CONFORMATIONAL EQUILIBRIA OF 5-SUBSTITUTED-1,3-DITHIANES - STUDY OF SOLVENT EFFECTS

The conformational equilibria of 5-substituted-1,3-dithianes (where th e 5-substituents are -CH3, -C2H5, -i-C3H7, -OCH3 and -SCH3) have been studied by the PM3 method in the gas phase and in solution. The solven t is treated as a continuum using the self-consistent reaction field a pproach to compute the solvation energy. The computed axial/equatorial relative free energies have been compared with available experimental data displaying a reasonable agreement. Differences with respect to t he corresponding 1,3-dioxane derivatives are also analysed. (C) 1997 E lsevier Science B.V.