Lewis Acidity of Organofluorophosphonium Salts: Hydrodefluorination by a Saturated Acceptor
Lewis Acidity of Organofluorophosphonium Salts: Hydrodefluorination by a Saturated Acceptor
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DOI：
10.1126/science.1241764
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发表时间：
2013-09-20
期刊：
影响因子：
56.9
通讯作者：
Stephan, Douglas W.
中科院分区：
文献类型：
--
作者：
Caputo, Christopher B.;Hounjet, Lindsay J.;Stephan, Douglas W.
典型的路易斯酸，如硼烷，其反应性来自电子不饱和。在这里，我们报道了电子饱和的磷中心亲电受体的Lewis酸性和催化应用。式[(C6F5)(3-x)PhxPF][B(C6F5)(4)](x=0或1；Ph，苯基)的有机氟膦盐与中性Lewis碱形成加合物，并与氟烷迅速反应生成二氟膦烷。在氢硅烷存在下，阳离子[(C6F5)(3)Pf](+)催化氟烷烃的加氢脱氟反应，生成烷烃和氟硅烷。这个机制证明了这个高度缺乏电子的磷离子中心令人印象深刻的氟离子亲和力。
Prototypical Lewis acids, such as boranes, derive their reactivity from electronic unsaturation. Here, we report the Lewis acidity and catalytic application of electronically saturated phosphorus-centered electrophilic acceptors. Organofluorophosphonium salts of the formula [(C6F5)(3-x)PhxPF][B(C6F5)(4)] (x = 0 or 1; Ph, phenyl) are shown to form adducts with neutral Lewis bases and to react rapidly with fluoroalkanes to produce difluorophosphoranes. In the presence of hydrosilane, the cation [(C6F5)(3)PF](+) is shown to catalyze the hydrodefluorination of fluoroalkanes, affording alkanes and fluorosilane. The mechanism demonstrates the impressive fluoride ion affinity of this highly electron-deficient phosphonium center.