Alcohol protection - [MOM] [MEM] [BOM] [SEM]
Diol protection - [Acetonide] [Benzylidene] [p-Methoxybenzylidene] [DTBS(OR)2]
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MOM - (methoxy methyl) ether

Standard Protection Procedure

To a solution of the glycoside in DCM (approx. 0.1M) and Hunig's base (N,N-diisopropylethyl amine, 2.0 eq) at 0°, MOM-Cl (1.5 eq) is added under an inert atmosphere.  The reaction is warmed to room temperature and stirred until complete by TLC (usually >8 h).  Ether is added and the mixture is washed 3 times with water and once with brine.  The organic layer is dried (magnesium sulfate), filtered and concentrated in vacuoThe resulting residue is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in 1:1 THF:6N HCl and heated to 55° with stirring until the reaction is complete by TLC (usually 8 h).  Saturated sodium chloride solution is then added and the reaction mixture is extracted three times with ether.  The combined organic layers are dried (sodium sulfate), filtered and concentrated in vacuo.  The residue is purified by flash chromatography (SiO2) if necessary.
References
   JACS, 1977, 99, 1275-1276.
   JOC, 1975, 40, 2025-2029.
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MEM - (methoxy ethoxy methyl) ether

Standard Protection Procedure

To a solution of the glycoside and MEM-Cl (1.5 eq) in dry DCM, diisopropylethylamine (1.5 eq) is added and stirred at room temperature under an inert atmosphere until complete by TLC (usually 5 h).  The reaction is diluted with DCM and extracted twice with water, once with brine, dried (sodium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
OR
To a mixture of NaH (1.2 eq) stirring in THF at 0°, the glycoside is added drop wise (as solution in THF)After stirring for 30 minutes, MEM-Cl (1.5 eq) is added drop wise and reaction is allowed to warm to room temperature.  The mixture is stirred until complete by TLC (usually overnight) and diluted with DCM.  The mixture is then extracted twice with water, once with brine, dried (sodium sulfate), and concentrated in vacuo.  The product is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in DCM and magnesium bromide etherate (excess) is added at room temperature under an inert atmosphere.  The reaction is stirred until complete by TLC (usually >24 h), at which time water is added and stirred for 30 additional minutes.  Aqueous HCl (1N) is added drop wise until the pH is 1-2 and the solution is clear.  The resulting solution is extracted three times with ethyl acetate, dried (magnesium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
References
    Tet. Lett., 1976, 11, 809-812.
    JOC, 1994, 59, 2314-2323.
    J. Chem. Soc. Perkin Trans. I, 1985, 2247-2250.
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BOM - (benzyloxy methyl) ether

Standard Protection Procedure

To a solution of the glycoside in DCM (approx. 0.1M) and Hunig's base (N,N-diisopropylethyl amine, 2.0 eq) at 0°, BOM-Cl (1.2 eq) is added under an inert atmosphere.  The reaction is warmed to room temperature and stirred until complete by TLC (usually >24 h).  Ether is then added and the mixture is washed 3 times with water and once with brine.  The organic layer is dried (magnesium sulfate), filtered and concentrated in vacuoThe resulting residue is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in EtOAc:Hex (1:2) and catalytic Pd(OH)2 is added (10mol%) under a hydrogen atmosphere.  The reaction is stirred at room temperature until complete by TLC (usually a few hours).  The mixture is then filtered and concentrated in vacuo.  The residue is purified by flash chromatography (SiO2) if necessary.
References
    JACS, 1975, 97, 6260.
    JACS, 1994, 116, 4674-4688.
    Tetrahedron, 1987, 43, 4395-4406.
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SEM - (trimethylsilyl) ethoxymethyl ether

Standard Procedure

To a solution of the glycoside under inert atmosphere at room temperature in DCM or THF (~2M), diisopropylethylamine (4 eq for each -OH) is added followed by the addition of SEM-Cl (3 eq for each -OH).  The reaction is stirred until complete by TLC, at which time saturated ammonium chloride is added.  The mixture is extracted with two portions of DCM and the combined organic layers are extracted twice with saturated bicarbonate and once with brine.  The solution is then dried (magnesium sulfate), filtered, and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in a 0.5M solution of sulfuric acid in 2:1 MeOH:THF at 0° under inert atmosphere.  The reaction is stirred until complete by TLC (usually <3 h) and saturated sodium bicarbonate solution is added slowly.  The mixture is then diluted with ethyl acetate and separated.  The aqueous layer is back extracted twice with ethyl acetate and the combined organic layers are extracted with saturated sodium bicarbonate and brine.  The organic solution is then dried (magnesium sulfate), filtered, and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
References
    Tet. Lett, 1993, 12, 1991-1994
    Tet. Lett, 1980, 21, 3343-3346
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Acetonide - (isopropylidene) ketal

Standard Protection Procedure

To a solution of the glycoside stirring in DMF, p-toluenesulfonic acid (10mol%) and 2,2-dimethoxypropane are added.  The result is stirred at room temperature under inert atmosphere until complete by TLC (usually >6 h).  The reaction is neutralized with 5% aqueous sodium bicarbonate and concentrated in vacuo.  The material is dissolved in ethyl acetate, washed with water, saturated sodium chloride, dried (sodium sulfate), and concentrated in vacuo. The product is then purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in 80-90% AcOH in water and stirred at 60-90° until complete by TLC (usually <3 h).  The solution is then concentrated in vacuo and purified by flash chromatography (SiO2) if necessary.
References
    Chem. Pharm. Bull., 1990, 38, 3366-3372.
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Benzylidene Acetal

