Chemistry 233 Exam 3 (Green) The Periodic Table

Transcription

1 Name: Last First MI Chemistry Exam (Green) Summer 7 Dr. J. sbourn Instructions: The first questions of this exam should be answered on the provided Scantron. You must use a pencil for filling in the Scantron sheet. Ensure all erasures are complete. Any questions left blank will be marked incorrect. Answer the remaining questions on the exam itself. Show all work and provide complete explanations. Please write your name on: The first page (Exam Cover Page) The second page (Grading Page) The Scantron Sheet Circle your Last Name Please bubble in your WVU Student ID Number on your Scantron sheet. The Periodic Table *Please do not rip off this cover sheet* Page of 9

2 Name: Last First MI Grading Page (Exam ): Page Points Possible Points Earned Multiple Choice (-6) TTAL Page of 9

3 Multiple Choice Choose the one best answer for each of the following questions. Using a pencil, record this answer on the provided Scantron sheet. ( points each). What is the common name for the alkyne shown below? a. isopropyl propyl ethyne b. tert-butyl propyl acetylene c. butyl tert-butyl acetylene d. tert-butyl propyl ethyne e. propyl tert-butyl acetylyne. The compound shown below has chemically distinct types of hydrogen and chemically distinct types of carbon. a. 5, b. 5, 4 c. 6, d. 8, 4 e. 6, 4. If the compound shown below were subjected to hydrogenation conditions, how many products would form? a. a pair of diastereomers b. a pair of enantiomers c. a pair of enantiomers and a constitutional isomer d. three diastereomers 4. In the compound shown below, proton is the most shielded and is the most upfield. a. IV, VI b. I, I c. VI, VI d. I, V e. V, I Pd/C II IV V I C VI C III Page of 9

4 5. Which one of the following is a carbene? Cl C C C C Cl a b c d e 6. Which of the following energy diagrams correctly represents the reaction shown below? a b c d 7. Which of the following is a valid enol tautomer of the ketone shown below? a. I and II b. I, II, and III c. I onle d. II only e. III only I II III 8. Which (if any) of the following statements is incorrect? a. g + is required as a catalyst in the hydration of terminal alkynes. b. ydroboration proceeds via the syn addition of B (-B) across a double bond. c. Carbocation rearrangement is not a concern in an alkene hydroboration reaction or alkene halogenation (reaction with X). d. A vinyl carbocation is more stable than a primary carbocation. e. All of the above statements are correct. 9. Which compound shown below will undergo hydrogenation (, Pd/C) at the fastest rate? a b c d Page 4 of 9

5 . The indicated proton in the compound below will appear as a in the NMR spectrum. C C C a. doublet b. triplet c. doublet of doublets d. doublet of triplets e. singlet. Consider the reaction shown below and determine the structure of the starting material.?. NaN. Na(s) N (l) -78 C a b c d e For questions -7, select the appropriate reagent from the reagent bank to accomplish each of the following transformations... C S 4 C Reagent Bank NaC (excess) a b c 4. ( equiv) gs 4 S 4 Pt d e ab 5.. B. Na S 4 6. ac ad ae 7. Lindlar Cat. (excess) bc bd be Page 5 of 9

6 For questions 8-, determine which structure from the structure bank corresponds to each NMR spectrum. Don t spend too much time on these three questions. Structure Bank N a b c d e ab ac 8. 6 sep, Make sure that your answers to questions - are all bubbled in on your Scantron sheet! Page 6 of 9

7 Completion Section Answer the remaining questions in the spaces provided. Show all work and provide complete explanations.. Provide IUPAC systematic names for each compound shown below. ( points each) (a) (b) F. Determine a reasonable synthesis for the compound shown below using the provided starting material. You may use any organic or inorganic reagents in your synthesis. Note: This is a synthesis, not a mechanism question! (4 points) Cl? C Cl. Draw the tautomer of the enol shown below then draw the complete electron pushing mechanism for the acid catalyzed tautomerization. (6 points) +, Mechanism: 4. Draw a representative NMR spectrum for the compound shown below. Label each peak (a, b, c, etc.) in your spectrum with the corresponding proton(s) in the molecule. (4 points) a d C b c ppm Page 7 of 9

8 5. Predict the major organic product(s) for each reaction shown below. For reactions indicated with an asterisk (*), be sure to include stereochemistry. If the reaction produces a racemic mixture, you only need to draw one enantiomer. ( points each) a.. B -TF. Na, b.. NaN. C Cl Cl excess c.* s 4 NM, Acetone d.* Cl ( equiv.) Pd/C e.* C I Lindlar's Cat. Zn(Cu) 6. For the reaction below, fill in the empty boxes with the appropriate intermediates, and then draw in curved arrows to show electron flow in each step. (7 points) Int Int 7. For each compound shown below: a) determine the number of chemically distinct. b) circle the proton that would have the highest chemical shift (you may need to draw it in). c) Determine the multiplicity for the hydrogen indicated by the arrows. ( points each) C C # of Distinct # of Distinct # of Distinct 8. The two NMR spectra on page 9 correspond to two different C5 isomers. Provide the structure that corresponds to each spectrum in the boxes below. (4 points each) Spectrum A Structure: Spectrum B Structure: Page 8 of 9

9 Spectrum A: IR indicates the presence of an alcohol functional group. NMR 6 quin, m, 5 4 Spectrum B: IR indicates the presence of an alcohol functional group. NMR s, 6 s, q, t, 5 4 Page 9 of 9