Reaction Diversity of the S–S Bond Promoted by Metal Coordination: From Discovery to Controllable Reactions

Promoted by NiCl 2 coordination in the mixed solvent MeOH/CH 2 Cl 2 , diverse in situ S–S bond reactions, such as S ‐oxidation and S–S and C–S bond scission, occurred in the disulfide ligand of 2‐ppds {bis[4‐(pyridin‐2‐yl)pyrimidin‐2‐yl]disulfane} to yield three new components identified as 2‐mpp [2‐methoxy‐4‐(pyridin‐2‐yl)pyrimidine], 2‐ppst { S ‐[4‐(pyridin‐2‐yl)pyrimidin‐2‐yl] 4‐(pyridin‐2‐yl)pyrimidine‐2‐sulfonothioate} and 2‐pps {bis[4‐(pyridin‐2‐yl)pyrimidin‐2‐yl]sulfane}. More importantly, such in situ reactions could be efficaciously controlled so that they proceed in a highly selective manner. Thus, NiCl 2 ‐mediated in situ reaction of 2‐ppds with the aid of continuous air bubbling through the reaction mixture exclusively led to 2‐pps, whereas replacement of NiCl 2 by Cu(OAc) 2 afforded 2‐mpp alone. A confirmatory experiment proved that 2‐ppst served as a decisive intermediate in these in situ reactions.