Photochemical Construction of Trifluoromethyl Bicyclo[1.1.1]pentyl-heterocycles

We describe a transition-metal-free photocatalytic synthesis of CF₃-BCP-oxindoles via radical cascade annulation. This mild and sustainable protocol employs a bench-stable thianthrenium CF₃-BCP reagent and activated anilides under visible-light irradiation to efficiently assemble complex scaffolds bearing dual (CF₃ and BCP) bioisosteric features. Mechanistic studies reveal that CF₃-BCP radical generation proceeds through a previously unreported electron donor-acceptor (EDA) complex between 4CzIPN and the thianthrenium salt, initiating a radical chain process. This method provides a practical photochemical platform for the late-stage incorporation of CF₃-BCP motifs into oxindole frameworks and expands the accessible bioisosteric chemical space for drug discovery.