Reactions of Sulfanyl Chlorides with Thiocamphor and Thiofenchone: Wagner?Meerwein Rearrangement of an Intermediate Thiocarbonylium Ion

The reaction of sulfanyl and disulfanyl chlorides with thiocamphor ( 6 ) in the presence of Et₃N leads to unsymmetrical di‐ and trisulfanes, respectively (Schemes 2 and 4). A reaction mechanism via a thiocarbonylium ion, which is immediately deprotonated, is proposed. The formation of a minor product 10 in the absence of a base, resulting from a Wagner? Meerwein rearrangement, is an additional evidence for the intermediacy of a thiocarbonylium ion (Scheme 3). On the other hand, the non‐enolizable thiofenchone ( 13 ) reacts with sulfanyl chlorides in CH₂Cl₂/Et₃N to give exclusively products with a rearranged bicyclic skeleton (Scheme 5). A Wagner? Meerwein rearrangement of the intermediate thiocarbonylium ion is the key step. The structures of the products 10 and 14 , which have rearranged bicyclic systems, have been established by X‐ray crystallography.