Experiment 3:. STEREOCHEMISTRY AND MOLECULAR MODELING OF CYCLOALKANES. OBJECTIVES. To learn how to construct various cyclohexane conformers using handheld molecular models and the HyperChem molecular modeling program.
STEREOCHEMISTRY AND MOLECULAR MODELING OF CYCLOALKANES
This conformer has more diaxial interactions, therefore is higher in energy!
Cis or Trans?
Most stable conformation?
1,2-dimethylcyclohexane, both groups axial
No: ring flips to more stable eq/eq conformer
1,2-dimethylcyclohexane, both groups equatorial
1,2-dimethylcyclohexane, one axial, one equatorial
1,3-dimethylcyclohexane, both groups axial
1,3-dimethylcyclohexane, both groups equatorial
1,3-dimethylcyclohexane, one axial, one equatorial
1,4-dimethylcyclohexane, both groups axial
1,4-dimethylcyclohexane, both groups equatorial
1,4-dimethylcyclohexane, one axial, one equatorialTable 3.1
Remember to include methyl substituents in the proper place and all of hydrogen atoms!
HyperChem refers to this as “dihedral” strain