Q8.4 StructureCH3CH3ВB EAH3CAIIIWhat substituent is positioned at B on Structure II?O -HO -CH3Q8.5 StructureCH3CH3ВAH3CÀF,IIIWhat substituent is positioned at C on Structure II?O HO -CH3Q8.6 StructureCH3CH3ВCВ ЕAH3C"A FFIIIWhat substituent is positioned at E on Structure II?O -H-CH3 Q8 Conformational Analysis of CycloalkanesIn this question you will look at the conformations of the following molecule:CH3CВ FCH3D-EAH3CFIIIEnergy Costs for Interactions in Alkane Conformers:Computed Energy Cost (kJ/mol)*3.8InteractionH+H eclipsedH+CH3 eclipsedCH3+CH3 eclipsedCH3+CH3 gaucheH»CH(CH3)2 gaucheH CH(CH:)2 eclipsedCH3+CH(CH3)2 gaucheCH3+CH(CH3)2 eclipsedHeC(CH:)3 eclipsedCH3+C(CH3)3 gaucheCH3+C(CH:)3 eclipsedH+I eclipsedI+CH3 gaucheI+CH3 eclipsed"Values computed with Gaussian09 using B3LYP/6-31G(d) for structure optimization andB3LYP/6-311+G(2df,3p) for the conformation energy. The calculations were performed inthe gas phase (no solvent).*This result for t-butyl is a bit peculiar given that the value is less than that for isopropyl,but there is an explanation that I can tell you about in office hours!4.812.63.7(0.0)3.13.617.32.813.618.76.71.215.5Steric Strain in Monosubstituted Cyclohexanes:1,3-Diaxial strainY(kJ/mol)(kcal/mol)F0.50.12CI, BrонCH3CH2CH3CH(CH3)2C(CH3)3CSHSCO2HCN1.00.252.10.50.90.951.12.71.50.70.13.84.04.611.46.32.90.4

Equatorial conformation is more stable than axial confirmation. The stable chair conformation of the…

Q8.4 Structure CH3 CH3 ВЕ .C -E D I II What substituent is positioned at B on Structure II? O -H O -CH3 Q8.5 Structure CH3 CH3 В ВЕ .C A -E H3C A I II What substituent is positioned at C on Structure II? O H O -CH3 Q8.6 Structure CH3 CH3 B E A H3C A F, F I II What substituent is positioned at E on Structure II? O -H -CH3

Q8.4 Structure CH3 CH3 ВЕ .C -E D I II What substituent is positioned at B on Structure II? O -H O -CH3 Q8.5 Structure CH3 CH3 В ВЕ .C A -E H3C A I II What substituent is positioned at C on Structure II? O H O -CH3 Q8.6 Structure CH3 CH3 B E A H3C A F, F I II What substituent is positioned at E on Structure II? O -H -CH3

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter3: Organic Compounds: Alkanes And Their Stereochemistry

Section3.SE: Something Extra

Problem 54AP: In the next chapter we'll look at cycloalkanesâ€”saturated cyclic hydrocarbonsâ€”and weâ€™ll see...

See similar textbooks

Similar questions

Use your answers from Problem 2.48 to complete the table showing correlations between cis,trans and axial,equatorial for disubstituted derivatives of cyclohexane. Draw the alternative chair conformations for the cis and trans isomers of 1,2-dimethylcyclohexane, 1,3-dimethylcyclohexane, 1,4-dimethylcyclohexane. (a) Indicate by a label whether each methyl group is axial or equatorial.
Gibbs free energy differences between axial-substituted and equatorial-substituted chair conformations of cyclohexane were given in Table 2.4. (a) Calculate the ratio of equatorial to axial tert-butylcyclohexane at 25C. (b) Explain why the conformational equilibria for methyl, ethyl, and isopropyl substituents are comparable but the conformational equilibrium for tert-butylcyclohexane lies considerably farther toward the equatorial conformation.
Draw the most stable conformation of pentane, using wedges and dashes to represent bonds coming out of the paper and going behind the paper, respectively.
2.(a) Different conformations are found in 2-methylpentane. (i) Using Newman Projection, draw all the possible staggered and eclipsed conformations of pentane by referring to the bond rotation at C3-C4.(ii) Compare their stability and explain your answer.
The potential energy of a CH3 group in ethane as it is rotated around the C-C bond can be written V= 1/2V0(1 +cos φ), where φ is the azimuthal angle as shown and V0 = 11.6 kJ mol-1. (a) What is the change in potential energy between the trans and fully eclipsed conformations? (b) Show that for smal lvariations in angle, the torsional (twisting) motion around the C-C bond can be expected to be that of a harmonic oscillator. (d) Estimate the vibrational frequency of this torsional oscil lation.
Sight along the C2-C1 bond of 2-methylpropane (isobutane).(a) Draw a Newman projection of the most stable conformation.(b) Draw a Newman projection of the least stable conformation.(c) Make a graph of energy versus angle of rotation around the C2-C1 bond.(d) Assign relative values to the maxima and minima in your graph, given that an H↔H eclipsing interaction costs 4.0 kJ/mol and an H↔CH3 eclipsing interaction costs 6.0 kJ/mol.
. Draw the conformational isomers of 1-bromo-2-chloroethane by rotating C-C single bond with dihedral angel 60°
Draw a potential-energy diagram for rotation about the C@2¬C@3 bond of pentane through 360°, starting with the least stable conformer.
2.34 Consider 1-bromopropane, CH3CH2CH2Br.(a) Draw a Newman projection for the conformation in which !CH3 and !Br are anti (dihedral angle 1808).(b) Draw Newman projections for the conformations in which !CH3 and !Br are gauche (dihedral angles 608 and 3008).(c) Which of these is the lowest energy conformation?(d) Which of these conformations, if any, are related by reflection?
Draw the conformational isomers of 1-bromo-2-chloroethane by rotating C-C single bond with dihedral angel 60°. AndWhy conformational isomers generally can not be separated from one another at room temperature?
Construct the chair structures with the molecular models for trans-1-ethyl-3-methylcyclohexane. Find the energy of each conformer, the equilibrium constant Keq, and the percentage of each conformer at 25oC. Indicate which conformer is more stable.
Consider rotation around the C2–C3 single bond of 2-methylpentane. Using the Newman projection templates shown below, (i) draw all possible conformations (ii) arrange these four conformations in the order most stable to least stable