title: Stereoselective syntheses of 4-hydroxy 4-substituted glutamic acids.
abstract: The 4-hydroxy 4-substituted glutamic acid moiety is a common substructure of biologically important natural products such as monatin [(2S,4S)-2], lycoperdic acid (3), and dysiherbaine (4). To develop methodology for syntheses of these natural products, cycloadditions of nitrone 5 with 2-substituted 2-propen-1-ols 6 and 2-substituted acrylates 8 were investigated. Reactions of nitrone 5 with alcohols 6 in the presence of MgBr2OEt2 gave cycloadducts 7 in a highly stereoselective manner, whereas noncatalyzed reactions of 5 with acrylates 8 afforded adducts 9. Using the former reaction, syntheses of monatin [(2S,4S)-2], monatin derivative 18, and lycoperdic acid (3) were accomplished. The C4-epimer of monatin [(2S,4R)-2)] was also synthesized by employing the latter cycloaddition.
authors.affiliation: Division of Pharmaceutical Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa 920-1192, Japan. tamura@p.kanazawa-u.ac.jp
authors.forename: Osamu
authors.initials: O
authors.lastname: Tamura
authors.forename: Tomoya
authors.initials: T
authors.lastname: Shiro
authors.forename: Mizuho
authors.initials: M
authors.lastname: Ogasawara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Toyao
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishibashi
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives* / Q000737:chemistry; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D002384:Catalysis; D003500:Cyclization; D018698:Glutamic Acid / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D007202:Indicators and Reagents; D007211:Indoles / Q000737:chemistry; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: C414924:4-hydroxy-4-(indol-3-ylmethyl)glutamic acid; D019086:Bridged Bicyclo Compounds, Heterocyclic; D007202:Indicators and Reagents; D007211:Indoles; C121741:dysiherbaine; D018698:Glutamic Acid; D000409:Alanine