Last Year's Exam #2

C3443x EXAM 2
Professor Horne
October 28, 1996

1. (4 pts ea. 25 pts) Answer True or False to the following statements.

a) Generally, the polarity of an aprotic solvent will have a greater effect on SN1 processes than for SN2 processes.

            T   or    F

b) The rate determining step in the hydrolysis of t-butylbromide to t-butanol is the attack by H2O.

            T   or    F

c) (Z)-2-butene is thermodynamically more stable than (E)-2-butene.

            T   or    F

d) The ratio [elimination products]/[substitution products] will be greater for the reaction of sodium acetate with cyclohexyltosylate than with isopropyltosylate.

            T   or    F

e) In order for two molecules to be diastereomerically related, each must be optically active and not superimposable on each other.

            T   or    F

f) Most organic reactions are driven by entropy.

            T   or    F

g) Organic chemistry is loads of fun (a bonus question, worth 1 point)

            T   or    F

2. (5 pts ea., 15 pts) Indicate whether or not each molecule below is optically active.

3. (5 pts ea.,15 pts) Identify each pair as enantiomers, diastereomers, identical, or non-isomeric.

4. (5 pts ea., 15 pts) Indicate which process would proceed with a higher activation energy (delta G‡) and briefly explain why using structures and/or no more than 15 words

a) The reaction between sodium chloride and methyliodide in (a) H2O or (b) H2O/DMF (1:1).

b) In DMF, the reaction between methyltosylate with (a) methylamine or (b) acetamide (CH3CONH2).

c) The dissociation of acetic acid in (a) H2O or (b) ethanol.

5. (10 pts) Provide a mechanism for the following transformation.

6. (4 pts ea., 20 pts) Give the major product(s) for the following reactions and clearly indicate stereochemistry when appropriate.