A General Strategy for Elaboration of the Dithiocarbonyl Functionality, -(C=0)SS-: Application to the Synthesis of Bis(chlorocarbonyl)disulfane and Related Derivatives of Thiocarbonic Acids

A variety of sulfenyl chlorides have been reacted with a variety of alkoxythiocarbonyl compounds to give adducts which then lose (spontaneously, or upon thermolysis, or in the presence of a Lewis acid catalyst) the alkyl chloride to provide an assortment of dithiocarbonyl compounds in good to excellent yields. The preparations of bis-(chlorocarbonyl)disulfane (1), ((trichloromethyl)dithio)carbonyl chloride (2), ((alkoxycarbonyl)dithio)carbonyl chlorides (3 and 4), and (((alkylthio)carbonyl)dithio)carbonyl chlorides (5 and 6) by this methodology were optimized; some of the (alkoxydichloromethyl)disulfanyl adducts, e.g., ROCCl₂SS(C=O)C1 (10) and ROCCl₂SS(C=O)OR′ (54), were reasonably stable and could be isolated. All new compounds were characterized by analytical data, ¹H and ¹³C NMR, ER, UV, and mass spectrometry, and high-yield derivatizations with alcohols or N-methylaniline. The reaction with N-methylaniline was also adapted to a rapid, convenient, and precise analytical-scale assay of mixtures of compounds containing acid chloride and/or sulfenyl chloride functionalities. The kinetics, mechanism, and stereochemistry of the dithiocarbonyl synthesis are discussed.