Summary of "SN2 Practice Questions"

Main Ideas and Concepts

SN2 Reaction Overview
- The SN2 (Substitution Nucleophilic Bimolecular) reaction is a bimolecular reaction where the rate depends on the concentrations of both the Nucleophile and the substrate.
- It is a concerted mechanism, meaning there are no intermediates formed.
- The reaction involves a backside attack, leading to stereochemical inversion.
Factors Affecting SN2 Reactions
- Steric Hindrance: SN2 reactions are sensitive to Steric Hindrance; they work best with primary or secondary alkyl halides.
- Nucleophile Quality: A strong Nucleophile is necessary for the reaction to occur.
- Solvent Preference: Polar Aprotic Solvents are preferred in SN2 reactions.
Predicting Products
- When predicting products of SN2 reactions, identify the leaving group and Nucleophile, and consider the stereochemistry.
- The Nucleophile attacks the carbon atom bearing the leaving group, displacing it.
Choosing Leaving Groups
- When multiple potential Leaving Groups are present, consider the hybridization of the carbon atom they are attached to (SN2 does not occur at sp2 hybridized carbons).
- The Reactivity of Leaving Groups is influenced by their steric environment and hybridization.
Ranking Reactivity
- Reactivity can be ranked based on the stability of the leaving group and the Steric Hindrance around the reacting site.
- The nature of the leaving group (e.g., I⁻ > Br⁻ > Cl⁻ > F⁻ in terms of stability) is crucial for determining Reactivity.

For Predicting Products:
- Identify the Nucleophile and leaving group.
- Determine the hybridization of the carbon attached to the leaving group.
- Consider the stereochemistry and whether inversion will occur.
For Choosing Leaving Groups:
- Assess the hybridization of the carbon to which the leaving group is attached.
- Choose the best leaving group based on Steric Hindrance and hybridization.
For Ranking Reactivity:
- Compare the positions of the Leaving Groups (primary, secondary, tertiary).
- Evaluate the stability of the Leaving Groups and their proximity to double bonds (allylic positions are more reactive).