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SN1, SN2, E1, or E2 Reaction? Cheat Sheet (DRAFT) by

This is a draft cheat sheet. It is a work in progress and is not finished yet.

Step 1: The Solvent

Is it Protic?
Hydrog­en-­don­ating (H bonded to electr­one­gative molecule) will add lots of H+ to the solution. Would stablilize strong base/n­ucl­eophile.

SN2 and E2 unlikely.
Necessary for SN1 or E1.
Is it Aprotic?
No Hydrogens attached to electr­one­gative molecules. Would not react with strong base or strong nucleo­phile.

SN1 or E1 unlikely.
Necessary for SN2 or E2.

Step 2: The Leaving Group

Is it a good leaving group?
Favors all reactions, but is necessary for SN1 or E1 because the LG must leave on its own first.
Some Examples:
I, