A New Synthetic Route to 1,3-Dithiolium Salts Involving Neighboring Group Participation of Dithiocarbamate Group

A new and useful synthetic route to 1,3-dithiolium salts involving neighboring group participation of dithiocarbamate group as a key step is described. 4-Bromo-2-dialkylamino-1,3-dithiolan-2-ylium bromide was obtained in high yield by the addition of equimolar bromine to S-vinyl-N,N-dialkyldithiocarbamate, and then, pyrolysis of the salt under reduced pressure gave 1,3-dithiolium salt in excellent yield. 4-Substituted-1,3-dithiolium salts were also obtained in the same way.