A new reaction of dithiocarbamates: CS2 elimination and two C–C bond formations leading to formation of cyclic ammonium salts

Sodium salts of N,N-dibenzyldithiocarbamate, N,N-diisopropyldithiocarbamate and pyrrolidine-1-carbodithioate gave cyclic products, 4-oxo-2,6-diphenyl-piperidinium, 2,2,6,6-tetramethyl-4-oxo-piperidinium and 3-oxo-8-azonia-bicyclo[3.2.1]octane cations, respectively, when treated with aluminum trichloride in acetone. The 2,2,6,6-tetramethyl-4-oxo-piperidinium thiocyanate salt has been characterized by X-ray crystallography. A plausible mechanism has also been suggested on the basis of preliminary DFT calculations.