The determination of the enantiomeric purity of Diels-Alder adducts derived from cyclopentadiene and a series of electron-deficient dienophiles is conveniently achieved by HPLC analysis on their 2,4-dinitrophenylhydrazine derivatives formed in one-pot directly from the cycloaddition reaction. (C) 2002 Elsevier Science Ltd. All rights reserved.