Palladium-Catalyzed Enantioselective Cycloaddition of Carbonylogous 1,4-Dipoles: Efficient Access to Chiral Cyclohexanones
作者:Barry M. Trost、Zhiwei Jiao
DOI:10.1021/jacs.0c11535
日期:2020.12.30
A novel palladium-mediated carbonylogous 1,4-dipole was developed by in situ deprotonation. By using our own-developed C2-unsymmetric phosphoramidite as supporting ligand, this dipole was applied to the asymmetric synthesis of chiral cyclohexanones via a catalytic [4+2] cycloaddition. Electron-deficient allyliccarbonate was used to generate the highly reactive palladium-mediated dipoles for the first
Synthesis and Visible Spectral Behaviour of Some New N-Bridgehead Heterocyclic Cyanine Dyes Incorporating Pyrazolo (4,5-b) Indolizine (Benzoindolizine)
作者:A. I. M. Koraiem、R. M. Abd El-Aal、N. S. Mohammed
DOI:10.1002/jccs.200200088
日期:2002.8
dimethine, meso substituted tetramethine and styryl cyanine dyes incorporating pyrazolo (4,5-b) indolizine (benzoindolizine) nuclei were prepared. Structural confirmation was carried out by elemental analyses, IR, H-NMR, massspectra and 13C-NMR with the aid of carbon DEPT spectral data. The visible absorption spectra for the newly synthesized cyanines were examined in 95% ethanol.
Convenient Selective Synthesis of Substituted Pyrido[2,3-d]pyrimidones and Annulated Derivatives
作者:Wafaa S. Hamama、Mohamed A. Ismail、Hana’a A. Al-Saman、Hanafi H. Zoorob
DOI:10.1515/znb-2007-0115
日期:2007.1.1
6-carboethoxy-3,5-diphenyl-2-cyclohexenone (13) or 2,6- bis(phenylmethylidene)cyclohexanone (15) afforded the corresponding pyrimido[4,5-d]quinoline- 2,4-diones 12, 14 and 16, respectively. Furthermore, a pyrido[2,3-d]pyrimidine incorporating 3,2’- bis(quinoline) derivative 18 was synthesized. Annulation of pyrido[2,3-d]pyrimidine with pyrazole or imidazole moieties was achieved via reaction of 1 with benzylidene
Efficient Synthesis of 4,7-Dihydro-1H-oxepino[2,3-c]pyrazoles by Potassium Carbonate Promoted [4+3] Annulation of Crotonate-Derived Sulfur Ylides with Benzylidenepyrazolones
作者:Dian Wang、Xue Wang、Xuange Zhang、Zhiwei Miao
DOI:10.1055/s-0037-1610693
日期:2019.5
crotonate-derived sulfurylides with benzylidenepyrazolones using K2CO3 as the base is reported. The ready availability of starting materials and the simple cyclization procedure make this approach suitable for the preparation of a diverse array of 4,7-dihydro-1H-oxepino[2,3-c]pyrazoles in good to excellent yields. The [4+3] annulation reaction of crotonate-derived sulfurylides with benzylidenepyrazolones
专用于100的庆典日南开大学周年 抽象的 报道了以K 2 CO 3为碱的巴豆酸衍生的硫酰化物与亚苄基吡唑并酮的[4 + 3]环化反应。原料的容易获得和简单的环化程序使该方法适用于以良好或优异的收率制备各种4,7-二氢-1 H-氧代庚并[2,3- c ]吡唑。 报道了以K 2 CO 3为碱的巴豆酸衍生的硫酰化物与亚苄基吡唑并酮的[4 + 3]环化反应。原料的容易获得和简单的环化程序使该方法适用于以良好或优异的收率制备各种4,7-二氢-1 H-氧代庚并[2,3- c ]吡唑。