Chirality in Organic Hosts

Chirality in organic hosts is observed with synthetic molecular receptors such as cyclodextrins, calixarenes and crown ethers, which exhibit inherent chirality or become chiral through asymmetric substitution with an achiral group or introduction of a chiral substituent. Molecular recognition of enantiomeric guests proceeds by chiral discrimination. This feature can be used for analytical applications or in asymmetric reactions, the latter by using chiral hosts as enzyme mimics. Generally, enhanced host–guest interactions that lead to more specifically defined complexes improve both chiral discrimination and enantioselectivity in synthesis.