Biomimetic catalytic aerobic oxidation of C-sp(3)-H bonds under mild conditions using galactose oxidase model compound CuIIL

Xiao-Hui Liu; Hai-Yang Yu; Jia-Ying Huang; Ji-Hu Su; Can Xue; Xian-Tai Zhou; Yao-Rong He; Qian He; De-Jing Xu; Chao Xiong; Hong-Bing Ji

doi:10.1039/d2sc02606f

Biomimetic catalytic aerobic oxidation of C-sp(3)-H bonds under mild conditions using galactose oxidase model compound Cu^IIL

Chem Sci. 2022 Jul 28;13(33):9560-9568. doi: 10.1039/d2sc02606f. eCollection 2022 Aug 24.

Authors

Affiliations

¹ Fine Chemical Industry Research Institute, School of Chemical Engineering and Technology, Sun Yat-sen University Zhuhai 519082 China zhouxtai@mail.sysu.edu.cn.
² CAS Key Laboratory of Microscale Magnetic Resonance, University of Science and Technology of China Hefei 230026 China sujihu@ustc.edu.cn.
³ Fine Chemical Industry Research Institute, School of Chemistry, Sun Yat-sen University Guangzhou 510275 China jihb@mail.sysu.edu.cn.

Abstract

Developing highly efficient catalytic protocols for C-sp(3)-H bond aerobic oxidation under mild conditions is a long-desired goal of chemists. Inspired by nature, a biomimetic approach for the aerobic oxidation of C-sp(3)-H by galactose oxidase model compound Cu^IIL and NHPI (N-hydroxyphthalimide) was developed. The Cu^IIL-NHPI system exhibited excellent performance in the oxidation of C-sp(3)-H bonds to ketones, especially for light alkanes. The biomimetic catalytic protocol had a broad substrate scope. Mechanistic studies revealed that the Cu^I-radical intermediate species generated from the intramolecular redox process of Cu^IILH₂ was critical for O₂ activation. Kinetic experiments showed that the activation of NHPI was the rate-determining step. Furthermore, activation of NHPI in the Cu^IIL-NHPI system was demonstrated by time-resolved EPR results. The persistent PINO (phthalimide-N-oxyl) radical mechanism for the aerobic oxidation of C-sp(3)-H bond was demonstrated.