AlsoTapered
Bluelighter
There's no reasonable way to do so without α-methyl. You need α-methylcinnamic acid to make a ketone. Alternatively, those glycidates can be made from benzaldehyde and piperonal by Darzens condensation.
( https://www.researchgate.net/public...ospective_search_in_German_profiling_database )
The link you give shows the glycidic acid rearranging to PMK.
Above is how the glycidate can be produced from the ethyl cinnamate.