Enantioselective Fluorination of Organic Molecules. I. Synthetic Studies of the Agents for Electrophilic, Enantioselective Fluorination of Carbanions

Abstract

In order to develop novel methods for electrophilic and enantioselective fluorination of active methine compounds, preliminary experiments were carried out. The N-tosyl derivative 5 obtained from D-phenylglycine was fluorinated with FClO₃ or diluted F₂ gas to give the N-fluoro-N-tosyl derivative 6. N-Tosyl- or N-mesyl-(S)-α-phenethylamine 7 or 8 was sujected to FClO₃ fluorination to produce the corresponding N-fluoro derivative, 10 or 11, respectively.Enantioselective flurination of some methine compounds was attempted employing the above N-fluoro agents. Best result was obtained when 2-benzyl-1-tetralone/KHMDS was treated with 10 to produce the fluorinated tetralone 17 in 53% yield with enantiomeric excess (ee) of 48%.