Photo-redox Catalyzed C-S and C-C Bond Forming Cascade Cy-clization/Dearomatization of Biaryls: Sustainable Route to Func-tionalized Spirocyclohexa[5.5] and [4.5]trienones

An efficient approach towards photo-oxidative cascade cyclization reaction between biaryls and AgSCF3 or ArSSAr or Ar-SO2H or ArCOCO2H is reported to obtain structurally diverse SCF3 or SAr or SO2Ar or COAr containing spirotrienone using 0.1 mol% RFTA as a photocatalyst under visible light irradiation. Single-crystal X-ray diffraction analysis was performed to confirm the final product. A series of control experiments, UV and fluorescence quenching study, radical inhibition experi-ments were performed to establish the reaction mechanism.