Chiral discrimination of 2-heptlyaminium salt by planar-chiral monohydroxy-functionalized pillar[5]arenes

Abstract

This paper reports the synthesis of a planar-chiral monohydroxy-functionalized pillar[5]arene amenable to a wide variety of chemical modifications. Chiral resolution was performed using derivatization with Mosher's acid chloride (S)-(+)-α-methoxy-α-trifluoromethylphenylacetyl chloride ((S)-(+)-MTPA-Cl), and the absolute configurations of the thus obtained MTPA ester-functionalized pillar[5]arenes were determined by single-crystal X-ray diffraction. Finally, the effect of hydroxy groups on the temperature-dependent rotational movement of pillar[5]arene units was investigated by chiral HPLC and its application as a chiral receptor for alkyl aminium salts was demonstrated.