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How do you perform a Williamson ether synthesis?

Answer 1

Use an alkoxide ion (formed from an alcohol) and alkyl halide or tosylate. Mechanism involves #S_N2# backside attack.

The Williamson ether synthesis is the most reliable and versatile ether synthesis. This method involves the #S_N2# attack of an alkoxide ion on an (unhindered) primary alkyl halide or tosylate. Secondary alkyl halides and tosylates are occasionally used in the Williamson synthesis, but elimination competes and the yields are often poor as a result.

General mechanism:

Note that the alkoxide is commonly made by adding Na, K, or NaH to an alcohol.

Wade, L. G., Simek, J. W. Organic chemistry, global edition, 9th ed.; Pearson Education Limited: Glenview, IL, 2016, pg 682.

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Answer 2

Skylar Alexander

To perform a Williamson ether synthesis, you need to react an alkyl halide with a deprotonated alcohol (alkoxide ion) in the presence of a strong base, such as sodium hydride or potassium tert-butoxide, in an appropriate solvent, typically an aprotic solvent like dimethyl sulfoxide (DMSO) or tetrahydrofuran (THF). The alkyl halide reacts with the alkoxide ion to form an ether product. This reaction is commonly carried out under reflux conditions to ensure completion.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.