Organic and Medicinal Chemistry Division, Indian Institute of Chemical Biology , 4-Raja S. C. Mullick Road, Jadavpur, Kolkata 700032, India.
J Org Chem. 2017 Dec 1;82(23):12406-12415. doi: 10.1021/acs.joc.7b02203. Epub 2017 Nov 7.
A silver- and copper-free rhodium-catalyzed C-H acetoxylation reaction of azaindoles has been achieved at near ambient temperature employing PIDA as a nonmetallic acetoxy source. The method is highly selective, efficient, and scalable and requires acetic anhydride as the sole additive. The scope of the reaction has been successfully tested with a wide array of medicinally important heterocyclic scaffolds with diverse functional group tolerance. A series of kinetic experiments was conducted to gain detailed insight into the reaction mechanism. The methodology developed could be successfully expanded for C7-acetoxylation of indoline derivatives using pyrimidine as a detachable directing group for the synthesis of 7-hydroxyindole.
一种新型的银铜自由的铑催化的 C-H 乙酰氧基化反应，可在近环境温度下，以 PIDA 作为非金属的乙酰氧基源，实现了靛红类化合物的高效、高选择性、可扩展的 C-H 乙酰氧基化反应。该方法只需要醋酸酐作为唯一的添加剂。该反应的适用范围已经通过一系列具有不同官能团容忍度的、广泛的、具有重要药用价值的杂环骨架得到了成功的测试。进行了一系列动力学实验，以深入了解反应机理。所开发的方法可以成功地扩展到使用嘧啶作为可分离的导向基团的吲哚啉衍生物的 C7-乙酰氧基化反应，以合成 7-羟基吲哚。
