Copper-catalyzed intramolecular dehydrogenative cyclization: direct access to sensitive formyl-substituted imidazo[1,2-a]pyridines
作者:Li-Hai Zhai、Li-Hong Guo、Bai-Wang Sun
DOI:10.1039/c5ra19085a
日期:——
A direct method for the synthesis of formyl-substituted imidazo[1,2-a]pyridines was achieved easily from cyclization of aminopyridines and cinnamaldehydes via copper catalysis. This oxidative cyclization process involved direct C–H bond functionalization, and C–C/C–N bond formation. In this transformation, the sensitive aldehyde group was preserved under oxidative conditions.
通过铜催化氨基吡啶和肉桂醛的环化,很容易实现直接合成甲酰基取代的咪唑并[1,2- a ]吡啶的直接方法。这种氧化环化过程涉及直接的C–H键功能化和C–C / C–N键形成。在该转化中,敏感的醛基在氧化条件下得以保留。
Copper- and DMF-mediated switchable oxidative C–H cyanation and formylation of imidazo[1,2-<i>a</i>]pyridines using ammonium iodide
作者:Xuan Li、Shoucai Wang、Jiawang Zang、Meichen Liu、Guangbin Jiang、Fanghua Ji
DOI:10.1039/d0ob01838d
日期:——
The cyanation and formylation of imidazo[1,2-a]pyridines were developed under copper-mediated oxidative conditions using ammonium iodide and DMF as a nontoxic combined cyano-group source and DMF as a formylation reagent. Mechanistic studies indicate that the cyanation of imidazo[1,2-a]pyridines proceeds through a two-step sequence: initial iodination and then cyanation. The cyanation has a broad substrate
咪唑并[1,2 - a ]吡啶的氰化和甲酰化是在铜介导的氧化条件下开发的,使用碘化铵和 DMF 作为无毒的组合氰基源,DMF 作为甲酰化试剂。机理研究表明,咪唑并[1,2 - a ]吡啶的氰化过程分为两步:初始碘化,然后是氰化。氰化具有广泛的底物范围和高官能团耐受性,并且可以在克级安全地进行。使用广泛可用的 DMF 作为甲酰化试剂和环境友好的分子氧作为氧化剂的新型铜介导的甲酰化也已被开发出来。该协议还为临床使用的沙利吡坦的合成提供了一种方便的方法。
Electrochemically Enabled Direct C3‐Formylation of Imidazopyridines with Me
<sub>3</sub>
N as a Carbonyl Source
作者:Zhicong Tang、Gang Hong、Shiyun Sun、Limin Wang
DOI:10.1002/asia.202300001
日期:——
A metal- and oxidant-free electrochemical methodology for C-3 formylation of imidazopyridines using trimethylamine as a one-carbon source has been established. The strategy demonstrated good functional-group tolerance and could be scaled up to gram scale, ensuring late-stage functionalization and total/formal synthesis of pharmaceutical molecules. Furthermore, unexpected hexafluoroisopropoxylation