Sulfur Bonding

Generation, Reactivity and Uses of Sulfines in Organic Synthesis

“…Although many authors prefer the structure i, most theoreticians do not regard the participation of sulfur d-orbitals as high, therefore the resonance structures ii and iii might actually be considered more accurate representations. [9] This resonance hybrid constitutes a 1,3-dipole. In recent years, measurements of sulfines have proven the structure to be nonlinear and have proven the predominant form to be structure ii in Figure 1.…”

“…[24] It was synthesised by the reaction of an alkanesulfonyl chloride 14 with a tertiary amine base. [9] The assignment of the E-and Z-geometry was made by proton NMR spectroscopy, melting points and dipole moment differences. This was confirmed years later, in 1963, by King and Durst, who also confirmed the existence of sulfines as stable geometrical isomers.…”

“…This was confirmed years later, in 1963, by King and Durst, who also confirmed the existence of sulfines as stable geometrical isomers. [9] The assignment of the E-and Z-geometry was made by proton NMR spectroscopy, melting points and dipole moment differences. Although the mechanism for the formation has since been elucidated [25] and yields have been increased by addition of p-toluenesulfonyl chloride, [26] this method -used to generate the first sulfine -is not very widely used nowadays (Scheme 4).…”

“…[122,[138][139][140][141] This process occurs by an electrocyclic ring closure of the sulfine to give an oxathiirane intermediate, which then extrudes sulfur forming the ketone product. Sulfines can also be reduced to thiocarbonyl compounds using phosphorus pentasulfide or thiophosphoryl bromide, [142] and deoxygenation has also been observed with triphenylphosphine, [143] Fe 2 (CO) 9 and Mo 2 (CO) 10 . [144] Deoxygenation of sulfines has also been reported in the literature.…”