Temperature effect on the stereoelective polymerization of methylthiirane in homogeneous phase

Chiral cadmium thiolates of cysteine with cyclohexyl or (−)menthyl ester groups were prepared and compared with similar compounds (with isopropyl or methyl ester groups) as initiators for stereospecific polymerization of methylthiirane in homogeneous phase. The resulting polymers are highly isotactic and in all cases stereoelection can be reversed with a small change in polymerization temperature. This temperature effect permitted to differentiate two stages in the polymerization corresponding to the formation of a precursor and to that of a high polymer, respectively.