Fig. 4: Reaction scope.

Isolated yields are provided. Selectivity determined by gas chromatography is reported as the percentage of the major regioisomer. GC yields with alkanes as the limiting reagent in parentheses: substrate 2 (0.3 mmol) and tetrasulfide 3 (0.45 mmol). ^aMethod A: tetrasulfide 3 (0.3 mmol, 1.0 equiv.), 2 (3 mmol, 10 equiv.), TBADT 2 mol%, Na₂S₂O₈ (0.45 mmol, 1.5 equiv.), solvent 3 mL (CH₃CN/H₂O, v/v, 2/1), 390 nm, Ar, 60 °C, and 12 h. ^bMethod B: tetrasulfide 3 (0.3 mmol, 1.0 equiv.), 2 (3 mmol, 10 equiv.), TBADT 2 mol%, solvent 3 mL [CH₃CN/(HCl aq. 1.0 M), v/v, 2/1], 390 nm, Ar, 60 °C, and 12 h. ^cUsing CH₃CN/H₂O (v/v, 2/1) as solvent. ^d2 (0.3 mmol, 1.0 equiv.), tetrasulfide 3 (0.45 mmol, 1.5 equiv.), TBADT 2 mol%, solvent 3 mL [CH₃CN/(HCl aq. 1.0 M), v/v, 2/1], 390 nm, Ar, 60 °C, and 12 h. ^eTetrasulfide 3 (0.3 mmol, 1.0 equiv.), substrate 2 (1.5 mmol, 5.0 equiv.), TBADT 2 mol%, Na₂S₂O₈ (0.45 mmol, 1.5 equiv.), solvent 3 mL (CH₃CN/H₂O, v/v, 2/1), 390 nm, Ar, 60 °C, and 12 h. ^fDetermined by ¹H NMR spectroscopy. ^gTetrasulfide 3 (0.45 mmol, 1.5 equiv.), substrate 2 (0.3 mmol, 1.0 equiv.), TBADT 2 mol%, Na₂S₂O₈ (0.45 mmol, 1.5 equiv.), solvent 3 mL (CH₃CN/H₂O, v/v, 2/1), 390 nm, Ar, room temperature, and 12 h.