8. What is the major product of the following reaction?

4. Which of the following statements is (are) true for the Diels-Alder reaction? (A) When the diene is electron-rich, the reaction works best when the dienophile contains one or more electron-withdrawing groups conjugated to its C=C. (B) Substituents which are cis in the dienophile remain cis in the product. (C) Dienes which cannot achieve an s-cis conformation do not react in Diels-Alder reactions. (D) Secondary orbital interactions typically cause the endo product to be favored kinetically over the exo. (E) All of the above.

5. What is the major product of the following reaction?

6. Which sequence of reagents works best to convert 3-hexene to 3-hexyne? (A) 1. HCl 2. NaNH2 (B) 1. BH3．THF 2. HO- , H2O2 3. NaNH2 (C) 1. NaNH2 2. HI 3. H3O+ (D) 1. Br2, CH2Cl2 2. NaNH2 (excess) (E) 1. Cl2, CH2Cl2 2. NaCN(excess)

7. Which of the following technique(s) can readily distinguish between: (A) NMR (B) IR (C) MS (D) A and B (E) A and C

9. What is the major product of the following reaction?

10. What is the major product from the following rearrangement?

11. At what position of the pyridine ring in the coenzyme below will oxidation-reduction reaction take place?  (A) 1 (B) 2 (C) 3 (D) 4 (E) 5

12. Which of the following reaction is called Knoevenagel reaction? 

13. Which of the following structures is a Fischer projection of (2R,3R,4S)-2,3,4-tribromoheptane?(A)(B)(C)(D)(E) None of the above

14. Arrange the following substrates in order of their increasing SN2 reactivity with NaCN: (I) 1-bromopentane, (II) 1-chloro-2,2-dimethylpentane, (III) 2-bromo-2-methylpentane, and (IV) 1-chloro-3,3-dimethylpentane. (A) IV < II < I < III (B) III < I < IV < II (C) IV < II < III < I (D) III < II < IV < I (E) None of the above