Sharma Ritika, Kumar Rakesh, Sharma Upendra
Natural Product Chemistry and Process Development Division and AcSIR , CSIR- IHBT , Palampur 176061 , India.
J Org Chem. 2019 Mar 1;84(5):2786-2797. doi: 10.1021/acs.joc.8b03176. Epub 2019 Feb 12.
The rhodium/O system-catalyzed distal C(sp)-H olefination of quinoline N-oxides is developed. Molecular oxygen has been explored as an economic and clean oxidant, an alternative to inorganic oxidants. A wide substrate scope with respect to quinoline N-oxides and olefins (activated acrylates and styrenes; unactivated aliphatic olefins) demonstrates the robustness of the developed catalytic method. Interestingly, 2-substituted quinoline N-oxides also afforded good yields of the corresponding C8-olefinated products. Kinetic isotope studies and deuterium-labeling experiments have been performed to understand the preliminary mechanistic pathway. The applicability of the developed method is demonstrated by utilizing natural product-derived substrates and by converting the C8-olefinated quinoline N-oxides into various other useful molecules.
铑/氧体系催化喹啉N-氧化物的远端C(sp)-H烯基化反应得以开发。分子氧已被探索作为一种经济且清洁的氧化剂，以替代无机氧化剂。就喹啉N-氧化物和烯烃（活化丙烯酸酯和苯乙烯；未活化脂肪族烯烃）而言，广泛的底物范围证明了所开发催化方法的稳健性。有趣的是，2-取代喹啉N-氧化物也能以良好的产率得到相应的C8-烯基化产物。已进行动力学同位素研究和氘标记实验以了解初步的反应机理途径。所开发方法的适用性通过使用天然产物衍生的底物以及将C8-烯基化喹啉N-氧化物转化为各种其他有用分子得以证明。
