Described herein is an efficient protocol for the site selective oxidative CâH activation/acetoxylation of a series of 2-aryl/heteroaryl/thiophenyl tethered dihydroquinolinones using palladium acetate as the catalyst and iodobenzene diacetate as an oxidant. All these transformations progressed well at less sterically encumbered and electronically favourable CâH bonds to give corresponding ortho-acetoxylated derivatives in good yields. Further, acetoxylation of thiophenyl embedded dihydroquinolinones resulted in single regioisomers, acetoxylated at the C-2 position on the thiophenyl moiety. However, when the C-2 position on the thiophene unit was blocked, the acetoxy group was exclusively installed at the C-4 position. Further, we noticed that acetoxylation of dihydroquinolin-5(6H)-one-oxime did not alter ligand preferentiality to give the ortho-acetoxylated product.
本文描述了一种高效的选择性氧化C–H活化/乙酰氧基化协议,适用于一系列连接有2-芳基/杂芳基/
噻吩基的二氢
喹啉酮,使用
醋酸钯作为催化剂,
碘苯二乙酸作为氧化剂。所有这些反应在立体障碍较小且电子性质良好的C–H键上进行良好,生成相应的邻位乙酰氧基化衍
生物,收率良好。此外,嵌入
噻吩基的二氢
喹啉酮的乙酰氧基化反应导致产生单一的区域异构体,乙酰氧基在
噻吩基部分的C-2位上。然而,当
噻吩单元的C-2位被阻塞时,乙酰氧基则会独占性地安装在C-4位上。此外,我们注意到,二氢
喹啉-5(6H)-酮-
肟的乙酰氧基化并未改变
配体的优先性,仍然生成邻位乙酰氧基化产物。