title: Bis(oxazolinyl)phenylborane: a Lewis acid-containing ligand for methide abstraction-based coordination to aluminum(III).
abstract: A compound that contains a Lewis acidic boron center and coordinating oxazoline groups, bis(4,4-dimethyl-2-oxazolinyl)phenylborane (PhB(Ox(Me2))2; 1), has been prepared and spectroscopically characterized. Solvent dependent 15N and 11B NMR spectroscopic properties and solid-state 11B NMR measurements provide support for intermolecular interactions involving Lewis acid and base sites. The bifunctional nature of oxazolinylborane 1 is demonstrated by its reaction with (AlMe3)2, which proceeds via methide abstraction by the boron and oxazoline coordination to aluminum to yield [(kappa(2)-PhMeB(Ox(Me2))2AlMe2] (2). Compound 2 contains a planar six-membered chelate ring, in contrast to related bis(pyrazolyl)boratoaluminum compounds that are puckered. Additionally, compound 2 and related bidentate tris(oxazolinyl)phenylborato dimethylaluminum are inert toward aluminum-methyl bond protonolysis. This robust nature suggested the possibility of using these oxazolinylboratoaluminum compounds in catalytic reactions, as is demonstrated by lactide ring-opening polymerization.
authors.affiliation: Department of Chemistry and US Department of Energy Ames Laboratory, Iowa State University, 1605 Gilman Hall, Ames, Iowa 50011-3111, USA.
authors.forename: James F
authors.initials: JF
authors.lastname: Dunne
authors.forename: Kuntal
authors.initials: K
authors.lastname: Manna
authors.forename: Jerzy W
authors.initials: JW
authors.lastname: Wiench
authors.forename: Arkady
authors.initials: A
authors.lastname: Ellern
authors.forename: Marek
authors.initials: M
authors.lastname: Pruski
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Sadow