Asymmetric aldol reaction organocatalyzed by (S)-proline-containing dipeptides: improved stereoinduction under solvent-free conditions.
The organocatalytic activity of the methyl ester of (S)-proline-(S)-phenylalanine, (S,S)-2, in the asymmetric aldol reaction between cyclohexanone and acetone with various aromatic aldehydes under solvent-free conditions in a ball mill has been evaluated. α,α-Dipeptide (S,S)-2 catalyzed the stereoselective formation of the expected aldol products, with higher diastereo- and enantioselectivity relative to similar reactions in solution, up to 91:9 anti:syn diastereomeric ratio and up to 95% enantiomeric excess.
Departamento de Química, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Apartado Postal 14-740, 07000 México, D.F., México.
Josè G
JG
Hernández
Eusebio
E
Juaristi
D000096:Acetone / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry; D002384:Catalysis; D003512:Cyclohexanones / Q000737:chemistry*; D004151:Dipeptides / Q000737:chemistry*; D004952:Esters / Q000737:chemistry; D015394:Molecular Structure; D011392:Proline / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D003512:Cyclohexanones; D004151:Dipeptides; D004952:Esters; D000096:Acetone; C036468:cyclohexanone; D011392:Proline