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Current time:0:00Total duration:11:07

Video transcript

if we take a look at this ether and notice we have an R group on either side of our oxygen like that and if we wanted to name ethers there are a couple different ways to do it we'll start off with the common way of naming ethers which follows the pattern of first naming one of the alkyl groups attached to your oxygen and then naming the other alkyl group and then followed by the word ether like that so alkyl alkyl ether let's look at an example of common nomenclature and we'll start with this molecule here so if I wanted to name this ether I would first focus in on what sort of alkyl groups do we have attached to our oxygen we're here on the Left that's a methyl group and over here on the right that's an ethyl group so we need to think about the alphabet rule and we know that e comes before M so we're going to write ethyl before methyl so it will be called ethyl methyl ether like that so let's do another one all right so our goal is to name this ether and we first of course take a look at the alkyl groups that we have attached to our oxygen so on the left here we recognize this as being a church butyl group and on the right we have a methyl group so in in thinking about using the alphabet rule right B comes before M so the tert-butyl group is going to come before the methyl group in the name so it should be called tert-butyl methyl ether like that so the tert part isn't isn't a part of the alphabet right you're comparing the butyl versus the methyl like that now Church butyl methyl ether might be the correct name although that's probably what you that's that's probably not what you will hear this molecule called in the laboratory usually you'll hear this called methyl tert-butyl ether or MTBE so MTBE is a very common organic solvent it works very well for a number of things and again MTBE is what you will hear but technically that's not the correct name let's look at an ether that has alkyl groups that are the same so if we have this as our ether we have two ethyl groups for this one so we're going to call this dye ethyl ether so dye ethyl ethers or you can use the prefix of dye here now diethyl ether of course is the is the famous one this is the one that everyone thinks of when they think about ethers let's look at another way to name ethers and this is the official IU PAC way of naming them now the common the common way of naming ethers is so common that it's accepted by IU PAC nomenclature but there is a there's an IU PAC way of doing it for more complicated molecules and that is to name your ether as a substituent which we call an alcohol C so we're going to name a Thurs as a substituent and then have a parent alkane so we're going to call these alkoxy alkanes like that alright so what you would do is if you had if you have just this generic ether here like this RoR prime you would you would find the larger alkyl group and that would be your parent name so let's say the R prime group was my was my longer carbon chain that would be my parent alkane alkane name like that and then you would name this portion of the molecule right as an alkoxy substituent on your alkane so let's look at an example of i u-pack nomenclature so let's go ahead and well that will name that first one that first ether that we did a few minutes ago right so the very first one we did we're doing common nomenclature right we call this ethyl methyl ether alright so let's go ahead and name it using using IU PAC nomenclature here so what we would do is find find the find the larger group and that's going to be my parent name so my larger group would be this over here on the right and if we were to number that right you could say that's you know number one and number two right here number one and number two if you wanted to you don't really have to for this example um but but just to get you thinking about longest carbon chain right that would be that would be ethane right there so go ahead and write ethane as our parent alkane name and then what do we have coming off of the ethane portion of the molecule here so what is our substituents this is this is the ether portion we're going to name it as an alkoxy and since we have one carbon to deal with right we know that our route is meth and as an alkoxy it be meth oxy so the complete I you pack name for this molecule would be methoxy ethane like that we don't worry about numbers since we have only only two carbons on our parent chain here so methoxy ethany the IU pack name for this molecule the common name would be ethyl methyl ether both are acceptable names let's do another one where we have a very similar-looking molecule except in this case we're going to add on another carbon there so if I'm thinking about my my parent alkane over here on the right there would be three carbons from my parent alkane so if I wanted to number that and be 1 2 & 3 a 3 carbon alkane is of course propane so I go ahead and write propane right here and I look at my my ether substituent once again and I look and I see how many carbons I have and there's there's one carbon there's one carbon on the substituent so once again it would be methoxy so I'll go ahead and write methoxy in here so methoxy propane ok this time I need to put I need to put a number on there and that group is coming off of carbon 2 so the complete die you pack name would be 2 methoxy propane like that let's do let's do a much more complicated one that has a little bit of stereochemistry in it so if this was the molecule that I was trying to name and let's go ahead and put a bromine here like that alright so for this one once again I have to think about the the larger group as my as my parent name so if I look at those two alkyl groups the alkyl group on the Left looks like the longest one to me and I want a number to give my substituents the lowest number possible so if I look over here on the left I can see that there are 4 carbons in my and my larger substituent so 4 carbons is going to be my parent's name here so I'm going to call this beauty let's go ahead and start naming it with butane right here so this would be butane so far now when I number that butane I want to get the lowest number as possible to my substituents so I could start from the left where I could start from the right and starting from the right makes more sense because I have a substituent coming off of carbon 1 I have a substituent coming off of carbon 2 and then 3 & 4 like that alright so if I'm thinking about those two substituents right let's think about how I would name them alright so over here on the right for my alkoxy substituent this time there are two carbons in my alkyl substituent right and right here so two carbons would be SW oxy and ethoxy is coming off of carbon 1 so I can go ahead and write that in here so 1 ethoxy butane is what I have so far and I also have a bromine coming off of carbon 2 so it'd be two bromo so I can go ahead and put in to bromo one-eighth oxy and that follows the alphabet right because becomes u4e so to promote wanna Thok see beauty and then we have to worry about the absolute configuration at this carbon right here so carbon 2 is a chirality Center so we need to think about how to assign priority to those four groups so if I think about if I think about the atoms directly attached to my chirality Center first let's go ahead and identify my chirality Center that would be this one right here right four different groups attached to it because there's also a hydrogen going away from me in space and I think about atomic numbers right so I have carbon versus carbon versus bromine right here so bromine of course has the highest atomic number gets highest priority like that now my hydrogen of course is going to get lowest priority so that's that's priority number four and now I have two groups to worry about right so I can I have two carbons to worry about let's go ahead and Mark those carbons again so which one of these carbons is going to get to higher priority well it's all about what they're attached to right so the carpet on the left is attached to another carbon and two hydrogen the carbon on the right is attached to an oxygen and two hydrogen's so in terms of atomic number right carbon versus oxygen the oxygen will win and this substituent on the right would get will get the highest priority so this is get a 2 over here all this stuff over the right we get a 2 and over here on the left this would be a 3 so we have we have 1 2 3 going around this way going around counterclockwise which is the s absolute configuration so this is s 2 bromo 1/8 oxy butane for the final name let's do one more example of naming and ether here so let's go ahead and look at one that has a ring and we'll put put a double bond in our ring like that and then we'll have our ether over here on the right ok so if I wanted to name this molecule I would think about my two alkyl groups and think about which one is a larger one and of course of course all this stuff on the left right is going to be my parent name and then this is going to be my alkoxy substituent like that so on the left eye i know what that molecule is i know that's called cyclohexene from earlier video right so this is cyclohexene as my parent name so cyclo hexane i now need to number my ring to give my alkoxy substituent the lowest number possible all right so if I wanted to number my ring to give my alkoxy substituent the lowest number possible I should start here and make that one two three and four like that so I think about what is that alkoxy substituent it is an ethoxy group right because an ethoxy substituent because i have two carbons right there so i have an ethics e coming off of carbon four so this would be 4 ethoxy and if you wanted to you you could put the one in here one cyclohexene you you could leave it out if you wanted to so it doesn't really matter but for oxy one cyclohexane gives you all the information that you need that you need if you wanted to draw this molecule so that does it for nomenclature of ethers