Highly enantioselective Rh-catalyzed asymmetric reductive dearomatization of multi-nitrogen polycyclic pyrazolo[1,5- a ]pyrimidines.

A highly enantioselective rhodium-catalyzed reductive dearomatization of 7-substituted pyrazolo[1,5- a ]pyrimidines has been realized for the first time by two strategies to afford chiral 4,5,6,7-tetrahydropyrazolo[1,5- a ]pyrimidines with excellent enantioselectivities of up to 98% ee. This method also provides an efficient approach for the synthesis of the powerful BTK inhibitor, zanubrutinib.