The reaction of selenium dichloride with divinyl sulfide

A synthesis of novel selenium heterocycles based on the reaction of selenium dichloride with divinyl sulfide has been described. At −50 °C the reaction affords 2,6-dichloro-1,4-thiaselenane in quantitative yield. At room temperature the reaction gives 2,6-dichloro-1,4-thiaselenane and 5-chloro-2-chloromethyl-1,3-thiaselenolane. Upon standing in chloroform solution, 2,6-dichloro-1,4-thiaselenane undergoes spontaneous rearrangement to 5-chloro-2-chloromethyl-1,3-thiaselenolane. Under the action of pyridine, 2,6-dichloro-1,4-thiaselenane is converted to 2-chloromethyl-1,3-thiaselenole in 95% yield.