Copper-Catalyzed Intermolecular Oxidative Cyclization of Halo- alkynes: Synthesis of 2-Halo-substituted Imidazo[1,2-<i>a</i>]pyridines, Imidazo[1,2-<i>a</i>]pyrazines and Imidazo[1,2-<i>a</i>]pyrimidines
AbstractAn efficient copper‐catalyzed method for the synthesis of 2‐haloimidazopyridines with aminopyridines and haloalkynes using molecular oxygen as oxidant in a one‐pot manner has been developed. In this process, the reaction appears to be very general and suitable for the construction of a variety of 2‐halo‐substituted imidazopyridines, imidazopyrazines and imidazopyrimidines. The intermolecular oxidative diamination of haloalkynes was achieved for the first time. Importantly, the mild reaction conditions and the efficient conversion of the alkyl‐substituted haloalkynes are great improvements over the existing methods. Moreover, the resultant 2‐haloimidazo[1,2‐a]pyridines could be efficiently converted to other functionalized imidazopyridine products via substitution, coupling reactions and other transformations, which further indicates potential applications of this method in synthetic and pharmaceutical chemistry.magnified image
A Cu(<scp>ii</scp>)-promoted tandem decarboxylative halogenation and oxidative diamination reaction of 2-aminopyridines with alkynoic acids for the synthesis of 2-haloimidazo[1,2-<i>a</i>]pyridines
作者:Yun Liu、Wenhui Wang、Junwen Han、Jinwei Sun
DOI:10.1039/c7ob02014g
日期:——
2-aminopyridines with alkynoic acids has been developed for the synthesis of 2-haloimidazo[1,2-a]pyridines. In this reaction, two C-N bonds and one C-halogen bond are formed in one pot, generating the desired products in good yields. This is the first report for the synthesis of 2- haloimidazo [1,2-a]pyridine derivatives from alkynoic acids.
Copper‐Promoted Annulation of Terminal Alkynes with 2‐Aminopyridines to Assemble 2‐Halogenated Imidazo[1,2‐
<i>a</i>
]pyridines
作者:Yun Liu、Yuxuan Zhang、Jinwei Sun
DOI:10.1002/jhet.3660
日期:2019.10
Copper‐promotedannulation reactions of terminalalkynes with 2‐aminopyridines have been developed for the synthesis of 2‐halogenatedimidazo[1,2‐a]pyridines using copper halide as the halogen source. A variety of substrates survived under the reaction conditions and gave the desired products in good yields. This reaction features advantages such as easily available starting materials, broad substrate
已开发了末端炔烃与2-氨基吡啶的铜促进环化反应,用于使用卤化铜作为卤素源来合成2-卤代咪唑并[1,2- a ]吡啶。在反应条件下,多种底物得以存活,并以良好的收率得到了所需的产物。该反应具有优点,例如容易获得的起始原料,广泛的底物范围和温和的反应条件。