Determination of the stereochemistry of 3-hydroxymethyl-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine by vibrational circular dichroism and the effect of DFT integration grids

Vibrational circular dichroism (VCD) spectra are presented for 3-hydroxymethyl-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine. The assignment of the stereochemistry has been done by comparison between the experimental spectra and theoretically calculated spectra for both enantiomers. The DFT calculations were found capable to correctly assign absolute configurations. The influence of the basis set used in the DFT calculations on the extent of the agreement between the theoretical and experimental findings was investigated by use of different Pople-style basis sets and correlation consistent basis sets, showing that 6-31G* is an acceptable basis set, and that cc-pVTZ yields the best agreement. Similarly, the effect of DFT integration grids was examined. A quantitative measure for the similarity between experimental and theoretical spectra is used.