Web Release Date: July 4,
Synthesis of 
-Substituted 
-Amino Acids with Use of
Iridium-Catalyzed Asymmetric Allylic Substitution
Graduate School of Pharmaceutical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan, and Faculty of Pharmaceutical Sciences, Mukogawa Women's University, 11-68 Koshien Kyuban-cho, Nishinomiya 663-8179, Japan
Received May 14, 2003
Abstract:
The asymmetric synthesis of -substituted -amino acids with use of iridium-catalyzed allylic
substitution was described. The Ir-catalyzed allylic substitution of diphenylimino glycinate with
allylic phosphates proceeded smoothly even at 0 
C and gave branch products with high
enantioselectivity (up to 97% ee), when chiral bidentate phosphite bearing the 2-ethylthioethyl
group was employed. In addition, both diastereomers of the branch products were synthesized
stereoselectively by simply switching the base employed. These methods were also applied to the
asymmetric synthesis of quaternary -amino acids.
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