Homogenous Iron-Catalysed hydrogenation of polar substrates with precise chemoselectivity

A Tetradentate Ligand Enables Iron‐Catalyzed Asymmetric Hydrogenation of Ketones in a CO‐ or Isocyanide‐Free Fashion

“…After the treatment with hydride donor (lithium aluminum hydride, LAH), the color of Fe‐2 changed to burgundy in THF solution (Scheme 2). 1 H NMR spectroscopy showed a signal at −17.1 ppm while two multiple peaks (87.4 and 68.9 ppm) were observed at on the 13 P NMR spectra, suggesting a low‐spin trans ‐dihydride species [13] . This newly formed complex Fe‐3 could catalyze hydrogenation of ketone with the presence of inorganic base.…”

“…1 H NMR spectroscopy showed a signal at À 17.1 ppm while two multiple peaks (87.4 and 68.9 ppm) were observed at on the 13 P NMR spectra, suggesting a low-spin trans-dihydride species. [13] This newly formed complex Fe-3 could catalyze hydrogenation of ketone with the presence of inorganic base. With 1 mol % Fe-1, 5 mol % t BuOK and 5 mol % LAH, the benchmark substrate acetophenone 5 a was hydrogenated with 15 % conversion and 30 % ee in THF at 50 °C under 80 bar of hydrogen atmosphere for 12 h (Table 1, entry 1).…”

Recent Progress in Homogeneous Catalytic Hydrogenation of Nitro Compounds

“…他们在标准条件下进行了一系列 NMR 实验, 最终提出 如下催化循环过程: 催化剂[FeF(P 4 )][BF 4 ]被氢气活化后 失去一分子 HF 形成[FeH(P 4 )] ＋ , 该中间体进一步与氢气 作用形成[FeH(H 2 )(P 4 )][BF 4 ], 这个活性中间体将硝基芳 烃还原为亚硝基化合物, 同时又生成[FeH(P 4 )] ＋ , 按照 之前描述的反应进程, 再循环两次即可将生成的亚硝基 化合物还原为相应的胺化合物.2023 年, 张绪穆课题组[28] 也发展了一种四磷配位 的 Fe 催化剂 24, 在 10 mol%的 K 2 CO 3 存在的条件下, 可 以实现各种硝基芳烃的氢化还原(Scheme 19). 该催化…”