Assignment of 1H and 13C NMR spectral data of diastereomeric acetals directly from their mixture by spectral simulation

Abstract

Herein, an NMR spectral analysis was performed of a mixture of diastereomeric acetals synthesized from 2-fluorobenzaldehyde and a racemic mixture of 4-methylpentan-2-ol. The simulated 1H- and 13C-NMR spectra of individual diastereomers, as well as their superimposed and summed spectra, were compared with the obtained experimental spectra. Spin simulation of proton signals was particularly useful for the assignment of the aromatic part of the molecules and of the diastereotopic protons of the methylene groups. The isomer NMR spectral data - chemical shifts, coupling constants, HMBC and NOESY interactions were systematized in appropriate tables and schemes.