Application Of Chiral P,N,N-Ligands In Asymmetric Hydrogenation

Asymmetric hydrogenation,as one of the most direct and effective methods to synthesize chiral compounds,has been favored by many chemists.The complexes formed by chiral organic ligands and transition metals have been proved to be very effective in asymmetric hydrogenation reactions and play an important role in the yield and ee value of the products.Among them,the research on chiral ligands?P,N-ligand,P,N,N-ligand?with phosphine and nitrogen as coordination atoms is the research direction that scientists pay great attention to.Herein we would like to report the designed and synthesis of a series of chiral P,N,N-ligands and application in the iridium catalyzed asymmetric hydrogenation of various substrates with excellent reasult.1.The chiral ferrocene ligand f-amphox were applied to asymmetric hydrogenation of?-ketonic esters.The optimal reaction condition was:ligand?1.1 mol%?,[Ir?COD?Cl]₂?0.5mol%?,methanol?2 mL?,^tBuOK?0.05 mmol?,10 bar H₂,and room temperature for 12 h.The?-hydroxyesters can be obtained in high enantioselectivities?up to 96%ee?and high yield?up to 95%?.2.Inspired by the chiral ferrocene ligand f-amphox,a novel phenylethylamine matrix P,N,N-ligand was designed and synthesized.The optimal reaction condition was dentified as follow:ligand?1.1 mol%?,[Ir?COD?Cl]₂?0.5 mol%?,^tBuOK?5 mmol%?,20 bar H₂,in MeOH?3 mL?at room temperature for 12 hours.The?-hydroxyesters can be obtained in high enantioselectivities?up to 82%ee?and high yield?up to 96%?.3.A novel chiral ferrocene P,N,N-ligand was applied to asymmetric hydrogenation of simple ketone.In ligand?1.1 mol%?,[Ir?COD?Cl]₂?0.5 mol%?,K₂CO₃?5 mmol%?,20 bar H₂,in MeOH?3 mL?at room temperature for 12 hours.A series of chiral alcoho ls were synthesized at high yield?up to 100%?and high enantioselectivity?up to 98%ee?.