Vinylic Substitutions Promoted by PhSeZnCl: Synthetic and Theoretical Investigations

Vinyl selenides can be easily obtained through nucleophilic substitution of the corresponding halides by using PhSeZnCl in THF as well as "on water" conditions. The reaction is stereospecific with retention of the alkene geometry. The only exception has been observed in the reaction conducted on a beta-chloro-alpha,beta-unsaturated ketone, which afforded the (Z) product starting from either the (E) or (Z) isomer. DFT calculations have been performed in order to investigate the reaction mechanism, the stereochemistry of the process and the role of the zinc atom.