章节大纲

  • Learning Goals: Know what is meant by "strain energy" of cycloalkanes and be able to explain why it is largest for ring sizes of 3 and 4, but also why it is small but non-zero for cyclopentane.  Know what is meant by chair and boat forms of cyclohexane, and which is more stable.  Also know the difference between axial and equatorial positions in cyclohexane and which one of these is energetically preferred by substituents, and why.  Be able to explain this using guache and anti conformational analysis.

    Reading: Soderberg section on cyclic compounds.

    Video lectures: There are no pencasts for this topic, but please use the link below (and follow the instructions below the link) to view about 45 minutes of Claude Wintner's video lecture.  (The sections 5.03, 5.04 and 5.06 that I have you skip over won't make sense until we talk more about stereoisomerism next week).

    You-tube video: Shows a molecular dynamics simulation of a molecule interconverting between chair, twist boat and boat forms.  The twist boat form is twisted just slightly from the pure boat form, and is slightly more stable because it minimizes the steric clash between H atoms on the "bow" and "stern" found in pure boat form.