for disulfides or tetrasulfides (Figure -E and S96-S123). When dimethyl disulfide was treated with DMF in the presence of di-n-propyl disulfide, di-n-hexyl disulfide, di-iso-butyl disulfide, di-iso-propyl disulfide, or di-tert-butyl disulfide, no more than trace reaction was observed at room temperature over 24 hours. One interesting exception was dibenzyl disulfide, which did undergo rapid metathesis with dimethyl disulfide in DMF, NMP, or DMSO. In these cases, dibenzyl disulfide is a uniquely reactive substrate, perhaps activated by neighboring group participation of the aryl group.