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Dr. Tomoyuki Ikai Dr. Masaki Ito Dr. Kosuke Oki Dr. Nozomu Suzuki Prof. Eiji Yashima 《Angewandte Chemie (International ed. in English)》2023,62(31):e202306252
A series of poly(biarylylacetylene)s (PBAs) bearing axially-chiral (S)-and (R)-pyridyl-N-oxide residues with a methoxy, propoxy, or acetyloxy substituent at the 3-position of the biaryl units was synthesized. All the PBAs formed a preferred-handed helix, while the helical sense preference was varied depending on the substituents despite the same twist-sense of the biaryl units. Among them, the propoxy-bound helical PBA showed an exceptionally high chiral recognition ability as a chiral stationary phase (CSP) for high-performance liquid chromatography (HPLC) and efficiently resolved not only various chiral aromatic alcohols, but also a variety of chiral aliphatic alcohols; the latter still remains difficult to resolve by commercially-available CSPs in HPLC. Such practically-useful both handed helical PBA-based CSPs can be produced from the racemic PBA composed of fully racemic monomer units through deracemization of the biaryl units with a chiral alcohol. 相似文献
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Helical polymers have attracted a great deal of attention and been extensively investigated due to their various applications.One of the most important applications of helical polymers is chiral recognition and resolution of enantiomers for the reason that a pair of enantiomers is commonly with different physiological and toxicological behaviors in biological systems.Helical polymers usually present unexpected high chiral recognition ability to a variety of racemic compounds.What's more,the chiral recognition and resolution abilities of the system are dependent on the highly ordered helical structures of the helical polymers.This mini review mainly focuses on the recent progress in chiral recognition and resolution based on helical polymers.The synthetic methodology for helical polymers is firstly discussed briefly.Then recent advances of chiral recognition and resolution systems based on helical polymers,especially polyacetylenes and polyisocyanides,are described.We hope this mini review will inspire more interest in developing helical polymers and encourage further advances in chiral-related disciplines. 相似文献
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Takaya Fujie Dr. Takeshi Yamamoto Prof. Dr. Michinori Suginome 《Angewandte Chemie (International ed. in English)》2023,62(23):e202301347
A single-handed poly(quinoxaline-2,3-diyl) (PQX) has been found to serve as a new type of chiral shift reagent (CSR) for determining the enantiomeric ratio by NMR spectroscopy. Even though there is no specific binding site in the PQX, its nonbonding interaction with chiral analytes leads to a significant shift of the NMR chemical shift, allowing quantification of the enantiomeric ratio. The new type of CSR has the advantages of a wide scope of analytes including ethers, haloalkanes, and alkanes, easy tunability of the degree of chemical shifts by measurement temperature, and erasability of proton signals of CSR because of the short spin-spin (T2) relaxation of the macromolecular scaffold. 相似文献
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Aromatic helical receptors P- 1 and P- 2 were slightly modified by aerobic oxidation to afford new receptors P- 7 and P- 8 with right-handed helical cavities. This subtle modification induced significant changes in the binding properties for chiral guests. Specifically, P- 1 was reported to bind d -tartaric acid (Ka=35500 M−1), used as a template, much strongly than l -tartaric acid (326 M−1). In contrast, its modified receptor P- 7 exhibited significantly reduced affinities for d -tartaric acid (3600 M−1) and l -tartaric acid (125 M−1). More dramatic changes in the affinities and selectivities were observed for P- 2 and P- 8 upon binding of polyol guests. P- 2 was determined to selectively bind d -sorbitol (52000 M−1) over analogous guests, but P- 8 showed no binding selectivity: d -sorbitol (1890 M−1), l -sorbitol (3330 M−1), d -arabitol (959 M−1), l -arabitol (4970 M−1) and xylitol (4960 M−1) in 5% (v/v) DMSO/CH2Cl2 at 25±1 °C. These results clearly demonstrate that even subtle post-modifications of synthetic receptors may significantly alter their binding affinities and selectivities, in particular for guests of long and flexible chains. 相似文献