Standard Protection Procedure

The glycoside is dissolved in DMF and benzyaldehyde dimethyl acetal (5 eq) is added.  To this solution stirring at room temperature under an inert atmosphere, toluene-p-sulfonic acid (0.3 eq) is added.  After the reaction is complete by TLC (usually overnight), the mixture is neutralized with triethylamine.  The solution is then concentrated in vacuo and purified by flash chromatography (SiO2) if necessary.
OR
The glycoside is dissolved in acetonitrile and benzyaldehyde dimethyl acetal (5 eq) is added.  To this solution stirring at room temperature under inert atmosphere, toluene-p-sulfonic acid (0.3 eq) is added.  After the reaction is complete by TLC (usually overnight), the mixture is diluted with chloroform and extracted twice with water.  The aqueous layer is then back extracted with chloroform.  The combined organic layers are dried and concentrated in vacuo. The resulting residue is purified by flash chromatography (SiO2) if necessary.
Complete Removal
The glycoside is dissolved in 50-80% AcOH in water and heated to 60-70° with stirring until complete by TLC (usually >4 h).  The solution is then concentrated and coevaporated with toluene 3 times.  The residue is purified by flash chromatography (SiO2) if necessary.
OR
To a solution of the glycoside in methanol at room temperature under an inert atmosphere, toluene-p-sulfonic acid (0.3 eq) is added.  The reaction is stirred until complete by TLC (usually overnight) and triethylamine is added to neutralize. The mixture is concentrated in vacuo and the residue is purified by flash chromatography (SiO2) if necessary.
OR
To a solution of the glycoside in methanol:t-butanol 1:1 at room temperature under a hydrogen atmosphere, Pd(OH)2-C (20mol%) is added.  The reaction is stirred until complete by TLC (usually overnight, if not complete up to one eq of HCl may be added) and filtered washing with methanol. The solution is concentrated in vacuo and the resulting residue is purified by flash chromatography (SiO2) if necessary.
Partial Removal
For primary benzyl and secondary -OH - To a solution of the glycoside in DCM under inert atmosphere at 0°, triethylsilane (5 eq) is added.  Trifluoroacetic acid (5 eq) is then added drop wise and the reaction mixture is allowed to warm to room temperature.  The reaction is stirred until complete by TLC (usually <3 h) and diluted with DCM.  The organic solution is then extracted twice with saturated aqueous sodium bicarbonate solution, dried (sodium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
For secondary benzyl and primary -OH - To a solution of the glycoside dissolved in DCM under an inert atmosphere at room temperature, 4A molecular sieves are added and stirred for one hour.  The mixture is then cooled to -78° and triethylsilane (3 eq) is added followed by PhBCl2 (3.4 eq).  After stirring for one hour, triethylamine and methanol are added and the mixture is diluted with chloroform.  The organic solution is washed with saturated aqueous sodium bicarbonate solution, dried (sodium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
References
    J. Chem. Soc., Perkin Trans. 1, 1996, 985-993.
    JOC, 1996, 61, 2401-2406.
    Tet. Lett., 1995, 36, 669-672.
    Tet. Lett., 2000, 41, 5547-5551.
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p-Methoxybenzylidene Acetal

Standard Protection Procedure

The glycoside and anhydrous zinc chloride are dissolved in dry pyridine and p-anisaldehyde (15 eq) is added at room temperature under an inert atmosphere.  The mixture is stirred until complete by TLC (usually >24 h) and then diluted with ethyl acetate, washed twice with water, dried (sodium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in 50-80% AcOH in water and heated to 60-70° with stirring until complete by TLC (usually >4 h).  The solution is then concentrated and coevaporated with toluene 3 times.  The residue is purified by flash chromatography (SiO2) if necessary.
OR
To a solution of the glycoside in methanol:t-butanol 1:1 at room temperature under a hydrogen atmosphere, Pd(OH)2-C (20mol%) is added.  The reaction is stirred until complete by TLC (usually overnight, if not complete up to one eq of HCl may be added) and filtered washing with methanol. The solution is concentrated in vacuo and the resulting residue is purified by flash chromatography (SiO2) if necessary.
OR
To a solution of the glycoside in acetonitrile:water (9:1), cerium ammonium nitrate (2 eq) is added at room temperature under an inert atmosphere.  The reaction is stirred until complete by TLC (usually 15 minutes) and the reaction is diluted with ethyl acetate.  The mixture is extracted twice with water, dried (sodium sulfate) and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
References
    Chem. Commun. 1984, 201-202.
    JACS, 1962, 84, 430-440.
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DTBS(OR)2 - Di-t-butylsilylene

Standard Protection Procedure

To a solution of the glycoside in DMF (0.25M) at 0° under an inert atmosphere is added silver nitrate (2.6 eq) followed by drop wise addition of di-tert-butyldichlorosilane (1.3 eq).  The mixture is warmed to room temperature and stirred until complete by TLC (usually 15 minutes).  Triethylamine (3 eq) is then added and the mixture is stirred for an additional 5 minutes.  The result is diluted with ethyl acetate and washed with saturated sodium bicarbonate.  The organic layer is then extracted twice with water, dried (magnesium sulfate), and concentrated in vacuo.  The resulting residue is purified by flash chromatography (SiO2) if necessary.
Removal
The glycoside is dissolved in acetonitrile and HF-acetonitrile (48%, excess) is added at room temperature under an inert atmosphere.  The result is stirred until complete by TLC (usually 15 minutes) and saturated sodium bicarbonate is slowly added to neutralize.   The mixture is diluted with ethyl acetate, extracted twice with saturated sodium bicarbonate and once with brine.  The organic layer is then dried (sodium sulfate) and concentrated in vacuo.  The product is purified by flash chromatography (SiO2) if necessary.
References
    Chem Lett. 1996, 97-100.
    JOC, 2000, 65, 7479-7494.
    Tet. Lett. 1982, 47, 4871-4874.
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