The Mannich-type condensation of hexaethylresorcin[6]arene with achiral primary amines results in S-6-symmetrical hexadihydro-1,3-oxazine derivatives, which are mesoforms. The reaction with individual enantiomers of alpha-phenylethylamine leads to C-3-symmetrical enantiomeric hexaoxazines, which crystallize from reaction mixtures in an analytically pure form. (C) 2011 Elsevier Ltd. All rights reserved.