Cucurbituril: chiral applications.

This review brings together the past and current methods for synthesizing the classical cucurbit[n]uril (Q[n]), structural variants, and derivatives. Here we refer to the first family of Q[n] as " classical," where the cavity is spheroidal and carry no substituents at any of the equatorial methine carbons or the methylene bridging carbons. The synthetic background and general physical and chemical properties of the Q[n] as molecular hosts is discussed. Particular attention is drawn to the synthesis of structural variants that have significance for chiral recognition properties such as (±)-bis-nor-seco-Q[6] and (±)-bis-nor-seco-Q[10]. Furthermore, examples of chiral recognition, enantio- and stereoselectivity using the achiral Q[n] as supramolecular structures with a chiral function directly or indirectly via another chiral agent are also discussed.