A novel consecutive reaction of lithium acetylides with 2-aryl-1-chlorovinyl p-tolyl sulfoxides leading to the formation of (Z)-enediynes

The reaction of (E)-2-aryl-1-chlorovinyl p-tolyl sulfoxides with lithium acetylides gave a variety of (Z)-3-arylhex-3-ene-1,5-diynes in yields of up to 80% with high stereoselectivity. The structure of the (Z)-enediyne was confirmed by X-ray molecular structure analysis. The result of the reaction with deuterium- and 13C-labeled sulfoxide suggested that the reaction proceeds through cleavage of the C–H bond at the β-position of the 2-aryl-1-chlorovinyl unit in sulfoxide.