Currently, the most competitive production routes for resorcinol are: (1) the alkylation of benzene with propylene, followed by the separation of *m*-diisopropylbenzene from the mixed dialkylation products and subsequent Hock reaction; and (2) the hydrolysis of *m*-phenylenediamine.
The research group led by Professor Haoran Li, affiliated with the Center for Chemistry of High-Performance & Novel Materials and the ZJU-NHU United R&D Center at Zhejiang University, has developed a novel synthetic route to resorcinol. While the ortho-monohydroxylation of benzoic acid has been achieved by groups including that of Jin-Quan Yu, the introduction of a second hydroxyl group at the other ortho position has proven challenging due to the insufficient oxidizing power of the oxidants and the deactivating effect of the first hydroxyl group on the aromatic ring. By introducing molybdenum into the traditional palladium-catalyzed system, this team has achieved the second hydroxylation step through a bimetallic synergistic mechanism that promotes the homolysis of tert-butyl hydroperoxide (TBHP) into radicals.
Notably, the carboxyl group can be removed upon heating. This study presents a new route to resorcinol starting from benzoic acid, which involves the initial ortho-dihydroxylation followed by decarboxylation. Alternatively, it can be produced from the monohydroxylated product salicylic acid (or its sodium salt) via a second hydroxylation and subsequent decarboxylation. This route has been granted a Chinese invention patent (CN121449500B), and its industrial viability is currently under evaluation and development.
The research findings have been published in the Journal of the American Chemical Society. Ph.D. candidate Dingmei Hu and Postdoctoral Fellow Renfeng Du are the co-first authors, and Professor Haoran Li is the corresponding author. This work was supported by the National Key Research and Development Program of China (2022YFA1503200) and the Chemistry Instrumentation Center of Zhejiang University. The authors also acknowledge valuable suggestions from Professor Zhan Lu of the Department of Chemistry during the preparation of the manuscript.
Original article: http://pubs.acs.org/doi/abs/10.1021/jacs.6c10830
Title: Pd/Mo-Catalyzed Ortho-Dihydroxylation of Aromatic Rings: Dual-Metal-Mediated C(sp²)–H Functionalization
Authors: Dingmei Hu, Renfeng Du, Yongtao Wang, Jia Yao, and Haoran Li*
