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Ch. 4 - Alkanes and CycloalkanesWorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins
Ch. 26 - Transition Metals
IUPAC Naming
Alkyl Groups
Naming Cycloalkanes
Naming Bicyclic Compounds
Naming Alkyl Halides
Naming Alkenes
Naming Alcohols
Naming Amines
Cis vs Trans
Conformational Isomers
Newman Projections
Drawing Newman Projections
Barrier To Rotation
Ring Strain
Axial vs Equatorial
Cis vs Trans Conformations
Equatorial Preference
Chair Flip
Calculating Energy Difference Between Chair Conformations
Additional Guides
t-Butyl, sec-Butyl, isobutyl, n-butyl

Now it’s time to start naming functional groups! We’ll start with alkyl halides because they are some of the easiest to name. 

Concept #1: How to name alkyl halides 


So I've got some good news. We're all done with alkanes. The bad news is that now we have to add some functional groups to the mix. The first and easiest one we're going to start off with is alkyl halides.
Alkyl halides are simply named by adding them as a substituent before the root chain indicating their location. What that means is that remember that at the beginning of this lesson we talked about substituents and modifiers; alkyl halides don't have modifiers. They're just called substituents just like an alkane would be, like an alkyl or whatever.
One thing we should note is our prefixes for these different halogens. So fluorine would get the prefix fluoro-. Chlorine gets the prefix chloro-. Bromine gets the prefix bromo-. And then iodine gets the prefix iodo-. These are going to be the prefixes that we use to assign the name to the alkyl halide.
The next thing that you should note is that alkyl halids have no priority, zero priority, when it comes to numbering the direction of the chain. What that means is a lot of people think, “Oh, I've got this long chain and this side has a chlorine on it so that must be the side that has the 1 that I start from.” No, not at all. Use the same rules that we did before, just you look at the closest substituent. It doesn't matter what it is. It could be a chlorine. It could be a methyl. It doesn't matter. You still make the chain start from the side that has the closest substituent.
So what I want to do is apply this to this alkl halide (a). Go ahead and try to solve it out on your own first. Draw it out. And then when you're done, you have your answer figured out, then go ahead and go to the next video. 

In summary:

  • Alkyl halides are named as substituentsnot modifiers (they are named before the chain, not within it).
  • Alkyl halides don't get priority when deciding where to start numbering a chain. We must start with the closest substituent.


Use the following prefixes for the halogens:

Example #1: Name the following compound 


All right guys, so this one is actually similar to one that we did earlier where it kind of looked like a tert-butyl, but it wasn't. My longest chain would look like that. That would be, it looks like six carbons. 1, 2, 3, 4, 5, 6. So my root is going to be hexane.
Now I have to decide which one gets the number 1. Is it red or is it blue? For this, I need to go ahead and see which one has the closest substituent. Red has a substituent on 2. Blue has a substituent on 2. So far there's a tie. So then I go to the next substituents. Red has its next substituent on 5. Blue has its next substituent – I keep doing that – still on 2 because there were two methyls in that location. It turns out that even though the iodine is all the way over here, my number 1 is still going to be the blue.
What that means is that now I look at substituents. For substituents, what do I got? I've got a 2,2-dimethyl and it looks like I also have a 5-iodo. Now all I have to do is piece that together. In terms of alphabetical order, which one would come first? Remember, di doesn't count, so I look at 'm' versus 'i' and 'i' comes in the alphabet first, so it would be 5-iodo-2,2-dimethylhexane. Not so bad right.
Hopefully, if you have questions, let me know. But if not, move on to the next question. I'm just going to let you guys know, the hardest part about the next question is actually just figuring out which chain you're going to use. So I want you guys to pay extra careful attention to that because this one's a little bit tricky. So go ahead and get started. 

Reminder: Always select the root chain before moving onto common substituents!


Quick tip for this next one:

  • Even though alkyl halides have no priority in numbering by location, they still have priority in alphabetical order. 

Example #2: Name the following compound 

Yeah, I know that one sucked. Sorry, just trying to help you guys kill this topic!