A New Diastereoselective Synthesis of anti-α-Alkyl α-Hydroxy β-Amino Acids

✍ Scribed by Giuliana Cardillo; Alessandra Tolomelli; Claudia Tomasini

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 215 KB
• Volume: 1999
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(199901)1999:1<155::aid-ejoc155>3.0.co;2-a

✦ Synopsis

Alkylation / Oxazolines / anti-α-Alkyl α-hydroxy β-amino acids / Lithium dianion / Penicillin G acylase As part of an ongoing project concerning the synthesis of conditions, affording in quantitative yield the corresponding hydroxy amides. The starting (R)-3-amino-3-phenyl-enantiomerically pure α-hydroxy β-amino acids, we have now developed a general strategy allowing the synthesis of propanoic acid and (S)-3-aminobutanoic acid were obtained in enantiomerically pure form by selective enzymatic anti-α-alkyl α-hydroxy β-amino acids. Our procedure involves the intermediate formation of trans-oxazolines, hydrolysis of the corresponding phenylacetylamides with penicillin G acylase. which are alkylated at C-5 with good to high diastereoselectivity and then hydrolysed under mildly acidic have now developed a general strategy allowing the intro- [a] Dipartimento di Chimica "G. Ciamician" and C.S.F.M., Univercorresponding benzamido ester (R)-4, which in turn was sita `di Bologna, cyclized to the oxazoline 5, in high yield and with high dia-