Phosphine-Free Palladium-Catalyzed Direct Arylation of Imidazo[1,2-a]pyridines with Aryl Bromides at Low Catalyst Loading
作者:Hai Yan Fu、Lu Chen、Henri Doucet
DOI:10.1021/jo300528b
日期:2012.5.4
Ligand-free Pd(OAc)2 was found to catalyze very efficiently the directarylation of imidazo[1,2-a]pyridines at C3 under very low catalyst concentration. The reaction can be performed employing as little as 0.1–0.01 mol % catalyst with electron-deficient and some electron-excessive aryl bromides.
Regioselective Synthesis of 2- and 3-Substituted Imidazo[1,2-<i>a</i>]pyridines
作者:Guoping Liu、Xuefeng Cong、Jiaheng He、Shunzhong Luo、Di Wu、Jingbo Lan
DOI:10.3184/174751912x13499663832261
日期:2012.12
A range of 2- or 3-substituted imidazo[1,2- a]pyridines were prepared from 2-aminopyridine derivatives and gem-dibromovinyl compounds by the tandem nucleophilic substitution (or nucleophilic addition)/cyclisation reaction.
Direct catalytic C–H arylation of imidazo[1,2-a]pyridine with aryl bromides using magnetically recyclable Pd–Fe3O4 nanoparticles
作者:Jaewoo Lee、Jooyoung Chung、Sang Moon Byun、B. Moon Kim、Chulbom Lee
DOI:10.1016/j.tet.2013.04.031
日期:2013.7
The direct C–H arylation of a heteroarene with aryl bromides has been achieved under the catalysis of magnetic nanoparticles. In the presence of bimetallic Pd–Fe3O4 heterodimer nanocrystals (1 mol % in palladium), the reaction of imidazo[1,2-a]pyridine with various aryl bromides gives the corresponding arylated products with exclusive C3-selectivity. The highly regioselective method is applicable to
在磁性纳米粒子的催化下,杂芳烃与芳基溴的直接C–H芳基化反应已经实现。在双金属Pd–Fe 3 O 4异质二聚体纳米晶体(在钯中为1 mol%)的存在下,咪唑并[1,2- a ]吡啶与各种芳基溴化物的反应提供了具有独占C3选择性的相应芳基化产物。高度区域选择性的方法适用于各种具有不同电子和空间特性的芳基溴化物。Pd–Fe 3 O 4纳米晶体可以通过简单的磁分离而回收,并且已经被回收了十次而没有失去催化活性。
Synthesis of 3-Arylimidazo[1,2-a]pyridines by a Catalyst-Free Cascade Process
作者:Xiangge Zhou、Zhiqing Wu、Yinyin Pan
DOI:10.1055/s-0030-1260669
日期:2011.7
A simple and efficient protocol to synthesize 3-arylimidazo[1,2-a]pyridines by a catalyst-free cascade process from 2-aminopyridine and 1-bromo-2-phenylacetylene or 1,1-dibromo-2-phenylethene in yields up to 86% is described.
Metal- and base-free synthesis of imidazo[1,2-<i>a</i>]pyridines through elemental sulfur-initiated oxidative annulation of 2-aminopyridines and aldehydes
作者:Jing Tan、Penghui Ni、Huawen Huang、Guo-Jun Deng
DOI:10.1039/c8ob00981c
日期:——
The elemental sulfur-promoted oxidative cyclization reaction for the efficient synthesis of substituted imidazo[1,2-a]pyridines has been developed. Easily available 2-aminopyridines and aldehydes were directly assembled in a highly atom-economical fashion through oxidative annulation under metal- and base-free conditions. Besides arylacetaldehydes, aliphatic aldehydes were also compatible with this
已经开发出用于有效合成取代的咪唑并[1,2- a ]吡啶的元素硫促进的氧化环化反应。容易获得的2-氨基吡啶和醛类在无金属和无碱条件下通过氧化环化法以高度原子经济的方式直接组装。除芳基乙醛外,脂族醛也与该体系相容,以具有克级合成能力的优异收率递送烷基取代的咪唑并[1,2- a ]吡啶。