S-Methyl xanthates of 2-cyclohexen-1-ol (IV), 3-methyl-2-cyclohexen-1-ol (V) and cis-3, 5-dimethyl-2-cyclohexen-1-ol (VI) transformed to dithiolcarbonates (VIII, IX and X) accompanying allylic shift (S_Ni'). On the other hand, S-methyl xanthate of 3, 5, 5-trimethyl-2-cyclohexen-1-ol (VII) transformed to 3, 5, 5-trimethyl-2-cyclohexenyl methyl dithiolcarbonate (XI), without allylic shift (S_Ni). Of polycyclic system, S-methyl xanthates of ⊿^{1, 9}-octalin-2-ol (XIII) and ⊿⁴-cholesten-3β-ol (XIX) were submitted to pyrolysis and consequently it was found that they decomposed into methylthio derivatives (XVI and XXI) via rearragement to the dithiolcarbonates (XV and XX). In homoallylic system, pyrolysis of S-alkyl xanthates of cholesterol in the presence of phenolic solvent caused the rearrangement to the corresponding dithiolcarbonates with retention of configuration. In each rearrangement reaction, reaction courses are discussed.