OrgoChem I

Stereochemistry

R S E Z enantiomers diastereomers and optical activity

Summary

Learn the decision rules and drill classification. Full reference is on the external link.

What you need to know:

This topic covers stereochemistry. Focus on mastering the key concepts in the "Must know checklist" below. Follow the study steps systematically, and use practice problems to reinforce your understanding. The external reference provides comprehensive coverage of all concepts.

Video Tutorial

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R and S Configuration Using Cahn Ingold Prelog Priority Rules

Click to watch on YouTube →

Must know checklist

0 / 5 complete

Stereocentercarbon with 4 different groups; chiral molecule has no plane of symmetry; meso compounds have stereocenters but are achiral
R and S Configuration Using Cahn Ingold Prelog Priority Rules - Leah4Sci→
Enantiomersmirror images, not superimposable; diastereomers: stereoisomers that aren't enantiomers; identical: same molecule
What Are Stereoisomers? Enantiomers, Diastereomers, and Meso Compounds→
R/S assignmentassign CIP priorities (atomic number), put lowest priority away, trace 1→2→3: clockwise=R, counterclockwise=S
How to Assign R and S Configuration Using CIP Priority Rules→
E/Z assignmentassign priorities to each side of double bond; E = high priority groups trans, Z = high priority groups cis
E–Z system | Alkenes and alkynes | Khan Academy→
Optical activitychiral molecules rotate plane-polarized light; racemic mixture (50:50 enantiomers) has no net rotation
Optical Activity and Racemic Mixtures - Chiral Molecules→

Common mistakes

Not putting the lowest priority group to the back before deciding R or S

Breaking CIP ties incorrectly at the first point of difference

Calling a compound chiral without checking symmetry