Fig. 5. Key mechanistic findings.

a The reaction of 1b and 2a under standard conditions for 12 h. b The reaction of 1b and 2a under standard conditions for 24 h. c The reaction of 1b and 2j under standard conditions for 24 h. d The catalytic system was analyzed by high-resolution mass spectrometry. e Investigation on the reaction mode of trisulfide 6a under different conditions. f Investigation on the reaction mode of unsymmetrical trisulfide 8 under different conditions. g The reaction of 1,2-dibenzyldisulfane 7a and 1,2-di-tert-butyldisulfane 9 under standard conditions for 24 h.