Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.
J Am Chem Soc. 2020 Sep 23;142(38):16188-16193. doi: 10.1021/jacs.0c07580. Epub 2020 Sep 11.
A synthetic cycle for aryl C-F substitution comprising oxidative addition, ligand metathesis, and reductive elimination at a -symmetric phosphorus triamide (, P{N[-NMe-CH]}) is reported. Reaction of with perfluoroarenes (Ar-F) results in C-F oxidative addition, yielding fluorophosphoranes ·[F][Ar]. The -fluoro substituent is exchanged for hydride by treatment with DIBAL-H, generating hydridophosphoranes ·[H][Ar]. Heating of ·[H][Ar] regenerates by C-H reductive elimination of Ar-H, where experimental and computational studies establish a concerted but highly asynchronous mechanism. The results provide well-characterized examples of the full triad of elementary mechanistic aryl C-X substitution steps at a single main-group site.
报道了一种包含芳基 C-F 取代的合成循环，包括氧化加成、配体交换和在对称磷三酰胺（，P{N[-NMe-CH]}}）上的还原消除。与全氟芳烃（Ar-F）反应导致 C-F 氧化加成，生成氟膦烷·[F][Ar]。用 DIBAL-H 处理，-氟取代基被氢化物取代，生成氢膦烷·[H][Ar]。·[H][Ar]的加热通过 Ar-H 的 C-H 还原消除再生·[F][Ar]，其中实验和计算研究确定了协同但高度异步的机制。这些结果提供了在单个主族位点上芳基 C-X 取代步骤的完整三元组的特征良好的例子。
