德克萨斯大学Michael J. Krische团队近日取得一项新成果。经过不懈努力，他们报道了甲酸介导的转移氢化芳基卤化物交叉偶联。2025年3月11日，国际知名学术期刊《Nature Chemistry》发表了这一成果。

转移加氢在化学工业的各个领域都有广泛的应用，但由于氢解反应的竞争，转移加氢在芳酰卤化物还原交叉偶联中的应用尚未开发。利用PdI不同的反应活性，描述了一种通过甲酸介导的氢转移催化活性芳基溴化物与芳基碘化物的还原性交叉偶联的高效催化体系。这些过程显示出铃木偶联和Buchwald-Hartwig偶联的正交性，因为氟哌啶醇硼酸盐和苯胺是耐受的，并且由于螯合中间体的干预，对挑战2-吡啶体系是有效的。实验和计算研究证实了还原性交叉偶联的独特催化循环，其中PdI预催化剂[Pd(I)(PtBu₃)]₂转化为重阴离子[Pd₂I₄][NBu₄]₂，其中芳基卤化物的氧化加成更容易。快速，可逆的钯到钯的金属转化提供了碘化物桥接的二芳基钯和杂二芳基钯二聚体的混合物。杂二芳基钯二聚体更稳定，具有较低的还原消除障碍，促进高水平的交叉选择性。

附：英文原文

Title: Aryl halide cross-coupling via formate-mediated transfer hydrogenation

Author: Cho, Yoon, Chang, Yu-Hsiang, Quirion, Kevin P., Strong, Zachary H., Dubey, Zachary J., Nguyen, Nam, Lee, Seoyoung, Taylor, Natalie S., Hoover, Jessica M., White, Nicholas A., Liu, Peng, Krische, Michael J.

Issue&Volume: 2025-03-11

Abstract: Transfer hydrogenation is widely practised across all segments of chemical industry, yet its application to aryl halide reductive cross-coupling is undeveloped because of competing hydrogenolysis. Here, exploiting the distinct reactivity of PdI species, an efficient catalytic system for the reductive cross-coupling of activated aryl bromides with aryl iodides via formate-mediated hydrogen transfer is described. These processes display orthogonality with respect to Suzuki and Buchwald–Hartwig couplings, as pinacol boronates and anilines are tolerated and, owing to the intervention of chelated intermediates, are effective for challenging 2-pyridyl systems. Experimental and computational studies corroborate a unique catalytic cycle for reductive cross-coupling where the PdI precatalyst, [Pd(I)(PtBu3)]2, is converted to the dianionic species, [Pd2I4][NBu4]2, from which aryl halide oxidative addition is more facile. Rapid, reversible Pd-to-Pd transmetallation delivers mixtures of iodide-bridged homo- and hetero-diarylpalladium dimers. The hetero-diarylpalladium dimers are more stable and have lower barriers to reductive elimination, promoting high levels of cross-selectivity.

DOI: 10.1038/s41557-024-01729-0

Source: https://www.nature.com/articles/s41557-024-01729-0