Neighboring Group Participation in the Sulfur Atoms and Formation of Dithiodications

Abstract

Monosulfoxide of 1,5-dithiacyclooctane was dissolved in cone. H4S04 to be converted to the 1, 5-dithiodication (1) which was idntified by 1H- and 13C-NMR. The dication (1) was isolated as a hygroscopic powder-like salt by quenching the H2SO4 solution with anhydrous ether. The dication (1) was further converted to the corresponding trifluoromethanesulfo-nates as a stable crystalline compound. Similarly, other monosulfoxides of various cyclic and acyclic 1, n-dithia derivatives were treated in cone. H2SO4 to give 1, n-dithiodications. These monosulfoxides underwent the Pummerer rearrangement upon treatment with AczO giving both α- and ω-acetoxy-1, n-dithioethers. Formation of 1, n-dithiodications was also observed during the reactions. New metacyclophanes(2, ll-dithia[3.3]metacyclophane) bearing a bridged sulfur atom between 9 and 18 positions in the rings were prepared. Both monosulfoxides or the cyclophane itself gave a new trithiodication where the charges are delocalized among three sulfur atoms with the central one taking a hypervalent structure. © 1987, The Chemical Society of Japan. All rights reserved.