4. Alkanes and Cycloalkanes

Equatorial Preference

4. Alkanes and Cycloalkanes

Equatorial Preference

Guided videos.

Learn with Johnny

Go to the course

Guided course

04:02

Equatorial Preference

Draw the following chair in the most stable conformation.

Practice this topic

Multiple Choice

Draw the MOST STABLE conformation of cis-1-tert-butyl-4-methylcyclohexane.

Draw the LEAST STABLE conformation of trans-1-tert-butyl-3-neopentylcyclohexane.

Which is the most stable chair structure for cis-1-isopropyl-3-methylcyclohexane?

1545

views

Textbook Question

Draw the most stable conformation of c. cis-1-tert-butyl-4-isopropylcyclohexane.

1616

views

Textbook Question

Draw the most stable conformation of b. 3-isopropyl-1,1-dimethylcyclohexane.

1330

views

Textbook Question

Draw the most stable conformation of a. ethylcyclohexane.

1783

views

Textbook Question

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable. c. cis-1-ethyl-3-methylcyclohexane d. trans-1-ethyl-3-methylcyclohexane

Draw the two chair conformations of each of the following substituted cyclohexanes. In each case, label the more stable conformation. a. cis-1-ethyl-2-methylcyclohexane b. trans-1,2-diethylcyclohexane

1573

views

Textbook Question

The most stable form of the common sugar glucose contains a six-membered ring in the chair conformation with all the substituents equatorial. Draw this most stable conformation of glucose. glucose

701

views

Textbook Question

[TABLE 3-6] shows that the axial–equatorial energy difference for methyl, ethyl, and isopropyl groups increases gradually: 7.6, 7.9, and 8.8 kJ/mol (1.8, 1.9, and 2.1 kcal/mol). The tert-butyl group jumps to an energy difference of 23 kJ/mol (5.4 kcal/mol), over twice the value for the isopropyl group. 1. Draw pictures of the axial conformations of isopropylcyclohexane and tert-butylcyclohexane 2. Explain why the tert-butyl substituent experiences such a large increase in axial energy over the isopropyl group.

1272

views

Textbook Question

Draw the most stable conformation of c. trans-1-tert-butyl-3-(1,1-dimethylpropyl)cyclohexane.

752

views

Textbook Question

Draw the most stable conformation of b. trans-1-tert-butyl-2-methylcyclohexane.

598

views

Textbook Question

Draw the most stable conformation of a. cis-1-tert-butyl-3-ethylcyclohexane.

642

views

Textbook Question

a. Draw both chair conformations of cis-1,4-dimethylcyclohexane, and determine which conformer is more stable. b. Repeat for the trans isomer. c. Predict which isomer (cis or trans) is more stable.

1343

views

Textbook Question

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable. e. cis-1-ethyl-4-methylcyclohexane f. trans-1-ethyl-4-methylcyclohexane

373

views

Textbook Question

Draw the two chair conformations of each compound, and label the substituents as axial and equatorial. In each case, determine which conformation is more stable. a. cis-1-ethyl-2-isopropylcyclohexane b. trans-1-ethyl-2-isopropylcyclohexane

463

views

Textbook Question

Draw the two chair conformations of each of the following substituted cyclohexanes. In each case, label the more stable conformation. c. cis-1-ethyl-4-isopropylcyclohexane d. trans-1-ethyl-4-methylcyclohexane

369

views

Textbook Question

Draw the two chair conformers for each of the following and indicate which conformer is more stable: f. cis-1-ethyl-4-isopropylcyclohexane

565

views

Textbook Question

Draw the two chair conformers for each of the following and indicate which conformer is more stable: c. trans-1-ethyl-2-isopropylcyclohexane

348

views

Textbook Question

Bromine is a larger atom than chlorine, but the equilibrium constants in Table 3.9 indicate that a chloro substituent has a greater preference for the equatorial position than does a bromo substituent. Suggest an explanation for this fact.

677

views

Textbook Question

Draw the most stable conformer of the following molecule. (A solid wedge points out of the plane of the paper toward the viewer. A hatched wedge points back from the plane of the paper away from the viewer.)

1068

views

Textbook Question

Which has a higher percentage of the diequatorial-substituted conformer compared with the diaxialsubstituted conformer: trans-1,4-dimethylcyclohexane or cis-1-tert-butyl-3-methylcyclohexane?

859

views

Textbook Question

The most stable form of glucose (blood sugar) is a six-membered ring in a chair conformation with its five substituents all in equatorial positions. Draw the most stable conformer of glucose by putting the OH groups and hydrogens on the appropriate bonds in the structure on the right.

Draw two chair conformations of the molecules below. Indicate which is most stable. (a)

848

views

Textbook Question

For each pair of conformations you drew in Assessment 3.41, indicate which is most stable.

332

views

Textbook Question

(••) For each pair of conformations shown, choose which is most stable. If both are equally stable, then write 'no difference.' [If both conformations have the same number of axial substituents, choose the one with the smallest axial substituents.] (e)

(•••) For each structure shown, draw the two chair conformations and choose which is most stable. Be sure that your second chair is the flipped version of the first. [Make sure that wedged substituents are up in the chair, regardless of whether up is equatorial or axial.] (e)

Draw the two chair conformers for each of the following and indicate which conformer is more stable: b. trans-1-ethyl-2-methylcyclohexane

636

views

Textbook Question

Draw the two chair conformers for each of the following and indicate which conformer is more stable: d. cis-1,2-diethylcyclohexane

342

views

Textbook Question

a. Draw the more stable chair conformer of cis-1-ethyl-2-methylcyclohexane.

824

views

Textbook Question

c. Which compound is more stable: cis-1-ethyl-2-methylcyclohexane or trans-1-ethyl-2-methylcyclohexane?

463

views

Textbook Question

c. Which compound is more stable: cis-1-ethyl-2-methylcyclohexane or trans-1-ethyl-2-methylcyclohexane?

406

views

Textbook Question

Draw the most stable chair conformation for the following trisubstituted cyclohexane.

<IMAGE>

558

views

Textbook Question

(•••) In contrast to ethane and other alkanes studied in this chapter, there is no free rotation around any bonds in cyclopentane (shown below). Why?

<IMAGE>

276

views

Textbook Question

For each of the following structures, draw the most stable chair conformer. a.

382

views

Textbook Question

b. For each pair, indicate which conformer is more stable.

847

views

Textbook Question

When a pyranose is in the chair conformation in which the CH2OH group and the C-1 OH group are both in axial positions, the two groups can react to form an acetal. This is called the anhydro form of the sugar (it has 'lost water'). The anhydro form of d-idose is shown here. Explain why about 80% of d-idose exists in the anhydro form in an aqueous solution at 100 °C, but only about 0.1% of d-glucose exists in the anhydro form under the same conditions.

617

views

Textbook Question

Draw the two chair conformers for each of the following and indicate which conformer is more stable:

e. cis-1-ethyl-3-isopropylcyclohexane

213

views

Textbook Question

For each of the following compounds, determine whether the cis isomer or the trans isomer is more stable.

709

views

Textbook Question

Predict which side of the equilibrium is favored for each of the chair–chair interconversions (ring flips) shown. (c)

348

views

Textbook Question

Predict which side of the equilibrium is favored for each of the chair–chair interconversions (ring flips) shown.

(a) <IMAGE>

386

views

Textbook Question

Which of the following conformers has the highest energy (is the least stable)?

<IMAGE>

364

views

Showing 44 of 44 practice