Chapter 3.SE, Problem 52AP

Increased substitution around a bond leads to increased strain. Take the four substituted butanes listed below, for example. For each compound, sight along the C2-C3 bond and draw Newman projections of the most stable and least stable conformations. Use the data in Table 3-5 to assign strain-energy values to each conformation. Which of the eight conformations is most strained? Which is least strained?

(a) 2-Methylbutane

(b) 2,2-Dimethylbutane

(c) 2,3-Dimethylbutane

(d) 2,2,3-Trimethylbutane