13C chemical shifts and conformational analysis of methyl substituted thiacyclopentanes
作者:G. Barbarella、P. Dembech
DOI:10.1002/mrc.1270130414
日期:1980.4
AbstractThe 13C NMR spectra of thiacyclopentane (thiolane) and its mono‐ and dimethyl derivatives at positions other than the heteroatom are reported. The 13C shieldings are found to be consistent with a description of these compounds in terms of equilibria between half‐chair conformers. An attempt has been made to establish the axial or equatorial preference of methyl groups adjacent to, or removed from, the sulphur atom in these systems. In agreement with previous observations on thiacyclohexanes (thianes), the conformational preference of a methyl group for the equatorial orientation is greater at the β than at the α position.