In this video, we're going to talk about how you can make ketones from nitriles. Like carbonyls, nitriles have a very strong dipole along the carbon-nitrogen bond, which is going to make the carbon highly electrophilic. This is very similar to carbonyls. That means that when you react a nitrile with a nucleophile, you can expect to get nucleophilic addition. Very popular nucleophiles that we've used in this section are organometallics like Grignards, R-MgBr, and RLi. Remember that these reagents have full negative charges on them. What's also advantageous about them is that they have alkyl groups so that they can add Rs. It turns out that if you use one of these reagents on a nitrile in an acidic environment, you're going to get a ketone. The R group here is actually coming from the Grignard or the organolithium. That R gets added to the carbon and winds up turning into a carbonyl. You might be a little bit confused because you're thinking, Johnny, what happened to the nitrogen? We had a nitrogen. It really looks nothing like the original compound. For this, we're going to have to go into the mechanism which yes, I'll show you the whole mechanism. But it turns out that this mechanism is going to make a lot more sense to you than you think because it's really just a variation of stuff we've learned before. In the next video, I'm going to show you the full mechanism for how you can turn a nitrile into a ketone.
Nitrile to Ketone - Online Tutor, Practice Problems & Exam Prep
General Reaction
Video transcript
Mechanism
Video transcript
For this mechanism, I'm just going to bring down the exact compound that we had, the exact nitrile. We just have to choose what R group we want to add to it. Let's just make it a methyl group to make it really easy. I'm going to use CH3MgBr. Keep in mind that we kind of separate these regions. We react with the Grignard first and then we have our H3O+ acid workup. The mechanism for the Grignard is so easy that everyone here should know it regardless of whether your professor likes mechanisms or not. You should know the first part. The second part, the acid work up, I'm going to show you anyway because I'm just that kind of guy. But it's a mechanism that you probably don't need to be able to draw but we'll just do it in case. The negative attacks the carbon. The electrons go up to the nitrogen. What we make is a compound that looks like this, NR2. This looks a lot like a ketone but it's got a nitrogen with a negative charge on it. How do we
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