An ethyl lactate derivative of p-tert-butylcalix[4]arene is able to differentiate the NMR spectra of 3,5-dinitrobenzoyl derivatives of amino acids methyl esters. The origin of enantiodiscrimination in solution was investigated by NMR spectroscopy and comparison with model chiral auxiliaries. (c) 2007 Elsevier Ltd. All rights reserved.