91Ó°ÊÓ

Draw the more stable chair conformation of the following molecules, and estimate the amount of strain in each: cis-1-Bromo-4-ethylecyclohexane.

Draw the more stable chair conformation of the following molecules, and estimate the amount of strain in each: cis-1-tert-Butyl-4-ethylcyclohexane

Identify each substituent in the following compound as axial or equatorial, and tell whether the conformation shown is the more stable or less stable chair form (green = Cl) :

Which isomer is more stable, cis-decalin or trans-decalin? Explain.

Question:Amantadine is an antiviral agent that is active against influenza type A infection. Draw a three-dimensional representation of amantadine, showing the chair cyclohexane rings.

Name the following cycloalkanes:

b. Name the following cycloalkanes:

Why do you suppose an axial cyano (–CN) substituent causes practically no 1,3-diaxial steric strain (0.4 kJ/mol)? Use molecular models to help with your answer.

Look at Figure 4-12 on page 105, and estimate the percentages of axial andequatorial conformations present at equilibrium in bromocyclohexane.

Name the following compound, identify each substituent as axial or equatorial, and tell whether the conformation shown is the more stable or less stable chair form

A trisubstituted cyclohexane with three substituents—red, green, and blue—undergoes a ring-flip to its alternate chair conformation. Identify each substituent as axial or equatorial, and show the positions occupied by the three substituents in the ring-flipped form.