Synthesis and stereochemistry of some new spiro and polyspiro-1,3-dithiane derivatives

The synthesis of new spiro and trispiro compounds with 2,4,8,10-tetrathiaspiro[5.5]undecane and 7,11,18,21-tetrathia[5.2.2.5.2.2]heneicosane units is reported. The structural analysis was carried out by NMR investigations and the X-ray single crystal molecular structure determined for one of the compounds. The barriers for the flipping of the 1,3-dithiane units are determined by variable temperature NMR experiments.