Practical Stereoselective Synthesis of β-Branched α-Amino Acids through Efficient Kinetic Resolution in the Phase-Transfer-Catalyzed Asymmetric Alkylations
Takashi Ooi, Daisuke Kato, Koji Inamura, Kohsuke Ohmatsu and Keiji Maruoka*
*Department of Chemistry, Graduate School of Science, Kyoto
University, Sakyo, Kyoto 606-8502, Japan, Email: maruokakuchem.kyoto-u.ac.jp
T. Ooi, D. Kato, K. Inamura, K. Ohmatsu, K. Maruoka, Org. Lett., 2007, 9, 3945-3948.
DOI: 10.1021/ol701558e
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Abstract
Phase-transfer-catalyzed alkylation of glycinate Schiff base with racemic secondary alkyl halides proceeded with excellent levels of syn- and enantioselectivities under the influence of a chiral quaternary ammonium bromide and 18-crown-6. The alkylation product can be selectively converted to the corresponding anti isomer, allowing the preparation of all the stereoisomers of β-alkyl-α-amino acid derivatives.
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T. Ooi, S. Takada, S. Fujioka, K. Maruoka, Org. Lett., 2005, 7, 5143-5146.
Key Words
O'Donnell Amino Acid Synthesis, Organocatalysis
ID: J54-Y2007-3060