Direct organocatalytic asymmetric aldol reactions of alpha-amino aldehydes: expedient syntheses of highly enantiomerically enriched anti-beta-hydroxy-alpha-amino acids.
[reaction: see text] A simple and efficient method for the synthesis of highly enantiomerically enriched beta-hydroxy-alpha-amino acid derivatives has been developed. Direct asymmetric aldol reactions of a glycine aldehyde (aminoacetaldehyde) derivative have been performed under organocatalysis using l-proline or (S)-5-pyrrolidine-2-yl-1H-tetrazole. The reactions afforded anti-beta-hydroxy-alpha-amino aldehydes in good yield with high diastereoselectivity (dr up to >100:1) and high enantioselectivity (up to >99.5% ee), which were easily transformed into beta-hydroxy-alpha-amino acid derivatives.
Thayumanavan
Rajeswari
R
Department of Chemistry and Molecular Biology and The Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Tanaka
Fujie
F
Barbas III
Carlos F
CF
D000447:Aldehydes / Q000737:chemistry*; D000596:Amino Acids / Q000138:chemical synthesis*; D002384:Catalysis; D007202:Indicators and Reagents; D015394:Molecular Structure; D011392:Proline / Q000737:chemistry; D013237:Stereoisomerism
D000447:Aldehydes; D000596:Amino Acids; D007202:Indicators and Reagents; D011392:Proline