The Williamson ether synthesis uses an alkyl halide and an alkoxide to form an ether

Added: 2026-06-04

[00:00:00]Someone asked me about how to make ethers today. So, this is the Williamson ether synthesis, which is one of my favorite reactions. It's just so clean and simple. And it what it does is you make ethers using an alkoxide and then an alkyl halide. And if you recognize these reaction conditions, it's because they should look familiar. This is simple SN2 conditions.

[00:00:19]We have our alkyl alkoxide here. We have our alkyl halide here.

[00:00:23]We're going to come kick this off in just SN2 fashion. We're going to make our ether right here, and then obviously you'd have a negatively charged halide.

[00:00:35]And you can just easily pull out this ether.

[00:00:37]Where this really shines is making unsymmetric ethers, and it's just nice, consistent, and reliable. So, say we want to make this benzyl ethyl ether right here. How would we do that?

[00:00:46]There's a couple different ways.

[00:00:49]But say we're going to start with We're going to use ethyl bromide as our alkyl halide. So, that means we need need to then take benz- benz- oxide?

[00:01:02]Benz- alkoxide, I guess, you'd call that.

[00:01:05]Because we need this right here. This deprotonated form. Well, how do we get that?

[00:01:12]That's simple. We just take benzyl alcohol, which you can buy, and deprotonate it using some good old sodium hydride.

[00:01:19]Oh my gosh, I forgot my Here we go.

[00:01:22]Deprotonate using some good old sodium hydride. It's going to rip that proton right off.

[00:01:27]You're going to lose H2 gas in the process. You don't have to worry about coming back. You're going to have this nice alkoxide right here that's going to just add right on.