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1.  In each of the following, give the structure of the indicated product.  

  Answer any other secondary questions that may be asked.

(a) (10 pts) see J. Org. Chem., 1996, 61, 6454.


(2 pts) What is the structure of DEAD?

(b) (8 pts) see J. Org. Chem., 1996, 61, 4572.

(6 pts, 2 pts ea)  What is Bn?   What is LHMDS?   

      What is the structure of NMO?

(c) (10 pts) see J. Org. Chem., 1996, 61, 4594.


(2 pts) What reagents are used in Swern oxidation?

(d) (7 pts) see J. Org. Chem., 1996, 61, 4641.


(e) (7 pts) see J. Org. Chem., 1996, 61, 4838.


2. (12 pts) Give a reasonable mechanism for the following transformation.
   see J. Org. Chem., 1996, 61, 6456.


3. (12 pts) Give a reasonable mechanism for the following transformation.
  see J. Org. Chem., 1996, 61, 4516.


4. (10 pts) Give a reasonable mechanism for the following transformation.
  see J. Org. Chem., 1996, 61, 4600.


(2 pts) What is the structure of DME?

5. (10 pts) Predict and briefly explain the stereochemistry of the methyl 
group in the product.  see J. Org. Chem., 1996, 61, 4617.


6. (8 pts) For the structure shown, the following nOe values were observed.   
    Ha-Hb = 13%;   Hb-Hc = 8%;  Hd - He = 10%.  Draw the structure with 
    the correct stereochemistry.
see J. Org. Chem., 1996, 61, 4655.


7. The following Diels-Alder reaction gave about 1.1% of product at 40¡C.
In the presence of LiClO4, (10% was produced and the reaction 
was reversible.  At 8 kbar, a 97% yield of product was obtained.
 
(10 pts) What is the purpose of adding LiClO4?  Why does 
increasing the pressure of this reaction enhance product formation?

(6 pts) Is the final product the result of endo approach or exo 
approach?   Is this the "normal" mode of reaction for a cyclic diene?
see J. Org. Chem., 1996, 61, 4816.

8. (8 pts) Explain the following transformation.  
see J. Org. Chem., 1993, 58, 600.
 

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