Protection for the Hydroxyl Group, Including 1,2-and 1,3-Diols

Conversion of Silyl Ethers to Other Functional Groups ESTERS 

Ethers are among the most used protective groups in organic synthesis. They vary from the simplest, most robust, methyl ether to the more elaborate, substituted, trityl ethers developed for use in nucleotide synthesis. They are formed and removed under a wide variety of conditions. Some of the ethers that have been used to protect alcohols are included in Reactivity Chart 1.  

See also C. B. Reese, Protection of Alcoholic Hydroxyl Groups and Glycol Systems, in Protective Groups in Organic Chemistry, J. F. W. McOmie, Ed., Plenum, New York and London, 1973, pp. 95-143 H. M. Flowers, Protection of the Hydroxyl Group, in The Chemistry of the Hydroxyl Group, S. Patai, Ed., Wiley-Interscience, 

Because of the increased acidity and reduced steric requirement of the carbohydrate hydroxyl, r-BuOK can be used as a base to achieve ether for- 

Mel or Me2S04, NaH or KH, THF. This is the standard method for introducing the methyl ether function onto hindered and unhitiered alcohols. 

Methoxymethyl, 27 Methylthiomethyl, 33 (Phenyldimethylsilyl)methoxymethyl, 35 Benzyloxymethyl, 36 p-Methoxybenzyloxymethyl, 37 p-Nitrobenzyloxymethyl, 38 o-Nitrobenzyloxymethyl, 38 (4-Methoxyphenoxy)methyl, 38 Guaiacolmethyl, 39 /-Butoxymethyl, 39 4-Pentenyloxymethyl, 40 Siloxymethyl, 41 

4-Methoxytetrahydrothiopyranyl S,S-Dioxide, 55 1 -[(2-Chloro-4-methyl)phenyl]-4-methoxypiperidin-4-yl, 55 1 -(2-Fluorophenyl)-4-methoxypiperidin-4-yl, 56 

1-Ethoxyethyl, 59 1-(2-Chloroethoxy)ethyl, 60 1 -[2-(Trimethylsilyl)ethoxy]ethyl, 61 1-Methyl-1-methoxyethyl, 61 1-Methyl-1-benzyloxyethyl, 62 1 -Methyl-1 -benzyloxy-2-fluoroethyl, 62 

2- Trimethylsi ylethyl, 64 2-(Benzylthio)ethyl, 65 2-(Phenylselenyl)ethyl, 65 

6- Difluorobenzyl, 97 p-Acylaminobenzyl, 97 p-Azidobenzyl, 97 4-Azido-3-chlorobenzyl, 98 2-Trifluoromethylbenzyl, 98 p-(Methylsulfinyl)benzyl, 98 

Methoxymethyl, 30 Methylthiomethyl, 38 (Phenyldimethylsilyl) methoxymethyl, 41 Benzyloxymethyl, 41 p-Methoxybenzyloxymethyl, 43 [(3,4-Dimethoxybenzyl)oxy] methyl, 43 p-Nitrobenzyloxymethyl, 44 o-Nitrobenzyloxymethyl, 44 [(i ) -1- (2-Nitrophenyl) ethoxy] methyl, 45 (4-Methoxyphenoxy)methyl, 45 Guaiacolmethyl, 46 [(p-Phenylphenyl)oxy]methyl, 47 f-Butoxymethyl, 47 4-Pentenyloxymethyl, 47 Siloxymethyl, 48 2-Methoxyethoxymethyl, 49 2-Cyanoethoxymethyl, 53 Bis(2-chloroethoxy)methyl, 53 2,2,2-Trichloroethoxymethyl, 53 2- (Trimethylsilyl) ethoxymethyl, 54 Menthoxymethyl, 58 0-Bis(2-acetoxyethoxy)methyl, 59 Tetrahydropyranyl, 59 

Greene s Protective Groups in Organic Synthesis, Fourth Edition, by Peter G. M. Wuts and Theodora W. Greene 

1- [2- (Trimethylsilyl) ethoxy] ethyl, 77 1-Methyl-l-methoxyethyl, 77 1-Methyl-l-benzyloxyethyl, 78 l-Methyl-l-benzyloxy-2-fluoroethyl, 79 1-Methyl-l-phenoxyethyl, 79 2,2,2-Trichloroethyl, 79 l,l-Dianisyl-2,2,2-trichloroethyl, 80 l,l,l,3,3,3-Hexafluoro-2-phenylisopropyl, 80 

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PROTECTION FOR THE HYDROXYL GROUP, INCLUDING 1.2- AND 1,3-DIOLS Half-lives for cleavage of 5 -protected thymidine in 80% AcOH at 15 ... 

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