104749-28-2Relevant academic research and scientific papers
Stereoselective Synthesis of Some γ- and δ-Fluoro-α-amino Acids
Kroeger, Stefan,Haufe, Guenter
, p. 1201 - 1206 (2007/10/03)
(R)-(-)-2-Amino-4-fluorobutyric acid (4c) (32percent ee) and six of its homologues 9 have been synthesized by diastereoselective alkylation (54-72percent yield) of (R)-(+)-camphor-based glycine ester imines 1 with 1-bromo-2-fluoro-alkanes 6, at low temperature, followed by deprotection.Similarly 1-bromo-3-fluoropropane was used for the preparation of (R)-(-)-5-fluoronorvaline (4d) (42percent ee).With 1-bromo-2-fluoropropane (6a) and its homologues (prepared by bromofluorination of 1-alkenes) partial resolution occurs in the alkylation step, yielding mixtures of four diastereomers.Using (R)-1-bromo-2-fluoro-4-methylpentane two diastereomeric alkylation products are formed (58percent de).The overall yield of the three-step procedure varied from 10percent to 32percent. - Keywords: Chiral auxiliaries; Glycine ester imines; Alkylations; Bromofluoro alkanes; Triethylamine tris(hydrofluoride)
