Excited‐State 2,3‐Dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ*) Initiated Organic Synthetic Transformations under Visible‐Light Irradiation

Abstract

The one‐electron oxidizing capacity of 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone (DDQ) improves significantly by visible‐light excitation. The exited‐state DDQ (DDQ*) even converts benzene, fluoroarenes, heteroarenes, benzyls and olefins into their corresponding radical cations as well as chloride and other anions into their radicals. These reactive intermediates have been utilized for the generation of C‐C and C‐X (N, O, or Cl) bonds in the synthesis of valuable organic compounds and natural products. This mini review provides an overview of such DDQ*‐initiated organic transformations with their scope and limitations and discusses the proposed reactions mechanisms.