Resolution of inherently chiral 1,4-2,5-calix[8]bis-crown-4 derivatives by enantioselective HPLC

The first example of the resolution of inherently chiral calix[8]arenes, 1,4-2,5-calix[8]bis-crown-4 1 and its methyl derivatives 2,-4, has been achieved using enantioselective HPLC methods. The enantiomeric nature of isolated (+)-1 and (-)-1 was confirmed by CD spectra, specific optical rotation and 1H NMR in the presence of Pirkle's reagent. A rationale is given for the observed HPLC enantioselectivity among compounds 2-4. (~) 1997 Elsevier Science Ltd