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- Title
The Enantioselective Synthesis of β-Amino Acids, their α-hydroxy derivatives, and the N-terminal components of bestatin and microginin.
- Authors
Jefford, Charles W.; McNulty, James; Lu, Zhi-Hui; Wang, Jian Bo
- Abstract
L-Aspartic acid by tosylation, anhydride formation, and reduction with NaBH4 was converted into (3 S)-3-(tosylamino)butan-4-olide ( 8; Scheme 1). Tretment of 8 with ethanolic trimethylsilyl iodide gave the N-protected deoxy-iodo-β-homoserine ethyl ester 9. The latter, on successive nucleophilic displacement with lithium dialkyl-cuprates ( → 10a-e), alkaline hydrolysis ( → 11a-e), and reductive removal of the tosyl group, produced the corresponding 4-substituted (3 R)-3-aminobutanoic acids 12a-e (ee > 99%). Electrophilic hydroxylation of 8 ( → 19; Scheme 3), subsequent iodo-esterification ( → 21; Scheme 4), and nucleophilic alkylation and phenylation afforded, after saponification and deprotection, a series of 4-substituted (2 S, 3 R)-3-amino-2-hydroxybutanoic acids 24 including the N-terminal acids 24e ( = 3) and 24f ( = 4) of bestatin and microginin (de > 95%), respectively.
- Publication
Helvetica Chimica Acta, 1996, Vol 79, Issue 4, p1203
- ISSN
0018-019X
- Publication type
Article
- DOI
10.1002/hlca.19960790426