this method is no so novel as it seems. It was briefly mentioned by GC_MS in his post [No 354361], route no.5, where he cites several routes for benzaldehyde syntheses from "Meyer: Synthese der Kohlenstoffverbindungen", but gives no direct "cooking" directions. I found it out right now as I was looking for "Meyer" in the search engine.
The method in my previous post is some kind of successor to the Meyers aldehyde synthesis, which originally involves reacting 4,4-dimethyl-2-oxazoline (prepared from formic acid and 2-amino-2-methylpropanole) with methyliodide, thus yielding the 3,4,4-trimethyl-2-oxazolium iodide, which in turn is reacted with the Grignard compound of an aryl halide to yield the corresponding aromatic aldehyde. The yield reported for p-methoxy benzaldehyde from p-bromoanisole is good, 85 % of the raw product.
Your idea of preparation for the HCOOMgBr salt is very interesting...and so easy
. But I have several concerns on this. Maybe the salt is not that stable or if it has water of crystallization in it, it may decompose on drying. Perhaps I'm wrong (I have no more data available about this synthesis and the HCOOMgBr salt), but I have the strong feeling that it is absolute essential to prepare the salt solution in THF, maintaining absolute anhydrous conditions. I don't even know if the HCOOMgBr stays in solution or precipitates out (it is not mentioned in the procedure from the book). If so (concerning precipitation), the THF could very well be needed to replace water in the lattice of the salt.
For those bees with access to databases and journals:
- the Meyers method is detailed in "A.I. Meyers, E.W. Collington, J. Am. Chem. Soc. 92,6676 (1970)"
- the successor method from the aforementioned post is detailed in "F. Sato, K. Oguro, H. Watanabe, M. Sato, Tetrahedron Lett. 1980, 2869"
Hopefully someone in here can come up with more info, because this synthetic route is really fascinating me. It seems to be easy, gives good yields...and it could work where the Sommelet fails. Btw., not a benzyl halide should be chosen, an aryl halide (e.g. bromobenzene) must be used as starting material. With a benzyl halide as starting material, the result will be phenylacetaldehyde
Quidquid agis, prudenter agas et respice finem!