In each of the compounds below, find the stereocenter, and label the four groups from 1 to 4 usi

In each of the compounds below, find the stereocenter, and...

Key Concepts

Stereocenter

A stereocenter, often referred to as a chiral center, is an atom within a molecule (typically a carbon) that is bonded to four different groups. This uniqueness leads to non-superimposable mirror images (enantiomers), which is foundational in the understanding of molecular chirality and stereochemistry.

Cahn-Ingold-Prelog System

The Cahn-Ingold-Prelog system is a standardized set of rules used to assign priorities to the substituents attached to a stereocenter. These priorities are based primarily on the atomic numbers of the atoms directly attached to the chiral center, which is critical for determining the absolute configuration (R or S) of the stereocenter.

Atomic Weight and Priority Assignment

When assigning priorities to the groups attached to a stereocenter, the process begins with the atomic weight (atomic number) of the atoms directly bonded to the chiral center. Higher atomic numbers are given higher priority, and in cases of ties, further rules such as subsequent atoms' atomic numbers or connectivity are used to establish the correct order.

Labeling of Stereocenters

Labeling the groups attached to a stereocenter according to their CIP priorities involves numbering them from 1 (highest priority) to 4 (lowest priority). This systematic labeling is crucial for describing the three-dimensional arrangement of the substituents and for determining the molecule's stereochemical configuration.

Transcript

00:02 So in this question, the first part of the question is asking what the chiral centers are.

00:09 So we know that a chiral center is a carbon molecule that is attached specifically to four different types of molecules.

00:17 So if a chiral center is attached to the same molecules, then it cannot be a chiral center.

00:23 So the first thing we can do is look at what carbon molecules are in this entire molecule.

00:30 So we can see that the first carbon molecule is right here.

00:32 Now this carbon molecule is attached to three hydrogens.

00:38 So it's one, two, and three hydrogens that this carbon molecule is attached to.

00:44 So clearly it is attached to three of the same types of molecules, so this cannot be a chiro center.

00:51 Now we're going to move to our second carbon atom.

00:53 So this carbon atom is going to be, it's going to be attached to two hydrogens, right? so since this molecule is attached to two hydrogens, again, we know that this molecule cannot be a chiro center because it has two of the same molecules.

01:08 Now we can move on to this one possibly.

01:10 So this molecule, it is attached to a ch3 over here, a ch3 over here, and this whole situation over here, but it is also attached to one hydrogen.

01:25 So this molecule cannot be a chiral center as well because, this is a ch3 and this is a ch3.

01:32 So since this molecule is attached to two ch3s, then it cannot be a chiral center.

01:37 So now we're going to look at the fourth carbon.

01:40 So this carbon, again, it is a ch3 molecule.

01:44 So obviously it is attached to three hydrogens.

01:47 So because it's attached to three hydrogens, it cannot be a chiral center.

01:51 And this molecule is also a ch3.

01:54 So as we know, it is attached to three hydrogens, so it cannot be a chiral center.

01:59 The only remaining molecule is or the only remaining carbon is this one.

02:03 In this carbon we can see it's attached to a chlorine, a fluorine, and two other carbon carbons and both of these carbons are different.

02:13 For example, this carbon is going to have only one ch3 attached to it while this carbon has two ch3 molecules attached to it.

02:21 So immediately we know that this is the cairo center of interest.

02:24 So i'm just going to saw it so that we can say okay that is the carol center.

02:35 Now next what we are going to look at is the priority of the functional groups.

02:40 So let's start with chlorine and fluorine.

02:43 So we know that the priority of the functional groups are determined when the function, or the priority of these two molecules depend on the mass because these two molecules are hetero atoms.

02:55 So we know that chlorine has a mass...

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