[Tosylate] [Mesylate] [Benzylsulfonate] [Allylsulfonate] [Back to Carb. Synthesis]

Ts - tosylate

Standard Procedure

To a solution of the glycoside in dry pyridine under an inert atomosphere at room temperature, p-toluene-sulfonyl chloride (2 eq) is added and stirred until complete by TLC (usually 16 h).  Water is then added to the solution and stirred for one hour.  The mixture is diluted with chloroform and washed with 10% aqueous HCl, saturated sodium bicarbonate, and water.  The organic layer is then dried and concentrated in vacuo.  The product can then be purified by flash chromotography (SiO2) if necessary.
References
    JOC, 1964, 29, 3654-3658.
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Ms - mesylate

Standard Procedure

To a solution of the glycoside dissovled in dry THF at room temperature under an inert atmosphere, mesyl chloride (3 eq) and triethylamine (2 eq) are added.  The mixutre is stirred until complete by TLC (usually less than 1 h) and concentrated in vacuo.  The residue can then be purified by flash chromotography (SiO2) if necessary.
References
   JACS, 1966, 2817-2822.
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Bs - benzyl sulfonate

Standard Procedure

The glycoside is dissolved in DCM at room temperature under an inert atmosphere and dry 2,6-lutidine (2.6 eq) is added followed by benzylsulfonyl chloride (2.5 eq).  The mixture is stirred until complete by TLC (usually 18 h) and concentrated in vacuo.  The residue is then dissolved in ether and extracted with 1N aqueous hydrochloric acid, saturated aqueous sodium bicarbonate and water.  The oragnic layer is dried (sodium sulfate) and concentrated in vacuo.  The residue can then be purified by flash chromotography (SiO2) if necessary.
Removal
To a solution of the glycoside dissolved in dry DMF at room temperature under an inert atmosphere, sodium amide (1 eq) is added.  The reaction is stirred until complete by TLC (usually 16 h) and methanol is added followed by acetic acid to neutralize the mixture.  The solution is then concentrated in vacuo and redissolved in ether.  The organic solution is extracted once with saturated aqueous sodium bicarbonate, once with water, dried (sodium sulfate), and concentrated in vacuoThe resulting residue can then be purified by flash chromotography (SiO2) if necessary.
References
        Bull. Chem. Soc. Jpn. 1986, 59, 1587-1592.
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Als - allyl sulfonate

Standard Procedure

The glycoside is dissolved in DCM at -30° under an inert atmosphere and dry 2,6-lutidine (2.6 eq) is added followed by allysulfonyl chloride (2.5 eq).  The mixture is allowed to warm to room temperature after 2 hours and stirred until complete by TLC (usually 6 h).  The mixture is concentrated in vacuo and the resulting residue is redissolved in ethyl acetate, extracted saturated aqueous sodium bicarbonate and brine.  The oragnic layer is dried (sodium sulfate) and concentrated in vacuoThe product can then be purified by flash chromotography (SiO2) if necessary.
Removal
To a solution of the glycoside in THF:morpholine:35% aqueous formic acid (4:1:1) at room temperature under an inert atmosphere, tetrakis-triphenylphosphine-palladium (cataytic) is added in the absence of light.  The reaction is stirred until complete by TLC (usually 3 h) and then concentrated in vacuo.  The resulting residue can then be purified by flash chromotography (SiO2) if necessary.
References
        Synlett, 1991, 163-164.
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