Use of shift reagent with diastereomeric MTPA esters for determination of configuration and enantiomeric purity of secondary carbinols in 1H NMR spectroscopy

Assignment of absolute configuration using chiral reagents and NMR spectroscopy

“…In many cases, the relative magnitudes of the lanthanideinduced shifts of either the 19 F signal of the CF 3 group of 1 H resonance of the methoxy group correlate with the absolute configuration. 20,21 Paramagnetic chelates cause line broaden- ing that is exacerbated at higher field strengths, which may preclude the use of this method in assigning absolute configuration on some NMR spectrometers.…”

Synthesis and evaluation of 18F-labeled mitiglinide derivatives as positron emission tomography tracers for β-cell imaging

“…The absolute configuration of (+)-o-FMIT and (−)-o-FMIT was determined by 1 H-NMR spectra using corresponding -methoxy--(trifluoromethyl)phenylacetic acid (MTPA) esters with Eu(fod) 3 [21][22][23][24]. (+)-o-FMIT and (−)-o-FMIT were transformed into corresponding diastereomeric esters 6 by reduction of the carboxyl group and esterification according to the method of Dale et al [25,26].…”

(S)-(−)-α-Methoxy-α-(trifluoromethyl)phenylacetic Acid

“…However, 1 H NMR spectroscopy of MTPA esters and amides has been more widely used in the assignment of configuration to chiral alcohols and amines. 37 Analysis of the chemical shifts of the MTPA methoxy peaks, in the presence of shift reagents, allows the correct stereochemical analysis of a series of bicyclic alcohols, such as (6). 15 The 1 H NMR shifts of the hydrogens directly attached to the carbinol carbons in MTPA esters have also been used to establish the configuration of chiral acyclic secondary alcohols.…”