Synthesis of New C2-Symmetric Chiral Benzimidazole Derivatives Having Norbornene/Dibenzobarrelene Skeletons

Racemic dicarboxylic acids were synthesized from the Diels-Alder cycloaddition reactions which formed the dibenzobarrelene and norbornene skeletons. The pure enantiomers of these compounds were obtained using brucine as the chiral auxiliary. Novel C2-symmetric chiral benzimidazole derivatives were synthesized from the reaction of the diaminobenzene and enantiomeric dicarboxylic acids in the presence of boric acid.