Sulfur‐containing optically active polymers. V. Synthesis and chiroptical properties of optically active poly(γ‐ketosulfide)s prepared by polyaddition of 1,3‐dimercaptobenzene to 4,4‐dimethyl‐2,5‐cyclohexadien‐1‐one or to trans, trans‐2,5‐heptadien‐3‐one in the presence of chiral amines

Optically active poly(γ-ketosulfide)s having the asymmetric centers disposed along the main chain have been prepared by step polyaddition of 1,3-dimercaptobenzene to 4,4-dimethyl-2,5-cyclohexadiene-1-one, or to trans, trans-2,5-heptadiene-3-one, in the presence of catalytic amounts of chiral amines. The extent of asymmetric induction on the resulting polymeric product is found to be higher when the alicyclic ketone reagent is employed and is enhanced by lowering the catalyst concentration. The comparison of stereochemical features and chiroptical properties of appropriate low molecular weight analogues with those of the polymeric derivatives indicates that a comparable asymmetric induction occurs in polymers and model compounds, and that the former systems do not display appreciable evidence of ordered secondary structures, in agreement with a low stereoregularity degree along the macromolecular backbone.