D3h-Symmetrical Shape-Persistent Macrocycles Consisting of Pyridine-Acetylene-Phenol Conjugates as an Efficient Host Architecture for Saccharide Recognition

Hexagonal shape‐persistent macrocycles (SPMs) consisting of three pyridine and three phenol rings linked with acetylene bonds were developed as a preorganized host for saccharide recognition by push–pull‐type hydrogen bonding. Three tert‐butyl or 2,4,6‐triisopropylphenyl substituents were introduced on the host to suppress self‐aggregation by steric hindrance. In spite of the simple architecture, association constants Ka of the host with alkyl glycoside guests reached the order of 106 m−1 on the basis of UV/Vis titration experiments. This glycoside recognition was much stronger than that in the cases of acyclic equivalent hosts because of the entropic advantage brought by preorganization of the hydrogen‐bonding sites. Solid–liquid extraction and liquid–liquid transport through a liquid membrane were demonstrated by using native saccharides, and much preference to mannose was observed. Grasp hexose: D3h‐Symmetrical shape‐persistent macrocycles (SPMs) were developed as a synthetic host for saccharide recognition. They consisted of a phenol–acetylene–pyridine structure, and steric hindrance was introduced on them to prevent self‐aggregation. A strong affinity for alkyl hexosides (see figure) was shown in organic solvent.