Enantioselective Iridium‐Catalyzed Hydrogenation of 1‐ and 3‐Substituted Isoquinolinium Salts

Asymmetric hydrogenation: The title reaction provides an efficient and rapid access to chiral 1- and 3-substituted 1,2,3,4-tetrahydroisoquinolines with excellent enantioselectivity (see scheme; L=ligand). A preliminary mechanistic study indicates that the 1,2-hydride addition might be the initial step in the reaction. The method has been used in the synthesis of urinary antispasmodic drug (+)-solifenacin.