Chem 25a
YOUR NAME ________________________________________________
3 hours duration, 360 points total.
1. Give a systematic name for each of the following compounds, including stereochemistry:
2. Which is the most stable from each set of three related structures?
3. Draw a meso form and two enantiomers of 3,4-dimethylhexane:
4. Predict the major product(s) of the following reactions (indicate stereochemistry):
5. What reagent(s) might you use in order to effect the following transformations in a practicable manner? Indicate solvents and/or conditions (e.g. temp.) where appropriate.
6. Show how you might perform either one of the syntheses shown below. You must use the starting material given as your sole source for
all carbons in the product (you need not
synthesize reagents which are not incorporated, however)
EITHER
(a)
OR (b)
7. 1-Chlorohexane reacts with -OCH3 ion as shown:
(a) Draw an energy curve for the
reaction, and indicate which points on the curve correspond to any
intermediates or transition states.
(b) Write a rate equation for
the reaction.
(c) Which would you expect to be
more reactive as a substrate in this reaction, 1-chlorohexane or 1-bromohexane?
(d) What functional group has
been formed in this reaction?
8. Explain why trans-1-bromo-4-tert-butylcyclohexane fails to react when heated with sodium ethoxide, whereas cis-1-bromo-4-tert-butylcyclohexane forms mainly alkene I.
9. In the reaction sequence shown below, indicate whether each structure would be expected to be optically active or not. Also, if the structure is a pure enantiomer, a racemic pair of enantiomers, or a mixture of diastereomers, indicate this. You will have to fill in the final structure (major one only) for yourself!
