(Diacetoxy)iodobenzene (PIDA)-mediated direct oxidative C–H amination for the synthesis of 3-amino substituted imidazopyridines has been achieved under metal-free conditions at room temperature in short reaction times. This methodology is also applicable for the regioselective amination of indolizines. Experimental results suggest that the reaction likely proceeds through a radical pathway.
Metal-free benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids
作者:Sonam Jaspal、Vikki N. Shinde、Neha Meena、Dhananjay S. Nipate、Krishnan Rangan、Anil Kumar
DOI:10.1039/d0ob01842b
日期:——
A simple and straightforward approach has been realized for the direct benzoylation of imidazoheterocycles by oxidative decarboxylation of arylglyoxylic acids in the presence of K2S2O8 as an oxidant. Various functional groups were tolerated on both imidazoheterocycles and arylglyoxylic acids and a wide range of C5-benzoyl-imidazoheterocycles were obtained in good to high yields (50–84%). Radical trapping
在 K 2 S 2 O 8作为氧化剂的存在下,通过芳基乙醛酸的氧化脱羧,实现了一种简单直接的咪唑杂环直接苯甲酰化方法。咪唑杂环和芳基乙醛酸均耐受各种官能团,并且以良好至高产率(50-84%)获得了范围广泛的 C5-苯甲酰基-咪唑杂环。自由基捕获实验证实了自由基途径的参与。开发的协议适用于放大反应。
Hypervalent iodine mediated synthesis of imidazo[1,2-<i>a</i>]pyridine ethers: consecutive methylene linkage and insertion of ethylene glycol
Hypervalent iodine mediated selective synthesis of imidazo[1,2-a]pyridine ethers using ethylene glycol as a methoxy ethanol source as well as solvent under metal-free conditions is described. The method is also applicable to other fused heterocycles such as benzo[d]imidazo[2,1-b]thiazoles, 2-(thiophen-2-yl)benzo[d]imidazo [2,1-b]thiazole and indazole. Control experiments suggest that, when the C-3
描述了在无金属条件下使用乙二醇作为甲氧基乙醇源以及溶剂的高价碘介导的咪唑并[1,2- a ]吡啶醚的选择性合成。该方法还适用于其他稠合杂环,例如苯并[ d ]咪唑并[ 2,1- b ]噻唑,2-(噻吩-2-基)苯并[ d ]咪唑并[ 2,1- b ]噻唑和吲唑。对照实验表明,当咪唑并[1,2- a ]吡啶的C-3位被封闭时,该反应不会在显示本方案区域选择性的任何其他位置发生。
TEMPO-Mediated Cross-Dehydrogenative Coupling of Indoles and Imidazo[1,2-<i>a</i>]pyridines with Fluorinated Alcohols
作者:Dhananjay S. Nipate、Sonam Jaspal、Vikki N. Shinde、Krishnan Rangan、Anil Kumar
DOI:10.1021/acs.orglett.1c00031
日期:2021.2.19
A simple and highly efficient metal-free method has been developed for hydroxyfluoroalkylation of indoles and imidazo[1,2-a]pyridines via TEMPO-mediated C(sp3)–H and C(sp2)–H bond cross-dehydrogenative coupling of fluorinated alcohols and indoles. The protocol showed broad substrate scope, afforded good yields of hydroxyfluoroalkylated products, and was amenable for scale-up. Mechanistic investigation
已经开发了一种简单高效的无金属方法,用于通过TEMPO介导的C(sp 3)–H和C(sp 2)–H键交叉脱氢偶联将吲哚和咪唑并[1,2- a ]吡啶进行羟基氟烷基化氟化醇和吲哚。该方案显示出广泛的底物范围,提供了良好的羟基氟烷基化产物收率,并且适合规模扩大。机理研究表明该自由基途径的参与。
Visible-light-promoted direct C3-trifluoromethylation and perfluoroalkylation of imidazopyridines
作者:Meichen Li、Gaolin Li、Chenxun Dai、Wenjun Zhou、Wenqiang Zhan、Muyang Gao、Yuan Rong、Ze Tan、Wei Deng
DOI:10.1039/d1ob01417j
日期:——
efficient method for direct trifluoromethylation and perfluoroalkylation at C3 of imidazopyridines through visible light-promoted C–H bond functionalization was developed. Under the irradiation of a blue LED, a series of C3-perfluoroalkyl-substituted imidazopyridines were synthesized from the corresponding imidazopyridines and perfluoroalkyl iodides in moderate to good yields at room temperature. It should
开发了一种通过可见光促进的 C-H 键官能化在咪唑并吡啶 C3 处直接三氟甲基化和全氟烷基化的有效方法。在蓝色 LED 的照射下,由相应的咪唑并吡啶和全氟烷基碘化物在室温下以中等至良好的产率合成了一系列 C3-全氟烷基取代的咪唑并吡啶。应该提到的是,该反应是在没有任何过渡金属催化剂、氧化剂和光催化剂的情况下进行的。