The anti-dithietane-1,3-dioxide --> syn-dithietane-1,3-dioxide isomerizatio
n reaction has been theoretically studied on the frame of MO theory both in
the gas phase and in solution. in the gas phase the anti (IIa) <----> syn
(II) equilibrium is slightly displaced to the anti isomer formation. The sy
n concentration ([Syn]) is ca. 36% in the gas phase, whereas in low polarit
y solvent. such as carbon tetrachloride, [Syn] is ca. 63%. In medium-high p
olarity solvents like acetonitrile and dimethyl-sulfoxide the [ anti]/[ syn
] ratio is Ca. 0.37. (C) 2001 Academic Press.