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tert-Butyldiphenylsilyl ethers


T. W. Green, P. G. M. Wuts,
Protective Groups in Organic Synthesis,
Wiley-Interscience, New York, 1999, 141-144, 708-711.



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

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 40C and on rare occasions in DMF from 24 to 80C. 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.