Equatorial Preference Practice Problems

Illustrate which of the chair conformations of  cis-1-isopropyl-2-methylcyclohexane is more stable.

Consider the line structure shown below. Sketch the most stable chair form of the trisubstituted cyclohexane.

Draw the two chair conformers of the compound given below and identify the more stable conformer.

trans-1-ethyl-2-isopropylcyclohexane

In disubstituted cyclohexanes, the bulkier substituent favors an equatorial position due to the steric interactions. methyl, ethyl, and isopropyl groups (when at axial positions) do not increase the ring strain as much as the tert-butyl group on the axial position.

Draw the chair form for the axial conformations of cis-1-isopropyl-3-methylcyclohexane and cis-1-tert-butyl-3-methylcyclohexane to explain why the tert-butyl group causes a large increase in energy compared to the isopropyl group.

Write the most stable conformer of the chemical structure shown below.
(A hatched wedge represents a chemical bond that points away from the viewer, while a solid wedge represents a chemical bond that points toward the viewer.)

For each of the compounds shown below, draw the chair conformer with the lowest energy.

Draw the most stable chair conformation of the following substituted cyclohexane: trans-1-tert-butyl-4-ethylcyclohexane.

Draw and label the more and less stable chair conformations for each of the two substituted cyclohexanes given below.

a. trans-1-Isopropyl-4-methylcyclohexane
b. trans-1,4-Dimethylcyclohexane

Determine the more stable conformation from the given pair shown below. If both conformations have equal stability, indicate "they have the same relative stability."

Illustrate the chair conformations of the following compound, and identify the conformation that exhibits greater stability.

Determine the percentage of molecules of cyclohexyl bromide that have the −Br group in an axial position at 25℃ using the information given below.

The most unstable chair conformation of idose sugar has all the hydroxyl substituents axial. Draw this chair conformation.

D-Idose

A tert-butyl group has a greater preference for the equatorial position than does a methyl group. Explain why this is true.

Shown below is the chemical structure of a glucose derivative. The most stable form of the glucose derivative is a six-membered ring in a chair conformation with all equatorial positions occupied by substituents.
Place the OH groups and hydrogens on the appropriate bonds in the structure on the right and draw the most stable conformer of the glucose derivative.

Draw the most stable chair conformation of the following substituted cyclohexane: cis-1-Isopropyl-4-methylcyclohexane.

Draw the most stable chair conformation of the following substituted cyclohexane: Isopropycyclohexane,

Which is the more stable conformation from the given pair below? If both conformations have equal stability, indicate "they have the same relative stability".

Determine which of the chair conformations of  trans-1-isopropyl-2-methylcyclohexane is more stable.

Draw the two chair conformations for each given structure and determine the more stable from the pair. The second chair must be the flipped version of the first. The substituents must be indicated by wedges positioned upward in the chair, regardless of whether upward corresponds to the equatorial or axial position.

Two disubstituted cyclohexanes are given below. Draw the two chair conformations for each of them and label the more stable conformation.

a. cis-1-(tert-butyl)-2-methylcyclohexane
b. trans-1,2-dibromocyclohexane

For each pair of conformers shown below, identify the more stable conformer.

Determine which is more stable between cis-1-isopropyl-2-methylcyclohexane and trans-1-isopropyl-2-methylcyclohexane.

Illustrate the two chair conformations of the given structure below and determine which is the more stable of the pair. The second chair must be the flipped version of the first. The substituents must be indicated by wedges positioned upward in the chair, irrespective of whether it corresponds to the equatorial or axial position.

Illustrate the two chair conformers of the compounds listed below and identify the more stable conformer.

cis-1,2-dimethylcyclohexane

Draw the conformation that results when a chair-chair interconversion is done on each ring of the conformation of a cis-decalin derivative shown here.

Each of the compounds given below has a diequatorial-substituted conformer and a diaxial-substituted conformer. Which compound has a higher percentage of the diequatorial-substituted conformer?

(i) trans-1-ethyl-4-methylcyclohexane

(ii) cis-1-tert-butyl-3-ethylcyclohexane

Identify the more stable conformation from the provided pair of conformations.

The CH₂OH group and the C1 OH group in the chair conformation of a pyranose can react with each other when they are both in axial positions to form an acetal, which is also known as the anhydro form of the sugar. Shown below is the anhydro form of a D-idose derivative.

Although at 25℃ most of the D-idose derivative in an aqueous solution exist in the anhydro form, only a small amount of D-galactose exists in the anhydro form under the same conditions. Provide a brief explanation for this observation.