Synthesis of 3,3-diphenyl-3H-pyrazoles applying vinyl sulfones as chemical equivalents of acetylenes in reaction of 1,3-dipolar cycloaddition to diphenyldiazomethane
作者:V. A. Vasin、V. V. Razin、E. V. Bezrukova、D. Yu. Korovin、P. S. Petrov、N. V. Somov
DOI:10.1134/s1070428015080138
日期:2015.8
α-bromovinyl phenylsulfones and a-bromovinyl methyl sulfones with diphenyldiazomethane afforded the corresponding 3-bromo- 5,5-diphenyl-3-sulfonyl-Δ1-pyrazolines. The first among them at 20°C suffered spontaneous elimination of molecular nitrogen and converted into 1-bromo-2,2-diphenyl-1-(phenylsulfonyl)cyclopropane whose structure was established by X-ray diffraction analysis. The action of DBU on another
An efficient and straightforward route to terminal vinyl sulfones via palladium-catalyzed Suzuki reactions of α-bromo ethenylsulfones
作者:Yewen Fang、Meijuan Yuan、Juncong Zhang、Li Zhang、Xiaoping Jin、Ruifeng Li、Jinjian Li
DOI:10.1016/j.tetlet.2016.02.065
日期:2016.3
A general and simple protocol for the synthesis of α-substituted alkenylsulfones has been developed firstly via palladium-catalyzed Suzuki reactions between α-bromo ethenylsulfones and organoborons. Using a catalyst composed of Pd(OAc)2 and SPhos, a variety of aryl, heteroaryl, and alkylboron reagents could efficiently couple with α-bromo ethenylsulfones under mild conditions. Moreover, it has been
Improved Heteroatom Nucleophilic Addition to Electron-Poor Alkenes Promoted by CeCl<sub>3</sub>·7H<sub>2</sub>O/NaI System Supported on Alumina in Solvent-Free Conditions
environmental consciousness in chemical research, the solvent-freeMichaeladdition has attracted our attention. In continuation of our ongoing program to develop synthetic protocols utilizing cerium trichloride, we report an extension of the CeCl3·7H2O/NaI combination supported undersolvent-freeconditions to promote heteroatom Michaeladdition. Using neutral alumina (Al2O3) as solid support permits us
杂原子亲核试剂与强吸电子基团共轭的碳-碳双键的共轭加成是合成有机化学中最重要的新成键策略之一。在这些迈克尔加成方法中,路易斯酸已显示出最佳的启动子活性,特别是,浸渍在无机载体上的试剂的使用正在迅速增加。随着化学研究中环境意识的增强,无溶剂迈克尔的加入引起了我们的关注。在我们正在进行的利用三氯化铈开发合成方案的计划的继续中,我们报告了CeCl 3 ·7H 2的扩展O / NaI组合在无溶剂条件下得到支持,以促进杂原子迈克尔的加成。使用中性氧化铝(Al 2 O 3)作为固体载体可以避免某些与无机载体为硅胶的过程相关的问题。CeCl 3 ·7H 2 O / NaI / Al 2 O 3该系统对于利用弱亲核试剂(例如咪唑和氨基甲酸酯)的杂配迈克尔加成反应很好,并且在不同于α,β-不饱和羰基化合物的迈克尔受体的情况下,反应也以良好的收率进行。该方法的重要合成应用是生产4-哌啶酮衍生物时的分子内氮杂-
α-Trifluoromethyl Carbanion-catalyzed Intermolecular Stetter Reaction of Aromatic Aldehydes with 2-Bromo-3,3,3-trifluoropropene: Synthesis of β-Alkoxyl-β-trifluoromethylated Ketones
作者:Yingying Cai、Huanfeng Jiang、Chuanle Zhu
DOI:10.1021/acs.orglett.1c03553
日期:2022.1.14
intermolecular Stetter reaction of aromaticaldehydes with 2-bromo-3,3,3-trifluoropropene is achieved by the in situ generated α-trifluoromethyl carbanion catalyst. It not only represents the first example for α-trifluoromethyl carbanion-catalyzed umpolung reaction but also reveals a new protocol for the umpolung of aldehydes. Various useful β-alkoxyl-β-trifluoromethylated ketones were obtained in high yields