Question

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.

Explanation:

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.