coupled with aryl bromides in the presence of an iron catalyst, metallic magnesium, a diamine ligand and an organic dihalide oxidant at 0 °C. The use of a 1:1 mixture of tetrahydrofuran and 1,4‐dioxane is essential for this CH bond activation reaction. The reaction has wider scope of the substrate compared with the reaction using a separately prepared Grignard reagent, and proceeds with lower catalyst
Room-Temperature Chromium(II)-Catalyzed Direct Arylation of Pyridines, Aryl Oxazolines, and Imines Using Arylmagnesium Reagents
作者:Olesya M. Kuzmina、Paul Knochel
DOI:10.1021/ol502623v
日期:2014.10.3
We report a CrCl2 catalyzed oxidative arylation of various pyridines, aryl oxazolines, and aryl imines using aromatic Grignard reagent in the presence of 2,3-dichlor-obutane (DCB). Most of the reaction proceed rapidly at 25 degrees C and do not require any additional ligand Benzo[h] quinoline, 2-arylpyridine, aryl oxazoline, and imines were successfully arylated in good yields under these conditions. A TMS-substituent was used to prevent double arylation. After oxidative cross-coupling the TMS-group was further converted to a second ortho-aryl substituent. Remarkably, inexpensive aryl N-butylimine derivatives are excellent substrate for this oxidative arylation.