Affiliation:
1. College of Chemistry and Chemical Engineering Qingdao University 308 Ningxia Road Qingdao 266071 China
2. School of Ecology and Environment Ningxia University 489 Helan Mountain West Road Yinchuan 750021 China
Abstract
AbstractNew methods and strategies for the direct oxidation of benzylic C−H bonds are highly desirable, owing to the importance of ketone motifs in significant organic transformations and the synthesis of valuable molecules, including pharmaceuticals, pesticides, and fine chemicals. Herein, we describe an electrochemical benzylic C−H oxidation strategy for the synthesis of ketones using MeOH as an oxygen source. Inexpensive and safe KBr serves as both an electrolyte and a bromide radical precursor in the reaction. This transformation also offers several advantages such as mild conditions, broad functional group tolerance, and operational simplicity. Mechanistic investigations by control experiments, radical scavenging experiments, electron paramagnetic resonance (EPR), kinetic studies, cyclic voltammetry (CV), and in‐situ Fourier transform infrared (FTIR) spectroscopy support a pathway involving the formation and transformation of benzyl methyl ether via hydrogen atom transfer (HAT) and single‐electron transfer (SET). The practical application of our strategy is highlighted by the successful synthesis of five pharmaceuticals, namely lenperone, melperone, diphenhydramine, cinnarizine, and flunarizine.
Funder
National Natural Science Foundation of China
Subject
General Energy,General Materials Science,General Chemical Engineering,Environmental Chemistry