Name each of the following alkenes

Name: Problem 27, Chapter 22: Chemistry
Uploaded: 2020-03-27T03:52:03-08:00
Duration: 4 min 51 s
Channel: Sara Ross
Description: Name each of the following alkenes

Key Concepts

Substituent Naming and Ordering

When additional groups are attached to the main carbon chain, it’s important to name and order these substituents correctly in the compound’s name. This involves identifying substituents, assigning their locants based on the numbering rules, and arranging them in alphabetical order, which ensures that the resulting name is unambiguous and standardized.

Stereochemistry of Alkenes

Many alkenes exhibit stereoisomerism due to the restricted rotation around the carbon-carbon double bond. This concept includes the understanding of cis/trans or E/Z nomenclature, which describes the spatial arrangement of substituents around the double bond and is essential for determining the distinct physical and chemical properties of the isomers.

Locant Assignment for Double Bonds

Locant assignment refers to the numbering of the carbon atoms in the main chain such that the double bond receives the lowest possible position number. This assignment is crucial in differentiating structural isomers and ensuring clarity in communication across chemical literature.

IUPAC Nomenclature for Alkenes

This concept involves using the International Union of Pure and Applied Chemistry (IUPAC) rules to systematically name alkenes. The process includes identifying the longest carbon chain that contains the double bond, determining the position of the double bond by numbering the chain with the lowest possible numbers, and applying standard suffixes like '-ene' to indicate unsaturation.

Transcript

00:01 This question is asking us to name a set of three alkenes.

00:05 And an alken is just a hydrocarbon with a double bond.

00:10 So the way that you name an alken is you number the carbons in the chain that gives you the longest, continuous set of carbons, starting with the carbon that positions the double bond on the lowest carbon.

00:25 So taking a, for example, i don't want to start here because.

00:30 This double bond is closer to the carbon over here.

00:35 So my first carbon will be the one that is closest to the double bond.

00:40 And then that means that's the second, that's the third, and that's the fourth.

00:44 Now, if this were an alkan, a chain of four carbons would have the root name butane.

00:51 Because this is an alken, because it has that double bond, the root here is going to be butene.

00:57 And then the other thing you want to do with an alkyne is you want to identify any substituents.

01:05 There are none.

01:07 This is just a four carbon chain.

01:10 But you also want to include the position of the double bond.

01:15 And in this case, the double bond is connected to the first carbon.

01:20 So a is one because the double bond is coming off of the first carbon, butene, because it is a four -carbon chain.

01:31 And we don't have to worry about any substituents on a because it's just that simple continuous chain.

01:39 For b, we want to start with the same process, although this will look a little more complex because there is a substituent hanging off of the chain here.

01:49 So i'm going to start numbering my carbons on this end.

01:53 This will be my first because my double bond is over here.

01:56 So i want to start numbering the carbon that's closest to the double bond.

02:02 Two, three, that's four.

02:07 And then this is five up here, because remember we're going for the longest continuous chain...

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