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研究开发了一个实用高效的钯铜共催化体系,1%Pd(OAc)2与10%CuCl2.2H2O双金属组合催化剂在弱碱和0.5 equiv PPh3配体存在下,顺利催化苯并唑类杂环与各种芳基溴的直接芳基化,并得到良好的收率.该钯铜共催化体系具有钯催化计量低、配体廉价易得、底物适用范围广、反应条件温和等特点. 相似文献
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寻找全新的具有优异光物理特性的荧光母体骨架, 构筑功能各异的荧光分子是目前荧光染料发展和应用领域的迫切需要. 目前通过有机合成方法学的研究来发现新的荧光核心骨架已经开始受到越来越多的关注. 四川大学化学学院游劲松研究组结合对杂环与芳基溴的直接C-芳基化反应的研究, 合成了一系列C8-芳基化黄嘌呤类衍生物. 首次对该类化合物的荧光特性进行了系统研究, 并依据推-拉电子模式通过C—H活化反应设计合成了化合物1, 发现该化合物不仅在众多溶剂中具有强烈的荧光, 并且具有强的固体荧光, 更重要的是, 作者成功地将化合物1应用于对LL2细胞和HEK293细胞的荧光标记. 相似文献
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二芳基碘鎓盐属于有机高价碘化合物,具有无毒、反应条件温和以及良好的选择性等优点,在有机合成中具有重要地位,受到广大化学工作者的关注。近年来,利用二芳基碘鎓盐在金属催化下进行的芳基化反应为一些难以合成的杂环化合物的合成提供了简便、高效的方法;同时,二芳基碘鎓盐在无催化剂下进行的芳基化反应,为C—C偶联反应开辟了新的绿色合成路线。本文综述了近年来二芳基碘鎓盐在有机合成中促进芳基化反应的最新进展,着重介绍了利用二芳基碘鎓盐作为芳基化试剂与有机金属试剂、烯烃和炔烃类以及杂环化合物进行芳基化反应的研究;总结了二芳基碘鎓盐与杂环化合物反应中钯催化和铜催化下芳基化反应的机理,最后对二芳基碘鎓盐在今后有机合成中的应用作出了展望。 相似文献
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新颖的纳米镍催化芳基硼酸与芳基溴的偶联反应 总被引:7,自引:0,他引:7
纳米镍用于催化芳基硼酸与芳基溴的偶联反应,合成了一系列4,4′-双烷基环己基联苯类液晶,纳米镍在相转移剂十六烷基三甲基溴化铵的存在下回流反应15h,目的产物的收率为60%-65%。讨论了纳米镍催化偶联反应的可能活性位,镍催化剂经SEM-EDS表征平衡粒径为80nm,定量分析表明氧含量为33%;XRD测试结果表明纳米镍体相以单质态存在,但其特征谱线的d值普遍增大;由XPS分析得聘书纳米镍的结合能(2p3/2和2p1/2)为854.1eV和871.8eV,峰间距为17.7eV,表明纳米镍是以介于单质镍和氧化镍之间的价态存在。 相似文献
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Direct Arylation of N‐Heteroarenes with Aryldiazonium Salts by Photoredox Catalysis in Water 下载免费PDF全文
Prof. Dr. Dong Xue Zhi‐Hui Jia Cong‐Jun Zhao Yan‐Yan Zhang Prof. Dr. Chao Wang Prof. Dr. Jianliang Xiao 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(10):2960-2965
A highly effective visible light‐promoted “radical‐type” coupling of N‐heteroarenes with aryldiazonium salts in water has been developed. The reaction proceeds at room temperature with [Ru(bpy)3]Cl2 ? 6 H2O as a photosensitizer and a commercial household light bulb as a light source. Pyridine and a variety of substituted pyridines are effective substrates under these reaction conditions, and only monosubstituted products are formed with different regioselectivities. Using aqueous formic acid as solvent, an array of xanthenes, thiazole, pyrazine, and pyridazine are compatible with this new arylation approach. The broad substrate scope, mild reaction conditions, and use of water as reaction solvent make this procedure a practical and environmentally friendly method for the synthesis of compounds containing aryl‐heteroaryl motifs. 相似文献
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自由基氟烷基化是向有机分子中引入氟烷基的一类非常重要的方法,也是目前有机化学研究的热点之一.近几年来,由于广泛的官能团兼容性和温和的反应条件等优点,可见光促进的氧化还原催化反应得到了长足的发展,已经成为化学键的构建和活化的有力工具.因此,光氧化还原催化的自由基氟烷基化反应,作为向有机化合物中引入氟烷基的有效途径,受到了广泛关注.本文报道了我们发展的氟烷基砜作为一类方便易得的新型氟烷基自由基前体,在可见光氧化还原催化下实现对烯烃的自由基氟烷基化反应.该反应可以高效地向芳基烯烃中引入三氟甲基、二氟甲基、1,1-二氟乙基、苯基二氟甲基等各种含氟烷基基团,并实现对芳基烯烃的双官能团化转化. 相似文献
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M. Sc. Durga Prasad Hari Prof. Dr. Burkhard König 《Angewandte Chemie (International ed. in English)》2013,52(18):4734-4743
The use of diazonium salts for aryl radical generation and C? H arylation processes has been known since 1896 when Pschorr first used the reaction for intramolecular cyclizations. Meerwein developed it further in the early 1900s into a general arylation method. However, this reaction could not compete with the transition‐metal‐mediated formation of C(sp2)? C(sp2) bonds. The replacement of the copper catalyst with iron and titanium compounds improved the situation, but the use of photocatalysis to induce the one‐electron reduction and activation of the diazonium salts is even more advantageous. The first photocatalyzed Pschorr cyclization was published in 1984, and just last year a series of papers described applications of photocatalytic Meerwein arylations leading to aryl–alkene coupling products. In this Minireview we summarize the origins of this reaction and its scope and applications. 相似文献
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The anti-Markovnikov hydroazidation of alkenes has been accomplished under visible-light irradiation by using [Ir(dF(CF3)ppy)2(dtbbpy)]PF6 as the photocatalyst and trimethylsilyl azide as the azidating agent. The reactions were greatly facilitated by water, the beneficial effect of which can be attributed to its participation in the reaction as the hydrogen donor, as indicated by deuterium isotope experiments. The reactions proceed under solvent free conditions in the presence of water. 4-Dimethylaminopyridine also exhibited a beneficial effect on the reactions. The present method enabled hydroazidation of several types of unactivated alkenes with good yields and high regioselectivity. 相似文献
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(49):15850-15854
The direct catalytic C−H amination of arenes is a powerful synthetic strategy with useful applications in pharmaceuticals, agrochemicals, and materials chemistry. Despite the advances in catalytic C−H functionalization, the use of aliphatic amine coupling partners is limited. Described herein is the construction of C−N bonds, using primary amines, by direct C−H functionalization with an acridinium photoredox catalyst under an aerobic atmosphere. A wide variety of primary amines, including amino acids and more complex amines are competent coupling partners. Various electron‐rich aromatics and heteroaromatics are useful scaffolds in this reaction, as are complex, biologically active arenes. We also describe the ability to functionalize arenes that are not oxidized by an acridinium catalyst, such as benzene and toluene, thus supporting a reactive amine cation radical intermediate. 相似文献