A method for concurrent synthesis of vanillin and isovanillin has been developed by a nonregioselective Vilsmeier-Haack reaction of O-alkyl guaiacols. O-Alkylation of guaiacol provided the corresponding O-alkyl guaiacol (1), which was then formylated with N-methylformanilide/phosphorus oxychloride to give a mixture of 4-alkoxy-3-methoxy-benzaldehyde (2) and 3-alkoxy-4- methoxybenzaldehyde (3). Finally, the obtained mixture underwent a selective dealkylation by anhydrous aluminium trichloride, while leaving methyl groups intact to simultaneously achieve the significant fine chemicals vanillin and isovanillin.
Palladium charcoal-catalyzed deprotection of O-allylphenols
Allyl aryl ethers can be easily cleaved by the use of 10% Pd/C under mild and basic conditions. The present reaction would involve a SET process rather than a π-allyl-palladium complex. The scope and limitation of this new deprotective methodology is also described.
Radical isomerization via intramolecular ipso substitution of aryl ethers: Aryl translocation from oxygen to carbon
Bromopropyl aryl ethers an converted to 3-arylpropanols under standard radical generating conditions in the presence of tributylstannane and AIBN. This rearrangement involves intramolecular ipso attack of the alkyl radicals which generates spiro cyclohexadienyl radical intermediates.
Lee, Eun,Lee, Chulbom,Tae, Jin Sung,Whang, Ho Sung,Li, Kap Sok
p. 2343 - 2346
(2007/10/02)
More Articles about upstream products of 29515-39-7