Chemistry 333. Final Examination

Transcription

1 Chemistry 333 Final Examination May 15, 2017 Professor Charonnat Be certain that your examination has ten (10) 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 and cell phones, 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. H 3 C H 2 cat. Pd/C B. t-buok OTs C. H 3 C CH 2 I 2 Zn/Cu D. H 3 C H a.) NaNH 2 b.) H 3 CI E. (H 3 CCH 2 ) 2 CuLi Br

3 2. (20 points) State whether each of the following reactions is non-enantioselective, partially enantioselective, completely enantioselective, non-diastereoselective, partially diastereoselective, and/or completely diastereoselective. If relevant, state if these reactions are enantiospecific and/or diastereospecific. Describe your reasoning clearly and succinctly. OH H 3 C SOCl 2 Cl H 3 C OH H 3 C SOCl 2 Cl H 3 C 3. (10 points) Use IUPAC nomenclature to write the systematic name of the following alkane. H 3 C H 3 C

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 5. (25 points) Write the specific reagent(s) necessary to effect the transformation shown, for each of the following three (3) questions. If more than one reaction is involved in an answer, be certain to distinguish the individual steps clearly. A. O O O B. H O O C. OH (racemic) CN

6 6. (20 points) Draw specific structures for each of the following five (5) categories. A. two compounds that are diastereomers of each other: B. a hydrocarbon whose mass spectrometric M+1 peak is 18% of the M + peak s intensity: C. a resonance-stabilized cation: D. a conformation with three 1,3-diaxial interactions: E. an alkene addition reaction that proceeds by an S N 2 mechanism with S N 1 character:

7 7. (25 points) Draw the structure of the major organic product that is formed from the reaction of the following primary alcohol with the Dess-Martin periodinane. Use letters to label all the sets of chemically equivalent carbons in this structure. The broadband proton-decoupled 13 C NMR spectrum of the product is shown below. DEPT 90 and DEPT 135 data are included in the table on the following page. Use this spectroscopic data to make clear assignments of all the resonances and determine the identity of the product. (A 13 C NMR correlation table is included separately.) OH DMP? H 3 CO PPM

8 7. (continued) C NMR assignments: chemical shift (ppm) assignment DEPT 90 DEPT 135 DEPT explanation present up absent absent absent absent present up present up 64.7 absent up 43.1 absent down 35.2 absent down 22.5 absent down structure:

9 8. (25 points) Draw the mechanism of the following reaction, using the curved-arrow notation to indicate the reorganization of electron density. Show all intermediates, unshared electrons, nonzero formal charges, countercharges, and reversibility or irreversibility. Finally, explain why the observed regiochemical results are obtained. I H 3 CCH 2 OH (excess) OCH H 3 CCH 2 O H H I _ Congratulations! 1 /25 2 /20 3 /10 4 /50 5 /25 6 /20 7 /25 8 /25 Total: /200