title: Boryltrihydroborate: synthesis, structure, and reactivity as a reductant in ionic, organometallic, and radical reactions.
abstract: Reaction of lithium 1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaborol-2-ide with borane.THF provides the first boryl-substituted borohydride: lithium [1,3-bis(2,6-diisopropylphenyl)-2,3-dihydro-1H-1,3,2-diazaborol-2-yl]trihydroborate. The compound is fully characterized by (11)B, (1)H, and (7)Li NMR spectra and other means, and these data are compared to neutral and anionic benchmark compounds. The compound crystallizes as a dimer complexed to four THF molecules. The dimer lacks the bridging B-H bonds seen in neutral boranes and is instead held together by ionic Li---HB interactions. A preliminary scan of reactions with several iodides shows that the compound participates in an ionic reduction (with a primary-alkyl iodide), an organometallic reduction (Pd-catalyzed with an aryl iodide), and a radical reduction (AIBN-initiated with a sugar-derived iodide). Accordingly the new borylborohydride class may share properties of both traditional borohydrides and isoelectronic N-heterocyclic carbene boranes.
authors.affiliation: Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-8656, Japan. nozaki@chembio.t.u-tokyo.ac.jp
authors.forename: Kyoko
authors.initials: K
authors.lastname: Nozaki
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Aramaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Yamashita
authors.forename: Shau-Hua
authors.initials: SH
authors.lastname: Ueng
authors.forename: Max
authors.initials: M
authors.lastname: Malacria
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Lacôte
authors.forename: Dennis P
authors.initials: DP
authors.lastname: Curran
mesh_terms: D001881:Borates / Q000138:chemical synthesis* / Q000737:chemistry*; D018360:Crystallography, X-Ray; D005609:Free Radicals / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D013237:Stereoisomerism
chemical_list: D001881:Borates; D005609:Free Radicals; D007477:Ions; D009942:Organometallic Compounds