A Convenient Synthesis of α-Alkylthio- or Arylthio-α,β-unsaturated Ketones, Esters and Nitriles

2-Alkylthio-2-cyclopenten-l-ones, 2-phenylthio-2-cyclopenten-l-one, 3-methylthio-3-pen-ten-2-one, methyl 2-alkylthioacrylates and 2-phenylthio-2-hexenenitrile were prepared by chlorination-dehydrochlorination of the corresponding α-alkylthio or arylthio ketones, esters and nitriles.