Vance Granville Community College Organic Chemistry Exam Practice

Practice Problems (Chapter THREE):

1) Sight down the C2 – C3 bond, and draw Newman Projection formulas for the

(a) most stable conformation of 2,2-dimethylbutane.

(b) two most stable conformations of 2-methylbutane.

(c) two most stable conformations of 2,3-dimethylbutane.

2) Draw all possible chair conformations for 1,4-diethylcyclohexane. Label each conformation as either cis or trans. Also label the most stable conformation.

3) Write a structural formula for the most stable conformation of each of the following compounds:

(a) 2,2,5,5-Tetramethylhexane (Newman projection of conformation about C3 – C4 bond).

(b) cis-1-Isopropyl-3-methylcyclohexane.

(c) trans-1-Isopropyl-3-methylcyclohexane.

(d) cis-1-tert-Butyl-4-ethylcyclohexane.

4) Identify the more stable stereoisomer in each of the following pairs:

(a) cis- or trans-1-Isopropyl-2-methylcyclohexane.

(b) cis- or trans-1-Isopropyl-3-methylcyclohexane.

(c) cis- or trans-1-Isopropyl-4-methylcyclohexane.