Inherently chiral calixarenes, whose chirality is based on the absence of a planar symmetry or an inversion center in the molecules as a whole through the asymmetric array of several achiral groups upon the three-dimensional calix-skeletons, are challenging and attractive chiral molecules, because of their potential in supramolecular chemistry. The synthesis and optical resolution of all varieties of inherently chiral calixarenes are systematically discussed and classified, and their applications in chiral recognition and asymmetric catalysis are thoroughly illustrated in this review.

Novel chiral mono and diamide derivatives of calix[4]arene have been prepared from the aminolysis reaction of 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 1 and 25,27-diethoxycarbonyl-methoxy-26,28-dihydroxycalix[4]arene 2 with chiral (S)-(-)-1-phenylethylamine (PEA) and (1S,2S)-(+)-2-amino-1-(4-nitrophenyl)-1,3-propanediol, respectively. Spectrophotometric titrations have been performed in CHCl(3) at 20-30 degrees C in order to obtain the binding constants (K) and the thermodynamic quantities (DeltaH and DeltaS) for the stoichiometric 1:1 inclusion complexation of various chiral amines with these new host compounds. Preliminary experiments were undertaken to confirm the complexation properties of receptors 9 and 13 with PEA by (1)H NMR in CDCl(3) at room temperature. The molecular recognition abilities and enantioselectivities for guests (R and S)-alpha-PEA and (R and S)-cyclohexylethylamine (CHEA) are discussed from a thermodynamic point of view. Chirality, 2007.(c) 2007 Wiley-Liss, Inc.