The Chemistry of the Thiosulfinyl Group: Preparation, Structure, and Spectroscopic and Chemical Properties of Cyclic Thionosulfites

Abstract

Treatment of the tetrahydrothiophene‐3,4‐diol 5 with 1,1′‐thiobis‐(1H‐benzimidazole) (6) furnished two diastereoisomers of the novel cyclic thionosulfite 4 with different configurations at the pseudo‐tetrahedral center of the thiosulfinyl (SS) group. The configuration of the SS group of the major diastereoisomer (isolated in 45% yield) was established to be syn to the thiolane ring, as determined by X‐ray crystallographic analysis, while that of the minor diastereoisomer (isolated in 10% yield) was anti. 1H‐NMR Spectroscopic analysis clarified that the shielding and deshielding zones of the SS group are similar to those of the well‐documented SO group. Characteristic absorptions of the SS group in the IR, Raman, and UV/VIS spectra were assigned on the basis of calculations at the B3LYP/6‐31G* level. The reactivity of the SS group toward thermolysis, hydrolysis, and oxidation was examined. The SS group is more resistant toward oxidation than the divalent sulfide S‐atom, but is oxidatively converted to the SO group.

Sulfur Monoxide Transfer from peri-Substituted Trisulfide-2-oxides to Dienes: Substituent Effects, Mechanistic Studies and Application in Thiophene Synthesis

“…The trapping of SO with 2,3-dimethylbutadiene has been used to identify reaction pathways in the oxidation of sulfines 6 and thionosulfite 7 , , and in the thermal degradation of the three-membered-ring vic -disulfoxide 8 . More recently, Nakayama has described novel transformations of SO generated from the room temperature breakdown of the bridged bicyclic sulfoxide 9 , produced in situ from the Diels−Alder reaction of 3,4-di- tert -butylthiophene 1-oxide with dimethylacetylenedicarboxylate .…”