Highly Enantioselective Ir-Catalyzed Hydrogenation of Pyrazolo[1,5-a]pyrimidine for the Synthesis of Zanubrutinib

A highly enantioselective catalytic reduction of pyrazolo[1,5-a]pyrimidine to zanubrutinib has been realized by the Ir/(R)-t-Bu-FcPhox complex. This chiral product could be obtained in up to >99% ee in the asymmetric transformation without any other additives, providing a new route for the asymmetric synthesis of zanubrutinib.