Question

multiple choice 2 points
in the lowest energy conformation of the compound below, how many alkyl substituents are equatorial?
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Explanation:

Step1: Analyze chair - conformation rules

In the lowest - energy chair conformation of cyclohexane, bulky groups prefer to be in the equatorial position to minimize steric hindrance.

Step2: Identify alkyl substituents

The alkyl substituents are the methyl ($-CH_3$), isopropyl ($-(CH_3)_2CH -$) and ethyl ($-CH_2CH_3$) groups.

Step3: Determine equatorial substituents

For the given cyclohexane derivative, the most stable (lowest - energy) conformation will have the largest substituents in the equatorial position. The isopropyl group is the largest, and in the lowest - energy conformation, it will be equatorial. The ethyl group will also be equatorial to minimize steric interactions. The methyl group can be either axial or equatorial, but in the lowest - energy conformation, we can arrange it such that it is equatorial. So, all 3 alkyl substituents can be in the equatorial position in the lowest - energy conformation.

Answer:

3