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Bis(oxazolinyl)phenylborane: A Lewis acid-containing ligand for methide abstraction-based coordination to aluminum(III)

TitleBis(oxazolinyl)phenylborane: A Lewis acid-containing ligand for methide abstraction-based coordination to aluminum(III)
Publication TypeJournal Article
Year of Publication2010
AuthorsDunne JF, Manna K, Wiench JW, Ellern A, Pruski M, Sadow AD
Journal TitleDalton Transactions
Volume39
Pages641-653
Date Published02
ISBN Number1477-9226
Accession NumberISI:000272843100044
Keywordscatalysis, EXCHANGE, lactide, methyl complexes, nmr, ray crystal-structure, ring-opening polymerization, scorpionate ligands, solid angles, tris(pentafluorophenyl)borane
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 N-15 and B-11 NMR spectroscopic properties and solid-state B-11 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))(2)AlMe2] (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 oxazolinylborato-aluminum compounds in catalytic reactions, as is demonstrated by lactide ring-opening polymerization.
URL<Go to ISI>://000272843100044
DOI10.1039/B911851a