Practical iron- and cobalt-catalyzed cross-coupling reactions between n-heterocyclic halides and aryl or heteroaryl magnesium reagents

Article abstract of DOI:10.1002/chem.201500747

The reaction scope of iron- and cobalt-catalyzed cross-coupling reactions in the presence of isoquinoline (quinoline) in the solvent mixture tBuOMe/THF has been further investigated. Various 2-halogenated pyridine, pyrimidine, and triazine derivatives were arylated under these mild conditions in excellent yields. The presence of isoquinoline allows us to perform Fe-catalyzed cross-coupling reactions between 6-chloroquinoline and aryl magnesium reagents. Furthermore, it was found that the use of 10% N,N-dimethylquinoline-8-amine increases the yields of some Co-catalyzed cross-coupling reactions with chloropyridines bearing electron-withdrawing substituents. Iron out your coupling! The use of iron and cobalt catalysts in a combination with only 10% isoquinoline represents a practical method for the cross-coupling reactions of various 2-halogenopyridines, -pyrimidines, and -triazines, as well as 6-halogenoquinolines with functionalized aryl or heteroaryl Grignard reagents (see scheme).