tert-Butyldiphenylsilyl ethers
TBDPS-OR, TBDPS ether
T. W. Green, P. G. M. Wuts,
Protective Groups in Organic Synthesis,
Wiley-Interscience, New York, 1999, 141-144, 708-711.
Stability
| H2O: | pH < 1, 100°C | pH = 1, RT | pH = 4, RT | pH = 9, RT | pH = 12, RT | pH > 12, 100°C |
| 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 |
An efficient and chemoselective protocol using LiOAc as a bifunctional Lewis
acid-Lewis base catalyst allows the selective deprotection of aryl silyl ethers
in the presence of acetates, epoxides, and aliphatic silyl ethers.
B. Wang, H.-X. Sun, Z.-H. Sun, J. Org. Chem., 2009,
74, 1781-1784.
With either 1.0 or 0.10 equivalent of DBU, smooth desilylation of various
aryl silyl ethers was accomplished selectively in the presence of base-sensitive
groups such esters and alkyl silyl ethers. A direct transformation of aryl silyl
ethers into biaryl ethers was possible through tandem desilylation and SNAr
reaction with activated aryl fluorides.
C.-E. Yeom, H. W. Kim, S. Y. Lee, B. M. Kim, Synlett, 2007,
146-150.
A microwave-assisted, chemoselective and efficient method for the cleavage of
silyl ethers is catalyzed by Selectfluor. A wide range of TBDMS-, TIPS-, and
TBDPS-protected alkyl silyl ethers can be chemoselectively cleaved in high yield
in the presence of aryl silyl ethers. In addition, the transetherification and
etherification of benzylic hydroxy groups in alcoholic solvents is observed.
S. T. A. Shah, S. Singh, P. J. Guiry, J. Org. Chem., 2009,
74, 2179-2182.
Reactions of alcohols with silyl chlorides in the presence of N-methylimidazole
were significantly accelerated by addition of iodine. A general and high
yielding method for efficient silylation of primary, secondary, and tertiary
alcohols was developed.
A. Bartoszewicz, M. Kalek, J. Nilsson, R. Hiresova, J. Stawinski, Synlett, 2008,
37-40.
Various tert-butyldimethylsilyl (TBDMS) ethers as well as tert-butyldiphenylsilyl
(TBDPS) ethers can be easily deprotected by employing a catalytic amount of
acetyl chloride in dry MeOH in good yields. This mild and convenient method
tolerates various other protecting groups and does not lead to acylated or
chlorinated byproducts.
A. T. Khan, E. Mondal, Synlett, 2003, 694-698.
A commercially available proazaphosphatrane is an efficient and mild
catalyst for the silylation of a wide variety of alcohols and phenols,
including acid-sensitive, base-sensitive, and hindered substrates, using
tert-butyldimethylsilyl chloride (TBDMSCl). The reactions are carried
out in acetonitrile from 24 to 40°C and on rare occasions in DMF from 24 to
80°C. Although representative primary alcohols, secondary alcohols, and
phenols were silylated using the more sterically hindered reagent tert-butyldiphenylsilyl
chloride (TBDPSCl), tertiary alcohols were recovered unchanged.
B. A. D'Sa, J. G. Verkade, J. Am. Chem. Soc., 1996,
118, 12832-12833.
Tris(pentafluorophenyl)borane, B(C6F5)3, is
an effective catalyst for a mild and efficient dehydrogenative silation of
alcohols using a variety of silanes. Only the most bulky silanes (Bn3SiH
and iPri3SiH) were not reactive under these conditions.
Generally, the reactions are clean and high yielding, with dihydrogen as the
only byproduct.
J. M. Blackwell, K. L. Foster, V. H. Beck, W. E. Piers, J. Org. Chem.,
1999,
64, 4887-4892.
