C341/Spring 2010
1. For the alkenes illustrated below, assign each as E (entgegen) or Z (zusammen). Chapter 5 & 6 Worksheet
2. The alkenes below are isomers of each other with the molecular formula C7H12. For the following pair of alkenes shown below, name them and rank them in order of stability. (Please notice the greater than signs and use them to answer the question). A
C
B
Name A: Name B: (2E,4E)‐hepta‐2,4‐diene most stable B > A > C least stable 3. The following compounds belong to a family of compounds called terpenes. Draw the structure for the monomer unit called isoprene and then circle the isoprene units found in the following naturally occurring molecules. 4. Provide a structure for the following name: (4R,5S)‐4,5‐dibromo‐1‐cyclohexene: Page 1 of 6
C341/Spring 2010
Chapter 5 & 6 Worksheet
You will need to use extra paper to execute this worksheet due to length of the mechanisms. 5. Draw the mechanism for a hydrohalogenation reaction which illustrates Markovnikov’s rule in the following reaction. 6. Provide a step‐wise mechanism for the following acid‐catalyzed hydration. 7. Draw a step‐by‐step mechanim for the reaction of bromine in CCl4 (called halogenation). Contrast this mechanism of bromine CCl4 to if the solvent was water (called halohydrin) for the same alkene. Finally, what would be the outcome be if the halohydrin reaction was performed in methanol instead? Br
Br
Br
Br
CCl4
non-nucleophilic
solvent
Br
Br
Br
+
Br
+ enantiomer intermediate
formed by
reaction with the
enantiomer
intermediate
H2O
H
Br
Br
Br
OH
Br
+ Br
Br
Br
OH
OH
+
H2O
+ enantiomer intermediate
formed by
reaction with the
enantiomer
intermediate
Page 2 of 6
C341/Spring 2010
Chapter 5 & 6 Worksheet
CH3OH
H
Br
Br
Br
OCH3
Br
+ Br
Br
Br
OCH3
OCH3
+
f ormed by
reaction with the
enantiomer
intermediate
CH3OH
+ enantiomer intermediate
8. Provide stereochemically accurate products for the following alkene and all the addition reactions it undergoes. 9. Predict the products of the following reactions. List the special considerations that you want to note with certain reagents, i.e. proceeds through a three‐coordinate intermediate, forms the most stable carbocation, can or cannot undergo rearrangements, the –OH add to the most or least substituted carbon, etc. For further practice, you should draw the mechanisms for these reactions too. This will help you be aware of any possible rearrangements or ring expansions. Remember oxidation/reduction reactions have no mechanisms we will discuss. Page 3 of 6
C341/Spring 2010
Chapter 5 & 6 Worksheet
a. b. c. d. e. Page 4 of 6
C341/Spring 2010
Chapter 5 & 6 Worksheet
f. (1R,2R,3S,4S)-2,3-dichlorobicyclo[2.2.1]heptane
Cl2
Cl
Cl
CCl4
Cl
g. (1R,2R,3R,4S)-2,3-dichlorobicyclo[2.2.1]heptane
h. i. Page 5 of 6
Cl
C341/Spring 2010
Chapter 5 & 6 Worksheet
j. Page 6 of 6