Nucleophilic substitution of S-phenyl thiol esters by electrogenerated polysulfide ions in N,N-dimethylacetamide

Abstract

The reactivity of electrogenerated S^⅓– polysulfide ions S₃^˙– (⇌S₆^2–) towards S-phenyl thiol esters RC(O)SPh [R = Me (1), Et (2), Prⁱ (3)] has been followed by spectroelectrochemistry in N,N-dimethylacetamide at 24 °C. With 1 and 2 reactions readily lead to thiocarboxylate ions and phenyltetrasulfanide ions, PhS₄^–, from the nucleofugic benzenethiolate ions in presence of sulfur. With 3 kinetic studies imply that S₆^2– species are the nucleophilic S^⅓– agents rather than S₃^˙– radical anions in a second order rate process (k = 30 ± 3 dm³ mol^–1 s^–1).