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.