E2 vs SN2 competition (concerted bimolecular fork) (Strong nucleophile/base on unhindered carbon favors SN2; heat, bulk, and β-H favor E2)
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Strong nucleophile/base on unhindered carbon favors SN2; heat, bulk, and β-H favor E2
What each symbol means
| Symbol | What it stands for |
|---|---|
| Y⁻ | Hard base/nucleophile (e.g., OH⁻, RO⁻) |
| R–X | Typically 1°/2° alkyl halide |
When to use this
Polar aprotic favors SN2; high temperature increases elimination; tertiary substrate removes SN2 channel (E1/E1cb may appear instead).