Meeting 3 Problem Set - 30BL

1.Using PC Spartan 2002 at the Science Learning Center (4 Floor Young Hall, open from M-F 8-5 pm) do the following:

a. Draw camphor if you have not done it yet (Make sure that all hydrogen atooms are still attached!). Minimize the structures by clicking the minimize icon, , then save.

b. Go to the view mode by clicking the view icon, . Once in the view mode, click the Model menu and select Tube.

c. Select Calculations from the Setup menu.

The following window should appear. Select the options shown.



Verify the Charge is Neutral and Multiplicity is Singlet. Click OK.

• Select Submit from Setup menu.

  
  

  Under the Setup menu, select Surfaces. A window should appear. In this window click Add.

  

  A second window should appear. In this window, select the following

  

  Then click OK to exit dialog. Close the previous window.

  Select Submit from Setup menu. When the calculation is completed you will be notified.

  Under the Display menu, select Surfaces.

  

  A window should appear. In this window check the yellow box.

  

  Next, select the molecule by clicking on it. In the bottom right corner of the window, change the selection from Solid to Transparent.

d) Do the same (steps a-c) for 2-norbornanone.

2. Referring to the below reaction,

(endo/exo huh?)

answer the following questions:

a. Which isomer is expected to be the major product for this reaction? Why? (Include the LUMO diagram generated in question 1 to answer this question. Make sure to show the proper orientation! Hint: What are you trying to show here?)

b. What would change if NaBD₄ and D₂O were used in this reaction? Show the structure of the product.

c. Why is the LUMO orbital used to rationalize the stereochemistry in this reaction?

3. Referring to the below reaction,

answer the following questions:

a. Draw the products formed in this reaction

b. which product is the major and which is the minor? Explain using the LUMO generated above (Include the LUMO diagrams generated in question 1 to answer this question. Make sure to show the proper orientation!)

c. Why are the possible products not obtained in equal quantities?

4. Methanol is used as solvent in the reaction. Which problem does this choice pose for the reaction?

5. How many grams of sodium borohydride are required to reduce 0.200 g of camphor (in theory)? Show pertinent chemical equation and calculations.

6. After the reaction is completed, the reaction mixture chilled and water is added. What is the purpose of this step and what will the student observe?

7. Why is the crude product dissolved in diethyl ether?

8. The student observes bubbles that form on the surface of the drying agent. How can he explain this observation?

9. Why should only a very small sample be used to obtain the melting point?