使用钌/ N-杂环卡宾(NHC)催化剂,通过直接氢化完成对四氢咪唑并[1,2- a ]吡啶的对映选择性合成。该反应放弃了对保护基团或活化基团的需要,以完全的区域选择性,良好至优异的产率,高达98:2的对映体比例进行,并且耐受宽泛的官能团。5,6,7,8-四氢咪唑并[1,2一]吡啶,其在许多生物活性分子中发现,直接通过该方法获得的,其适用性是由几个功能性分子的(正式)合成证明。
Room-Temperature Transition-Metal-Free One-Pot Synthesis of 3-Aryl Imidazo[1,2-a]pyridines via Iodo-hemiaminal Intermediate
摘要:
A mild and efficient one-pot synthesis of 3-aryl imidazo[1,2-alpha]pyridines in up to 88% yield was developed. An adduct was formed after the simple mixing of 2-amino-4-methylpyridine, 2-phenylacetaldehyde, and N-iodosuccinimide in CH2Cl2, and the structure of the adduct was characterized by 2D NMR, IR, and high-resolution mass analysis. The adduct was readily cyclized by treatment with a saturated aqueous solution of NaHCO3. The reactions proceeded to completion after several hours at room temperature.
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.
Switching of Regioselectivity in a Perfluorohexyl Iodide Mediated Synthesis of Phenylimidazo[1,2-<i>a</i>]pyridines
作者:Irwan Iskandar Roslan、Gaik-Khuan Chuah、Stephan Jaenicke
DOI:10.1002/ejoc.201601586
日期:2017.1.18
An array of 3-phenylimidazo[1,2-a]pyridines has been synthesized via perfluorohexyl iodide-mediated coupling of 2-aminopyridines and phenylacetylenes. In-situ iodination of the terminal alkyne by perfluorohexyl iodide reverses the polarity by generating a transient electrophilic iodoalkyne, altering the regioselectivity of the phenyl group. The reaction then proceeds via a tandem electrophilic alkynylation
catalytic amount of Fe(TPP)Cl and Zn dust. The reaction precludes the traditional, more favored click reaction between an organic azide and alkynes, and instead proceeds by an unprecedented metalloradicalactivation. The method is anticipated to advance access to the construction of important basic nitrogen heterocycles, which will in turn enable discoveries of new drug candidates.
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。
Rhodium-Catalyzed Highly Regioselective C-H Arylation of Imidazo[1,2-a]pyridines with Aryl Halides and Triflates
作者:Yi Liu、Lin He、Guoqiang Yin、Guojie Wu、Yingde Cui
DOI:10.5012/bkcs.2013.34.8.2340
日期:2013.8.20
Accepted May 13, 2013A convenient Rh-catalyzed C-H arylation of imidazo[1,2-a]pyridines with a variety of aryl halides or triflateshas been reported. This process afforded a range of biaryl compounds in excellent yields and showed highactivity and broad scope. Key Words : Rhodium catalyst, Aryl halides, Regioselective arylation, Imidazo[1,2- a]pyridines, TriflatesIntroductionHeteroaromatics bearing aryl-heteroaryl