Expanding the Scope of Alkynes in C–H Activation: Weak Chelation-Assisted Cobalt-Catalyzed Synthesis of Indole C(4)-Acrylophenone <i>via</i> C–O Bond Cleavage of Propargylic Ethers
作者:Pranav Shridhar Mahulkar、Sofaya Joshi、Shyam Kumar Banjare、Lamphiza O Najiar、Ponneri C. Ravikumar
DOI:10.1021/acs.orglett.4c00389
日期:2024.3.15
Herein, we report the facile synthesis of indole C(4)-acrylophenone using a C–H bond activation strategy. For this conversion, an unsymmetrical alkyne (phenylethynyl ether) in the presence of cobalt(III)-catalyst works efficiently. In this process, alkyne gets oxidized in the presence of in situ generated water, which is the key step for this method, for which trifluoroethanol is the water source.
在此,我们报道了使用 C-H 键激活策略轻松合成吲哚 C(4)-丙烯酮。对于这种转化,不对称炔烃(苯乙炔基醚)在钴(III)催化剂存在下可以有效地发挥作用。在此过程中,炔烃在原位生成水的存在下被氧化,这是该方法的关键步骤,三氟乙醇是该方法的水源。新戊酰导向基团有效螯合生成钴环中间体,并通过高分辨率质谱 (HRMS) 进行检测。此外,双(2,2,2-三氟乙基)醚的形成已被证实并使用19 F NMR 进行定量。此外,通过对α,β-不饱和酮部分进行Nazarov环化和共轭加成,证明了所得吲哚C(4)-丙烯酮产品的适用性。