variety of different aromatic ketones could be converted to the corresponding
alcohols with up to 98% ee and turnover numbers up to 9,800, if a catalytic amount
of hexafluoro isopropanol (HFIP) was added [22].
2.2 Hydrogenation of Esters
Beller and coworkers were the first ones to report manganese-catalyzed hydrogenation of esters to alcohols in 2016. For this purpose, aliphatic pincer PNP ligands were
used. The investigation of the substituents on the phosphorous donors revealed
moderate reactivity for bulky groups such as isopropyl or cyclohexyl. In contradiction to that, ethyl groups on the donors resulted in high reactivity.
Scheme 7 Enantioselective hydrogenation of ketones catalyzed by Mn7, Mn8, and Mn9
The Role of Metal-Ligand Cooperation in Manganese(I)-Catalyzed. . .
233
alcohols with up to 98% ee and turnover numbers up to 9,800, if a catalytic amount
of hexafluoro isopropanol (HFIP) was added [22].
2.2 Hydrogenation of Esters
Beller and coworkers were the first ones to report manganese-catalyzed hydrogenation of esters to alcohols in 2016. For this purpose, aliphatic pincer PNP ligands were
used. The investigation of the substituents on the phosphorous donors revealed
moderate reactivity for bulky groups such as isopropyl or cyclohexyl. In contradiction to that, ethyl groups on the donors resulted in high reactivity.
Scheme 7 Enantioselective hydrogenation of ketones catalyzed by Mn7, Mn8, and Mn9
The Role of Metal-Ligand Cooperation in Manganese(I)-Catalyzed. . .
233