Specifically, it was found that cyclic trisulfides contained in 5-member rings do not react with themselves and undergo ring-opening S-S metathesis in DMF (S186-S189). However, a linear trisulfide can react with such cyclic trisulfides to form a mixture of polysulfides and ring-opened products (S189-S191), which suggests that the linear trisulfide can form a reactive intermediate that is not accessible to the trisulfides contained in 5-member rings.