Determination of absolute configuration using vibrational circular dichroism spectroscopy: the chiral sulfoxide 1-thiochromanone S-oxide.
We reexamined the absolute configuration (AC) of the chiral sulfoxide 1-thiochromanone S-oxide (1) using vibrational circular dichroism (VCD) spectroscopy. The VCD spectrum of 1 was analyzed using density functional theory (DFT). DFT predicts two stable conformations of 1, separated by <1 kcal/mole. Their VCD spectra were calculated using the DFT/GIAO methodology. The VCD spectrum predicted for the equilibrium mixture of the two conformations of (S)-1 is in excellent agreement with the experimental spectrum of (+)-1. The AC of 1 is therefore definitively R(-)/S(+).
Devlin
F J
FJ
Department of Chemistry, University of Southern California, Los Angeles 90089-0482, USA.
Stephens
P J
PJ
Scafato
P
P
Superchi
S
S
Rosini
C
C