Chen Youwei, Li Jide, Xu Jiaxi, Yang Zhanhui
Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, China.
Molecules. 2024 Dec 14;29(24):5912. doi: 10.3390/molecules29245912.
In this study, an iridium-catalyzed selective 1,4-reduction of α,β-unsaturated carbonyl compounds is realized, with water as a solvent and formic acid as a hydride donor. The new efficient iridium catalyst features a 2-(4,5-dihydroimidazol-2-yl)quinoline ligand. The chemoselectivity and catalyst efficiency are highly dependent on the electronic and steric properties of the substrates. For α,β-unsaturated amides, acids, and esters, only the electron-deficient C=C bonds are reduced (1,4-reduction), and the other functional groups are left intact. The ratio and initial TOF reach 7000 and 18,480 h, respectively. A gram-scale 1,4-reduction is also performed. Deuterium labeling shows that the β-hydrogens of the products originate from the formyl hydrogen in the formic acid. The application of the 1,4-reduction for the modification the structures of some medications is demonstrated.
在本研究中，实现了铱催化的α,β-不饱和羰基化合物的选择性1,4-还原反应，以水为溶剂，甲酸作为氢化物供体。新型高效铱催化剂具有2-(4,5-二氢咪唑-2-基)喹啉配体。化学选择性和催化剂效率高度依赖于底物的电子和空间性质。对于α,β-不饱和酰胺、酸和酯，只有缺电子的C=C键被还原（1,4-还原），其他官能团保持不变。产率和初始TOF分别达到7000和18480 h⁻¹。还进行了克级规模的1,4-还原反应。氘标记表明产物的β-氢原子来源于甲酸中的甲酰基氢。展示了该1,4-还原反应在一些药物结构修饰中的应用。
