Synthesis of Chiral Adamantanes via Ni/Al Bimetal-Catalyzed Tertiary C-H Annulation of Formyladamantanes with Alkynes.

Chiral adamantane motifs are widely distributed in bioactive molecules, and their synthesis has attracted a considerable amount of research attention. Among existing synthetic approaches, asymmetric C-H activation of adamantanes stands out as one of the most atom- and step-economical synthetic strategies. Nevertheless, owing to the inert and sterically hindered C-H bonds of adamantanes, current methods have to depend on noble rhodium catalysts and suffer from moderate enantioselectivity. Herein, we report a Ni/Al bimetal-catalyzed enantioselective tertiary C-H annulation of formyladamantanes with alkynes, affording chiral adamantanes in up to 83% yield and 95% ee.