Asymmetric synthesis of beta-hydroxy amino acids via aldol reactions catalyzed by chiral ammonium salts.
The Cinchona alkaloid derived chiral ammonium salt developed by Park and Jew functions as an effective catalyst for the synthesis of beta-hydroxy alpha-amino acids via asymmetric aldol reactions under homogeneous conditions. The syn diastereomers are obtained in good ee, and aryl-substituted aliphatic aldehydes are the best substrates for the reaction. These results represent the highest ee's obtained to date in direct aldol reactions of glycine equivalents catalyzed by inexpensive, readily prepared chiral ammonium salts.
Mettath
Sashikumar
S
Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
Srikanth
G S C
GS
Dangerfield
Benjamin S
BS
Castle
Steven L
SL
D000447:Aldehydes / Q000737:chemistry*; D000596:Amino Acids / Q000138:chemical synthesis*; D002384:Catalysis; D009682:Magnetic Resonance Spectroscopy; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012492:Salts / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D000596:Amino Acids; D000644:Quaternary Ammonium Compounds; D012492:Salts; C116609:3-hydroxybutanal