# Silver-promoted reaction of alkyl halide with diphenyl sulfide

What is the major product formed when 1-chloro-3-iodopropane reacts with diphenyl sulfide in the presence of one equivalent of $$\ce{AgBF4}$$?

I know that sulfur is nucleophilic and that it can displace a halide in a SN2 reaction, but the resulting molecule will have a positive charge. Is that okay? What possible use does the product have?

In the presence of $$\ce{AgBF4}$$, diphenylsulfide is alkylated to 3-chloropropyl diphenylsulfonium tetrafluoroborate. The sulfonium salt is stable and can be isolated as a crystalline product.
This sufonium salt can be deprotonated (e.g. with $$\ce{NaH}$$ in $$\ce{THF}$$) to the corresponding sulfonium ylide.
In the latter, intramolecular displacement of $$\ce{Cl-}$$ yields cyclopropyl diphenylsulfonium tetrafluoroborate, which again is a stable solid.