Cobalt-catalyzed intramolecular C-N and C-O cross-coupling reactions: Synthesis of benzimidazoles and benzoxazoles

Cobalt(ii)-complex catalyzes efficiently the intramolecular C-N and C-O cross-couplings of Z-N′-(2-halophenyl)-N-phenylamidines and N-(2-bromophenyl)benzamides to afford the corresponding substituted benzimidazoles and benzoxazoles in the presence of K2CO3 at moderate temperature. The protocol is general, air stable and affords the products selectively in moderate to high yield. © 2010 The Royal Society of Chemistry