Modular Synthesis of <i>gem</i>-Difluorotetrahydrocarbazolone Scaffolds via Copper-Catalyzed Cascade Reaction of Bromodifluoroacetyl Indoles and Olefins

A novel and efficient modular synthesis of <i>gem</i>-difluorotetrahydrocarbazolone scaffolds via copper-catalyzed radical cascade cyclization of bromodifluoroacetyl indoles and olefins has been reported. This operationally simple protocol provides straightforward and practical access to a series of privileged <i>gem</i>-difluorotetrahydrocarbazolone scaffolds from readily available starting materials, with the feature of broad functional group tolerance and mild reaction conditions. Moreover, the method could be used for the late-stage functionalization of bioactive molecules, which opens up the possibility for practical applications.