Electrochemical Radical–Radical Cross-Coupling Approach between Sodium Sulfinates and 2<i>H</i>-Indazoles to 3-Sulfonylated 2<i>H</i>-Indazoles
作者:Wansoo Kim、Hun Young Kim、Kyungsoo Oh
DOI:10.1021/acs.orglett.0c02144
日期:2020.8.21
A direct cross-coupling between sodium sulfinates and 2H-indazoles has been developed under electrochemical conditions. The utilization of a graphite anode and platinum cathode in an undivided cell with a constant current of 7 mA allowed the concurrent oxidations of sulfinates and 2H-indazoles to sulfonyl radical and radical cationic 2H-indazoles, facilitating the direct radical–radical coupling strategy
operationally simple method for the regioselective synthesis of 2-aryl-substituted 2H-indazoles is reported. The Pd-catalyzed reaction between easily available 2-bromobenzyl bromides and arylhydrazines employing Cs2CO3 as the base and t-Bu3PHBF4 as the ligand in DMSO at 120 °C in a sealed tube delivers the 2-substituted-2H-indazoles in a single synthetic step with yields up to 79%. The newmethod is based on
报道了直接和操作简单的方法用于区域选择性合成2-芳基取代的2 H-吲唑。容易获得的2-溴苄基溴化物和芳基肼采用铯之间的Pd-催化反应2 CO 3作为碱和吨-Bu 3 PHBF 4作为在密封管中120℃下在DMSO中配体递送2-取代- 2 ħ -吲唑在单个合成步骤中的收率高达79%。该新方法基于区域选择性的分子间N-苄基化,然后进行分子内N-芳基化和氧化。
Iron complex-catalyzed N-arylation of pyrazoles under aqueous medium
作者:Hang Wai Lee、Albert S.C. Chan、Fuk Yee Kwong
DOI:10.1016/j.tetlet.2009.08.018
日期:2009.10
diamine ligand is a highly effective catalyst for N-arylation of pyrazoles using aryl and heteroaryl iodides. It is notable to show that this complex is tolerable under aqueous medium and particularly the whole reaction utilizes water as the sole solvent without any additional organic co-solvents and surfactants. Attempted study using other nitrogennucleophiles is described. This newly developed system provides
Access to 2-substituted-2<i>H</i>-indazoles<i>via</i>a copper-catalyzed regioselective cross-coupling reaction
作者:Rong Zhang、Zheng Liu、Qiujun Peng、Yijun Zhou、Lanting Xu、Xianhua Pan
DOI:10.1039/c8ob00128f
日期:——
cross-coupling reaction using commercially available 1H-indazoles with diaryliodonium salts is described. The methodology features ample structural versatility, affording 2-substituted-2H-indazole in good yields and complete N(2)-regiocontrol. Furthermore, the utility of the reaction was demonstrated in the synthesis of a known estrogen receptor β agonist. Mechanistic studies using density functional
Synthesis of (2
<i>H</i>
)‐Indazoles from Azobenzenes Using Paraformaldehyde as a One‐Carbon Synthon
作者:Rina Chun、Saegun Kim、Sang Hoon Han、Sangil Han、Suk Hun Lee、Neeraj Kumar Mishra、Young Hoon Jung、Hyung Sik Kim、In Su Kim
DOI:10.1002/adsc.201801547
日期:2019.4
hydroxymethylation followed by intramolecular annulation of azobenzenesusingparaformaldehyde as a valuable C1‐feedstock is described. The method is readily extended to the coupling reaction between azobenzenes and trifluoroacetaldehyde. This transformation efficiently produces a range of C3‐unsubstituted and C3‐trifluoromethylated (2H)‐indazoles, which are important targets in the development of novel