A Practical, Metal-Free Synthesis of 1<i>H</i>-Indazoles
作者:Carla M. Counceller、Chad C. Eichman、Brenda C. Wray、James P. Stambuli
DOI:10.1021/ol800053f
日期:2008.3.1
The synthesis of 1H-indazoles is achieved from o-aminobenzoximes by the selective activation of the oxime in the presence of the amino group. The reaction occurs with a variety of substituted o-aminobenzoximes using a slight excess of methanesulfonyl chloride and triethylamine at 0-23 degrees C and is amenable to scale-up. The synthesis of 1H-indazoles under these conditions is extremely mild compared
Copper-Promoted Oxidative Intramolecular C-H Amination of Hydrazones to Synthesize 1<i>H</i>
-Indazoles and 1<i>H</i>
-Pyrazoles Using a Cleavable Directing Group
A facile and efficient copper‐promoted oxidative intramolecular C–H amination of hydrazones for the synthesis of 1H‐indazoles and 1H‐pyrazoles was developed using a tracelessly cleavable directing group. This reaction is characterized by its mild conditions, operational simplicity, readily available reagents, and excellent yields. A tentative mechanism for Cu‐mediated C–H‐oxidative amination was proposed
Design and Application of New Imidazolylsulfonate-Based Benzyne Precursor: An Efficient Triflate Alternative
作者:Szabolcs Kovács、Ádám I. Csincsi、Tibor Zs. Nagy、Sándor Boros、Géza Timári、Zoltán Novák
DOI:10.1021/ol300529j
日期:2012.4.20
cycloadditions involving benzyne intermediates. The precursor offers an efficient alternative for generating benzynes compared to widely used ortho TMS triflates under similar reaction conditions. With the utilization of this new precursor, the formation of potentially genotoxic trifluoromethanesulfonate side product is eliminated. The applicability of the new benzyneprecursor was demonstrated in different
Synthesis of dihydroindazolo[2,3-<i>f</i>]phenanthridin-5(6<i>H</i>)-ones <i>via</i> Rh(<scp>iii</scp>)-catalyzed C–H activation of 2-aryl indazoles and annulation with iodonium ylides
An efficient syntheticroute to indazole-fused dihydrophenanthridinones in excellent to almost quantitative yields under mild reaction conditions was developed. The reaction utilizes the acid-controlled Rh(III)-catalyzed C–H activation of 3-arylindazoles followed by their annulation with readily available hypervalent iodonium ylides. This methodology afforded a wide range of products that could be
开发了一种在温和反应条件下以优异至几乎定量的产率合成吲唑稠合二氢菲啶酮的有效合成路线。该反应利用酸控制的 Rh( III ) 催化的 3-芳基吲唑的 C-H 活化,然后用现成的高价碘鎓叶立德进行环化。这种方法提供了广泛的产品,只需简单的过滤即可分离,无需柱层析。此外,催化体系可以循环使用至少八次,收率很高,这可能使其适合工业生产。此外,合成的二氢吲唑并[2,3 - f ]phenanthridin-5(6 H)-表示它们可能具有作为新型荧光材料的潜在应用。
Rhodium‐Catalysed Selective C−H Allylation of 1<i>H</i>‐Indazoles with Vinylethylene Carbonate: Easily Introducing Allylic Alcohol
作者:Xiang Zhao、Junwei Huang、Yadong Feng、Xiuling Cui
DOI:10.1002/ejoc.202300823
日期:2023.10.21
An efficient rhodium(III)-catalyzed C−H bond activation/allylation reaction of 3-aryl-1H-indazoles with easily available vinylethylene carbonate has been reported. A series of allyl alcohol substituted 3-aryl-1H-indazoles were obtained.