Naming Epoxides - Video Tutorials & Practice Problems
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There are 3 distinct ways to name cyclic ethers. But before we get into them, let’s first specifically define what an epoxide is.
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concept
Defining what an epoxide (oxirane) is.
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Alright, guys. And let's talk about naming a pox sides. So it turns out that a pox sides are just cyclic ethers. That's basically the definition and some types of cyclic ethers. Remember that in ethers R o r um, are gonna be named as their own functional group due to increased reactivity. Okay. And the specific ones that we usually name as their own functional group are three member ethers. Okay, because there happens to be a lot of strain in those rings. They're out of their normal bonding preferences, so or their normal angle preferences. What that means is that they're very reactive and very easy to open them up. And what we call these three members cyclic ethers is too. There's actually two common names for them. We call them a pox sides. So go ahead and write that down. Okay? They're also called in some textbooks and professors like to use the word ox serene. OK, och, serene. These are really synonyms for each other. Okay. And a pox side and an ox rain are the same. Exact thing is just a three member cyclic either
Cycloalkane Convention
Name the ring as a cycloalkane, adding the prefix oxa- and location if necessary.
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concept
How to name cyclic ethers using the cycloalkane convention.
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cool so far. Right now, the challenge becomes How do we name these guys? Because sometimes, first of all, they're not always three members rings. And second of all, there is a lot of substitue INTs. So it turns out that there's three different common ways to name a pox sides, and I'm gonna go over all of them right now. Let's start off with what we call the cyclo Al Cane convention. Okay? In this type of naming system, what we do is we named the entire ring as if it was an Al Cain first. Okay, so as you can see here, I have a six numbered ring. Okay, but how many of those atoms are actually carbons? Onley? Five of them are. I've got 12345 Now, you might be wondering why I started with one there. I didn't need to. I'm just using that. I'm I mean, maybe I did, but I'm just using that as an example right now just to count carbons. Okay, so I have five carbons. But what I'm telling you is that we should actually name it as a cyclo Al Cain, not by the number of carbon So what that means is that usually when we're naming and out came, we would say there's five carbon, so it would be cyclo painting, but it's not. We're going to call this actually cyclo hexane because we go by the shape. Okay. What we're worried about here is the shape of the molecule, not how maney carbons it has in it. Okay, so this would be a cyclo hexane first. Well, as our route. Okay, Now, the difference is, if we have oxygen's inside of a ring, which is by definition, a cyclic ether, right? Then we're gonna add the prefix Ochse, Okay? And what Aqsa is gonna tell us is that there is one member of this ring that is an oxygen. Okay, so if I call it aqsa Cyclo heck, saying what I'm saying is that I have a six member dring where one of the atoms is an oxygen, not a carbon. Okay, and then obviously location, if necessary. So let's go ahead and just talk about this for a second. The route is gonna be the oxus cyclo hexane, and I have that written here. Now you just have to talk about locations. How do we know where to put those guys. Well, it turns out that the oxygen is always going to get your one spot. So when I put the one here, that didn't really count. That wasn't true, Numbering the way that I should really number it is starting from the oxygen because that's the highest priority, Adam inside the ring. And then obviously I should number to give, you know, the lowest overall number or to go to the next highest priority, etcetera. Okay, so this would be three metal, one Oxus cycle hike scene. Cool. So far, just you guys know this also applies to rings that more than one oxygen. If I had to Oxygen's, That would be what was called a Die Aqsa. Okay, just putting that out there, you could use prefixes as well. Okay, so now let's go ahead and talk about another naming system. By the way, One word really quick, this is gonna be commonly used for non three member rings. So if not three members, as you can see, I was doing with a six member one here. This is usually the one we use. Okay, So if it's four member five number six number, etcetera. You would use this naming system. Now, if it is a three member ID ring, we could still use it. But this is not going to be the most common way to name it, okay?
Epoxy Convention
Name as a typical alkane, and then include epoxy as a di-located substituent.
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How to name epoxides using the epoxy convention.
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if we are dealing with a three member bring, there is much more common ways. One is Thea Poxy convention. So what the epoxy convention basically says is this We have a substitute Wint named in a poxy group. Okay. And we're just going to name our longest carbon chain as normal and then label the three remembered ring as just a substitute coming off of that chain. Okay? And obviously give it the lowest number. One other thing about this that's interesting is that you actually have to name the locations of both of the atoms that the three member ring is attached to. So, as you can see here, um, my hip oxide is gonna get priority over the metal, So I would choose this to be my first carbon over here. Okay, that means that my epoxy group is, or my epoxy substitue int is across the two and the three. Therefore, I'm actually gonna call this a to comma three dash epoxy substitue int. Because I'm basically saying that I have a bond. Oh, across those two carbons. Okay, thin. The rest of it, We're just gonna name, like always. So this would be two three epoxy five. Metal Hexi. Not so bad, Right? Okay, so it's just something to consider that you could also use the epoxy convention. It's perfectly legit.
Oxide Convention
Name as an imaginary alkene, then follow with the word oxide.
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concept
How to name epoxides using the oxide convention.
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2m
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Now there's on top of that. There's even one more way to name it Poch sides and that this one actually comes from even further back in the history. Um, this one is actually like a reaction. Okay? What they're basically saying is, name it as an AL Keen. So pretend that the epoxy wasn't even there. Replace it with an AL Keen. Okay, Name it as Theo Alky entire name, and then at the end, just add the word oxide. Okay, Now, how does that make sense? The reason that makes sense is because what we're saying is that we we're basically assuming that we start off with a double bond, and then we did in a pox ID ation to put in a pox side group on that double bond. Now, you might not know how to do that yet, and that's fine. We're gonna actually learn that pretty soon. Um, but I'm just saying that this is almost coming from the reactivity side of things, saying, Well, I could start from a double bond, and if I do an approximation, I could get in a pox side. So then I would call it an oxide of that double bond. Okay, so in this case, I would call this on this would be heck scene, Right? Because I've got a six remembered, um, chain noticed that my double bond would be across the two and the three. But the way that I named Double Bonds is different from the way that I name hip oxides. I actually don't say that this is a 23 AL Keen. I would just start where? At the lowest number. So in this case, this is actually gonna be what we call a to heck seen. So don't get them confused. This would never be called a 23 Heck. Seen you on Lee Do that for the epoxy substitue int. Okay, so we know you have a to hack seen. Now we need a substitue int the five metal right on the five. So this would be five metal to heck seen oxide. All right, now, just you know, if your professor require stereo chemistry, if your professor is asking about stereo chemistry, remember, that's just like cis and trans and stuff. Um, then you would have to provide it here. Okay?
Note: I forgot to address in the videos that both of these would be trans due to the alkyl groups facing opposite sides of the ring.
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Problem
Problem
Which of the following is the correct name of the following compound:
A
1,1-dimethyl-1,3-dioxacyclopentane
B
4,4-dimethyl-1,3-dioxacyclopentane
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4,4-dimethyl-dimethoxycycloethyleneoxide
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1,3-dimethyl-dimethoxycycloethyleneoxide
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Problem
Problem
Which of the following is the correct name of the following compound: