title: Phenanthrene synthesis by iron-catalyzed [4+2] benzannulation between alkyne and biaryl or 2-alkenylphenyl Grignard reagent.
abstract: The [4+2] benzannulation reaction of internal or terminal alkynes with 2-biaryl, 2-heteroarylphenyl, or 2-alkenylphenyl Grignard reagents in the presence of Fe(acac)(3), 4,4'-di-tert-butyl-2,2'-bipyridyl, and 1,2-dichloro-2-methylpropane takes place at room temperature in 1 h to give 9-substituted or 9,10-disubstituted phenanthrenes and congeners in moderate to excellent yields. The reaction tolerates sensitive functional groups such as bromide and olefin. When applied to a 1,3-diyne, the annulation reaction takes place on both acetylenic moieties to give a bisphenanthrene derivative.
authors.affiliation: Department of Chemistry, School of Science, The University of Tokyo, Hongo, Tokyo 113-0033, Japan.
authors.forename: Arimasa
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Laurean
authors.initials: L
authors.lastname: Ilies
authors.forename: Eiichi
authors.initials: E
authors.lastname: Nakamura