title: Diborylated magnesium anthracene as precursor for B2H5(-)-bridged 9,10-dihydroanthracene.
abstract: 9,10-(Bpin)2-anthracene (3, HBpin = pinacolborane) was synthesized from 9,10-dibromoanthracene in a stepwise lithiation/borylation sequence. The reaction of 3 with highly activated magnesium furnished the diborylated magnesium anthracene 4, which was quenched in situ with ethereal HCl to yield cis-9,10-(Bpin)2-DHA (cis-5, DHA = 9,10-dihydroanthracene). Compound cis-5, in turn, can be reduced with Li[AlH4] in THF to give its diborate Li2[cis-9,10-(BH3)2-DHA] (Li2 [cis-6]). In the crystal lattice, the THF solvate Li2[cis-6]⋅3 THF establishes a dimeric structure with Li-(μ-H)-B coordination modes. Hydride abstraction from Li2[cis-6] with Me3SiCl yields the B-H-B-bridged DHA Li[7]. This product can also be viewed as a unique cyclic B2H7(-) derivative with a hydrocarbon backbone. Treatment of Li2[cis-6] with the stronger hydride abstracting agent Me3SiOTf (HOTf = trifluoromethanesulfonic acid) in THF affords the THF diadduct of cis-9,10-(BH(OTf))2-DHA.
authors.affiliation: J. W. Goethe-Universität, Institut für Anorganische und Analytische Chemie, Max-von-Laue-Straße 7, 60438 Frankfurt (Main) (Germany), Fax: (+49) 69-798-29260.
authors.forename: Steffen
authors.initials: S
authors.lastname: Pospiech
authors.affiliation: J. W. Goethe-Universität, Institut für Anorganische und Analytische Chemie, Max-von-Laue-Straße 7, 60438 Frankfurt (Main) (Germany), Fax: (+49) 69-798-29260.
authors.forename: Michael
authors.initials: M
authors.lastname: Bolte
authors.affiliation: J. W. Goethe-Universität, Institut für Anorganische und Analytische Chemie, Max-von-Laue-Straße 7, 60438 Frankfurt (Main) (Germany), Fax: (+49) 69-798-29260.
authors.forename: Hans-Wolfram
authors.initials: HW
authors.lastname: Lerner
authors.affiliation: J. W. Goethe-Universität, Institut für Anorganische und Analytische Chemie, Max-von-Laue-Straße 7, 60438 Frankfurt (Main) (Germany), Fax: (+49) 69-798-29260. Matthias.Wagner@chemie.uni-frankfurt.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Wagner
keywords: boranes; hydride abstraction; hydrido complexes; magnesium anthracenes; reduction