Draw each of the following substituted cylobutanes in its two intervonverting puckered conformations (Figure 4-3). When the

Question:

Draw each of the following substituted cylobutanes in its two intervonverting "puckered" conformations (Figure 4-3). When the two conformations differ in energy, identify the more stable shape and indicate the form(s) of strain that raise the relative energy of the less stable one.
(a) Methylcyclobutane
(b) cis-1,2-Dimethylcyclobutane
(c) cis-1,2-Dimethylcyclobutane
(d) cis-1,3-Dimethylcyclobutane
(e) trans-1,3-Dimethylcyclobutane
Which is more stable: cis- or trans1,2-dimethylcyclobutane; cis- or trans-1,3-dimethylcyclobutane?