Chiral Brønsted acid-catalyzed enantioselective three-component Povarov reaction.
Résumé
The three-component Povarov reaction of aldehydes (2), anilines (3), and benzyl N-vinylcarbamate 4 in the presence of 0.1 equiv of chiral phosphoric acid 5 afforded cis-2,4-disubstituted tetrahydroquinolines (1) in good yields and excellent enantiomeric excesses. The shortest synthesis of torcetrapib reported to date, which features this key three-component reaction, is documented.