Conjugate Addition of 3‑Buytn-2-one to Anilines in Ethanol: Alkene Geometric Insights through In Situ FTIR Monitoring

A convenient, mild and effective conjugate addition of 3-butyn-2-one to a variety of anilines in ethanol is reported. The reaction was monitored and characterized through in situ FTIR, and the dynamics of the facile E/Z alkene geometry interconversion of the resultant aniline-derived enaminones was explored through NMR, FTIR and X-ray crystallography. A straightforward purification protocol that employs direct Kugelrohr distillation was identified, and the method was further extended to other amines and ynones, allowing rapid access to these interesting compounds.本研究报道了一种在乙醇介质中，3-丁炔-2-酮（3-butyn-2-one）与各类苯胺类化合物发生共轭加成反应的便捷、温和且高效的合成策略。该反应通过原位傅里叶变换红外光谱（in situ FTIR）进行监测与表征，研究团队还借助核磁共振波谱（NMR）、傅里叶变换红外光谱（FTIR）及X射线晶体学（X-ray crystallography），对产物苯胺衍生烯胺酮类化合物的烯烃E/Z构型快速几何异构动力学过程展开了探究。本研究确立了一种采用直接库尔格罗尔蒸馏（Kugelrohr distillation）的简易纯化流程，并将该方法进一步拓展至其他胺类与炔酮类（ynones）底物，从而可快速获取这类具有研究价值的目标化合物。