The two candidate structures are:
|Experimental||Structure A||Structure B|
This data clearly supports structure b for citronillal. Particularly the values for the carbon peaks observed at 50.9, and 124. These display the largest change in the two calculated spectra, and both values are closer to those calculated for structure b.
The calculated spectrum also is useful for distinguishing between the two CH3 groupls on the quaternary carbon of the alkene. The CH3 in the cis position has the smaller chemical shift.
Calculated Carbon Spectrum
Calculated Proton Spectrrum