Yang Wen, Yao Yongqi, Yang Xin, Deng Yingying, Lin Qifu, Yang Dingqiao
Key Laboratory of Theoretical Chemistry of Environment, Ministry of Education, School of Chemistry and Environment, South China Normal University Guangzhou 510006 People's Republic of China
RSC Adv. 2019 Mar 18;9(16):8894-8904. doi: 10.1039/c9ra00577c. eCollection 2019 Mar 15.
A Pd-catalyzed Sonogashira cross-coupling reaction for the synthesis of C4-alkynylisoxazoles from 3,5-disubsitituted-4-iodoisoxazoles and terminal alkynes was described, which could afford the corresponding products with high yield (up to 98%). The results indicated that the steric effect from the group at the C3 position of the isoxazole had greater influence on the cross-coupling reaction than that from the group at the C5 position. In addition, the group at the C3 position of the isoxazole showed negligible electronic effects on the cross-coupling reaction. Furthermore, a gram-scale reaction of the Sonogashira coupling reaction was also investigated. Finally, a plausible mechanism for the Sonogashira coupling reaction was proposed.
描述了一种钯催化的Sonogashira交叉偶联反应，用于从3,5-二取代-4-碘异恶唑和末端炔烃合成C4-炔基异恶唑，该反应能以高产率（高达98%）得到相应产物。结果表明，异恶唑C3位基团的空间效应比C5位基团对交叉偶联反应的影响更大。此外，异恶唑C3位基团对交叉偶联反应的电子效应可忽略不计。此外，还研究了Sonogashira偶联反应的克级规模反应。最后，提出了Sonogashira偶联反应的合理机理。
