Alkane Stereochemistry

1
Chapter 4

• Alkane Stereochemistry

2
Cycloalkane Strain Energy
3
Cycloalkanes
Eclipsed
Not quite eclipsed
Nearly gauche
4
Cyclohexane
Axial Hydrogens Equatorial Hydrogens
5
Cyclohexane
Staggered conformation
6
Methylcyclohexane
Equatorial More Stable
Axial
7
Axial Methylcyclohexane
3.8 kJ/mole strain
7.6 kJ/mole strain
8
Equatorial Methylcyclohexane
9
Steric Strain in Substituted Cyclohexane
Values are for a single 1,3 interaction. Double
each value to see the total strain energy.
10
Boat Cyclohexane
Completely Eclipsed
11
cis- and trans-Decalin
cis-Decalin
trans-Decalin