Synthesis of optically active alicyclic polyimides from a chiral, nonracemic dianhydride

Optically active alicyclic polyimides were prepared for the first time from (−)‐[1S*,5R*,6S*]‐3‐oxabicyclo[3.2.1]octane‐2,4‐dione‐6‐spiro‐3′‐(tetrahydrofuran‐ 2′,5′‐dione) [(−)‐DAn] via polycondensation with diamines and subsequent chemical or thermal imidization. The dianhydride (−)‐DAn was synthesized by an asymmetric Diels–Alder reaction of a chiral itaconic acid derivative as a key step. Colorless or slightly yellow flexible films were obtained for the (−)‐DAn‐derived polyimides {PI[(−)‐DAn]s}. PI[(−)‐DAn]s showed good solubility toward dipolar aprotic solvents and pyridine. For 1,4‐dioxane and chloroform, the optically active polyimides showed slightly better solubility than the corresponding polyimides prepared from rac‐DAn [PI(rac‐DAn)s]. PI[(−)‐DAn]s showed glass‐transition temperatures of 267–268 °C and 10% weight‐loss temperatures of 416–424 °C in nitrogen. These values were almost identical to those of PI(rac‐DAn)s. The circular dichroism spectra of PI[(−)‐DAn]s showed exciton coupling patterns indicating that to some extent these polyimides had a higher order structure in solution.