Vibrational Circular Dichroism Discrimination of Diastereomeric Cedranol Acetates

<jats:title>ABSTRACT</jats:title><jats:p>The reliability of vibrational circular dichroism (VCD) spectroscopy to discriminate four diastereomeric cedranol acetates <jats:bold>1</jats:bold>, <jats:bold>2</jats:bold>, <jats:bold>3</jats:bold>, <jats:bold>4</jats:bold> by means of their absolute configuration is examined. The usage of Compare<jats:italic>VOA</jats:italic> software to quantify comparisons of the measured infrared (IR) and VCD spectra with the corresponding simulated spectra at the B3LYP/DGDZVP and B3PW91/DGDZVP levels of theory for each diastereomer enabled the B3PW91 functional to be qualified as superior to the B3LYP functional for vibrational calculations of <jats:bold>1</jats:bold>, <jats:bold>2</jats:bold>, <jats:bold>3</jats:bold>, <jats:bold>4</jats:bold>. Analogously, a set of quantitative VCD spectra cross‐comparisons of <jats:bold>1</jats:bold>, <jats:bold>2</jats:bold>, <jats:bold>3</jats:bold>, <jats:bold>4</jats:bold> unambiguously distinguished the diastereomers using B3PW91 and failed using B3LYP. Remarkably, quantitative IR spectra cross‐comparisons of <jats:bold>1</jats:bold>, <jats:bold>2</jats:bold>, <jats:bold>3</jats:bold>, <jats:bold>4</jats:bold> using B3PW91 or B3LYP functionals demonstrated that the achiral spectroscopic IR technique is not able to distinguish cedranol acetate diastereomers. VCD comparisons using anisotropy <jats:italic>g</jats:italic>‐factor values of bands in the 1550–950 cm<jats:sup>‐1</jats:sup> region of the spectra were of aid to facilitate visual spectra matching for each diastereomer. <jats:italic>Chirality 25:939‐951, 2013</jats:italic>. © 2013 Wiley Periodicals, Inc.</jats:p>