Page 36 Flashcards
What type of reaction is discussed for cis- and trans-1-chloro-2-methylcyclohexane?
A: E2 dehydrohalogenation reaction.
How many conformations does the cis isomer of 1-chloro-2-methylcyclohexane exist in?
A: Two conformations, A and B.
What is the position of the groups in conformation A of the cis isomer?
A: One group is axial, and the other is equatorial.
Which conformation of the cis isomer undergoes the E2 reaction?
A: Conformation B, which contains an axial chlorine atom.
Why must E2 elimination occur from conformation B?
A: E2 elimination requires the leaving group (Cl) to be in the axial position for the anti periplanar geometry.
What geometry is required for E2 elimination to occur?
A: Anti periplanar geometry.
What happens to conformation A during the reaction?
A: It does not react because the chlorine is not in the axial position.
Which isomer, cis or trans, has a more favorable geometry for the E2 reaction?
A: The trans isomer, as it more easily adopts the anti periplanar geometry.
What role does the axial position of the Cl atom play in E2 reactions?
A: It facilitates proper alignment with the β-hydrogen for elimination.
Why is the trans isomer generally more reactive in E2 eliminations?
A: The anti periplanar geometry is naturally favored in the trans isomer.
