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A Chiral Nonracemic Enolate with Dynamic Axial Chirality: Direct Asymmetric α ‐Methylation of α ‐Amino Acid Derivatives
Author(s) -
Kawabata Takeo,
Suzuki Hideo,
Nagae Yosikazu,
Fuji Kaoru
Publication year - 2000
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/1521-3773(20000616)39:12<2155::aid-anie2155>3.0.co;2-n
Subject(s) - racemization , methylation , chirality (physics) , chemistry , amino acid , stereochemistry , yield (engineering) , biochemistry , physics , particle physics , thermodynamics , chiral symmetry breaking , nambu–jona lasinio model , gene , quark
The crucial intermediate A with a racemization barrier of 16 kcal mol −1 at −78 °C is proposed for the asymmetric α ‐methylation of 1 to give 2 in 81 % ee and 96 % yield (see scheme). The asymmetric α ‐methylation occurs in other amino acid derivatives (Dopa, Val, Leu, Trp, His, Tyr) in 78–93 % ee.