Shelf-Stable ( E )- and ( Z )-Vinyl-λ 3 -chlorane: A Stereospecific Hyper-vinylating Agent.

We report the first stereoselective synthesis of stable (E)- and (Z)-beta-chlorovinyl-lambda(3)-chlorane via direct mesitylation of 1,2-dichloroethylene with mesityldiazonium tetrakis(pentafluorophenyl)borate under mild reaction conditions. The structure of the (E)-vinyl-lambda(3)-chlorane was established by single-crystal X-ray analysis. Because of the enormously high leaving group ability of the aryl-lambda(3)-chloranyl group, vinyl-lambda(3)-chloranes undergo not only SNVs-type reaction with extremely weak nucleophiles such as perfluoroalkanesulfonate, iodobenzene, and aromatic hydrocarbons but also coupling with phenylcopper(I) species.