Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
Leibniz Institute for Catalysis (LIKAT Rostock), Albert-Einstein-Str. 29 a, 18059, Rostock, Germany.
Chemistry. 2018 Jul 20;24(41):10531-10540. doi: 10.1002/chem.201801871. Epub 2018 Jun 27.
A dimethylxanthene-based phosphine/borane frustrated Lewis pair (FLP) is shown to effect reversible C-H activation, cleaving phenylacetylene, PhCCH, to give an equilibrium mixture of the free FLP and phosphonium acetylide in CD Cl solution at room temperature. This system also reacts with B-H bonds although in a different fashion: reactions with HBpin and HBcat proceed via C-B/B-H metathesis, leading to replacement of the -B(C F ) Lewis acid component by -Bpin/-Bcat, and transfer of HB(C F ) to the phosphine Lewis base. This transformation underpins the ability of the FLP to catalyze the hydroboration of alkynes by HBpin: the active species is derived from the HB(C F ) fragment generated in this exchange process.
一种基于二甲基呫吨的膦/硼烷受阻路易斯对（FLP）被证明可以有效地实现 C-H 活化，将苯乙炔（PhCCH）裂解，在室温的 CDCl3溶液中得到自由 FLP 和磷翁乙炔化物的平衡混合物。该体系也可以与 B-H 键反应，但其反应方式不同：与 HBpin 和 HBcat 的反应是通过 C-B/B-H 复分解反应进行的，导致-B（C6F5）路易斯酸部分被-Bpin/-Bcat 取代，并且 HB（C6F5）转移到膦路易斯碱上。这种转化为 FLP 催化 HBpin 对炔烃的硼氢化反应提供了基础：活性物种源自于在这个交换过程中生成的 HB（C6F5）片段。
