Organic Chemistry: Concepts and Applications - Headley Allan D. 2020

Nucleophilic Substitution Reactions at sp3 Carbons
End of Chapter Problems

1. 15.23 Classify each of the following alkyl halides as methyl, primary, secondary, or tertiary.Image

2. 15.24 Using no more than five carbons, give the structures and IUPAC names of the following type of molecules.

1. Primary halide

2. Secondary halide

3. Tertiary halide

3. 15.25 Give the structure and IUPAC names for all isomers that have the formula C5H11Cl. Also, classify each as primary, secondary, or tertiary.

4. 15.26 For each over-all substitution reaction below, identify the electrophilic atom in the organic substrate, the nucleophile and its nucleophilic atom, and the leaving group.

1. CH3CH2Br + Na+ −:SC2H5 → (CH3CH2)2S + Na+ Br

2. C6H5CH2O2CH3 + Na+ −:CN → C6H5CH2CN + CH3CO2 Na+

3. CH3CH2OH + HI(excess) → CH3CH2I + H2O

4. CH3CH2Br + :NH2CH3 → CH3CH2N+HCH3 Br

5. CH3CH2I + :P(C2H5)2 → (CH3CH2)3P+ + I

5. 15.27 Of the following pairs of alkyl halides, which is the most reactive by an SN2 mechanism?

1. CH3Cl and CH3CH2Cl

2. CH3Cl and CH3Br

3. CH3CH2CH2Cl and (CH3)2CHCl

4. (CH3)3CCl and (CH3)2CHCl

6. 15.28 Of the following pairs of alkyl halides, which is the most reactive by an SN1 mechanism?

1. CH3Cl and CH3CH(CH3)Cl

2. CH3CH(CH3)Cl and CH3CH(CH3)Br

3. CH3CH2CH2Cl and CH3CH(CH3)Cl

4. (CH3)3CCl and (CH3)2CHCl

7. 15.29 (CH3)3CCH(Br)CH2CH3 undergoes SN1/E1 reactions in aqueous solvent, give the structures of the products that are formed.

8. 15.30 What is the principal organic product of the E2 reaction of (1R, 2S)-1-iodo-1,2-diphenylbutane in the presence of hydroxide ions (HO)?Image

9. 15.31 Of the following pairs of carbocation, which is the most stable?

10. 15.32 Show how to carry out the transformation shown below. Clearly indicate different steps in your synthesis, solvents, reaction conditions and any other reagents used for your synthesis.Image

11. 15.33 In an aqueous solution, I catalyzes the SN2 reaction shown below.Image

The catalysis depends upon I being a better nucleophile than OH and a better leaving group than Cl.

1. Give a two-step sequence for the I catalysis reaction.

2. Starting with (R)-2-chlorobutane, show the stereochemistry of both steps of your mechanism.

12. 15.34 Suggest an alkyl halide and appropriate nucleophile that would react to form the products shown.Image

13. 15.35 For the following reaction, explain (with the aid of an appropriate mechanism) the formation of each of the products shown.Image

14. 15.36 Predict the major product for each of the following reactions (include stereochemistry where appropriate).Image

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15. 15.37 Complete the following reactions by giving the structures of the reactant, missing reagents above the arrow or major organic product. Note: some transformations may require more than one step and these steps must be indicated clearly. Indicate stereochemistry where appropriate.Image

16. 15.38 Rearrangement of carbocation intermediates often occurs for SN1 reactions. With this information in mind, explain by appropriate mechanisms (i.e., step-by-step descriptions and curved arrows to indicate electron movements) the formation of the organic products shown for the following reaction.Image

17. 15.39 Show how to carry out the following transformations. For each step in your synthesis, clearly show all reagents and reaction conditions.(Hint: identify the bond of the functional group in the product that must be made, then work backward to identify an appropriate molecule and reaction type to make that bond).Image