Synthesis of some racemic?-fluoro-?-amino acids

Abstract

Summary. Versatile three-step procedures for syntheses of seven racemic 7-fluoro-a-amino acids are described.Alkylation of tert-butyl N-(diphenylmethylene)glycinate with 1-bromo-2-fluoroalkanes gave Nprotected aminoacid esters both in anhydrous medium using lithiumdiisopropylamide as base at low temperature or in a two phase system of 50% aqueous sodium hydroxide and methylene chloride with triethylbenzylammonium chloride as the phase transfer catalyst at room temperature. Subsequent two-step deprotection with citric acid and hydrochloric acid gave the title compounds in 13-33% overall yields.

Stereoselective Synthesis of γ-Fluorinated α-Amino Acids Using 2-Hydroxy-3-pinanone as an Auxiliary

“…[12,13] Using a Schiff base of (ϩ)-(R)-camphor and glycine esters for diastereoselective synthesis of γ-fluoro α-amino acids, moderate to good diastereomeric excesses have been achieved. [14,15] …”

Synthesis of γ-fluoro-α-amino acids by Claisen rearrangement

“…Our own research interest was focused on synthesis of g-fluoro-aamino acids from glycine or alanine derivatives and 1-bromo-2-fluoroalkanes [33][34][35] or 2-fluoroallyl bromide [36][37][38]. The latter reaction gave access to 2-amino-4-fluoropent-4-enecarboxylic acid, which can be seen as an isostere of asparagine [37].…”

Fluorine-induced polarity increases inhibitory activity of BPTI towards chymotrypsin

“…Methodologies for obtaining fluorinated α-amino acids were recently reviewed by our group. 16 In the past, access to MfeGly has been especially limited. 17 In consequence there are no structures described in the protein data bank (PDB) containing this non-canonical amino acid and only a limited number of studies including this amino acid have been published.…”