Synthesis of 3-Ethoxy-4-Hydroxy-Allylbenzene from 3-Methoxy-4-Hydroxy-Allylbenzene (Eugenol)
Nenokischi Hirao
Bull. Chem. Soc. Japan 11, 179-184 (1936) (https://www.thevespiary.org/rhodium/Rhodium/pdf/eugenol2homogenol.pdf)
(https://www.thevespiary.org/rhodium/Rhodium/pdf/eugenol2homogenol.pdf)
I found this article in an abstract database, where they only told that it contained a procedure for converting the Methoxy group of Eugenol to the Ethoxy homolog (called Homogenol by the authors), with no further details given. Great, I thought, then it most definitely contains a procedure for demethylation of eugenol to form 3,4-Dihydroxyallylbenzene (5-allylpyrocatechol), an excellent precursor to safrole. However, when I actually found the article, I saw that it contained a rather byzantine route for the insertion of that extra CH2 group.
(https://www.thevespiary.org/rhodium/Rhodium/hive/hiveboard/picproxie_docs/000448125-file_gbog.gif)
However, the article contains some rather interesting chemistry anyway, and various compounds which very likely can be used as precursors to other substances than safrole.