Helical polymers for efficient enantiomer separation

Abstract

The separation of enantiomers by high-performance liquid chromatography (HPLC) using the helical polymers mainly synthesized in my group over the past 40 years is described. In 1979, a one-handed helical poly(triphenylmethyl methacrylate) (PTrMA) was synthesized by asymmetric anionic polymerization. This is the first example of the asymmetric synthesis of a one-handed helical polymer, and the polymer exhibited an unexpected high chiral recognition to many racemates. A practically useful chiral stationary phase (CSP) for HPLC was developed by coating the polymer on silica gel. In 1982, the CSP was commercialized as the first chiral column based on a chiral polymer. Following this study, various helical polymers have been synthesized for use as CSPs by many researchers including ourselves and, in many cases, the helical structure of the polymers has played an important role in chiral recognition. In 1984, we found that cellulose trisphenylcarbamate coated on silica gel showed a very high chiral recognition and afforded a very useful CSP. Among the many phenylcarbamate derivatives of cellulose and amylose, the tris(3,5- dimethylphenylcarbamate)s show very attractive abilities. Today, these polysaccharide-based CSPs are most frequently used to analyze or preparatively separate chiral compounds. © Springer-Verlag Berlin Heidelberg 2013.