Regioselective addition of pyrrole to methyl 3-aryl-2-cyanoacrylates was achieved, in high yields, with copper(II) triflate as the catalyst in toluene. C-Alkylated pyrroles afforded novel pyrrolizin-3-ones, in good to high yields and high diastereomeric ratio by an intramolecular cyclization reaction under mild reaction conditions.
α-proton in the cyclization process. The acidity dependence of the cyclization reactions and 13C NMR studies of a model compound, methyl cyanoacetate, in various acidic media were consistent with the involvement of the O,N-diprotonated dication of methyl cyanoacetate, a distonic dication, in strong acid, and this is considered to be the de facto electrophile in the present cyclization reaction of arylcyanopropionates
我们介绍了芳基氰基丙酸酯的超强酸催化的分子内环化反应,以中等至高收率得到环化的五元和六元β-烯胺酯。质子化的腈与芳族碳原子的已知分子内闭环反应限于6元情况。有趣的是,观察到的氰基官能度反应性的显著协同增加,和氰基的氮原子被转化成氨基,当酯基存在于一个孪位的布置。氘交换实验排除了α-质子去质子化在环化过程中的参与。环化反应和13的酸度依赖性在各种酸性介质中对模型化合物氰基乙酸甲酯的13 C NMR研究与强酸中氰基乙酸甲酯的O,N-二质子化指示剂(二元体指示剂)在强酸中的参与一致,这被认为是事实上的亲电子试剂。在本发明的芳基氰基丙酸酯的环化反应中。
Diastereoselective Synthesis of Spiro[2.3]hexanes from Methylenecyclopropane and Cyanoalkenes Catalyzed by a Tin-Ate Complex
with cyanoaokenes substituted with ester groups catalyzed by a Sn and Mg ate complex. The diastereoselectivity was affected by the halogen of the catalyst and electron‐withdrawing groups on the cyanoalkene. The transformation of the spirohexane was carried out to afford a cyclopentanoid which has been prepared only by a transition metal catalyst.
Microporous polyurethane material for size selective heterogeneous catalysis of the Knoevenagel reaction
作者:Sandeep Kumar Dey、Nader de Sousa Amadeu、Christoph Janiak
DOI:10.1039/c6cc02578a
日期:——
The first polyurethane material which is microporous (BET surface area of 312 m2 g‒1) is prepared by solvothermal synthesis and acts as highly efficient and recyclable heterogeneous catalyst in the...
Design and Construction of a Chiral Cd(II)-MOF from Achiral Precursors: Synthesis, Crystal Structure and Catalytic Activity toward C–C and C–N Bond Forming Reactions
作者:Vijay Gupta、Sanjay K. Mandal
DOI:10.1021/acs.inorgchem.8b03307
日期:2019.3.4
dicarboxylic acid (H2L) and a conformationally flexible bidentate linker (bpp), a thermally stable chiral metalorganicframework [Cd(bpp)(L)(H2O)]·DMF}n (1), where H2L = 4,4′-(dimethylsilanediyl)bis-benzoic acid, bpp = 1,3-bis(4-pyridyl)propane and DMF = N,N-dimethylformamide, has been solvothermally synthesized and crystallographically characterized. It consists of 1D helical chains linked at the cadmium