Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

7. Substitution Reactions

SN2 Reaction

Organic Chemistry

7. Substitution Reactions

SN2 Reaction

Previous problemNext problem

1:06 minutes

Problem 11b

Textbook Question

Practice your electron-pushing skills by drawing a mechanism for the following S_N2 reactions.
(b)

Verified step by step guidance

Step 1: Identify the nucleophile and electrophile in the reaction. In an Sₙ2 reaction, the nucleophile is typically a negatively charged or lone-pair-bearing species, and the electrophile is the carbon atom attached to the leaving group.

Step 2: Recognize the leaving group. The leaving group is the atom or group that will depart during the reaction. Common leaving groups include halides (e.g., Cl⁻, Br⁻, I⁻) or sulfonates.

Step 3: Draw the backside attack mechanism. In an Sₙ2 reaction, the nucleophile approaches the electrophilic carbon from the side opposite the leaving group. This results in a single-step mechanism where the bond between the nucleophile and the carbon forms as the bond between the carbon and the leaving group breaks.

Step 4: Show the transition state. The transition state in an Sₙ2 reaction is a pentavalent carbon intermediate where the nucleophile and leaving group are partially bonded to the carbon simultaneously. Represent this with dashed lines to indicate partial bonds.

Step 5: Complete the reaction by showing the products. The leaving group departs with its lone pair of electrons, and the nucleophile is now fully bonded to the carbon. Ensure stereochemistry is inverted at the carbon center if it is chiral, as Sₙ2 reactions proceed with inversion of configuration.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Sₙ2 Mechanism

The Sₙ2 (substitution nucleophilic bimolecular) mechanism involves a nucleophile attacking an electrophile simultaneously as the leaving group departs. This concerted process results in the inversion of configuration at the carbon center, making it essential to understand stereochemistry in these reactions. The rate of the reaction depends on both the nucleophile and the substrate, which is why it is classified as bimolecular.

Nucleophiles

Nucleophiles are species that donate an electron pair to form a chemical bond in a reaction. They are typically negatively charged or neutral molecules with lone pairs of electrons. In Sₙ2 reactions, strong nucleophiles are crucial as they effectively attack the electrophilic carbon, facilitating the substitution process. Common examples include hydroxide ions (OH⁻) and alkoxide ions (RO⁻).

Leaving Groups

Leaving groups are atoms or groups that can depart from the substrate during a chemical reaction, taking with them the electrons from the bond they formed with the substrate. A good leaving group is typically stable after departure, such as halides (Cl⁻, Br⁻, I⁻) or tosylate (OTs). In Sₙ2 reactions, the quality of the leaving group significantly influences the reaction rate and mechanism.

Watch next

Master Drawing the SN2 Mechanism with a bite sized video explanation from Johnny

Start learning

Related Videos

Related Practice

Textbook Question

The rate of the reaction of methyl iodide with quinuclidine was measured in nitrobenzene, and then the rate of the reaction of methyl iodide with triethylamine was measured in the same solvent. The concentration of the reagents was the same in both experiments.

a.Which reaction had the larger rate constant?

Textbook Question

Draw a transition state for the following substitution reaction.

Textbook Question

Predict the major products of the following reactions.

(a) ethyl tosylate + potassium tert-butoxide

(b) isobutyl tosylate + NaI

Textbook Question

Practice your electron-pushing skills by drawing a mechanism for the following S_N2 reactions.

(a)

Textbook Question

Which S_N2 reaction would you expect to be faster? Explain your answer.

Textbook Question

For each pair, choose the haloalkane that would react most quickly in an S_N2 reaction.

(b)

Textbook Question

For each pair, choose the haloalkane that would react most quickly in an S_N2 reaction.

(d)

Textbook Question

The following reaction, though run under standard solvolysis conditions, occurs via an S_N2 reaction. Why?

Show more practices

Download the Mobile app

Privacy

Do not sell my personal information

Accessibility

Patent notice

Sitemap

Practice your electron-pushing skills by drawing a mechanism for the following SN2 reactions. (b)

Key Concepts

Sₙ2 Mechanism

Nucleophiles

Leaving Groups

Watch next

Practice your electron-pushing skills by drawing a mechanism for the following S_N2 reactions.
(b)