Bu<sub>4</sub>NI-catalyzed, oxidative C<sub>(sp2)</sub>–C<sub>(sp3)</sub> cross dehydrogenative coupling for the regioselective direct C-3 benzylation of 2<i>H</i>-indazoles
作者:Lalit Yadav、Sandeep Chaudhary
DOI:10.1039/d0ob01282c
日期:——
A Bu4NI-catalyzed, DTBP-promoted, regioselective C(sp2)–C(sp3) cross dehydrogenative coupling (CDC) protocol for the direct C-3 benzylation of 2H-indazoles is reported. The metal-free protocol is operationally simple and proceeds mechanistically via the generation of stable benzylic free-radicals followed by regioselective addition at the C-3 position of 2H-indazoles which afforded C-3 benzylated 2H-indazoles
报道了一种 Bu 4 NI 催化、DTBP 促进的区域选择性 C (sp 2 ) -C (sp 3 )交叉脱氢偶联 (CDC) 方案,用于 2 H-吲唑的直接 C-3 苄基化。无金属方案操作简单,通过产生稳定的苄基自由基,然后在 2 H-吲唑的 C-3 位置进行区域选择性加成,得到 C-3 苄基化的2H-吲唑的产率高达 87%。该方法显示出一系列不同的官能团耐受性和广泛的底物兼容性。克级合成进一步突出了这种方法的重要性和通用性。
A Facile One-Step Synthesis of 2-Arylindazoles via Reductive Cyclization of<i>N</i>-(2-nitroarylidene)amines
作者:Wei Lin、Minghua Hu、Xian Feng、Chengpao Cao、Zhibin Huang、Daqing Shi
DOI:10.1002/jhet.2221
日期:2015.7
A mild and efficient synthesis of 2‐arylindazole derivatives via the reductivecyclization of nitro‐aryl substrates mediated by a low‐valent titanium reagent (TiCl4/Sm/Et3N) has been developed. The attractive features of the current method include an N–N bond formation and the selective reduction of the C = N bond and nitro group, both of which were easily achieved in one‐pot by controlling the pH
通过低价钛试剂(TiCl 4 / Sm / Et 3 N)介导的硝基芳基底物的还原环化,可以温和有效地合成2-芳基吲唑衍生物。当前方法的吸引人的特征包括N–N键的形成以及C = N键和硝基的选择性还原,通过控制反应混合物的pH值,很容易在一个锅中完成这两个操作。
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