The experimental optical rotation (OR), electronic circular dichroism (ECD) and vibrational circular dichroism (VCD) spectra of (R)-3-hydroxy-4,5-dimethylfuran-2(5H)-one (sotolon, 1) and (R)-5-ethyl-3-hydroxy-4-methylfuran-2(5H)-one (maple furanone, 2) taken in chloroform were compared to their spectra calculated with time-dependent density functional theory (TDDFT). Sotolon was shown to exist as a dimer in chloroform while maple furanone remains a monomer. Transition state barriers for the enol/keto tautomerization of sotolon were calculated and found to be high. The VCD method offers promise to ultimately distinguish between the presence of monomers or dimers.