1. CH 7-3: E2 Reaction - Stereospecific Elimination
To form overlapping p-orbitals in the alkene product, the b-hydrogen and leaving group must be “anti-coplanar” in the transition state...……..”anti-elimination”.
When the leaving group OR b-hydrogen is at a chiral center, the stereochemistry of elimination becomes important in determining the geometry of the alkene product.

2. Stereochemistry in the E2 Reaction: Elimination at Chiral Centers
Look at the Neuman Projection for the alkyl halide:
Note that if Ha is anti with Br, that the trans alkene forms.

3. Note that if Hb is anti with Br, that the cis (less stable) alkene forms.

4. SN1/E1 Substitution & Elimination Reactions in Cycloalkanes…non-Stereospecific

5. SN2/E2 Substitution & Elimination Reactions in Cycloalkanes…Stereospecific!!!