For each compound below, find all stereocenters, and determine their configuration. IMAGE IS NOT

For each compound below, find all stereocenters, and...

Key Concepts

Stereocenter

A stereocenter is an atom, typically a carbon, that is bonded to four different substituents, creating a point of chirality in the molecule. The presence of a stereocenter allows for the existence of stereoisomers—molecules that have the same connectivity but differ in the spatial arrangement of atoms.

Chirality

Chirality refers to the property of a molecule that makes it non-superimposable on its mirror image. This lack of superimposability occurs due to the presence of stereocenters, and chiral molecules often exist as pairs of enantiomers that have identical physical properties except for the way they interact with plane-polarized light and other chiral substances.

Cahn-Ingold-Prelog Priority Rules

The Cahn-Ingold-Prelog (CIP) priority rules provide a systematic method for ranking the substituents attached to a stereocenter based on the atomic numbers of the atoms directly attached to it. These rules form the basis for assigning the priorities necessary to determine the stereochemical configuration, ensuring consistency in naming and comparing chiral centers.

R/S Configuration

Once the substituents around a stereocenter have been prioritized using the CIP rules, the configuration is assigned as either R (from the Latin 'rectus' meaning right) or S (from 'sinister' meaning left). This designation is determined by orienting the molecule so that the lowest priority group is directed away from the observer and then observing whether the sequence of the remaining groups decreases in priority in a clockwise (R) or counterclockwise (S) direction.

Transcript

00:01 So in this question we have to determine the configuration of this molecule.

00:06 So the first part of the question is to determine if the molecule determine the chiro center.

00:12 So we know that a chiro center is a carbon that is surrounded by four different types of molecules.

00:17 So we're going to evaluate the carbons in this molecule and determine which one is the chiro center.

00:22 So now we have these two carbons right over here that are surrounded by two hydrogens.

00:27 And clearly they can't be the chirocenture because a chiro center is a carbon that's around you by four different molecules and both of these have two hydrachines.

00:35 So they completely disqualify as a chiro center.

00:38 And then the remaining carbons right over here cannot be chirocentres either because they're part of a double bond and a carbon that is part of a double bond can never be the chiro center.

00:47 So the only carbon that's left is this carbon right over here.

00:50 And this carbon clearly is the chiro center because it has a chlorine on one side and then it has a hydrogen on one side over here.

00:58 It's not shown, but we can assume there's a hydrogen here because carbon needs to be surrounded by four molecules.

01:04 And then it has this cyclic compound here and this cyclic compound here, which are very different because one has a double bond and the other doesn't.

01:13 So this is the chirocentral, so i'm going to label this purple.

01:17 And then the next part of the question, we need to prioritize this is the two that are surrounding the chiro center, the carbon.

01:23 And we need to determine the configuration of the molecule...

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