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Enantiomerically Pure 3-Substituted 2-Phenylprolines by Caesium Fluoride/Tetramethoxysilane Mediated 1,4-Addition of (3S,5R)-Diphenylmorpholin-2-one to Acrylates.-In continuation of the asymmetric synthesis of nonproteinogenic amino acids, the silane-mediated 1,4-addition of acrylates (II) to the chiral 3,5-disubstituted morpholine (I) and the TFA-promoted cyclization of the resulting adducts (III) to lactams (IV)/(V) are described. The major isomers (cf. (IVb)) may be converted to enantiopure α-phenyl prolines (VII). -(HARWOOD, L. M.; HAMBLETT, G.; JIMENEZ-DIAZ, A. I.; WATKIN, D. J.; Synlett (1997) 8, 935-938; Dep.

aminocarboxylic acidsaminocarboxylic acids (hydrazinocarboxylic acids) and esters (benzene compounds) Q 0440 -134Application of Enantiopure Templated Azomethine Ylids to β-Hydroxy-α-amino Acid Synthesis.-Treatment of the morpholinone (I) with aldehydes leads to azomethine ylids which undergo efficient and highly diastereocontrolled cycloaddition with a second molecule of aldehyde to afford products of type (IV). The products can easily be transformed into pure threo β-hydroxy-α-amino acids. -(ALKER, D.; HAMBLETT, G.; HARWOOD, L. M.; ROBERTSON, S. M.; WATKIN, D. J.; WILLIAMS, C. E.; Tetrahedron 54 (1998) 22, 6089-6098; Dep. Chem., Univ. Reading, Whiteknights, Reading, Berkshire RG6 2AD, UK; EN)