Photocatalyst-free EDA-complex-enabled radical difluoroalkylation/cyclization for access to difluoroalkylated polycyclic coumarin derivatives

Abstract

A photocatalyst-free and electron donor–acceptor (EDA)-complex-enabled radical difluoroalkylation/cyclization of unactivated alkenes with bromodifluoroacetamides has been developed for the efficient synthesis of difluoroalkyl-containing polycyclic coumarin derivatives, affording a total of 32 target compounds. In this transformation, persulfates act as electron donors and bromodifluoroacetamides serve as electron acceptors to generate an EDA complex, enabling visible-light-induced radical processes without the need for external photocatalysts. This method features mild reaction conditions, operational simplicity, metal-free nature, and broad functional group tolerance.