Constitutional isomers, stereoisomers and conformers of bis[di-tert-butyl(trimethylsilyl)cyclopentadienyl]disulfane

Reaction of tBu2(Me3Si)C5H2Li with S2Cl2 leads first to a pair of diastereomers of [tBu2(Me3Si)C5H2]2S2 with each sulfur attached to an allylic position of the cyclopentadiene ring systems. Both disulfanes rearrange with a different rate to the constitutional isomers stable at room temperature, which are again a pair of diastereomers with sulfur now in vinylic positions. In the crystalline state, each pair of diastereomers exists as a racemate of RS,SR and RR,SS enantiomers, respectively. One allylic and both vinylic isomers are characterized by single crystal X-ray diffraction.