Modular Synthesis\nof <i>gem</i>-Difluorotetrahydrocarbazolone\nScaffolds via Copper-Catalyzed Cascade Reaction of Bromodifluoroacetyl\nIndoles and Olefins

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