Sulphur-substituted organometallic compounds. Part II. Reaction of vinyltin compounds with arenesulphenyl halides and thiocyanates and some properties and reactions of the (2-arylthio-1-halogenoethyl)-triphenyltin addition products

Abstract

Vinyltin compounds, [R₃Sn(CHCH₂)](R = Me and Ph), react with sulphenyl chlorides and thiocyanates, R′SX, in aprotic solvents to give products of addition (Markownikoff) to the vinyl bond and cleavage of the vinyl–tin bond [equation (i)]. Cleavage products are exclusively obtained from the most reactive sulphenyl chloride [R₃Sn(CHCH₂)]+ R′SX →[R₃Sn(CHXCH₂SR′)]+ CH₂CHSR′+[R₃SnX](i) used, p-MeC₆H₄SCI, while both cleavage and addition occur with the less-electrophilic species, 2-O₂N-4-YC₆H₃SX (Y = H, Me, or NO₂; X = Cl or SCN). Sulphenate esters do not react. The adducts, [Ph₃Sn-(CHXCH₂SR′)], are thermally unstable in polar solvents, such as CHCl₃, and give CH₂= CHSR′. They react with sulphenyl halides, R″SX′, to give unsymmetric disulphides, R′SSR″, CH₂CHX. and [Ph₃SnX′]. This type of reaction is in contrast to those with Br₂, I₂, CF₃CO₂H, Hg[O₂Me]₂, and HgCl₂ in which initially phenyl–tin bond cleavage occurs to give [Ph₂ZSn(CHXCH₂SR′)]. The latter species are not stable and generally break down to CH₂CHSR′ and [Ph₂SnXZ](Z = Cl, Br, I, CF₃CO₂, or MeCO₂).