Identifying Chiral Centers in Organic Molecules

Chirality centers can be identified by locating carbon atoms with four different groups attached.

### Identifying Chiral Centers in Organic Molecules
* 🔬 In this video, we focus on finding **chiral centers**, starting with a molecule containing **chlorine, bromine, and a methyl group**.
* A chiral carbon is defined as a carbon atom with **four different groups**, and primary carbon atoms, like CH3 with three hydrogens, **cannot be chiral centers**.
* 🌟 The first chiral center is identified at the carbon with the **chlorine atom**, having **four distinct groups** including an **invisible hydrogen**.
* 🔍 Another chiral center is found with the bromine atom, which also has **four different groups** including an **invisible hydrogen**.
* 📊 The total number of chiral centers identified in this example is **two**, leading to a total of **four possible stereoisomers** calculated as **2 squared**.
* 📏 In the next example, we identify two more chiral centers based on the presence of **distinct groups attached to the carbon atoms**.
* ⚠ Some carbons, like primary carbons or secondary carbons with equivalent groups, are **not chiral centers**, which we confirm in various examples.
* 🔢 Finally, in the last example, we identify **seven chiral centers**, confirming that the total number is **critical for determining stereoisomers** in organic chemistry.

In this video, we're going to focus on finding chirality centers. So, in this example, we have a chlorine atom, a bromine atom, and also a methyl group. So, how many chiral carbons can we identify in that molecule? So, a chiral carbon is basically a carbon atom with four different groups. Primary carbon atoms are not chiral. This one is a CH3 and so it has three hydrogens on it, so it can't be a chiral center because it can have four different groups. Now, this carbon with the chlorine atom is chiral. We have a methyl group on the left, a chlorine atom, an invisible hydrogen atom, and then this entire thing makes up the fourth group. So, this is the first chiral center. Now, we have another chiral center here because this group, that's one group, the bromine makes the second group, this is the third group, and the fourth group is the invisible hydrogen. Now, what about this carbon? Is that a chiral center? Well, that carbon doesn't have four groups because it's

attached to two methyl groups, so this is not a chiral center. So, we have a total of two chiral centers. So, how many possible stereoisomers can we get for this molecule? The number of stereoisomers that can be produced is 2 to the n, so it's 2 squared in this case. It's going to be 4. Now, what about this example? How many chiral centers can you identify in this molecule? So, is this carbon a chiral center? It turns out that it is. We have a methyl group, hydroxyl group, the right side of the molecule, and the invisible hydrogen. So, this is the first chiral center, which means this carbon is also a chiral center. Now, any primary carbons at the end, those are not chiral centers. They have three hydrogen atoms, and secondary carbon atoms in the middle that don't have any other substituent attached to them. Those are CH2s, and so because they have two hydrogen atoms on them, they're not going to be a chiral center. Now, what about this carbon? Is that a

chiral center. So, we have a hydrogen attached to it, an NH2 group, but notice that the right side is the same as the left side. So, because the right side is the same as the left side, these two groups are equivalent. So, it doesn't have four different groups, so this is not a chiral center. Now, how about this example? How many chiral centers can you identify in this molecule? So, let's analyze this carbon. Is that a chiral center? Notice that the left side is the same as the right side. So, therefore, this is not a chiral center. And the same is true for this carbon. The right side is the same as the left side. So, there are no chiral centers in this molecule. Now, let's move on to our next example. So, let's say we have an OH group, a methyl group, and a fluorine atom. Identify all of the chiral centers in this molecule. So, is this a chiral center? Notice that the left side and the right side are the same. So, this is not going to be a chiral

center. Now, what about the carbon with the CH3? That is a chiral center. This is the first group, this is the second, the third, and the invisible hydrogen. So, that carbon has four different groups, and this two is a chiral center. We have a methyl group, the group on the left, the fluorine atom, and the hydrogen. So, there are two chiral centers that we can identify in that molecule. Now, let's try one final example for the sake of practice. So, go ahead and determine the number of chiral centers. So, this is going to be the first chiral center, this one is the second one, here's the third, fourth, fifth, sixth, and seventh. So, I've counted a total of seven chiral centers. Now, this one is not a chiral center because of the two methyl groups, but everything else that is listed here is the chiral center. You

Finding Chirality Centers

This channel focuses on providing tutorial videos on organic chemistry, general chemistry, physics, algebra, trigonometry, precalculus, and calculus.

Disclaimer:  Some of the links associated with the videos in my channel may generate affiliate commissions on my behalf.  As an amazon associate, I earn from qualifying purchases that you may make through such affiliate links.


My Patreon Membership Program:  (Full Extended Videos + Worksheets)
https://www.patreon.com/MathScienceTutor


The Organic Chemistry Tutor

Chiral carbons have four different groups attached to them, making them the centers of chirality.

In the example, the carbon with the chlorine atom and the carbon with the bromine atom both qualify as chiral centers.

The primary carbon with three hydrogens and the other carbon with three identical groups do not meet the criteria for chirality.

Identifying Chiral Centers and Stereoisomers

The molecule has two chiral centers, leading to a total of four possible stereoisomers.

The first chiral center is identified by a methyl group, hydroxyl group, and an invisible hydrogen.

Primary and secondary carbon atoms with identical substituents do not qualify as chiral centers.

Chiral centers require four different groups attached to a carbon atom, but if two groups are equivalent, it is not a chiral center.

In the first example, both analyzed carbons have the same groups on either side, resulting in no chiral centers.

The third example also shows a carbon with equivalent groups, indicating that it is not a chiral center as well.

The carbon with the CH3 group is a chiral center, having four different groups attached.

There are two chiral centers identified in the molecule.

In a final example, a total of seven chiral centers are counted, with one carbon not being a chiral center due to having two methyl groups.