Cover Sheet! EXAM 4 CHEM230-001 SPRING 2005 PRINT your name legibly on the line below. PRINT your student id number on the line below.2005 Organic Chemistry CHE230-001 EXAM 4 Page 1 of 6 Name: _______________________________ Student ID No:_____________________ Place your student identification on your desk. A proctor will come around to check your ID. Put your name and number on your test? It is critically important that your answers be written in a clear, unambiguous manner. s in which your intentions are unclear may not receive credit. SHOW YOUR WORK! Problem Number Points possible Score 1. 15 _____ 2. 10 _____ 3. 10 _____ 4. 10 _____ 5. 10 _____ 6. 10 _____ 7. 10 _____ 8. 10 _____ 9. 10 _____ 10. 10 _____ 11. 10 _____ 12. 10 _____ 13. 10 _____ 14. 10 _____ 15. 10 _____ 16. 10 _____ 17. 15 _____ 18. 10 _____ 19. 10 _____ ----------------------------------------------------------------------------------------------- Total 200 _____2005 Organic Chemistry CHE230-001 EXAM 4 Page 2 of 6 NEW STUFF NCNHab cdefg 1. (15 pts.) See the figure above. Circle the molecules with aromatic electronic configuration. 2. (10 pts.) Very briefly make a comparison between the transition states of the Diels-Alder reaction and of hydride shifts in carbocation rearrangements. What fundamental aspect do they share? Why are they both so relatively fast? 2. ____________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ +RR'R'RR'RCRR'HHHCCRR'HHHCCRR'HHHProblem 22005 Organic Chemistry CHE230-001 EXAM 4 Page 3 of 6 3. (10 pts.) Predict the product of the following Diels-Alder reaction. There is stereochemistry and regiochemistry involved. For a bare bones Diels-Alder reaction see problem 2. ON+Problem 3 4. (10 pts.) What structural/ electronic feature(s) is (are) making the reaction in 3 go from left to right? In other words, why is the reaction exothermic in problems 2 and 3? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ 5. (10 pts.) Devise a synthesis of the following molecule. Problem 52005 Organic Chemistry CHE230-001 EXAM 4 Page 4 of 6 6. (10 pts.) Which diene participates fastest in the Diels-Alder reaction? _____ Which diene participates slowest in the Diels-Alder reaction? _____ You must get both right for any credit. abcdProblem 6 7. (10 pts.) Predict the product of the following reaction. NBSNBS=NOOBrProblem 7light 8. (10 pts.) Circle the molecule that absorbs light at the lowest energy? (The lowest energy photons, the longest wavelength). For partial credit you can offer a brief explanation.2005 Organic Chemistry CHE230-001 EXAM 4 Page 5 of 6 Old Stuff 9. (10 pts) Put the product at the right of the arrow above. BH32) H2O2, NaOH(aq)ether1)Problem 9. 10. hexane (solvent)O2tBu2small amount (10 pts) Put the product at the right of the arrow above. The reaction conditions are such that methylystyrene (material at left) is very concentrated. The reaction will result in polymerization. Draw a few units of the polymer.2005 Organic Chemistry CHE230-001 EXAM 4 Page 6 of 6 11. (10 pts.) Draw an E2 product of the molecule below. There is stereochemistry to consider. You will not get full credit unless you include stereochemistry in your answer. HBrHProblem 11. 12. (10 pts.) In the molecule in problem 11, what is the absolute stereochemistry of the carbon atom attached to Br, R or S? _____ What is the absolute stereochemistry of the other stereogenic atom? _____ 13. (10 pts.) Complete the figure below to show a diastereomer of the reactant in problem 11. HBrHProblem 13.2005 Organic Chemistry CHE230-001 EXAM 4 Page 7 of 6 14. Count the 13C NMR signals in the following molecules. a. (5 pts.) OOOOOO __________ b. (5 pts.) NNN __________ 15. (10 pts.) Name the following molecule. BrFProblem 15 ______________________________ 16. (10 pts.) Put the product at the right of the arrow below. hexane (solvent)+OOOHProblem 162005 Organic Chemistry CHE230-001 EXAM 4 Page 8 of 6 17. (10 pts.) Circle the protons that are most acidic. FHProblem 17HHHHHHHHHH 18. (Think) a. (8 pts.) How are carbocations, carbenes and radicals alike? What makes them all unstable? _______________________________________________________________________ _______________________________________________________________________ _______________________________________________________________________ (7 pts.) So I know what you are talking about, draw Lewis Structures of methyl radical, methyl cation and methylene. Label the structures. Include all atoms as letter symbols, include all electrons and charges. 19. (10 pts.) On the back of this page draw a reaction energy diagram of an exothermic SN1 (unimolecular) reaction (this reaction has one
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