title: Stereoselective synthesis of unnatural spiroisoxazolinoproline-based amino acids and derivatives.
abstract: A route to spiroisoxazolinoproline-based amino acid derivatives is reported in which exo-methyleneprolinate 4 (tert-butyl ester) reacts as a dipolarophile with nitrile oxides to generate spiroisoxazolinoprolinates 7/10/11 in good yields (70-75%) and with ca. 1:4 cis:trans diastereoselectivity. tert-Butyl spiroisoxazolinoprolinates were separable by column chromatography and amenable to scale-up leading to single diastereoisomers of N-Boc and N-Fmoc protected spiroisoxazolinoproline amino acids.
authors.affiliation: Department of Chemistry, University of California, One Shields Avenue, Davis, California 95616-5295, USA.
authors.forename: Wei-Chieh
authors.initials: WC
authors.lastname: Cheng
authors.forename: Yannan
authors.initials: Y
authors.lastname: Liu
authors.forename: Melissa
authors.initials: M
authors.lastname: Wong
authors.forename: Marilyn M
authors.initials: MM
authors.lastname: Olmstead
authors.forename: Kit S
authors.initials: KS
authors.lastname: Lam
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Kurth
mesh_terms: D000596:Amino Acids / Q000138:chemical synthesis* / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D010080:Oxazoles; D011392:Proline / Q000031:analogs & derivatives* / Q000737:chemistry; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D000596:Amino Acids; D010080:Oxazoles; D011392:Proline