Stereoselective synthesis of enantiopure 4,5-disubstituted pyrrolidin-2-ones by consecutive cuprate addition and N-acyliminium coupling
摘要:
The enantiopure gamma-lactam (R)-1-acetyl-5-isopropoxy-3-pyrrolin-2-one (1), prepared from (S)-malic acid, undergoes cuprate addition at C4 with complete trans-stereoselectivity. The products react with pi-nucleophiles in the presence of Lewis acid at C5 to provide enantiopure 4,5-disubstituted pyrrolidin-2-ones.
and economical one-pot approach to chiral fused tricyclic lactams from readily available ketoesters was developed by using cheap ammonium salts as the nitrogen source through ruthenium-catalyzed tandem dynamic kinetic asymmetric reductive amination/lactamization. This protocol provides highly efficient access to drug intermediates and organocatalysts containing chiral polycyclic N-heterocycles.