Base-Mediated Selective Synthesis of Diversely Substituted <i>N</i>-Heterocyclic Enamines and Enaminones by the Hydroamination of Alkynes
作者:Megha Joshi、Monika Patel、Rakesh Tiwari、Akhilesh K. Verma
DOI:10.1021/jo300782n
日期:2012.7.6
Regio- and stereoselective alkynylation of various N-heterocycles 1a–l using potassium and cesium salts in DMSO is described. Terminal alkynes 2a–k and internal alkynes 4a–f provided the kinetically stable Z-enamines 3a–l and 5a–i in good to excellent yields using KOH at 120 °C. Addition of heterocyclic amines to 1,3- and 1,4-diethynylbenzene 6a–b provided the mixture of E/Z isomers with KOH; however
描述了在DMSO中使用钾盐和铯盐对各种N杂环1a – l进行区域和立体选择性炔基化反应。使用120°C的KOH,末端炔烃2a – k和内部炔烃4a – f提供了动力学稳定的Z-烯胺3a – l和5a – i。将杂环胺加到1,3-和1,4-二乙炔基苯6a - b中可提供E / Z异构体与KOH的混合物;但是,对于Cs 2CO 3选择性Z-异构体7ab - db通过一个三键的加氢胺化反应获得。这种发达的方法还为烯胺酮10a – c的合成提供了一种简便而新颖的途径。详细的工作还通过在铜催化的吲哚和吡咯并[2,1- a ]异喹啉的铜催化串联合成中优先添加邻卤代芳基炔烃,然后进行分子内C2芳基化来支持顺式异构体的形成。