Gay Brittany L, Wang Ya-Nong, Bhatt Shreeja, Tarasewicz Anika, Cooke Daniel J, Milem E Grace, Zhang Bufan, Gary J Brannon, Neidig Michael L, Hull Kami L
University of Texas at Austin, 100 E. 24th Street, Austin, Texas 78712, United States.
Stephen F. Austin State University, SFA Station, P.O. Box 13006, Nacogdoches, Texas 75962, United States.
J Am Chem Soc. 2023 Aug 30;145(34):18939-18947. doi: 10.1021/jacs.3c05790. Epub 2023 Aug 16.
Aminoboration of simple alkenes with nitrogen nucleophiles remains an unsolved problem in synthetic chemistry; this transformation can be catalyzed by palladium aminopalladation followed by transmetalation with a diboron reagent. However, this catalytic process faces inherent challenges with instability of the alkylpalladium(II) intermediate toward β-hydride elimination. Herein, we report a palladium/iron cocatalyzed aminoboration, which enables this transformation. We demonstrate these conditions on a variety of alkenes and norbornenes with an array of common nitrogen nucleophiles. In the developed strategy, the iron cocatalyst is crucial to achieving the desired reactivity by serving as a halophilic Lewis acid to release the transmetalation-active cationic alkylpalladium intermediate. Furthermore, it serves as a redox shuttle in the regeneration of the Pd(II) catalyst by reactivation of nanoparticulate palladium.
简单烯烃与氮亲核试剂的氨基硼化反应在合成化学中仍是一个未解决的问题；这种转化可以通过钯催化的氨基钯化反应，随后与二硼试剂进行转金属化反应来实现。然而，这种催化过程面临着固有的挑战，即烷基钯（II）中间体对β-氢消除反应不稳定。在此，我们报道了一种钯/铁共催化的氨基硼化反应，该反应能够实现这种转化。我们用一系列常见的氮亲核试剂在多种烯烃和降冰片烯上展示了这些反应条件。在开发的策略中，铁共催化剂通过作为亲卤路易斯酸释放转金属化活性阳离子烷基钯中间体，对于实现所需的反应活性至关重要。此外，它通过重新激活纳米颗粒钯在钯（II）催化剂的再生中作为氧化还原穿梭体。
