A method for reproducible preparation of chiral polysiloxanes with regular repeat units as stationary phases for capillary gas chromatography

Abstract

Abstract Trifluoroethyl ester‐functionalized polysiloxanes can be prepared by block condensation of 3‐dichloromethylsilyl‐2‐methylpropionic acid 2′,2′,2′‐trifluoroethyl ester with 1,5‐bis(diethylamino)hexamethyltrisiloxane or with disodium tetramethyldisiloxane‐1,3‐diolate. The functionalized polysiloxanes may serve as supports for a variety of selector groups; for instance, nucleophilic displacements with L‐valine‐t‐butylamide or L‐α‐naphthylethylamine lead to chiral polysiloxanes in high yields and with high reproducibility. Imidazole accelerates the rate of nucleophilic displacement. Capillary columns coated with such chiral polysiloxanes exhibit high enantioselectivity and thermostability.