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Synfacts 2005(0): 0085-0085  
DOI: 10.1055/s-2005-869889
Polymer-Supported Synthesis
© Georg Thieme Verlag Stuttgart · New York

Asymmetric PTC for Preparation of a-Amino Acids

Contributor(s): Yasuhiro Uozumi, Yoichi M. A. Yamada, Naoshi Fukuyama
H-g. Park*, M.-J. Kim, M.-K. Park, H.-J. Jung, J. Lee, S-h. Choi, Y.-J. Lee, B.-S. Jeong, J.-H. Lee, M.-S. Yoo, J.-M. Ku, S-s. Jew*
Seoul National University, Korea
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Publication History

Publication Date:
20 July 2005 (online)

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Significance

A polystyrene resin-bound phenylmethyleneglycinimine tert-butyl ester was prepared from a Merrifield resin in two steps. The polymer-bound glycinimine was alkylated with alkyl halides (e.g., hexyl bromide, allyl bromide, propargyl bromide, benzyl bromide, etc.) in the presence of 10 mol% of a cinchona-derived phase transfer catalyst and 50% aqueous CsOH in toluene/chloroform at 0 °C, for four days to give the corresponding non-natural α-amino acids in 50-82% yields with up to 99% ee. Eleven examples of the alkylation are shown.