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Enantioselective Preparation of 2‐Aminomethyl Carboxylic Acid Derivatives: Solving the β 2 ‐Amino Acid Problem with the Chiral Auxiliary 4‐Isopropyl‐5,5‐diphenyloxazolidin‐2‐one (DIOZ). Preliminary Communication
Author(s) -
Seebach Dieter,
Schaeffer Laurent,
Gessier François,
Bindschädler Pascal,
Jäger Corinna,
Josien Delphine,
Kopp Sascha,
Lelais Gérald,
Mahajan Yogesh R.,
Micuch Peter,
Sebesta Radovan,
Schweizer Bernd W.
Publication year - 2003
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200390149
Subject(s) - chemistry , isopropyl , electrophile , enantiomer , enantioselective synthesis , yield (engineering) , amino acid , enantiomeric excess , organic chemistry , chiral auxiliary , catalysis , medicinal chemistry , stereochemistry , biochemistry , materials science , metallurgy
Multigram amounts of suitably protected β 2 ‐amino acids with 17 of the 20 proteinogenic side chains are prepared by diastereoselective reactions of Li, B, or Ti enolates of the corresponding 3‐acyl‐4‐isopropyl‐5,5‐diphenyloxazolidin‐2‐ones (acyl‐DIOZ; 1 ) with appropriate electrophiles (amidomethylation, hydroxyalkylation, (benzyloxycarbonyl)methylation) in yields of 55–90% and with diastereoselectivities of 80 to >97% ( Scheme ). The primary products 2 – 8 thus obtained are converted to protected β 2 ‐amino acids by standard procedures ( Table 1 ). Many of the DIOZ derivatives are highly crystalline compounds (31 X‐ray crystal structures in Table 2 ). The chiral auxiliary DIOZ, readily prepared in either enantiomeric form, is recovered with high yield.