在含有微量水的 MeCN 中,在Et 3 N 存在下,分子碘介导的 3-乙酰基-2 H -chromen -2-ones、β-溴代-β-硝基苯乙烯和吡啶合成角氧杂三嗪核心是发达。该反应通过 2-oxo-2-(2-oxo-2 H -chromen-3-yl)-1-(pyridin-1-ium-1-yl)ethan-1-ide 与溴硝基苯乙烯的分子间迈克尔反应进行通过分子内迈克尔反应和消除步骤。典型产品的立体化学证据来自单晶 X 射线分析。该策略的重要特征是它形成了三个具有良好选择性的立体中心。
Quinonoid compounds via reactions of lawsone and 2-aminonaphthoquinone with α-bromonitroalkenes and nitroallylic acetates: Structural diversity by C-ring modification and cytotoxic evaluation against cancer cells
作者:Thekke V. Baiju、Renata G. Almeida、Sudheesh T. Sivanandan、Carlos A. de Simone、Lucas M. Brito、Bruno C. Cavalcanti、Claudia Pessoa、Irishi N.N. Namboothiri、Eufrânio N. da Silva Júnior
DOI:10.1016/j.ejmech.2018.03.079
日期:2018.5
Morita-Baylis-Hillmanacetates and α-bromonitroalkenes have been employed in cascade reactions with lawsone and 2-aminonaphthoquinone for the one-pot synthesis of heterocycle fused quinonoid compounds. The reactions reported here utilized the 1,3-binucleophilic potential of hydroxy- and aminonaphthoquinones and the 1,2/1,3-bielectrophilic potential of bromonitroalkenes and Morita-Baylis-Hillman acetates
Imidazoles from nitroallylic acetates and α-bromonitroalkenes with amidines: synthesis and trypanocidal activity studies
作者:Elumalai Gopi、Tarun Kumar、Rubem F. S. Menna-Barreto、Wagner O. Valença、Eufrânio N. da Silva Júnior、Irishi N. N. Namboothiri
DOI:10.1039/c5ob01444a
日期:——
Cascade reactions of amidines with nitroallylic acetates and α-bromonitroalkenes provide potentially bioactive imidazoles in good to excellent yields in most cases. While 2,4-disubstituted imidazol-5-yl acetates are formed in the first case, 2,4-disubstituted imidazoles, bearing no substituent at position 5, are the products in the second case. These two series of imidazoles, viz. 2,4,5-trisubstituted
A Highly Enantioselective Synthesis of Functionalized 2,3-Dihydrofurans by a Modified Feist-Bénary Reaction
作者:Xiaowei Dou、Fangrui Zhong、Yixin Lu
DOI:10.1002/chem.201202504
日期:2012.10.29
Organocatalysis: A modifiedFeist–Bénaryreaction employing acyclic β‐ketoesters as the dinucleophile and (E)‐β,β‐bromo nitrostyrenes as the dielectrophile was developed for the asymmetric synthesis of 2,3‐dihydrofurans. L‐Threonine‐derived tertiary amine/thiourea catalysts were found to be the most efficient catalysts, inducing the reaction in a highlyenantioselective manner (see scheme; TBDPS=t
Highly Chemoselective [2+1] Annulation of α-Alkylidene Pyrazolones with α-Bromonitroalkenes: Synthesis of Pyrazolone-Based Vinylcyclopropanes and Computational Studies
作者:Ya-Jun Zhong、Ting Qi、Yan-Ling Ji、Hua Huang、Xiang Zhang、Hai-Jun Leng、Cheng Peng、Jun-Long Li、Bo Han
DOI:10.1021/acs.joc.0c02674
日期:2021.2.5
A highly chemoselective [2+1] annulation of α-alkylidene pyrazolones with α-bromonitroalkenes has been achieved undermildconditions. α-Alkylidene pyrazolones were unprecedentedly used as a C1 synthon to participate in annulation reactions, providing access to diverse vinylcyclopropane-based pyrazolone products. In addition, a spectrum of pharmaceutically interesting pyrazole-fused pyranone oximes
ylidene)acetonitriles, undergo a formal Huisgen 1,3-dipolarcycloaddition with β-bromo-β-nitrostyrenes to afford a diastereoselective synthesis of highly substituted pyrrolidin-2-ylidene derivatives. When β-nitrostyrenes were used as the alkene component, 2-(4,5-diaryl-1,5-dihydro-2H-pyrrol-2-ylidene)-1H-indene-1,3(2H)-diones were obtained. Efficient conversion of pyrrolidene-2-ylidenes to the corresponding
氢键辅助的偶氮甲碱叶立德,由 2-(苄氨基)-2-(1,3-二氧代-1,3-二氢-2 H-茚-2-亚基)乙腈生成,经过正式的 Huisgen 1,3-与 β-溴-β-硝基苯乙烯的偶极环加成反应非对映选择性合成高度取代的吡咯烷-2-亚基衍生物。当使用β-硝基苯乙烯作为烯烃组分时,2-(4,5-二芳基-1,5-二氢-2H-吡咯-2-亚基)-1H-茚-1,3(2H ) -二酮获得。在过量 Et 3 N存在下,在回流 1-丙醇中,吡咯烷-2-亚基有效转化为相应的吡咯-2-亚基。此外,通过 X 射线测定了吡咯烷-2-亚基衍生物的结构晶体学。