Asymmetric synthesis of amino acids via catalytic reduction of azalactone-substituted acylaminoacrylic acids. 21. Catalytic asymmetric synthesis of the phenylethylamide of N-acyl-p-difluoromethoxyphenylalanine

Autor: Godunova, L. F., Levitina, E. S., Karpeiskaya, E. I., Klabunovskii, E. I., Yagupol'skii, Yu. L., Kolycheva, M. T.
Zdroj: Russian Chemical Bulletin; February 1989, Vol. 38 Issue: 2 p351-354, 4p
Abstrakt: 1.Catalytic reductive aminolysis of the azalactones of N-acyl-p-difluoromethoxy-a-aminocinnamic acid in dimethoxyethane, isopropanol, and tert-butanol proceeds stereoselectively, leading to the a-phenylethylamides of N-acyl-p-difluoromethoxyphenylalanine with a 3–55% excess of the S,S-diastereomer.2.Replacement of dimethoxyethane by isopropanol or tert-butanol leads to an increase in the stereoselectivity of the process.3.Hydrogenation of the S-(+)-a-phenylethylamide of N-acyl-p-difluoromethoxy-a-aminocinnamic acid proceeds stereoselectively, and leads to production of the a-phenylethylamide of N-acyl-p-difluoromethoxyphenylalanine with a 9–18% excess of the R,S-diastereomer.
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