Chem 352 Winter 2006 students: We are behind my anticipated schedule. You should make a composite exam in the following way: On the 351 sample final exam try questions 1, 4-7, 17, On this exam (352 #1) try only questions 1-4, You should review alkene nomenclature and the use of cis/trans and E/Z designations. Also read the slides “How to draw a mechanism” which are found with the PowerPoint lecture slides. (“Merged” mechanisms are OK by me.)

1. Give the expected major product in each of the following reactions. Br 2 H2OH2O 1M H 2 SO 4 H2OH2O HBr peroxides conc HCl AB CD 2. Write the structure of the alkyne whose hydration product would be: a) b) D. PAVIA CHEM 352 SAMPLE EXAM ONE

3. It is difficult to synthesize an alkene from an alkyne. How can the following reaction be accomplished? Show specific reagents and explain. 4. Show the reactions you would use to prepare the following compounds starting with any alkene that you wish. Be sure your method gives the desired compound as the major compound. a) b)c)

5. Give the expected result for each of the following reactions. KOH ethanol / heat KOH ethanol / heat KOH ethanol / heat

KOH / EtOH heat

NaOEt / EtOH heat NaOEt / EtOH heat KOH / EtOH heat

6. Which of the following compounds will react with the fastest rate when allowed to undergo solvolysis (elimination) in warm ethanol? Explain briefly. a)b)c) 8. Draw comparative energy profile curves (overlaid) for each of the compounds in Problem What kind of elimination reaction takes place in Problem 6? __________

9. Classify each of the following reactions as either E1, E2 or E1cb.

10.Draw a complete mechanism for the following reaction. Include electron pairs, formal charges, and curved arrows. Also be sure to mark the rate-determining step. 11. How could you prepare the following compound? Give a method.

12. Name the following compounds. a) NaOCH 2 CH 3 b) c) 13. Show what reactions you would use to convert 1-pentene to 2-pentyne. 14. E2 eliminations always follow the Zaitsev Rule. True or false? Explain your answer.

a) 1-Butene reacts with concentrated HCl at a faster rate than any 2-butene. c) All three alkenes give the same major product. b) cis-2-butene reacts (same reagent) faster than trans-2-butene. 15. d) The reaction forming the product is exothermic in each case. e) The same intermediate is formed in each case. Draw an energy profile that explains the difference in the rates of reaction for these 3 alkenes. All three compounds may be drawn on the same set of coordinates. HINT. Remember the heats of hydrogenation studies on these three alkenes.

16.Consider the two isomeric alkenes: 2-butene and 2-methyl-1-propene. a) Which alkene would you expect to react fastest with concentrated HCl? b) Draw two energy profiles (one for each reaction) to illustrate (explain) your answer. c) What is the most important mechanistic reason that your choice reacts fastest? HINT: Think about intermediates.

17.Draw a complete mechanism, showing the formation of the correct major product, for the following reaction. Show all steps, all intermediates, all unshared pairs, and all charges where appropriate. Use curved arrows to indicate electron movement. Pay attention to stereochemistry. CH 3 CH 3 OH+ H 2 SO 4 (HINT: H 2 SO 4 ionizes completely in CH 3 OH.) 3M in methanol (no water)