Educational Materials for Organic Chemistry

Nucleophilic Substitution Dry Laboratory

Purpose

To utilize visualization tools to better understand the steric and inductive effects involved in the nucleophilic substitution mechanisms.

Steric Effect: Specific Learning Tasks

• View the spacefilling models in the table below - pay particular interest to the carbon with the leaving group attached, from all angles
• Imagine a nucleophile approximately the same size as the leaving group trying to approach that carbon
• Determine if the leaving group will be able to approach that carbon at all, from the side with the leaving group, or from the side without the leaving group.
• Consider what these determinations tell you about the ability of these molecules to react by the S_N2 mechanism.

Inductive Effect: Specific Learning Tasks

• Visualization tools to support this section of the exercise are under construction

NOTE: You will need the Chime plugin in order to view the three-dimensional models within the table below. The two-dimensional picture of each molecule can be clicked to receive the three-dimensional model which can be viewed with the Chime plugin or with RasMol

Models

Alkyl Halide	2-D Structure	3-D Structure	Expect SN2? (at a reasonable rate!)
1-Bromobutane			Yes. No.
1-Chlorobutane			Yes. No.
2-Bromobutane			Yes. No.
2-Chlorobutane			Yes. No.
2-Chloro-2-methylpropane			Yes. No.
Bromocyclohexane			Yes. No.
Bromobenzene			Yes. No.
Benzyl Chloride			Yes. No.
1-Bromo-2,2-dimethylpropane			Yes. No.

Last Modified: 10/31/96