Introduction of Ether Groups onto Electron-Deficient Nitrogen-Containing Heteroaromatics Using Radical Chemistry under Transition-Metal-Free Conditions
作者:Naoki Okugawa、Katsuhiko Moriyama、Hideo Togo
DOI:10.1002/ejoc.201500584
日期:2015.8
treated with benzoylperoxide in dioxane, tetrahydropyran, tetrahydrofuran, diethylether, and dipropyl ether at 80 °C to form alkylated nitrogen-containing heteroaromatics in good yields under transition-metal-free conditions. This method was successfully applied to the preparation of lariat aza-crown ethers using 18-crown-6 or 15-crown-5 with quinoline and isoquinoline in the presence of benzoyl peroxide
The reactions of dioxanyl and cyclohexylradicals with 2- and 3-X-pyridines (X = CN, COMe, CO2Me) give a single substitution product deriving by addition at the 5- and 6-positions respectively; with 4-X-pyridines substitution occurs preferentially at the 3-position. If the reactions are carried out with protonated pyridines other positional isomers are obtained. From the synthetic point of view the