1、.CHE 31: Organic ChemistryNameTest 1March 12, 1999 1. Multiple choice (2 points each)Which of the following is not true about aromatic compounds?(a) They have 4n + 2 p electrons.(b) They must have a cyclic arrangement of the atoms in the aromatic group.(c) They cannot be charged.(d) All atoms in the

2、 ring must be sp2 hybridized.(e) The aromatic ring is always planar.Which is the best method to accomplish the transformation shown?(a) (1) Mg, ether; (2) CH3CH2CHO; (3) H3O+; (4) NaBH4(b) (1) HOCH2CH2OH, H+; (2) Mg, ether; (3) CH3CH2CHO; (4) H3O+; (5) NaBH4(c) (1) TMSCl; (2) Mg, ether; (3) CH3CH2CH

3、O; (4) H3O+; (5) NaBH4(d) (1) LiAlH4; (2) H3O+; (3) HOCH2CH2OH, H+; (4) Mg, ether; (5) CH3CH2CHOWhich is the best method to prepare the ether shown?Which of the following species is not aromatic?Which is the best method to accomplish the transformation shown?(a) (1) Mg, ether; (2) CH3CH2CHO; (3) H3O

4、+; (4) PCC(b) (1) TMSCl; (2) Mg, ether; (3) CH3CH2CHO; (4) H3O+; (5) Jones reagent(c) (1) TMSCl; (2) Mg, ether; (3) CH3CH2CHO; (4) H3O+; (5) PCC(d) (1) Mg, ether; (2) CH3CH2CHO; (3) H3O+; (4) Jones reagent2. Propose a mechanism to account for the acid catalyzed hydrolysis of the imine shown below. U

5、se arrows to show the flow of electrons and show every step! (20 points)3. Provide the major products for the following reactions, indicating stereochemistry where relevant. (4 points each)4. Do two out of the following three synthesis problems. (10 points each)(a) (b) (c) 5. Electrophilic addition

6、of Br2 to isoprene yields the following product mixture. Of the 1,2-addition products, explain why 3,4-dibromo-3-methyl-1-butene (21%) predominates over 3,4-dibromo-2-methyl-1-butene (3%). Why is the major product the one shown? Explain, using energy level diagrams. (10 points)6. A student was direc

7、ted to purify maleic anhydride (shown below) by recrystallizing it from cyclopentane and she used cyclopentadiene by mistake. Show the reaction that is likely to happen in her heated mixture. (10 points)7. Anisole (C6H5OCH3) was reacted under conditions that would create methyl cations as an electrophile. Analyze the 1H NMR and IR spectra on the next page, and determine the structure of the major product from