Sulfenyl chloride chemistry. New precursors for diatomic sulfur transfer

When triphenylmethanesulfenyl chloride (1) (or its thio homologue 2) are treated with various bicycles, norbornene (5), or bicyclo[2.2.2]octene (6), dithio adducts 7 and 8 were produced in good isolated yields. Final products were obtained via an episulfide intermediate. The stereochemistry of addition has been determined by X-ray analysis. Treatment of thiosulfenyl chloride 2 (or its dithio homologue 3) with other olefins, cyclopentene (10), cyclohexene (11), or 1,4-dioxene (12), leads to the formation of disulfides (13-15 from 2) and trisulfides (16 and 17 from 3) in high isolated yields (ca. 92%). The structures of 7, 8, and 13-17 were established by H-1 and C-13 NMR and elemental analysis as well as by X-ray determination. When these adducts are warmed with a 1,3-diene 42, they deliver diatomic sulfur-trapped derivatives, cyclic di-49 and tetrasulfide adducts 46. A variety of solvents, temperatures, times, and concentrations were employed to optimize the yield of 46 and 49. The tetrasulfide adduct 46 is quantitatively converted to disulfide 49 with triphenylphosphine; this affords cyclic disulfides in >50% isolated yield from the diene. In addition, evidence has been obtained implicating dithietane intermediate 4.