136030-53-0Relevant articles and documents
General Method for the Synthesis of Enantiomerically Pure β-Hydroxy-α-amino Acids, containing Fluorine Atoms in the Side Chains. Case of Stereochemical Distinction between Methyl and Trifluoromethyl Groups. X-Ray Crystal and Molecular Structure of the Nickel(II) Complex of ...
Soloshonok, Vadim A.,Kukhar, Valeri P.,Galushko, Sergei V.,Svistunova, Nataly Yu.,Avilov, Dimitri V.,et al.
, p. 3143 - 3156 (2007/10/02)
The chiral NiII complex 1 of a Schiff's base derived from (S)-o-benzophenone (BPB) and glycine was treated with fluoro-substituted aldehydes (aliphatic and aromatic) in MeOH or CHCl3.The addition proceeds with high diastereoselectivity to give, if catalysed by MeONa in MeOH, the corresponding complexes of syn-(2R)-3-fluorophenylserines (84-100percent) d.e.) and syn-(2S)-fluoroalkylserines (90percent d.e.), and, if catalysed by NEt3 or DABCO (MeOH or CHCl3), the corresponding complexes of syn-(2S)-, and anti-(2S)-3-fluorophenylserines and fluoroalkylserines.The second-order asymmetric transformation may be successfully employed to obtain diastereoisomerically pure complexes of anti-(2R)-3-fluorophenylserines.Condensation of trifluoroacetone with complex 1, catalysed by MeONa, gave predominantly (at least >95percent d.e.) the diastereoisomeric complex, containing (2S,3S)-β-(trifluoromethyl)threonine, as shown by an X-ray diffraction structural study.Diastereoisomerically and enantiomerically pure fluorine-containing 3-phenyl- and 3-alkyl-serines were obtained from the corresponding diastereomerically pure complexes, separated by chromatography or crystallization.The initial chiral auxiliary BPB was recovered (80-98percent).The influence of the reaction's conditions and the nature of the corresponding fluoro-substituted aldehydes on the diastereoselectivity of the reactions is discussed.
