Cooperative 1,1-addition reactions of vicinal phosphane/borane frustrated Lewis pairs

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• 作者：Allan Jay P. Cardenas^a ; Yasuharu Hasegawa^b ; Gerald Kehr^b ; Timothy H. Warren^a ; ^{thw@georgetown.edu" class="auth_mail" title="E-mail the corresponding author} ; Gerhard Erker^b ; ^{erker@uni-muenster.de" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Frustrated Lewis pairs ; Nitric oxide ; Carbon monoxide ; Isonitriles ; Cooperative addition
• 刊名：Coordination Chemistry Reviews
• 出版年：2016
• 出版时间：1 January 2016
• 年：2016
• 卷：306
• 期：part_P2
• 页码：468-482
• 全文大小：3074 K

文摘

The unsaturated vicinal phosphane/borane frustrated Lewis pairs (P/B FLPs) Ph₂PC(p-tolyl) = C(R)B(C₆F₅)₂ (R = C₆F₅ or CH₃) react with tert-butyl isocyanide to give an equilibrium mixture of the starting materials, the borane/isonitrile adduct and the P/B addition product to the isonitrile carbon atom. The cooperative 1,1-adducts were exclusively formed upon treatment of these FLPs with n-butyl isocyanide. The saturated vicinal FLP Mes₂PCH₂CH₂B(C₆F₅)₂ reacts analogously with carbon monoxide yielding the respective five-membered zwitterionic carbonyl heterocycle. Similarly cooperative CO addition was observed starting from a norbornane based vicinal P/B FLP. These saturated vicinal P/B FLPs (and several related systems) undergo analogous cooperative 1,1-addition reactions to nitric oxide (NO) to give the corresponding persistent five-membered heterocyclic FLP-NO nitroxide radicals. They were characterized spectroscopically and by X-ray diffraction and shown to undergo typical N-oxyl radical reactions. Some vicinal P/B FLPs also undergo 1,1-addition reactions to mesityl azide. Anomalous Staudinger reactions were observed to take place upon subsequent thermolysis or (in one case) photolysis.