Rearrangement and trans-Elimination contrary to the Chugaev-Reaction Rule. VI. : Thermal Rearrangement of 2-Methylthioalkyl-S-methyl Xanthates and DL-trans-2-Methylthiocyclohexyl N, N-Dimethylthionocarbamate to Thiolesters

Abstract

Bordwell, et al.⁸⁾ had reported that DL-trans-2-p-tolylthiocyclohexyl S-methyl xanthate (IX) suffered cis-elimination by the Chugaev reaction. However, the present study revealed that the analogue (Ia) carrying a methylthio group in place of the tolylthio group in IX underwent rearrangement to the corresponding dithiolcarbonate. The rearrangement of Ia was attributed to the anchimeric power of the methylthio group. A variety of 2-methylthioalkyl S-methyl xanthates and DL-trans-2-methylthiocyclohexyl N, N-dimethylthionocarbamate (Ib) were thermally treated and the results provided evidences for this rearrangement mechanism which was analogous to that proposed in the case of 2-dialkylaminoalkyl S-methyl xanthates.