Stereochemistry Exam Review
Use CIP priorities, E/Z rules, and conformational reasoning to predict stereochemical outcomes.
1. Understand the Concept
Stereochemical questions demand a careful distinction between spatial inversion and R/S label changes. The exact label must be reassigned whenever the identity of a substituent changes.
Your goal: Use CIP priorities, E/Z rules, and conformational reasoning to predict stereochemical outcomes.
2. Step-by-Step Exam Strategy
Compare directly attached atomic numbers; if tied, move outward to the first point of difference.
With lowest priority pointing away, 1→2→3 clockwise is R and counterclockwise is S.
SN2 inverts geometry; SN1 often reduces stereospecificity; E2 requires anti-periplanar geometry.
Use high-priority substituents on each alkene carbon to classify E or Z; ring flips preserve up/down substituent identity.
3. Visual Reference
4. Worked Example
SN2 on a chiral alkyl halide
Backside displacement inverts the three-dimensional arrangement at the substitution carbon. Reassign CIP priorities before deciding whether the product is called R or S.
5. Common Mistakes
- Assuming that an R label always changes to S in SN2.
- Mistaking a chair flip for inversion of stereochemistry.
- Comparing lower-priority groups to assign E or Z.
6. Practice & Reinforcement
Try the interactive questions below. In Practice mode, each answer includes an explanation. In Mock Exam mode, explanations appear after submitting the full set.
Interactive questions load when JavaScript is available. Download the printable study sets for offline review.