Asymmetric synthesis of aminoacids by catalytic reduction of azlactones by substituted aminoacrylic acids. 20. Steric control in the reductive aminolysis of Δ2-oxazolin-5-ones

Autor: Karpeiskaya, E. I., Lutsenko, M. R., Lutsenko, A. I., Levitina, E. S., Godunova, L. F., Klabunovskii, E. I.
Zdroj: Russian Chemical Bulletin; October 1987, Vol. 36 Issue: 10 p2118-2123, 6p
Abstrakt: Conclusions 1.PMR examination of deuterated acetylphenylalanine α-phenylethylatnide and the methyl esters of acetyl- and benzoylphenylalanine, obtained by the reductive solvolysis of 2-methyl- and 2-phenyl-4-benzylideneoxazolin-5-ones, has shown that in the reduction of oxazolinones the hydrogen undergoes cis- and trans-addition in a ratio of 1∶1.2.Asymmetric induction in the reductive solvolysis of oxazolin-5-ones arises as a result of the fact that the proportions of cis- and trans-addition of hydrogen are different, and are strictly observed for the diastereoisomeric catalyst-substrate adducts,3.The enantioselectivity of the reaction is determined at the stage of protonation of the semi-hydrogenated intermediate, and is independent of differentiation between the sides of the plane of the double bond at the step in which the substrate is bound.
Databáze: Supplemental Index
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