1 of 9 Midterm Exam 3 [Chapters 7-9 (Carey, 9th Ed)] CHE201/203, A-C Professors Gong and Rzayev, Dr. Clizbe Fall 2015 Nov. 20, 2015 Version A (Exam duration: 1 h 30 min) Name:______________________________________________ Person #:____________________________________________ circle one: Drs. Clizbe, Gong, and Rzayev: Section (A, B, C) TA Name:____________________________ or CHE203 Page Total Possible Points (Possible Points per page) Points 2 30 3 11 4 19 5 30 6 20 7 15 8 15 9 Periodic Table TOTAL POSSIBLE: 140 YOUR TOTAL:_________ Molecular models are ALLOWED; calculators are NOT ALLOWED. No cell phones or extra paper will be provided. Fill out the exam in pen, use the back of the page if more room is needed.2 of 9 1. (30 pts) Circle the correct structure for each question. (5 points each) (a) Which of the following would act as the weakest nucleophile in an SN2 reaction? CH3OH CH3O- Br- CH3S- (b) Which of the following would not rotate polarized light? (c) Which of the following is the worst leaving group? (d) Which of the following alkyl bromides will react the fastest in an SN2 reaction? (e) Which of the following molecules has the highest pKa for the indicated hydrogen? (f) Which reagent would be used to quantitatively remove a proton from acetylene? NaNH2 NH3 NaOH NaOCH2CH3 HHHH3 of 9 2. What is the ratio of enantiomers in a mixture that has 30% ee? (4 points) 3. The enol shown below is the intermediate product in the HgSO4 catalyzed hydration of 1-butyne. The ketone is the isolated product. Use the arrow formalism to show the mechanism of how the enol is transformed into the ketone. (The mechanism starting from 1-butyne is not needed). (7 points)4 of 9 4. (19 points) (a) (10 points) Indicate the correct configuration (R or S) of the chiral centers for the following molecules. (2 pts each) (b) (9 points) Indicate the relationship of each pair of molecules (constitutional isomers, enantiomers, identical, or diastereomers) (3 pts each)5 of 9 5. (30 points) For the following reactions, indicate if the mechanism goes by SN2, SN1, E2 and/or E1. If more than one product is formed from the same pathway, state which product is major. Show stereochemistry where applicable. (6 pts each) (a) (b) (c) (d) (e)6 of 9 6. (20 points) Draw the structures of the missing organic product(s)/reactant(s) for each of the following reactions. Provide stereochemistry (wedge-dash notation) where applicable. For reactions producing more than one product, please only draw the major product. (5 pts each) (a) (b) (c) (d) H2SO4, H2OHgSO41.O32. H2O7 of 9 Reaction Mechanism (15 points) 7. Using the arrow formalism to show electron movement, provide a detailed mechanism showing each individual step of the reaction mechanism. Be sure each step is charge balanced and mass balanced. (15 pts)8 of 9 Multi-Step Synthesis (15 points) 8. Show how the following conversion can be accomplished in good yield. More than one step will be needed. Provide the reagent(s) needed to perform the following transformations in good yield. Also, include the product of each step. (Mechanism, transition states, mechanistic intermediates are not needed) (15 pts)9 of