cu- and Pd-catalyzed assembly/cyclization sequence allows the synthesis of densely functionalized BCBs, from readily accessible imine, allene, and diboron precursors. Preliminary results have identified enantioselective conditions for our protocol and highlighted,
苯并环丁烯 (BCB) 对材料和药物化学的兴趣越来越大,尽管其提供的一般途径仍未得到充分探索。模块化、发散和立体选择性的 Cu 和 Pd 催化的组装/环化序列允许从容易获得的亚胺、丙二烯和二硼前体合成密集功能化的 BCB。初步结果已经确定了我们协议的对映选择性条件,并强调了,例如,它适用于合成含 BCB 的肽。通过实验条件的简单变化或底物修饰,我们的策略扩展到提供二氢吲哚和喹啉衍生物,适合进一步操作。
Recyclable palladium catalyst for facile synthesis of imines from benzyl alcohols and nitroarenes
作者:Jing Chen、Shijun Huang、Jin Lin、Weiping Su
DOI:10.1016/j.apcata.2013.10.033
日期:2014.1
Using a supported palladium catalytic system, the reaction of nitroarenes with benzyl alcohols occurred smoothly via hydrogen transfer to produce imines in an atom-economical manner. The palladium species were dispersed well on hydrotalcite (HT) support and palladium nanoparticles with size of about 3.5 nm were formed during reaction. Both of the small size of palladium nanoparticles and the rich hydroxyl groups on HT surface enhanced the catalytic performance of Pd/HT. The catalytic system is recyclable and amenable to a variety of aromatic alcohols and nitro compounds. (C) 2013 Elsevier B.V. All rights reserved.
Synthesis of Schiff bases of 4-(4-aminophenyl)-morpholine as potential antimicrobial agents
作者:Perumal Panneerselvam、Rajasree R. Nair、Gudaparthi Vijayalakshmi、Ekambaram Harihara Subramanian、Seshaiah Krishnan Sridhar
DOI:10.1016/j.ejmech.2004.09.003
日期:2005.2
In the present study, a novel series of Schiff bases of 4-(4-aminophenyl)-morpholinewere synthesised and characterised by IR, H-1-NMR, C-13-NMR, Mass spectral and elemental analysis. The compounds were screened for antibacterial (Staphylococcus aureus (ATCC 9144), Staphylococcus epidermidis (ATCC 155), Bacillus cereus (ATCC 11778), Micrococcus luteus (ATCC 4678), and Escherichia coli (ATCC 25922)) and antifungal (Candida albicans (ATCC 2091) and Aspergillus niger (ATCC 9029)) activities. The minimum inhibitory concentrations of the compounds were also ascertained by agar streak dilution method. 4-(4-(4-Hydroxy-benzylidene-imino)phenyl)-morpholine (7) was found to be the most potent antimicrobial activity with MIC of 25, 19, 21, 16, 29, 20 and 40 mug/ml against S. aureus, S. epidermidis, B, cereus, M. luteus, E. coli, C albicans and A. niger, respectively. All the other compounds exhibited moderate activity against the bacterial and fungal organisms tested. (C) 2005 Elsevier SAS. All rights reserved.
Synthesis of Indolines via Base‐Mediated C−H Activation and Defluorinative C−N Coupling, with no Need for Transition‐Metals
作者:Christian Weindl、Lukas Hintermann
DOI:10.1002/chem.202401034
日期:2024.7.2
Syntheses of (partially) aromatic nitrogen heterocycles increasingly rely on transition‐metal catalyzed C−C‐ and C−N‐cross‐coupling reactions. Here we describe a different approach to the synthesis of indolines by a domino C(sp3)−H activation, 1,2‐addition, and defluorinative SNAr‐cyclization sequence to provide the target 1,2‐diarylindolines (1,2‐diaryl‐2,3‐dihydroindoles) from ortho‐fluorinated methyl‐arenes and N‐aryl imines (benzylidene anilines) in a cyclocondensation that is mediated by potassium hexamethyldisilazide (KHMDS) as base exclusively. This transition‐metal‐free process via C−H and C−F bond activation provides a one‐step entry into a wide array of indoline scaffolds (43 examples, up to 96 % yield). This privileged substructure is common in natural products and pharmaceuticals alike, and cannot be accessed by traditional condensation reactions.