Utilização de RMN de 1H na determinaçã o da configuração absoluta de álcoois

Abstract

This review reports the determination of absolute configuration of primary and secondary alcohols by 1H NMR spectroscopy, using the Mosher method. This method consists in the derivatization of an alcohol possessig unknown absolute configuration with one or both enantiomers of an auxiliary reagent. The resulting diastereoisomer spectra are registered and compared, and the chemical shift differences (ΔδR,S = δR - δS) are measured. The determination of the absolute configuration of the alcohol molecule is based on the correlation between its chiral center and the auxiliary reagent's chiral center. Therefore, the determination of the absolute configuration depends on aromatic ring shielding effects on the substituents of the alcohol as evidenced by the 1H NMR spectrum.