One‐Handed Helical Polyacetylenes Bearing Axially‐Chiral 2‐Arylpyridyl‐N‐Oxide Units for Efficient Chromatographic Enantioseparation of Chiral Aromatic and Aliphatic Alcohols

Abstract

AbstractA 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.