Asymmetric Environments in Encapsulation Complexes

Symmetrical, self-assembled capsules capable of surrounding two guests offer a new approach to enantioselection through coencapsulation:  when one guest is chiral, the space remaining is also chiral. This notion is explored within a cylindrical capsule. The dimensions of the capsule select appropriately sized combinations of guests, the shape of the capsule prevents tumbling of rigid molecules, and the chemical surface of the capsule orients polar functions within. Chiral carboxylic acids such as mandelic acid and α-Br-butyric acid are identified as promising compounds for this purpose, but diastereoselection is modest (<25% de).