The Electrophilic Character of Bunsen's Cacodyl Disulfide, Me₂As(S)‐S‐AsMe₂

Abstract

Abstract The behaviour of Bunsen's cacodyl disulfide, Me 2 As(S)‐S‐AsMe 2 towards Lewis bases of group 15 of the Periodic Table was studied mainly by 1 H NMR. While Ph 3 N did not react, 4‐dimethylaminopyridine and triethylamine isomerized the disulfide to Me 2 AsSSAsMe 2 . Ph 3 P, (PhO) 3 P, (MeO) 3 P, (EtO) 3 P and Ph 3 As desulfurized the disulfide to Me 2 AsSAsMe 2 . (PhS) 3 P also desulfurized the disulfide but Me 2 As‐S‐SPh was also produced. Me 2 As‐S‐SPh was the main product with (PhS) 3 As nucleophile. In most systems, cationic and anionic species were formed. The results are best interpreted by initial attack of the nucleophile on the electrophilic As=S sulfur.