A possible synthesis of a compound found in jasmine flower oil is shown - AQA - A-Level Chemistry - Question 21 - 2019 - Paper 3

In the provided synthesis pathway, we see the transformation of a compound through various functional groups. The mechanisms to consider are:

1. Electrophilic substitution: This is likely used, particularly in aromatic compounds, where electrophiles replace hydrogen.
2. Nucleophilic substitution: This could be involved when nucleophiles add onto electrophilic centers, such as the edges of the synthesis drawing.
3. Nucleophilic addition-elimination: This mechanism concerns reactions where a nucleophile adds to a carbonyl compound, followed by elimination of a leaving group.
4. Free-radical substitution: Generally involves radicals and would not be consistent with the shown pathways.

After reviewing the mechanisms, the one that is not utilized in this synthesis is C. Free-radical substitution.