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Swern oxidation

  • Page ID
    15019
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    Below is a standard procedure for the Swern oxidation of an alcohol.

    Procedure

    Swern_oxidation.png

    To a solution of oxalyl chloride (5 mmol) and 3 Å MS in CH2Cl2 (1 mL) at -78 °C under N2 is added dropwise a solution of DMSO (10 mmol) in CH2Cl2 (1 mL). After 15 min a solution of the alcohol in CH2Cl2 (3 mL) is slowly added dropwise. After 30 min, Et3N (15 mmol) is added dropwise. The reaction is stirred 30 min at -78 °C then slowly allowed to warm to rt.

    Notes:

    • Dichloromethane is usually the solvent of choice for this reaction, but Et2O or THF may also be used.
    • For secondary alcohols, warming the reaction to -40 °C after the addition of the alcohol for 20 min may help.
    • Bulkier amines such as diisopropylethylamine can be used instead of triethylamine in case of epimerization of the α-center

    Mechanism

    Swern_oxidation_mech.png

    Contributors


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