Spectroscopy:
1. Run IR spectra on both of your purified products and on pinacolone.
Comment on any features of interest, including the C=O stretch frequencies.
2. Obtain, and interpret, electron-impact induced mass spectra of both products.
3. Obtain 1H and 13C nmr spectra of both products, as solutions in CDCl3.
(Remember that, in DEPT 90 and 135 spectra, peaks which ‘should' vanish, when compared with the CH decoupled spectrum., may not do so completely. If they are present, they will be present at very greatly reduced intensity, however.)
(a) Interpret the spectra of the enone, from Stage 1, as thoroughly as you can. Establish the compound's stereochemistry using the coupling constant associated with the splitting of the 1H nmr resonance of the vinyl protons. Use resonance arguments to explain why the α-vinyl proton is more deshielded than its β-vinyl counterpart.
(b) Use the integrations in the 1H nmr spectrum of the Stage 2 product to establish the relative numbers of protons resonating at the various chemical shift values. Which resonance (integration and multiplicity) corresponds to the t-butyl group?
Which resonance (integration and multiplicity) corresponds to the CH part of the isopropyl group?
Which two resonances (integration and multiplicity) correspond to the two isopropyl methyl groups