title: Selective iron-catalyzed cross-coupling reactions of grignard reagents with enol triflates, acid chlorides, and dichloroarenes.
abstract: Cheap, readily available, air stable, nontoxic, and environmentally benign iron salts such as Fe(acac)(3) are excellent precatalysts for the cross-coupling of Grignard reagents with alkenyl triflates and acid chlorides. Moreover, it is shown that dichloroarene and -heteroarene derivatives as the substrates can be selectively monoalkylated by this method. All cross-coupling reactions proceed very rapidly under notably mild conditions and turned out to be compatible with a variety of functional groups in both reaction partners. A detailed analysis of the preparative results suggests that iron-catalyzed C-C bond formations can occur via different pathways. Thus, it is likely that reactions of methylmagnesium halides involve iron-ate complexes as the active components, whereas reactions of Grignard reagents with two or more carbon atoms are effected by highly reduced iron-clusters of the formal composition [Fe(MgX)(2)](n) generated in situ. Control experiments using the ate-complex [Me(4)Fe]Li(2) corroborate this interpretation.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, D-45470 Muelheim/Ruhr, Germany.
authors.forename: Bodo
authors.initials: B
authors.lastname: Scheiper
authors.forename: Melanie
authors.initials: M
authors.lastname: Bonnekessel
authors.forename: Helga
authors.initials: H
authors.lastname: Krause
authors.forename: Alois
authors.initials: A
authors.lastname: Fürstner