= Solution
\Image[/past-exam-of-the-chemistry-course-of-the-year-3-of-the-natural-sciences-course-of-the-university-of-cambridge/2022/paper-3-q39-full-structure.png]
{title=Complete constitution: cinnamoyloxymethyl at cyclohexene position 1 and a tertiary-alcohol substituent at position 4}
The constitution is \b[\[4-(2-hydroxypropan-2-yl)cyclohex-1-en-1-yl\]methyl (E)-3-phenylprop-2-enoate], with absolute configuration at the saturated substituted ring <carbon> unspecified.
The OCH$_2$ side chain is attached to the \b[unprotonated <alkene> <carbon> 4]: F correlates through the ring junction to the <alkene> carbons and an allylic methylene, while its correlation to 1 fixes the <ester> linkage. The $\mathrm{C(OH)(CH_3)_2}$ side chain is attached to \b[methine <carbon> 12], as shown by the methyl-to-12 <HMBC> correlations and the contiguous ring <COSY> network.
The formula check gives 19 carbons and 24 hydrogens including OH. Its <degree of unsaturation> is eight: four from phenyl, one <ester> <carbonyl>, one cinnamate C=C, one <cyclohexene> C=C and one ring. No additional double bond or hidden second <carbonyl> is needed.
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