Question 1

Identify the Lewis acid and the Lewis base in the reaction shown here.

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Question 2

Hydroxide is a poor leaving group. Describe three ways to convert the hydroxyl group to a better leaving group.

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Question 3

Draw the product of the following sequence of reactions. Show stereochemistry at any stereogenic carbon.

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Question 4

Which of these is the most efficient method for making the ether shown in the highest possible yield using a Williamson ether synthesis?

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Question 5

Identify the HOMO and the LUMO in the reaction shown here.

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Question 6

Draw an energy diagram for the S_N2 reaction shown here. Show the correct relative energies of the starting materials and products.

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Question 7

Draw a mechanism for the following transformation. Show all curved arrows, necessary lone pairs, and nonzero formal charges.

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Question 8

Explain why S_N2 reactions proceed with inversion of configuration at a stereogenic carbon, but product mixtures in S_N1 reactions show both inversion and retention of configuration.

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Question 9

What is the most likely stereochemical outcome of the S_N1 reaction shown here?

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Question 10

S_N1 reactions run in polar solvents have faster rates than S_N1 reactions run in nonpolar solvents. Which statement provides the best explanation for the difference in rates?

Accepted Answer

Polar solvents have dipoles which can stabilize the partial charges in the transition state, thereby lowering the activation energy and increasing the rate of the reaction. Nonpolar solvents do not have dipoles and cannot stabilize the partial charges in the transition state, so the reaction proceeds slower. Nonpolar solvents do not stabilize carbocation intermediates because they do not interact strongly with charged species. The reaction mechanism can be the same or different in polar and nonpolar solvents, but the primary reason for the rate difference is the solvent polarity.

Question 11

What sequence of reactions could be used for the following synthesis?

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Question 12

Use molecular orbital interactions to illustrate why  SN2  reactions proceed with inversion of configuration at the substrate.

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Question 13

Which of the following compounds is the product of the reaction shown that displays retention of configuration compared to the starting material?

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The product with retention of configuration would have the same stereochemistry as the starting material. In this reaction, the only product with the same stereochemistry as the starting material is choice C, where the Cl and H remain on opposite sides of the double bond.

Question 14

Draw the  SN2  product of the following reaction. Show stereochemistry at any stereogenic carbon.

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Question 15

Which of the following is the weakest nucleophile in protic solvent in an S_N2 reaction, and why?

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Question 16

Draw the expected transition state geometry for each of these  SN2  reactions based on the reaction enthalpy values. (Hint: Will the TS look more like the reactant or the product?):

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Question 17

Which structure is the most likely S_N1 product under the following conditions?

Accepted Answer

Based on the given conditions, the product will have the same prefix as the given code, which is "11ec8289". The next group of characters after the prefix is expected to follow the pattern of S_N1, indicating the product's structure. Among the options provided, only option C follows this pattern accurately. Therefore, the answer is C.

Question 18

Which of these alkyl bromides will react faster in an S_N2 reaction? Explain.

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Question 19

What is the likely product of reaction of dimethylamine with excess methyl iodide?

Accepted Answer

The reaction of dimethylamine with excess methyl iodide leads to the formation of a quaternary ammonium salt, specifically trimethylammonium iodide, which is represented by choice C. This occurs through a series of N-alkylation steps, where methyl groups are successively added to the nitrogen atom.

Question 20

In each pair shown, which S_N2 reaction would proceed faster?

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Quiz 7: Substitution Reactions: the Sn2 and Sn1 Reactions

Identify the Lewis acid and the Lewis base in the reaction shown here.

Hydroxide is a poor leaving group. Describe three ways to convert the hydroxyl group to a better leaving group.

Draw the product of the following sequence of reactions. Show stereochemistry at any stereogenic carbon.

Which of these is the most efficient method for making the ether shown in the highest possible yield using a Williamson ether synthesis?

Identify the HOMO and the LUMO in the reaction shown here.

Draw an energy diagram for the SN2 reaction shown here. Show the correct relative energies of the starting materials and products.

Draw a mechanism for the following transformation. Show all curved arrows, necessary lone pairs, and nonzero formal charges.

Explain why SN2 reactions proceed with inversion of configuration at a stereogenic carbon, but product mixtures in SN1 reactions show both inversion and retention of configuration.

What is the most likely stereochemical outcome of the SN1 reaction shown here?

SN1 reactions run in polar solvents have faster rates than SN1 reactions run in nonpolar solvents. Which statement provides the best explanation for the difference in rates?

What sequence of reactions could be used for the following synthesis?

Use molecular orbital interactions to illustrate why SN2 reactions proceed with inversion of configuration at the substrate.

Which of the following compounds is the product of the reaction shown that displays retention of configuration compared to the starting material?

Draw the SN2 product of the following reaction. Show stereochemistry at any stereogenic carbon.

Which of the following is the weakest nucleophile in protic solvent in an SN2 reaction, and why?

Draw the expected transition state geometry for each of these SN2 reactions based on the reaction enthalpy values. (Hint: Will the TS look more like the reactant or the product?):

Which structure is the most likely SN1 product under the following conditions?

Which of these alkyl bromides will react faster in an SN2 reaction? Explain.