Enantioselective synthesis of atropisomeric amides by dynamic resolution: Thermodynamic control with a proline-derived diamine resolving agent

By exploiting the thermal instability about the Ar-CO axis at high temperature, atropisomeric amides can be dynamically resolved to provide material with up to 96.5% ee in 70-80% overall yield from racemic starting material. The amides are coupled with a diamine resolving agent and equilibrated to single diastereoisomers. Hydrolysis returns enantiomerically enriched amide (see reaction scheme).