Cobalt-Catalyzed Selective Synthesis of Disiloxanes and Hydrodisiloxanes
作者:Sandip Pattanaik、Chidambaram Gunanathan
DOI:10.1021/acscatal.9b00305
日期:2019.6.7
independent experiments confirmed the catalytic oxidation of silane to silanol, and further dehydrocoupling processes are involved in syntheses of symmetrical siloxanes, cyclotetrasiloxanes, and siloxane cage compounds, whereas the unsymmetrical monohydrosiloxane syntheses from silanes and silanols proceeded via dehydrogenative coupling reactions. Overall these cobalt-catalyzed oxidative coupling reactions
分别从硅烷和二氢硅烷与水的反应中获得对称的硅氧烷和环四硅氧烷的选择性合成,并且该反应由NNN H t Bu钴(II)钳形配合物催化。有趣的是,当苯硅烷用水进行催化时,获得了由12个硅和18个氧中心组成的硅氧烷笼,反应明显进行,释放出3当量的分子氢(36 H 2)在温和的实验条件下。在硅烷与不同的硅烷醇反应后,通过钴催化实现了高选择性和受控的高级单氢硅氧烷和二甲氧基单氢硅烷的合成。释放的分子氢是在所有这些转化中观察到的唯一副产物。机理研究表明,反应是通过均质途径发生的。动力学和独立实验证实了硅烷催化氧化为硅烷醇的过程,并且进一步的脱氢偶联过程还涉及对称硅氧烷,环四硅氧烷和硅氧烷笼型化合物的合成,而硅烷和硅烷醇的不对称一氢硅氧烷则通过脱氢偶联反应进行合成。总体而言,这些钴催化的氧化偶联反应基于Si–H,Si–OH,和硅烷,硅烷醇和水的O–H键活化。建议使用由Co(II)中间体组成的催化循环。
We report a highlyselective synthesis of siloxane building blocks containing SiH2or SiH functionalities. AuCl(PPh3)/PPh3 or AuCl(PPh3)/PnBu3 system catalyzed the reaction of trihydrosilanes with silanols giving SiH2-containing siloxanes exclusively. On the other hand, a highlyselectivereaction of dihydrosilanes with silanols to afford SiH-containing siloxanes was achieved by simply changing the
我们报告了含有SiH 2或SiH官能团的硅氧烷构建基的高度选择性合成。AuCl(PPh 3)/ PPh 3或AuCl(PPh 3)/ P n Bu 3体系催化三氢硅烷与硅烷醇的反应,仅得到含SiH 2的硅氧烷。另一方面,通过简单地将膦配体改变为双齿的黄磷,实现了二氢硅烷与硅烷醇的高度选择性反应以提供含SiH的硅氧烷。的有用性的SiH 2含硅氧烷用三硅氧烷等的合成证明3具有SiH功能的SiOSi(Ph)(H)OSi t BuMe 2和五硅氧烷Ph 2 Si(OSiHPhOSiEt 3)2。
protocol for the construction of Si−O−Si moieties under cobalt catalysis. The reaction has a broad scope and can be used to synthesize a wide range of silicon buildingblocks, including challenging dihydrosiloxanes and functionalized silsesquioxanes. Most importantly, the results are placed into context by benchmarking with state-of-the-art methods. Remarkably, the utilized PNP-Co catalyst enables the development