An Enantioselective Synthesis of Spirobilactams through Copper-Catalyzed Intramolecular Double N-Arylation and Phase Separation

Spirobicyclic structures are versatile building blocks for functional chiral molecules. An enantioselective synthesis of chiral spirobilactams via a copper-catalyzed double N-arylation was developed. Amplification of solution ee by insitu precipitation of the racemate was observed with this method and enantioenriched spirobilactams were obtained with excellent ee values through simple solid-solution phase separation.