Visible-Light [4+2] Homodimerization of Decomposition-Prone Styrenes via Electron Transfer Catalysis of Diaryl Diselenides

The facile electron transfer catalysis of diaryl diselenides
was
utilized for the visible-light [4+2] homodimerization of decomposition-prone
styrenes. The reaction required only 0.5 mol % TPT+BF4– photocatalyst and 1.5 mol % electron transfer
catalyst (ArSe)2. The spontaneous electron transfer capability
of diaryl diselenides was demonstrated for the first time, leading
to the sequestration of redox-prone radical cation intermediates via
electron transfer processes. A variety of polymerization-prone styrenes
smoothly underwent the visible-light-promoted [4+2] homodimerization
to tetralin derivatives.