Asymmetric synthesis of binaphthyls through photocatalytic cross-coupling and organocatalytic kinetic resolution

By capitalizing on the capability of photoredox catalysis to generate reactive radical intermediate under mild conditions, we established a photocatalytic cross-coupling protocol that could deliver both derivatives from 1-bromo-2-naphthols in combination with 2-naphthols or 2-naphthylamines. This distinct activation mode could overcome structural or electronic limitation associated with conventional coupling pathways. Additionally, a novel kinetic resolution protocol of unprotected BINOLs has been established with azodicarboxylates via chiral phosphoric acid (CPA) catalysis. Selectivity factor of up to 175 could be achieved and delivered to both enantiomers in atropisomerically enriched form after a simple work-up.