Stereochemical analysis of β‐keto sulfoxides by circular dichroism

July 30, 2019

Title

Stereochemical analysis of β‐keto sulfoxides by circular dichroism

Author

Marcin Górecki, Maria Annunziata M. Capozzi, Gianluigi Albano, Cosimo Cardellicchio, Lorenzo Di Bari, Gennaro Pescitelli

Year

2017

Journal

Chirality

Abstract

Three β‐keto sulfoxides (1–3) were synthesized in enantiopure form and investigated by means of circular dichroism (CD) spectroscopy, both in electronic and vibrational range (ECD, VCD), in combination with quantum chemical calculations. For compound 2, the X‐ray structure was available; thus, the ECD in the solid state was also considered to reveal the differences between the molecular species in both states. Despite the simplicity of all β‐keto sulfoxides under investigation (29 atoms), reproducing even the major spectral VCD features failed for two compounds, making the use of VCD not ideal to assign their absolute configuration in a reliable way. We demonstrated, however, that the use of ECD spectroscopy, both in solution and solid state, can easily, unambiguously, and without any complication simulate all bands by applying the standard protocol for calculations. This study may stimulate the debate on the need of the use of two chiroptical methods simultaneously in the determination of absolute configurations.

Instrument

FVS-6000

Keywords

Vibrational circular dichroism, chiroptical spectroscopy, conformational search, density functional calculations, solid‐state ECD/TDDFT, solvent effects