Filling the Gaps in the Challenging Asymmetric Hydrogenation of Exocyclic Benzofused Alkenes with Ir-P,N Catalysts

Herein, we report a chiral phosphine-triazole ligand for the Ir-catalyzed asymmetric hydrogenation of exocyclic benzofused alkenes. Overcoming previous limitations, the catalytic system is able to successfully hydrogenate exocyclic olefins bearing a benzofused five- and six-membered ring motif (ee’s between 92 to 99%). The catalyst tolerates well the presence of several substituents and substitution patterns at both aromatic rings. The absence of a competing isomerization process together with the perfect fit of the olefins in the catalyst chiral pocket are key to surpass the previous limitations in the hydrogenation of both 5- and 6-membered ring benzofused exocyclic olefins.