This preview shows page 1. Sign up to view the full content.
Unformatted text preview: 5.12 Practice Exam #3 Prof. B. Imperiali Exam will be held on Monday April 14th at noon. Notes and calculators will not be allowed in the exam but you will be provided with a periodic table and you may bring use molecular models to use. The exam will cover material from 3/12-4/11. The practice exam key will be posted as a separate file so that you can print up the exam and take it as a “real practice” before you check out the answers. Page 2 Short questions (1-9 3 points each and 10-12 4 points) 1. Estimate the pKa of the proton indicated. H A. 50 B. 35 C. 25 D. 5 2. Estimate the pKa of the proton indicated. OH A. 30 B. 10 C. 5 D. 1 3. Identify the major product of the reaction shown. H H Br H H Br H Br Br H H Br Br2
(in the dark) H A. B. C. 4. Identify the major product of the reaction shown. KO(CH3)3 Br O A. B. C. Page 3 Short questions Name __________________ 5. Which of the following terms is the best description of the alkene shown below. HO Cl F A. Cis Alkene C. Z Alkene B. Trans Alkene D. E Alkene 6. Which of the following is the most stable free radical? A. CF 3 B. C. D. 7. Which of the following compounds are formed when ethene is bubbled into an aqueous solution of bromine and sodium chloride? I. BrCH2CH2Br I. ClCH2CH2Br I. BrCH2CH2OH A. I and II B. I and III C. II and III D. I, II and III 8. Which of the following reagents effectively cleaves carbon-carbon double bonds? A. Br2 and light C. OsO4 follwed by H2O2 B. meta-chloroperoxybenzoic acid D. O3 followed by (CH3)2S Page 4 Short questions Name __________________ 9. Ozonolysis of an unknown compound gave CH2=O, CH3CHO and CH3COCHO. What are possible structures for the unknown compound? I. II. III. IV. A. I and II B. I and IV C. II and III D. II and IV 10. Which of the following reactions does NOT occur as shown A. CH3C B. CH3C C. CH3C D. CH3C
C Na+ C Na+ + CH3CO2H + CH3OH + + NaNH2 NaOH CH3CO2-Na+ CH3O-Na+ NH3 H2O + + + CH3C + CH3C CH CH
C Na+ C Na+ CH CH CH3C CH3C 11. Compound J undergoes a rearrangement to yield compounds K and L. Based on the potential energy diagram below which of the following statements is true?
Potential energy A. K is formed faster and is more stable than L. J K L
Reaction coordinate B. K is formed faster and is less stable than L C. L is formed faster and is less stable than K D. L is formed faster and is more stable than K Page 5 Short questions Name_________________ 12. Label the following pairs of molecules as E (enantiomers), D (diastereomers), or S (same molecule). Br Br Br Br Br Br OH OH Br Br Br Br CH3 CH3 Page 6 Long questions (Points as shown) Name __________________ 13. (16 points) For the following compounds, indicate whether they will react under SN1 conditions (EtOH, D), SN2 conditions (KI/acetone), both, or neither. Indicate the products and by which mechanism they are produced. H3C I H3C CH3 OTf Br H3CO Cl H3C H3C CH3 OMs Br OCH3 Br Page 7 Long questions (Points as shown) Name__________________ 14. (20 points) Design syntheses of compounds I and II (10 points each). The pool of carbon-containing starting materials that you can use are shown in the square brackets. You may use any other common reagents.
H O H OH H Br O II. HC CH Br Br Note: a clear retrosynthetic analysis will be useful for figuring these problems out. Partial credit will be given for a retrosynthetic analysis even if the synthesis is incomplete. Page 8 Long questions (Points as shown) Name __________________ 15. (24 points) Provide a detailed stepwise mechanism to account for the following transformations. 8 points each. a.
O H Cl D D Na+ OMe- H MeO O D D b. H+ClHO O c. OH
HBr D Br SN1 conditions Br ...
View Full Document