Rh(III)-Catalyzed C–H Cyanation of 2H-Indazole with N-Cyano-N-phenyl-p-toluenesulfonamide
摘要:
A Rh(III)-catalyzed direct cyanation of 2H-indazoles with N-cyano-N-phenyl-p-toluenesulfonamide has been realized via a chelation-assisted strategy. The methodology enables regioselective access to various ortho-cyanated phenylindazoles in good yields with a broad substrate scope and good functional group compatibility. The obtained cyanated indazoles could further be converted into other value-added chemicals. Importantly, the current protocol is featured with several characteristics, including a novel cyanating agent, good regioselectivity, and operational convenience.
Gold Modified Zeolite: An Efficient Heterogeneous Catalyst for <I>N</I>-Arylation of Indazole
作者:P Emayavaramban、K Kadirvelu、N Dharmaraj
DOI:10.1166/jnn.2016.12905
日期:2016.9.1
We herein report N-arylation of indazole with aryl halides using gold modified zeolites (Au-zeolites) as an efficient catalytic system. Au-zeolites with three different gold loading were prepared by ion-exchange method and characterized by UV-visible diffuse reflectance spectroscopy (UV-DRS), transmission electron microscopy and energy-dispersive X-ray spectroscopy (TEM-EDX) and X-ray photoelectron spectroscopy (XPS). The Brunauer-Emmett-Teller (BET) and Langmuir surface areas of the prepared Au(5)-zeolite catalyst were found to be 644 and 929 m2g−1 respectively. Goldmodified zeolites performed as an efficient catalytic system for N-arylation of indazole using diverse aryl halides afforded N1 arylated products in appreciable yield under mild reaction conditions. The catalyst was reusable for at least five times with only a marginal loss of activity. This simple, effective and environmentally benign heterogeneous protocol provides a safer alternative to hazardous, corrosive and more polluting conventional catalysts.
我们在此报告使用金修饰沸石(Au-zeolites)作为高效催化体系,对吲唑与芳基卤化物进行 N-芳基化反应。我们采用离子交换法制备了三种不同金负载的金沸石,并通过紫外可见漫反射光谱(UV-DRS)、透射电子显微镜和能量色散 X 射线光谱(TEM-EDX)以及 X 射线光电子能谱(XPS)对其进行了表征。制备的金(5)沸石催化剂的布鲁纳-艾美特-泰勒(BET)和朗缪尔表面积分别为 644 和 929 m2g-1。金改性沸石是一种高效的催化体系,可在温和的反应条件下,利用各种芳基卤化物对吲唑进行 N-芳基化反应,并以可观的产率获得 N1 芳基化产物。该催化剂可重复使用至少五次,活性仅略有下降。这种简单、有效和对环境无害的异构方案为危险、腐蚀性和污染性更强的传统催化剂提供了更安全的替代品。
Regiodivergent Cu-Promoted, AcOH-Switchable Distal Versus Proximal Direct Cyanation of 1-Aryl-1<i>H</i>-indazoles and 2-Aryl-2<i>H</i>-indazoles via Aerobic Oxidative C–H Bond Activation
作者:Richa Sharma、Sandeep Chaudhary
DOI:10.1021/acs.joc.2c01603
日期:2022.12.16
A copper-promoted regiodivergent, AcOH-switchable, distal and proximal direct cyanation of N-aryl-(1H/2H)-indazoles via aerobic oxidative C(sp2)–H bondactivation has been developed. The inclusion or exclusion of AcOH as an additive is the foremost cause for the positional switch in the C–CN bond formation method that results in (C-2′)-cyanated 2-aryl-2H-indazoles 3a–j, (C-2′)-cyanated 1-aryl-1H-indazoles
开发了一种通过有氧氧化 C(sp 2 )–H 键激活对N -芳基-(1 H /2 H )-吲唑进行铜促进区域发散、AcOH 可切换、远端和近端直接氰化反应。添加或排除 AcOH 作为添加剂是导致 (C-2')-氰化 2-芳基-2 H-吲唑3a-j的 C-CN 键形成方法中位置转换的主要原因,(C -2')-cyanated 1-aryl-1 H -indazoles 4a–j [distal], 或 C-3 cyanated 2-aryl-2 H -indazoles 5a–i [proximal] 产品具有良好至优异的产率并显示出各种功能群体耐受性。氰化物(CN– ) 离子替代物是通过二甲基甲酰胺和碘化铵 (NH 4 I) 的统一生成的。使用分子氧(有氧氧化策略)作为一种清洁安全的氧化剂可以带来大量的附加值。通过将合成的氰化产物转化为许多其他官能团,证明了所开发协议的进一步针对性,这无疑