Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, 7-3-1 Bunkyo-ku, Tokyo 113-8656, Japan.
J Am Chem Soc. 2010 Aug 25;132(33):11449-51. doi: 10.1021/ja105277u.
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.
锂 1,3-双(2,6-二异丙基苯基)-2,3-二氢-1H-1,3,2-二氮硼杂环戊二烯-2-化物与硼烷反应。THF 提供了第一个取代硼的硼氢化物：锂[1,3-双(2,6-二异丙基苯基)-2,3-二氢-1H-1,3,2-二氮硼杂环戊二烯-2-基]三氢硼酸盐。该化合物通过 (11)B、(1)H 和 (7)Li NMR 光谱和其他方法进行了全面表征，并将这些数据与中性和阴离子基准化合物进行了比较。该化合物结晶为二聚体，与四个 THF 分子配位。二聚体缺乏中性硼烷中看到的桥接 B-H 键，而是通过离子 Li---HB 相互作用结合在一起。对几种碘化物反应的初步扫描表明，该化合物参与离子还原（与伯烷基碘化物）、有机金属还原（Pd 催化与芳基碘化物）和自由基还原（AIBN 引发与糖衍生碘化物）。因此，新的硼基硼氢化物类可能同时具有传统硼氢化物和等电子 N-杂环卡宾硼烷的性质。
