Essential Organic Chemistry, Global Edition
3rd Edition
ISBN: 9781292089034
Author: Paula Yurkanis Bruice
Publisher: PEARSON
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Chapter 5, Problem 39P
Given that the twist-boat conformer of cyclohexane is 5.3 kcal/mol higher in free energy than the chair conformer, calculate the percentage of twist-boat conformers present in a sample of cyclohexane at 25 °C. Does your answer agree with the statement made on page 103 about the relative number of molecules in these two conformations?
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On a cyclohexane ring, an axial carboxyl group has a conformational energy of 5.9 kJ (1.4 kcal)/mol relative to an equatorial carboxyl group. Consider the equilibrium for the alternative chair conformations of trans-1,4-cyclohexanedicarboxylic acid. Draw the less stable chair conformation on the left of the equilibrium arrows and the more stable chair on the right. Calculate DG0 for the equilibrium as written and calculate the ratio of the more stable chair to the less stable chair at 25°C.
From studies of the dipole moment of 1,2-dichloroethane in the gas phase at room temperature (25°C), it is estimated that the ratio of molecules in the anti conformation to gauche conformation is 7.6 to 1. Calculate the difference in Gibbs free energy between these two conformations.
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. Draw pictures of the axial conformations of isopropylcyclohexane and tert-butylcyclohexane, and explain why the tert-butyl substituent experiences such a large increase in axial energy over the isopropyl group
Chapter 5 Solutions
Essential Organic Chemistry, Global Edition
Ch. 5.1 - Prob. 1PCh. 5.1 - Draw the structure for each of the following: a....Ch. 5.1 - What is each compounds systematic name?Ch. 5.3 - Prob. 4PCh. 5.3 - Prob. 5PCh. 5.3 - Prob. 7PCh. 5.4 - a. For which reaction in each set below will S be...Ch. 5.6 - Prob. 9PCh. 5.6 - How many different alkenes can be hydrogenated to...Ch. 5.6 - The same alkane is obtained from the catalytic...
Ch. 5.6 - Prob. 12PCh. 5.6 - Rank the following compounds in order from most...Ch. 5.7 - The rate constant for a reaction can be increased...Ch. 5.7 - Prob. 15PCh. 5.7 - Prob. 16PCh. 5.9 - Draw a reaction coordinate diagram for a two-step...Ch. 5.9 - Prob. 18PCh. 5.9 - Draw a reaction coordinate diagram for the...Ch. 5.10 - Which of the following parameters would be...Ch. 5 - What is each compounds systematic name?Ch. 5 - Draw the structure of a hydrocarbon that has six...Ch. 5 - Which of the following compounds is the most...Ch. 5 - Prob. 24PCh. 5 - Prob. 25PCh. 5 - Prob. 26PCh. 5 - Prob. 27PCh. 5 - Name the following:Ch. 5 - Prob. 29PCh. 5 - Prob. 30PCh. 5 - Prob. 31PCh. 5 - Prob. 32PCh. 5 - Prob. 33PCh. 5 - Prob. 34PCh. 5 - Prob. 35PCh. 5 - Name each of the following:Ch. 5 - Prob. 38PCh. 5 - Given that the twist-boat conformer of cyclohexane...Ch. 5 - a. The G for conversion of axial fluorocyclohexane...Ch. 5 - Prob. 1PCh. 5 - Prob. 2PCh. 5 - Prob. 3PCh. 5 - Prob. 4PCh. 5 - Prob. 5PCh. 5 - Prob. 6PCh. 5 - Prob. 7PCh. 5 - Prob. 8PCh. 5 - Prob. 9PCh. 5 - Prob. 10P
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- Which conformation in the picture attached represents the most stable ECLIPSED conformation of 2,3-dimethylbutane along the C2-C3 bond?arrow_forwardThe following are representations of two forms of glucose. The six-membered ring is known to exist in a chair conformation in each form. Draw clear representations of the most stable conformation of each. Are they two different conformations of the same molecule, or are they stereoisomers that cannot be interconverted by rotation about single bonds? Which substituents (if any) occupy axial sites?arrow_forwardConsider 2-methylbutane (isopentane). Looking along the C2-C3 bond: a) Draw a Newmann projection of the most stable conformation. b) Draw a Newmann projection of the least stable conformation. c) Indicate the gauche form. d) State the eclipsed Newmann projection. An eclipsed CH3-CH3 interaction has an energy value of 11 kJ / mol and a gauche CH3-CH3 interaction has an energy value of 3.8 kJ / mol, the data are given if you need them.arrow_forward
- Treatment of -D-glucose with methanol in the presence of an acid catalyst converts it into a mixture of two compounds called methyl glucosides (Section 25.3A). In these representations, the six-membered rings are drawn as planar hexagons. (a) Propose a mechanism for this conversion and account for the fact that only the OH on carbon 1 is transformed into an OCH3 group. (b) Draw the more stable chair conformation for each product. (c) Which of the two products has the chair conformation of greater stability? Explain.arrow_forwardConsider the following reaction. (a) Draw a structural formula for the compound with the molecular formula C8H12. (b) Do you predict the product to be the cis isomer, the trans isomer, or a mixture of cis and trans isomers? Explain. (c) Draw a suitable stereorepresentation for the more stable chair conformation of the dicarbaldehyde formed in this oxidation.arrow_forwardKetones react with alcohols to yield products called acetals. Why does the all-cis isomer of 4-tert-butyl-1,3-cyclohexanediol react readily with acetone and an acid catalyst to form an acetal, but other stereoisomers do not react? In formulating your answer, draw the more stable chair conformations of all four stereoisomers and the product acetal for each one.arrow_forward
- The most stable conformation of the pyranose ring of most D-aldohexoses places the largest group, CH2OH, in the equatorial position. An exception to this is the aldohexose D-idose. Draw the two possible chair conformations of either the a or ß anomer of D-idose. Explain why the more stable conformation has the CH2OH group in the axial position.arrow_forwardLabel the following pairs as A) distereoisomers, B) enantiomers, C) conformers, or D) the same. b1 c1 d1 e1 a2 b2 c2 The structures above are labeled a1, a2, b1, b2 ...etc. Using these labels, indicate which compounds above would have an optical rotation ofarrow_forwardWhat is the ratio of concentrations of the two conformations at 25 °C? (Calculate the ratio as the conformation present in a higher concentration over the lower one.)arrow_forward
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