jo5b00706_si_001.pdf (2.93 MB)
Chiral Recognition Studies of α‑(Nonafluoro-tert-butoxy)carboxylic Acids by NMR Spectroscopy
journal contribution
posted on 2015-06-19, 00:00 authored by Anikó Nemes, Tamás Csóka, Szabolcs Béni, Viktor Farkas, József Rábai, Dénes SzabóThree
chiral α-(nonafluoro-tert-butoxy)carboxylic
acids (R)-1, (RS)-2, (R)-3 were synthesized to
examine their application as chiral solvating agents with amines.
As a model compound, first (S)- and/or (RS)-α-phenylethylamine was used, and their diastereomeric salts
were investigated by 1H and 19F NMR and ECD
spectroscopy. The NMR spectroscopic studies were carried out at room
temperature using the slightly polar CDCl3 and apolar C6D6 as solvents in 5 mM and 54 mM concentrations.
The difference of the chemical shifts (Δδ) in the diastereomeric
complexes is comparable with other, well-known chiral derivatizing
and solvating agents (e.g., Mosher’s acid, Pirkle’s
alcohol). Diastereomeric salts of racemic acids (RS)-1 and (RS)-2 with biologically
active amines (1R,2S)-ephedrine
and (S)-dapoxetine were also investigated by 19F NMR spectroscopy.