The development of catalysts based on earth abundant metals in place of noble metals is becoming a central topic of catalysis. We herein report a cobalt/tetraphosphine complex catalyzed homogeneous hydrogenation of polar unsaturated compounds using an air- and moisture-stable and scalable precatalyst. By activation with potassium hydroxide, this cobalt system shows both high efficiency (up to 24000
of various nitrogenheterocycles, including but not limited to quinolines, isoquinolines, indoles and pyridinium salts, in an aqueous solution of HCO2H/HCO2Na under mild conditions. The catalyst shows excellent functional‐group compatibility and high turnover number (up to 7500), with catalyst loadings as low as 0.01 mol % being feasible. Mechanistic investigation of the quinolinereduction suggests
在温和条件下,显示出环金属化的铱络合物在HCO 2 H / HCO 2 Na的水溶液中催化各种氮杂环的转移加氢反应,包括但不限于喹啉,异喹啉,吲哚和吡啶鎓盐。该催化剂表现出出色的官能团相容性和高周转率(最高7500),催化剂用量低至0.01 mol%是可行的。对喹啉还原反应的机理研究表明,转移氢化反应是通过1,2和1,4加成途径进行的,催化转化受氢化物转移步骤的限制。
Pd/C Catalyzed Decarboxylation-Transfer Hydrogenation of Quinoline Carboxylic Acids
作者:Xiao-Yu Zhou、Xia Chen
DOI:10.2174/1570178617999201005211251
日期:2020.10.5
Pd/C catalyzed decarboxylation-transfer hydrogenation of quinoline carboxylicacids and transferhydrogenation of quinolines had been developed for the synthesis of 1,2,3,4- tetrahydroquinolines. These two processes were implemented smoothly using Pd/C (0.9 mol%) as a catalyst with ammonium formate as a hydrogen source in ethanol at 80 °C. The reaction system can also be applied to transfer hydrogenation
Pd/C催化的喹啉羧酸的脱羧-转移加氢和喹啉的转移加氢已被开发用于合成1,2,3,4-四氢喹啉。这两个过程使用 Pd/C (0.9 mol%) 作为催化剂,以甲酸铵作为氢源,在 80 °C 的乙醇中顺利实施。该反应体系也可用于苯并[h]喹啉和2,9-二甲基-1,10-菲咯啉的转移加氢,收率良好。并对催化剂的克级规模和回收利用进行了测试,效果良好。此外,还提出了Pd/C催化还原喹啉羧酸和喹啉的机理。
Iridium-Catalyzed Transfer Hydrogenation of 1,10-Phenanthrolines using Formic Acid as the Hydrogen Source
The iridium‐catalyzed highly regioselective transfer hydrogenation of a variety of 2‐substituted and 2,9‐disubstituted 1,10‐phenanthrolines under mild conditions with formic acid as the hydrogen source is described. In the presence of a catalytic amount of the iridium complex [Cp*IrCl2]2, the transfer hydrogenation proceeded smoothly in 1,4‐dioxane under ligand‐free conditions, exclusively leading