CHEMISTRY 2430 - Principles of Organic Chemistry I - Exam II
February 19, 1999 - Dr. Howard Black

Name                   KEY

Throughout this exam, give answers only in the provided spaces (boxes or lines). Answers not in these spaces will not be graded, even if correct.

1. (12 pts) Give IUPAC names for the following compounds, being sure to address alkene geometry and R/S configuration where appropriate.
 

 

2. (16 pts) The structures of three pharmacologically important molecules are drawn below. Indicate whether the absolute configuration of each specified carbon atom is R, S, or neither (N).
 

 

A =__R__ B =__S__ C =__N__ D =__R__ E =__R__ F =__R__ G =__R__ H =__R__


3. (12 pts) Draw all of the carbocations formed by the addition of H+ to each of the following alkenes, and indicate (by circling the appropriate word) which is the more stable, less stable, or if each carbocation is of equivalent (equiv.) stability.
 

 
4. (18 pts) Consider the reaction coordinate diagram in the box below. Using the letters on the graph, identify each part or feature of the diagram. If there is more than one of a given feature, designate them by #1, #2, etc.
 
A = starting materials

B = energy of activation #1

C = transition state #1

D = reactive intermediate

E = transition state #2

F = energy of activation #2

G = reaction enthalpy (DH)
 

Is this reaction exothermic or endothermic?            exothermic                  What is the sign of DH?     negative
 
What is the difference between a transition state and a reactive intermediate?

   A transition state has only partial bonds (partially formed or broken), while in reactive intermediates the

   bonds are complete  (fully broken and/or fully formed).
 


5. (20 pts) Complete the following reactions by supplying either the reagent(s) or product. If more than one product is produced, draw only the major one.
 

 
6. (14 pts) For each molecule below, designate with the appropriate letter whether it would most likely function as a Lewis acid (A), Lewis base (B), or neither (N).
 

 
7. (8 pts) Draw the mechanism for the addition of HCl to propene.
 

 
 
Bonus (5 pts, no partial credit possible)

The reaction in the box is an example of a good method for the preparation of oxygen-containing ring compounds. Its mechanism is very similar to one already known to you. Draw the reaction mechanism below

 

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