Copper-Catalyzed Decarboxylative Three-Component Reactions for the Synthesis of Imidazo[1,2-a]pyridines
作者:Thiruvengadam Palani、Kyungho Park、Manian Rajesh Kumar、Hyun Ming Jung、Sunwoo Lee
DOI:10.1002/ejoc.201200679
日期:2012.9
Imidazo[1,2-a]pyridine derivatives were synthesized through multicomponent coupling reactions of 2-aminopyridines, aldehydes, and alkynecarboxylic acids in the presence of 10 mol-% CuI/Cu(OTf)2. Both aryl- and alkyl-substituted alkynecarboxylic acids, including propiolic acid, were good alkyne sources and afforded the desired imidazo[1,2-a]pyridines in good yields through the decarboxylative coupling
在 10 mol% CuI/Cu(OTf)2 存在下,通过 2-氨基吡啶、醛和炔羧酸的多组分偶联反应合成了咪唑并 [1,2-a] 吡啶衍生物。芳基和烷基取代的炔烃羧酸,包括丙炔酸,都是良好的炔烃来源,并通过脱羧偶联反应以良好的产率提供所需的咪唑并 [1,2-a] 吡啶。芳基炔羧酸是通过芳基碘化物和丙炔酸之间的钯催化偶联反应合成的,并与 2-氨基吡啶和醛反应,有或没有纯化步骤。在这两种情况下,都以良好的收率获得了所需的咪唑并[1,2-a]吡啶。机理研究表明,在丙炔酸的情况下,脱羧加成优于末端炔加成。