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exam3_blank - 1 CHEM 322b Fall 2011  Practice...

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Unformatted text preview: 1 CHEM 322b Fall 2011  Practice Exam III I. Multiple Choice 1. Circle the reaction condition or conditions below that would convert the carboxylic acid below into an aldehyde, as shown (ignore work ­up steps). OH H O O P CC A. LiAlH4 B. DIBAL-H C. 1. LiAlH4 D. 2. PCC 2. Circle the order (from most reactive to least reactive) that correctly ranks the reactivity of the following compounds toward nucleophilic attack at the carbonyl carbon. O O O O H I II Cl III IV A. IV > III > I > II C. IV > III > II > I B. III > IV > II > I D. III > II > IV > I 2 3. Circle the order (from most reactive to least reactive) that correctly ranks the reactivity of the following compounds toward nucleophilic attack at the carbonyl carbon. O O O O O O NH2 Cl I II O Na III IV A. II > I > IV > III C. II > III > I > IV B. IV > II > I > III D. II > I > III > IV 4. Predict the products of the following reaction. CH3 O O C H NaOH CH2CH3 H2O HO O H A. O B. C CH2CH3 H CH3 + H3CH2C C OH H CH3 O + HO O Na D. CH3 O O Na C. C H C H 2C H 3 O O O Na + H3CH2C C CH3 3 5. Circle the nucleophile or nucleophiles below that would react with the ester below to give a nucleophilic substitution product. O Nucleophile O O Cl O NH3 HCN 6. Circle the compound or compounds below that will yield benzaldehyde (C6H5CHO) upon reaction in an aqueous acidic solution? O C6H5 O O O C6H5 C6H5 O O C 6H 5 O O 7. The following transformation can best be effected by which set of reaction conditions listed below. O O O O O A. Zn(Hg), HCl, HOAc, and heat B. DIBAL ­H C. 1. NH2NH2 2. KOH and heat D. LiAlH4 4 8. Circle the compound or compounds below that will readily undergo decarboxylation with heating alone. OH O O OH O O O OM e O O OH 9. Given the following starting material and reaction conditions, circle the choice that represents the major product or products of the reaction. O Br2 NaOH CH3 Br O O Br + A. CH3 CH3 OH OH + B. CH3 CH3 O C. O O + D. H3C Br Br CH3 5 10. Circle the reaction condition or conditions that would selectively lead to the formation of the product below as the major product. O O A. NaOH / CH3CH2Br B. NaOEt / CH3CH2Br C. 1. LDA 2. CH3CH2Br D. 1. BuLi 2. CH3CH2Br 11. Circle the nucleophile or nucleophiles below that will selectively lead to the addition product below as the major product. Nu Nu O O CH3CH2O CH3CH2MgBr CH3CH2CH2CH2Li CN 12. Circle the least acidic compound. O O O O O O O H 6 13. Circle the strongest base. O LiOH CH3OLi LiH2C Li H 14. Circle the structure or structures below that represent an enolate formed under under kinetc control. O O O O H 15. A retrosynthetic analysis of the following compound can lead to which of the following reactant/condition combinations. H O A. + P(C6H5)3 B. HO P(C6H5)3 + O H2SO4 C. heat D. AlCl3 + Cl excess E. F. All of the above. None of the above. 7 16. Circle the structure below that is most reactive toward nucleophilic addition at the carbonyl carbon under basic conditions. O H II. O O H 3C O CH3 H H 3C CH3 Complete the Reactions 17. Note that stereochemistry is not important here (E or Z is not important). OH O and/or O OH H O 18. 1. Br 2. Compound A H O Compound A + H H 8 19. O O 20. O O O O Compound A O Compound A Cl 9 21. O O O NaBH4 Compound A Compound A O H+ Compound B Compound B 1. 2 eq. CH3CH2MgBr 2.cold, dilute H3O+ 22. NCN + N O 10 23. O O OH O O H H 24. O O OE t Compound A Compound A O 11 25. N H H+ Compound X O 1. CH3CH2CH2Cl Compound X 2. H3O+ 26. H 3O + H 2O H OH + H OH O C H 3C C H 3 27. O 1. LDA H 3C O 2. C6H5CH2Br 12 III. Draw the Mechanism 28. Draw the complete “electron ­pushing” reaction mechanism for the transformation below. O O 1. LDA (0 oC) 2. CH3CH2Br Li LDA = N 13 29. Draw the complete “arrow ­pushing” reaction mechanism for the transformation below. Indicate the structures of species A and B. Br 1. P(C6H5)3 A 2. nBuLi A + B C6H5CHO + (C6H5)3P=O 14 IV. Synthesis 30. Outline an efficient synthesis for the product below using the indicated starting material and any saturated alcohols of 4 carbons or fewer (i.e., methanol, ethanol, both C3H8O alcohols, or any C4H10O alcohols) as the only carbon sources. Consider the major products of individual steps for use in subsequent steps. Note that the product is formed only as the isomer given (no other isomers are possible). O O O O ...
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