武汉大学程强/戚孝天ACIE:氧-自由基捕获助力镍催化两分子亲核试剂的C(sp2)-杂原子偶联反应
Hypervalent transition-metal complexes serve as pivotal intermediates enabling reductive elimination for carbon–heteroatom bond formation. Significant efforts have focused on nickel-catalyzed couplings of aryl(pseudo)halides with nucleophiles, utilizing, for example, photo- or electrochemical strategies to access high-valent Ni(III) species. Nevertheless, the analogous Ni(III)-mediated oxidative cross-coupling of two nucleophilic partners for carbon–heteroatom bond construction remains elusive, despite the central role of such nucleophiles, for example, boronic acids, in cross-coupling chemistry. Herein, we report a general oxygen-radical capture strategy that accelerates the single-electron oxidation of Ni(II) and subsequent reductive elimination, enabling diverse carbon–heteroatom bond formations with arylboronic acids. We demonstrate the oxidative coupling of aryl boronic acids with alcohols, a transformation that has never been realized by nickel catalysis, likely due to the facile β-hydride elimination of the corresponding metal alkoxides. Mechanistic investigations and DFT calculations suggest the crucial role of the tert-butoxyl radical in the transformation of Ni(II) to Ni(III), enabling facile reductive elimination that bypass other possible side pathways. Furthermore, we show that a broad range of nucleophiles can be employed for the construction of C–O, C–S, C–N, and C–P bonds using this method.图3. DFT计算自由基捕获和还原消除过程（图片来源于ACIE）图4. 醇和芳基硼酸的氧化C-O键偶联反应底物拓展（图片来源于ACIE）图5. 后期氧化C-O键偶联和C-X偶联反应（图片来源于ACIE）In conclusion, we have developed a general oxygen-radical capture strategy for Ni-catalyzed oxidative C–heteroatom bond construction from aryl boronic acids and diverse nucleophiles. The favored C–O bond formation with alcohols was achieved by radical-capture accelerated Ni(III)-generation followed by facile reductive elimination. The reaction demonstrates an expanded substrate scope that accommodates both electron-poor aryl boronic acids and sterically hindered alcohols, which typically exhibit low reactivity in conventional catalytic oxidative C-O cross-couplings. Alcohol oxidation via β-hydride elimination was also suppressed to a promising extent with our strategy. The broad applicability of the oxygen-radical capture strategy is demonstrated by the construction of C–N, C–S, and C–P bonds from the corresponding nucleophilic substrates.DOI: doi.org/10.1002/anie.8724182声明：本文中广告内容由广告主提供，请您在购买任何商品或服务前，以书面合同形式明确约定双方权利义务，本账号不对其后续经营行为承担持续担保责任
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