title: Copper- and palladium-catalyzed intramolecular aryl guanidinylation: an efficient method for the synthesis of 2-aminobenzimidazoles.
abstract: [reaction: see text] The formation of 2-aminobenzimidazoles via intramolecular C[bond]N formation between an aryl halide and a guanidine moiety can be achieved using either copper or palladium catalysis. Inexpensive copper salts such as CuI are generally superior to the use of palladium catalysts. Regioselective cyclizations, where R(3) = H, can be achieved in high yield under CuI/1,10-phenanthroline-catalyzed conditions, whereas palladium catalysis results in the formation of regioisomeric products.
authors.affiliation: Davenport Research Laboratories, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario, M5S 3H6, Canada.
authors.forename: Ghotas
authors.initials: G
authors.lastname: Evindar
authors.forename: Robert A
authors.initials: RA
authors.lastname: Batey
mesh_terms: D001562:Benzimidazoles / Q000138:chemical synthesis*; D002384:Catalysis; D003300:Copper / Q000737:chemistry; D003500:Cyclization; D019791:Guanidine / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry
chemical_list: D001562:Benzimidazoles; D010165:Palladium; D003300:Copper; C027391:2-aminobenzimidazole; D019791:Guanidine