Visible‐light Catalysed Trifluoromethylthiolation and Related Dearomative Spirocyclizations

Abstract We conceptualized a radical cyclization approach for the synthesis of SCF 3 , SAr, SO 2 Ar and COAr featured spirocyclic [4.5] and [5.5] trienone between biaryls and ArSO 2 H or ArCOCO 2 H in presence of RFTA as a photocatalyst whereas the insertion of ArSSAr or AgSCF 3 devoid of photocatalyst via an energetically demanding dearomative transformation under visible‐light catalysis. The photo‐excited charge transfer complex with biaryl tethered ynones provides a way to promote S‐centered radical generation followed by its insertion to enable a wide range of biologically important molecules.