Polymérisation de thiirannes différemment substitués à l'aide du système chiral ZnEt2/(S)‐dihydroxy‐2,2′ binaphtyl‐1,1′, 1. Stéréoélectivité de la polymérisation

Differently substituted thiiranes were polymerized using an atropoisomeric chiral initiator: ZnEt2/(S)‐2,2′‐dihydroxy‐1,1′‐binaphthyl (DHBN) (mole ratio 1/1). It was observed that high stereoelectivities are obtained with monomers bearing small alkyl substituents and that the resolution efficiency of the initiator decreases as the bulkiness of the substituent increases. From the comparison of the results obtained with another initiator system, ZnEt2/(R)‐3,3‐dimethyl‐1,2‐butanediol (DMBD) (mole ratio 1/1), the use of ZnEt2/(S)‐DHBN could be shown to be more suitable for the polymerization of thiiranes with linear alkyl substituents. Contrary to the case of polymerization initiated by the system ZnEt2/(R)‐DMBD, the polymerization reaction of thiiranes with ZnEt2/(S)‐DHBN was usually accompanied by the production of the corresponding olefins in various amounts.