Synthesis and reactions of poly[(4-chlorobutyl)thiirane]: evidence for backbone-assisted solvolysis

Abstract

(4-Chlorobutyl)thiirane is prepared in 80% yield in a single step from (4-chlorobutyl)oxirane. Homopolymerization of (4-chlorobutyl)thiirane with ZnEt2—CH3OH or CdCO3 initiator systems provides poly[(4-chlorobutyl)thiirane] as a soft elastomer with inherent viscosity 0.2dL/g. Reaction of poly[(4-chlorobutyl)thiirane] with tetra-n-butylammonium benzoate in N,N-dimethylacetamide proceeds by direct displacement, without involvement of the backbone sulfur atom. Solvolysis under more strongly ionizing conditions (acetic acid/chloroform) occurs with repeating unit isomerization, most probably via a cyclic intermediate formed by attack of the backbone sulfur atom on the chloromethyl group at the side chain terminus.