Merging Photoredox with Brønsted Acid Catalysis: The Cross-Dehydrogenative C-O Coupling for sp3 C-H Bond Peroxidation

Qing Xia; Qiang Wang; Changcun Yan; Jianyang Dong; Hongjian Song; Ling Li; Yuxiu Liu; Qingmin Wang; Xiangming Liu; Haibin Song

doi:10.1002/chem.201701755

Merging Photoredox with Brønsted Acid Catalysis: The Cross-Dehydrogenative C-O Coupling for sp³ C-H Bond Peroxidation

Chemistry. 2017 Aug 10;23(45):10871-10877. doi: 10.1002/chem.201701755. Epub 2017 Jul 17.

Authors

Qing Xia¹, Qiang Wang¹, Changcun Yan¹, Jianyang Dong¹, Hongjian Song¹, Ling Li¹, Yuxiu Liu¹, Qingmin Wang^{1

2}, Xiangming Liu¹, Haibin Song¹

Affiliations

¹ State Key Laboratory of Elemento-Organic Chemistry, Research Institute of Elemento-Organic Chemistry, Nankai University, Tianjin, 300071, P. R. China.
² Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300071, P. R. China.

PMID: 28577327
DOI: 10.1002/chem.201701755

Abstract

A photoredox and Brønsted acid synergistically catalyzed cross-dehydrogenative C-O coupling reaction is developed in which isochroman peroxyacetals are formed through sp³ C-H bond peroxidation. The reported method is characterized by its extremely mild reaction conditions, excellent yields, and broad substrate scope. An oxocarbenium ion p-chlorobenzenesulfonate was speculated to be the reactive intermediate. The role of hemiacetals and oxygenated dimers on the effective stabilization of the oxocarbenium ion was investigated; the presence of acid appeared to establish equilibrium between hemiacetals and oxygenated dimers with the oxocarbenium ion pairs. The broad applicability of the method highlights the potential of the protocol for molecule synthesis.

Keywords: Brønsted acid; C−O coupling; electron transfer; radical reactions; redox chemistry.