Chemistry 333. Final Examination

Transcription

1 Chemistry 333 Final Examination December 9, 2010 Professor Charonnat Be certain that your examination has eleven (11) pages including this one. Put your name on each page of this examination booklet. By putting your name on this examination booklet you agree to abide by California State University, Northridge policies of academic honesty and integrity. Molecular models are allowed for this examination. All electronic devices, including calculators, are unnecessary and are not allowed.

2 1. (25 points) Draw the structure of the expected major organic product for each of the following five (5) questions. Specify stereochemistry clearly, if relevant. A. Br t-buok B. Br 2 hν C. Br KCN D. Ph Br CuLi 2 E. Cl H Zn aq. HCl

3 2. (25 points) Design a synthesis of the following racemic bromohydrin from acetylene and any organic compounds that contain three or fewer carbons. Use any inorganic reagents that are necessary. Show all reagents and stable synthetic intermediate compounds. (N.B. Do not draw mechanisms for each transformation!) Finally, label each compound that is formed as a racemic mixture. OH Br (racemic) 3. (25 points) Use IUPAC nomenclature to write the systematic name of the following thiol. Then draw the enantiomer and provide its systematic name. SH

4 4. (50 points) Circle the letter that corresponds to the correct answer for each of the following ten (10) questions. These questions are unavailable due to copyright considerations.

5 4. (cont.)

6 5. (25 points) Draw specific structures for each of the following eight (8) categories. A. a carbene: B. an E-trisubstituted alkene: C. a carbocation: D. another carbocation, that is more stable than the carbocation in part C: E. a nucleophile: F. an electrophile: G. an organic compound with an odd molecular weight: H. an organic compound that possesses significant angle strain:

7 6. (25 points) Given the reaction-energy diagrams below for four hypothetical reactions, A D, answer the following five (5) questions by writing the letter(s) of the appropriate diagram(s). A B potential energy potential energy reaction progress reaction progress C D potential energy potential energy reaction progress reaction progress reaction(s) proceeding via an intermediate fastest reaction reaction(s) in which an equilibrium between starting material and product would lie toward starting material possible diagram(s) for an E1 reaction reaction(s) with only one transition state, that is an early transition state

8 7. (25 points) Draw the major organic product that is formed from the following reaction. The 1 H NMR spectrum of the product is shown below. The labels next to each of the resonances signify the integrals and multiplicities observed in the spectrum (s = singlet, d = doublet, t = triplet, dt = doublet of triplets, tsept = triplet of septets). Use this spectroscopic evidence to determine the identity of the compound. Make clear assignments of all resonances to explain your reasoning. (A 1 H NMR correlation table is included separately.) PCC? OH s 3H d 6H t 2H overlapping tsept overlapping dt 2H 1H 2 PPM 1 0

9 7. (cont.) 1 H NMR assignments: chemical shift (ppm) assignment explanation of multiplicity structure: Congratulations! 1 /25 2 /25 3 /25 4 /50 5 /25 6 /25 7 /25 Total: /200