Visible-Light-Driven Reductive Carboxylation of Benzyl Bromides with Carbon Dioxide Using Formate as Terminal Reductant

Wei Hang; Danyun Li; Song Zou; Chanjuan Xi

doi:10.1021/acs.joc.2c01840

Visible-Light-Driven Reductive Carboxylation of Benzyl Bromides with Carbon Dioxide Using Formate as Terminal Reductant

J Org Chem. 2023 Apr 21;88(8):5007-5014. doi: 10.1021/acs.joc.2c01840. Epub 2022 Sep 20.

Authors

Wei Hang¹, Danyun Li², Song Zou¹, Chanjuan Xi^{1

3}

Affiliations

¹ MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
² Department of Chemical Engineering, Tsinghua University, Beijing 100084, China.
³ State Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin 300071, China.

PMID: 36126282
DOI: 10.1021/acs.joc.2c01840

Abstract

Cheap and available formate can be seen formally as a carbon dioxide radical anion (CO₂^•-) combined with a hydrogen atom, where the CO₂^•- is not only a highly active radical but also a very powerful reductant. In this paper, we successfully realized a visible-light-driven carboxylation of benzyl bromides with carbon dioxide to prepare high-value arylacetic acids using potassium formate as a terminal reductant. This reaction is characterized by mild reaction conditions and a wide range of substrates. Moreover, under nitrogen atmosphere, the reaction can also achieve the carboxylation of benzyl bromides utilizing an excess of potassium formate. Mechanistic experiments indicate this carboxylation proceeded through CO₂^•-, which was generated from the oxidation of 1,4-diazabicyclo[2.2.2]octane with excited photosensitizer Ir(ppy)₂(dtbbpy)PF₆ in the presence of the potassium formate.