Draw the major product of the reaction shown.

Question

IV is not the correct answer.

Answer 1

MeO- is a strong base, therefore this is an E2 mechanism, requiring the Cl and adjacent H to be eliminated to assume antiperiplanar geometry. In a cyclohexane, that arrangement is only possible when both the halogen and adjacent hydrogen are axial (yes, you actually have to remember chair conformations). Since the isopropyl group is trans to the chlorine, it will also be axial when the chlorine is axial. Therefore, only the less substituted carbon to the left of the halogen can provide the necessary geometry for a hydrogen. The product is answer I.

Answer 2

The major product of this reaction is going to be structure I. This is the trans isomer of 1-chloro-2-isopropylcyclohexane reacting with methoxide, therefore, the major product will only be I. The isopropyl group will retain it's stereochemistry. If the starting reactant was the cis isomer, there would be two products, I and IV, with IV being the major product, according to the Zaitsev rule.