- An efficient and chemoselective deprotection of tert-butyldimethylsilyl (TBDMS) ethers using tailor-made ionic liquid
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Phenolic tert-butyldimethylsilyl (TBDMS) ethers can be deprotected to yield phenols in excellent yield using tailor-made ionic liquid [dihexaEGim][OMs] (dihexaEGim = dihexaethylene glycolic imidazolium salt) as an organic catalyst with alkali-metal fluoride in tert-amyl alcohol. On the contrary, all TBDMS protecting groups can be cleaved cleanly from the bis-TBDMS ether using the same reaction in CH3CN solvent instead of tert-alcohol at 100 °C. This [dihexaEGim][OMs]/tert-amyl alcohol media system allows the highly selective phenolic deprotection reaction of various bis-TBDMS ethers containing both phenolic and aliphatic TBDMS ethers to provide the corresponding phenols in high yield.
- Jadhav, Vinod H.,Lee, Sang Bong,Jeong, Hwan-Jeong,Lim, Seok Tae,Sohn, Myung-Hee,Kim, Dong Wook
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- COMPOUNDS USEFUL IN THE TREATMENT OF NEOPLASTIC DISEASES
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The present invention refers to compounds of formula: (formula A), wherein R1 is selected from (formula I), (formula II), (formula (III), (formula IV), (formula V), or (formula B), and wherein R2, R3, R4 and Rs
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Page/Page column 30
(2015/04/15)
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- Selective O-deallylation of o-allyloxyanisoles
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o-Allyloxyanisoles are selectively and easily deallylated by treatment with sec- or tert-butyllithium at low temperature. The reaction is proposed to proceed through a tandem intermolecular carbolithiation-β;-elimination process, which can also be considered an SN2′ attack of the organolithium on the allyl ether.
- Sanz, Roberto,Martínez, Alberto,Marcos, César,Fa?ańas, Francisco J.
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experimental part
p. 1957 - 1960
(2009/05/26)
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- Selective deprotection of either alkyl or aryl silyl ethers from aryl, alkyl bis-silyl ethers
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A pair of complementary methods was developed using CeCl3·7H2O/CH3CN and LiOH/DMF to selectively deprotect alkyl and aryl silyl ethers, respectively, from the corresponding bis-silyl ethers in excellent yields.
- Ankala, Sudha V.,Fenteany, Gabriel
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p. 4729 - 4732
(2007/10/03)
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- Selective desilylation of tert-butyldimethylsilyl ethers of phenols using potassium fluoride-alumina and ultrasound
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The use of potassium fluoride on basic alumina in acetonitrile with ultrasound for the selecting deprotection of tert-butyldimethylsilyl ethers of phenols is described. The method, which features a non-aqueous work-up, readily cleaves tert-butyldimethylsilyl ethers of phenols at room temperature, whereas tert-butyldimethylsilyl ethers of benzyl alcohols or 2-(trimethylsilyl) ethoxymethyl ethers of phenols are stable.
- Schmittling, Elisabeth A.,Sawyer, J. Scott
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p. 7207 - 7210
(2007/10/02)
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