Electrochemical Reduction of Diarylketones and Aryl Alkenes

Ce Bi, Xiangyu Zhao, Zhiqi Jia, Yongxin Chang, Hang Yang, Mengyuan Song, Xin Zhang, Yahui Zhang, and Guangyan Qing*

ChemCatChem 2023, e202300258.

Selective hydrogenation reactions of ketones and alkenes are of high priority among numerous chemical transformations due to their broad range of applications, encompassing both natural products to food industries. However, classical reduction methods usually require the precise design of ligands, the need for metals with low natural abundance, the challenge of removing and recovering synthetic catalysts, the generation of waste and harsh reaction conditions, which greatly limit their practical applications. Hence, the development of environmentally friendly, economical, simple, and safe reduction methods are urgently needed. 

      Guangyan Qing, Yahui Zhang, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, China, and colleagues have presented a new approach for the electrochemical hydrogenation of C=O and C=C bonds under mild conditions. Thereinto, the mixed solvent system of CH3CN/THF provided the foundation for the successful completion of this electrochemical reaction and the addition of N,N-diisopropylethylamine (DIEA) played a dual role in promoting the electrolysis of CH3CN and serving as a proton donor to facilitate the hydrogenation of unsaturated compounds. In addition, the successful completion of gram-scale experiments highlights the potential for this strategy in industrial applications.

      In brief, a high-yield electrochemical reduction protocol for ketones and alkenes is reported, and excellent substrate tolerance, smooth amplification experiments, and detailed mechanism study are exhibited in this electrochemical strategy. These typical characteristics provide an available protocol for efficient industrial hydrogenation.