title: Room-temperature chromium(II)-catalyzed direct arylation of pyridines, aryl oxazolines, and imines using arylmagnesium reagents.
abstract: We report a CrCl2-catalyzed oxidative arylation of various pyridines, aryl oxazolines, and aryl imines using aromatic Grignard reagents in the presence of 2,3-dichlorobutane (DCB). Most of the reactions proceed rapidly at 25 °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 substrates for this oxidative arylation.
authors.affiliation: Department of Chemistry, Ludwig-Maximilians-Universität , Butenandtstr. 5-13, 81377 Munich, Germany.
authors.forename: Olesya M
authors.initials: OM
authors.lastname: Kuzmina
authors.forename: Paul
authors.initials: P
authors.lastname: Knochel