Ch. 7 - Substitution ReactionsWorksheetSee all chapters
All Chapters
Ch. 1 - A Review of General Chemistry
Ch. 2 - Molecular Representations
Ch. 3 - Acids and Bases
Ch. 4 - Alkanes and Cycloalkanes
Ch. 5 - Chirality
Ch. 6 - Thermodynamics and Kinetics
Ch. 7 - Substitution Reactions
Ch. 8 - Elimination Reactions
Ch. 9 - Alkenes and Alkynes
Ch. 10 - Addition Reactions
Ch. 11 - Radical Reactions
Ch. 12 - Alcohols, Ethers, Epoxides and Thiols
Ch. 13 - Alcohols and Carbonyl Compounds
Ch. 14 - Synthetic Techniques
Ch. 15 - Analytical Techniques: IR, NMR, Mass Spect
Ch. 16 - Conjugated Systems
Ch. 17 - Aromaticity
Ch. 18 - Reactions of Aromatics: EAS and Beyond
Ch. 19 - Aldehydes and Ketones: Nucleophilic Addition
Ch. 20 - Carboxylic Acid Derivatives: NAS
Ch. 21 - Enolate Chemistry: Reactions at the Alpha-Carbon
Ch. 22 - Condensation Chemistry
Ch. 23 - Amines
Ch. 24 - Carbohydrates
Ch. 25 - Phenols
Ch. 26 - Amino Acids, Peptides, and Proteins

Solution: Rank the SN2 reaction rates for the following compounds:2-bromo-3-methylbutane, bromomethane, 1-bromo-3-methylbutane, 2-bromo-2-methylbutane

Solution: Rank the SN2 reaction rates for the following compounds:2-bromo-3-methylbutane, bromomethane, 1-bromo-3-methylbutane, 2-bromo-2-methylbutane

Problem

Rank the SN2 reaction rates for the following compounds:

2-bromo-3-methylbutane, bromomethane, 1-bromo-3-methylbutane, 2-bromo-2-methylbutane

Solution

We’re being asked to rank the reaction rates of each compound for an SN2 reaction.


Recall that the SN2 reaction follows a backside attack from the nucleophile:



Steric interactions from additional R-groups makes it harder for the nucleophile to attack. This means a more substituted alkyl halide will have a slower reaction rate.


The relative rates for an SN2 reaction are: methyl (fastest) > 1˚ > 2˚ > 3˚ (slowest or no reaction)


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