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Reactions >> Protecting Groups >> Stability

tert-Butyl ethers

T. W. Green, P. G. M. Wuts,
Protective Groups in Organic Synthesis,
Wiley-Interscience, New York, 1999, 65-67, 708-711.

 

Stability

H2O: pH < 1, 100C pH = 1, RT pH = 4, RT pH = 9, RT pH = 12, RT pH > 12, 100C
Bases: LDA NEt3, Py t-BuOK Others: DCC SOCl2
Nucleophiles: RLi RMgX RCuLi Enolates NH3, RNH2 NaOCH3
Electrophiles: RCOCl RCHO CH3I Others: :CCl2 Bu3SnH
Reduction: H2 / Ni H2 / Rh Zn / HCl Na / NH3 LiAlH4 NaBH4
Oxidation: KMnO4 OsO4 CrO3 / Py RCOOOH I2, Br2, Cl2 MnO2 / CH2Cl2

Protection


An eco-compatible method for the formation of tert-butyl ethers of alcohols and phenols is performed in solvent-free conditions at room temperature using catalytic amount of Er(OTf)3. The catalyst is easily recovered and reused several times without loss of activity. In addition, the tert-butyl group is removed very quickly from alcohols and phenols in methanol in the presence of Er(OTf)3 using MW irradiation.
A. Procopio, P. Costanzo, M. Curini, M. Nardi, M. Oliverio, R. Paonessa, Synthesis, 2011, 73-78.


A mild reaction for the protection of alcohols as t-butyl ethers proceeds with Mg(ClO4)2 and Boc2O and shows general applicability. In addition, preliminary results indicate that the CeCl37H2O/NaI system is a very suitable catalyst for the deprotection of t-butyl ethers.
G. Bartoli, M. Bosco, M. Locatelli, E. Marcantoni, P. Melchiorre, L. Sambri, Org. Lett., 2005, 7, 427-430.

Deprotection


Aqueous phosphoric acid is an effective, environmentally benign, selective and mild reagent for the deprotection of tert-butyl carbamates, tert-butyl esters, and tert-butyl ethers. CBZ carbamates, azetidine, benzyl and methyl esters, TBDMS, and methyl phenyl ethers are tolerated. The reactions are high yielding, and the workup is convenient.
B. Li, M. Berliner, R. Buzon, C. K.-F. Chiu, S. T. Colgan, T. Kaneko, N. Keene, W. Kissel, T. Le, K. R. Leeman, B. Marquez, R. Morris, L. Newell, S. Wunderwald, M. Witt, J. Weaver, Z. Zhang, Z. Zhang, J. Org. Chem., 2006, 71, 9045-9050.


A mild reaction for the protection of alcohols as t-butyl ethers proceeds with Mg(ClO4)2 and Boc2O and shows general applicability. In addition, preliminary results indicate that the CeCl37H2O/NaI system is a very suitable catalyst for the deprotection of t-butyl ethers.
G. Bartoli, M. Bosco, M. Locatelli, E. Marcantoni, P. Melchiorre, L. Sambri, Org. Lett., 2005, 7, 427-430.


A. Procopio, P. Costanzo, M. Curini, M. Nardi, M. Oliverio, R. Paonessa, Synthesis, 2011, 73-78.

Other Syntheses of t-Butyl-protected Hydroxyl Groups


A palladium-catalyzed synthesis of aryl tert-butyl ethers from a variety of unactivated aryl bromides or chlorides is described. The ether products, which are precursors to phenols, are obtained in very good yield in the presence of air-stable dialkylphosphinobiphenyl ligands.
C. A. Parrish, S. L. Buchwald,  J. Org. Chem, 2001, 66, 2498-2500.


A practical and environmentally friendly oxidation of aryl olefins to arylethanone derivatives by using a Cu(I) catalyst and tert-butyl hydroperoxide (TBHP) provides 2-tert-butoxy-1-arylethanones in good yields under mild conditions with high selectivity. In this method, TBHP acts not only as an oxidant but also as the tert-butoxy and carbonyl oxygen sources.
J. Zhang, D. Xiao, H. Tan, W. Liu, J. Org. Chem., 2020, 85, 3929-3935.