Luo Yun-Cheng, Wang Ming-Kuan, Yu Ling-Chao, Zhang Xingang
Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai, 200032, China.
School of Chemistry and Material Sciences, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, 1 Sub-lane Xiangshan, Hangzhou, 310024, China.
Angew Chem Int Ed Engl. 2023 Sep 11;62(37):e202308690. doi: 10.1002/anie.202308690. Epub 2023 Aug 1.
The selective transition-metal catalyzed C-F bond functionalization of inexpensive industrial fluorochemicals represents one of the most attractive approaches to valuable fluorinated compounds. However, the selective C(sp )-F bond carbofunctionalization of refrigerant hydrofluoroolefins (HFOs) remains challenging. Here, we report a nickel-catalyzed selective C(sp )-F bond alkylation of HFO-1234yf with alkylzinc reagents. The resulting 2-trifluoromethylalkenes can serve as a versatile synthon for diversified transformations, including the anti-Markovnikov type hydroalkylation and the synthesis of bioactive molecule analogues. Mechanistic studies reveal that lithium salt is essential to promote the oxidative addition of Ni (L ) to the C-F bond; the less electron-rich N-based ligands, such as bipyridine and pyridine-oxazoline, feature comparable or even higher oxidative addition rates than the electron-rich phosphine ligands; the strong σ-donating phosphine ligands, such as PMe , are detrimental to transmetallation, but the less electron-rich and bulky N-based ligands, such as pyridine-oxazoline, facilitate transmetallation and reductive elimination to form the final product.
廉价工业含氟化学品的选择性过渡金属催化C-F键官能团化是合成有价值的含氟化合物最具吸引力的方法之一。然而，制冷剂氢氟烯烃（HFOs）的选择性C(sp )-F键碳官能团化仍然具有挑战性。在此，我们报道了一种镍催化的HFO-1234yf与烷基锌试剂的选择性C(sp )-F键烷基化反应。所得的2-三氟甲基烯烃可作为一种通用的合成子用于多种转化反应，包括反马氏规则型氢烷基化反应以及生物活性分子类似物的合成。机理研究表明，锂盐对于促进Ni (L )对C-F键的氧化加成至关重要；电子云密度较低的N-配体，如联吡啶和吡啶-恶唑啉，与富电子膦配体相比具有相当甚至更高的氧化加成速率；强σ-供体膦配体，如PMe ，不利于金属转移，但电子云密度较低且体积较大的N-配体，如吡啶-恶唑啉，有利于金属转移和还原消除以形成最终产物。
