Synthesis and Thermal Decomposition of 1,3-Dithietane and Its S-Oxides

Article abstract of DOI:10.1021/ja00375a030

Syntheses of 1,3-dithietane (1), 1,3-dithietane 1-oxide (2), 1,3-dithietane 1,1-dioxide (3), cis-1,3-dithietane 1,3-dioxide (4), trans-1,3-dithietane 1,3-dioxide (5), and 1,3-dithietane 1,1,3-trioxide (6) are reported for the first time.These compounds are converted in high yield to the previously described sulfene dimer 1,3-dithietane 1,1,3,3-tetraoxide (7).The structures of 2 and 7 are found to be respectively puckered (by microwave spectroscopy) and planar (by X-ray crystallography).Spectroscopic and physical data are discussed (photoelectron (PE) and NMR spectros copy, pK_a values, oxidation potentials) along with some data on base-catalyzed H/D exchange.The PE spectra are assigned using MO models on different levels, including PNO/CEPA for thioformaldehyde (CH2S).Thermal decomposition is investigated using three independent methods: mass, microwave, and PE spectroscopy.Two types of decomposition channels are observed: retro 2+2 and retro 3+1.Among others, species like thioformaldehyde and sulfine (CH2SO, thioformaldehyde S-oxide) are produced.They are characterized by their microwave structure as well as by their PE ionization patterns and IR spectra.