Böhnke Julian, Arrowsmith Merle, Braunschweig Holger
Institut für Anorganische Chemie , Julius-Maximilians Universität Würzburg , Am Hubland, 97074 Würzburg , Germany.
Institute for Sustainable Chemistry & Catalysis with Boron , Julius-Maximilians Universität Würzburg , Am Hubland, 97074 Würzburg , Germany.
J Am Chem Soc. 2018 Aug 15;140(32):10368-10373. doi: 10.1021/jacs.8b06930. Epub 2018 Aug 6.
The desymmetrization of the cyclic (alkyl)(amino)carbene-supported diboracumulene B(cAAC) (cAAC = 1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethylpyrrolidin-2-ylidene) by monoadduct formation with IMe (1,3-dimethylimidazol-2-ylidene) yields the zerovalent sp-sp diboron compound B(cAAC)(IMe), which provides a versatile platform for the synthesis of novel symmetrical and unsymmetrical zerovalent sp-sp diboron compounds by adduct formation with IMe and CO, respectively. Furthermore, B(cAAC)(IMe) displays enhanced reactivity compared to its symmetrical precursor, undergoing spontaneous intramolecular C-H activation and facile twofold hydrogenation, the latter resulting in B-B bond cleavage and the formation of the mixed-base parent borylene (cAAC)(IMe)BH.
环状（烷基）（氨基）卡宾负载的二硼累积烯B（cAAC）（cAAC = 1-（2,6-二异丙基苯基）-3,3,5,5-四甲基吡咯烷-2-亚基）与IMe（1,3-二甲基咪唑-2-亚基）形成单加合物，从而实现去对称化，生成零价sp-sp二硼化合物B（cAAC）（IMe），该化合物分别通过与IMe和CO形成加合物，为合成新型对称和不对称零价sp-sp二硼化合物提供了一个通用平台。此外，与对称前体相比，B（cAAC）（IMe）表现出更高的反应活性，能自发进行分子内C-H活化和容易的双重氢化反应，后者导致B-B键断裂并形成混合碱母体硼烯（cAAC）（IMe）BH。
