The use of 1-amino-2-phenyl-1-cyclohexanecarboxylic acids as chiral auxiliaries in asymmetric Diels-Alder reactions.

This report describes the behavior of four 1-amino-2-phenyl-1-cyclohexanecarboxylic acids, obtained in enantiomerically pure form starting from asymmetric Diels-Alder reactions between 1,3-butadiene and chiral (E)-2-cyanocinnamates, as chiral auxiliaries in the asymmetric Diels-Alder reactions of cyclopentadiene with chiral methyl N-acryloyl-1-amino-2-phenyl-1-cyclohexanecarboxylates. A model based on the formation of an intramolecular hydrogen bond accounts for the stereochemical outcome in the catalyzed reactions.