(?)-Sparteine: The compound that most significantly influenced my research |
| |
Authors: | Yoshio Okamoto |
| |
Institution: | Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan |
| |
Abstract: | A chiral diamine alkaloid, (?)-sparteine (Sp), has been found to be very effective as a ligand for Grignard reagents when used for the enantiomer-selective polymerization of racemic RS-1-phenylethyl methacrylate. The enantiomeric excess of the initially polymerized monomer is 93%, and at about a 60% conversion, nearly optically pure R-monomer is recovered. This enantiomer selectivity is today the highest in polymer chemistry. Triphenylmethyl methacrylate (TrMA) is a unique monomer that gives a highly isotactic polymer even during radical polymerization. When TrMA is polymerized with the Sp complex with n-butyllithium in toluene at ?78 °C, an optically active, isotactic polymer poly(triphenylmethyl methacrylate) (PTrMA)] with a one-handed helical conformation is obtained. The helical structure is maintained even at room temperature in solution. Analogous helical polymethacrylates that show various conformational changes have also been found. One-handed helical PTrMA exhibits high chiral recognition to a variety of racemates as a chiral stationary phase (CSP) for high-performance liquid chromatography. This finding has led to the development of very powerful CSPs based on polysaccharides, such as cellulose and amylose. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4480–4491, 2004 |
| |
Keywords: | amylose trisphenylcarbamate asymmetric polymerization cellulose trisphenylcarbamate enantiomer-selective polymerization helix-sense-selective polymerization high performance liquid chromatography (HPLC) optically active polymers 1-phenylethyl methacrylate resolution triphenylmethyl methacrylate chiral anionic polymerization |
|
|