Twenty-one unsymmetrical carbonyl disulfides, RC (O) SSR', were synthesized by reaction of thio acids with thiolsulfonates (eq 1) or with sulfenyl chlorides (eq 2; usually preferred). Absence of symmetrical disulfides was demonstrated by tlc and occasionally by glpc also. Structures were confirmed by ir, nmr, and mass spectra, and by identity of 3 products synthesized using both eq 1 and 2. The reactivity of methyl acetyl disulfide (1) differed ...