Three different models, depending on the Lewis acid used as a catalyst and the a-amino acid used as a chiral auxiliary, account for the diastereofacial selectivity obtained in reactions of cyclopentadiene with N-acryloyl derivatives of L-proline, L-phenylalanine, L- alanine, and N-methyl-L-alanine esters. For a-amino acids without an NH group and aluminum catalysts, a reactive conformer with antiplanar enoate conformation similar to ...
