title: Oxidative cyclization reaction of 2-aryl-substituted cinnamates to form phenanthrene carboxylates by using MoCl5.
abstract: The oxidative cyclization reaction of 2-aryl cinnamates and derivatives thereof can be easily performed with MoCl5 as the oxidant. This powerful reagent allows oxidative coupling reactions for which other reagents fail. The best results are obtained when the 2-phenyl substituent of the cinnamate is equipped with two methoxy groups. Even iodo moieties in the bay region of phenanthrene are tolerated under the reaction conditions. If naphthalene moieties are involved, a rearrangement of the skeleton occurs, providing an elegant route to highly functionalized angular arenes. The cyclization is demonstrated for 15 example substrates with isolated yields of up to 99 % for the phenanthrene derivative. The broad scope of the reaction underlines the usefulness of MoCl5 and MoCl5 /TiCl4 in the oxidative coupling reaction.
authors.affiliation: Mainz University, Institute for Organic Chemistry, Duesbergweg 10-14, 55128 Mainz (Germany), Fax: (+49) 6131 3926777.
authors.forename: Kathrin
authors.initials: K
authors.lastname: Wehming
authors.forename: Moritz
authors.initials: M
authors.lastname: Schubert
authors.forename: Gregor
authors.initials: G
authors.lastname: Schnakenburg
authors.forename: Siegfried R
authors.initials: SR
authors.lastname: Waldvogel
mesh_terms: D002264:Carboxylic Acids / Q000737:chemistry; D002712:Chlorides / Q000737:chemistry*; D002934:Cinnamates / Q000737:chemistry*; D003500:Cyclization; D008982:Molybdenum / Q000737:chemistry*; D010084:Oxidation-Reduction; D010616:Phenanthrenes / Q000737:chemistry*
chemical_list: D002264:Carboxylic Acids; D002712:Chlorides; D002934:Cinnamates; D010616:Phenanthrenes; C031181:phenanthrene; D008982:Molybdenum; C085192:molybdenum chloride
keywords: CC coupling; arene coupling; cyclization; molybdenum; oxidative coupling