A few new d‐mannitol‐based monoaza‐15‐crown‐5 type chiral lariat ethers and 18‐crown‐6 type macrocycles were synthesized. These crown compounds were used as phasetransfercatalysts in asymmetric Michael addititons and in a Darzens condensation under mild conditions to afford the corresponding products in a few cases in good to excellent enantioselectivities. In the Michael addition of diethyl acetoxymalonate
Reactions of electron-deficient alkenes with dibromomethylene compounds activated by cyanide and ester groups were promoted by LiI to afford the corresponding cyclopropanes in high yields.
Electrocatalytic transformation of dialkyl malonates and arylidene- or alkylidenemalononitriles into dialkyl esters of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acids
作者:M. N. Elinson、S. K. Feducovich、T. A. Zaimovskaya、A. N. Vereshchagin、S. V. Gorbunov、G. I. Nikishin
DOI:10.1007/s11172-006-0008-6
日期:2005.7
Electrolysis of alcoholic solutions of dialkyl malonates and arylidene- or alkylidenemalononitriles in the presence of NaBr in an undivided cell gave dialkylesters of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acids in 60–90% yields.
Periodic Mesoporous Organosilicas as Efficient Nanoreactors in Cascade Reactions Preparing Cyclopropanic Derivatives
作者:Hang Huo、Yanqiu Jiang、Tingting Zhao、Junlei Wang、Defeng Li、Xianzhu Xu、Kaifeng Lin
DOI:10.1002/asia.201900043
日期:2019.5.2
as the result of different sizes and compositions of the organosilica precursors. The three mesoporous organosilicas were applied as heterogeneous catalysts in the one‐pot cascade Knoevenagel and Michael cyclopropanic reactions for the synthesis of cyclopropanic derivatives and showed excellent activity and selectivity. The highest conversion was obtained with mesoporous catalyst (MC)‐HQ owing to its
在这项工作中,通过缩合3-异氰酸根合丙基三乙氧基硅烷和对苯二酚(HQ),双酚A(BPA)或1,1'-bi-2-萘酚(BN)的偶联剂,合成了三种由氨基甲酸酯部分官能化的有机硅前体。这些有机硅前体在水热处理下,通过原硅酸四乙酯(TEOS)的共缩合和水解作用,在周期性介孔有机硅的框架内共价键合。用FTIR,XRD,热重/差热分析(TG / DTA),29 Si NMR,13表征了组成和物理性质。C NMR光谱学,SEM,TEM和BET技术。这些特征表明,由于有机硅前体的尺寸和组成不同,形成了三种不同的结构。三种介孔有机硅作为多相催化剂用于一锅级联Knoevenagel和Michael环丙烷反应中,用于合成环丙烷衍生物,并显示出优异的活性和选择性。与MC-BAP和MC-BN相比,由于介孔催化剂(MC)-HQ的有序介孔结构,最大表面积和最弱的有机连接基团立体反应,使其转化率最高。
Cyclopropanation of electron-deficient alkenes with activated dibromomethylene compounds mediated by lithium iodide or tetrabutylammonium salts
Reactions of electron-deficient alkenes with dibromomethylene compounds activated by cyano and ester groups were promoted by Lil or tetrabutylammonium bromide to afford the corresponding cyclopropanes in high yields. (C) 2009 Elsevier Ltd. All rights reserved.