Cleavage of ethers

Protecting Groups

Recent Literature

A new reagent for the deprotection of various aromatic methyl ethers, 2-(diethylamino)ethanethiol, affords the corresponding phenols in good to excellent yields. Both the reagent and the byproduct 2-(diethylamino)ethyl methyl sulfide are soluble in dilute acid, which allows an essentially odorless workup.
J. Magano, M. H. Chen, J. D. Clark, T. Nussbaumer, J. Org. Chem., 2006, 71, 7103-7105.

In bromination of alkenes by dibromine and dealkylation of aromatic ethers by boron tribromide, a fluorous phase acts as a liquid membrane permitting passive transport of the reagents at the bottom to the top layer involving the substrates, thereby regulating the reactions.
I. Ryu, H. Matsubara, S. Yasuda, H. Nakamura, D. P. Curran, J. Am. Chem. Soc., 2002, 124, 12946-12947.

The ionic liquid [bmim][Br] confers high nucleophilicity on the bromide ion for the nucleophilic displacement of an alkyl group to regenerate a phenol from the corresponding aryl alkyl ether in good yield in the presence of p-toluenesulfonic acid. Dealkylation of various aryl alkyl ethers could also be achieved using stoichiometric amounts of concentrated hydrobromic acid in [bmim][BF₄].
S. K. Boovanahalli, D. W. Kim, D. Y. Chi, J. Org. Chem., 2004, 69, 3340-3344.

Pd(0)-catalyzed deprotection of allyl ethers using barbituric acid derivatives in protic polar solvent such as MeOH and aqueous 1,4-dioxane proceeds at room temperature without affecting a wide variety of functional groups. Control of the reaction temperature allows selective and successive cleavage of allyl, methallyl, and prenyl ethers.
H. Tsukamoto, T. Suzuki, Y. Kondo, Synlett, 2007, 3131-3132.

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 are also described.
M. Ishizaki, M. Yamada, S.-I. Watanabe, O. Hoshino, K. Nishitani, M. Hayashida, A. Tanaka, H. Hara, Tetrahedron, 2004, 60, 7973-7981.