Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of PdII: Cyclic Transition State versus Difluorocarbene Release,Angewandte Chemie International Edition

当前位置： X-MOL 学术 › Angew. Chem. Int. Ed. › 论文详情

Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)

Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of PdII: Cyclic Transition State versus Difluorocarbene Release
Angewandte Chemie International Edition ( IF 16.1 ) Pub Date : 2018-10-17 , DOI: 10.1002/anie.201808229
Maoping Pu ₁ , Italo A. Sanhueza _{1,

2} , Erdem Senol ₁ , Franziska Schoenebeck ₁

Affiliation

The transmetalation is a key elementary step in cross‐coupling reactions. Yet, the precise nature of its mechanism and transition state geometry are frequently elusive. This report discloses our study of the transmetalation of [Pd^II]‐F complexes with the silane‐ and stannane‐based trifluoromethylation agents, R₃SiCF₃ and R₃SnCF₃. A divergent reactivity was uncovered, with the stannane showing selective R‐group transfer, and the silane selective CF₃‐group transfer. Using a combined experimental and computational approach, we uncovered a hitherto unrecognized transmetalation mechanism with the widely employed R₃SiCF₃ reagent, explaining its unique activity in metal‐catalyzed trifluoromethylations. While the stannane reacts via a cyclic, 4‐membered transition state, the silane undergoes a fundamentally different pathway and releases a difluorocarbene in the transmetalation event. Molecular dynamics studies clearly reinforced the liberation of a free CF₂ carbene, which reacts with [Pd^II]‐F to ultimately generate [Pd^II]‐CF_3.

中文翻译：

PdII的三氟甲基化反应中锡烷和硅烷的不同反应性：循环过渡态与二氟卡宾的释放

重金属化是交叉偶联反应中的关键基本步骤。然而，其机理和过渡态几何形状的精确性质常常难以捉摸。该报告公开了我们对[Pd ^II ] -F配合物与硅烷和锡烷基三氟甲基化剂R ₃ SiCF ₃和R ₃ SnCF ₃的金属转移的研究。发现了不同的反应性，其中锡烷显示出选择性的R-基团转移，而硅烷显示了选择性的CF _3-基团转移。使用组合的实验和计算方法，我们发现了R ₃ SiCF ₃被广泛采用的迄今无法识别的重金属化机理试剂，解释了其在金属催化的三氟甲基化反应中的独特活性。锡烷通过环状的四元过渡态反应时，硅烷经历了根本不同的途径，并在重金属化事件中释放出二氟卡宾。分子动力学研究清楚地增强了游离CF ₂卡宾的释放，其与[Pd ^II ] -F反应最终生成[Pd ^II ] -CF _3。

更新日期：2018-10-17

点击分享查看原文

点击收藏

阅读更多本刊最新论文本刊介绍/投稿指南11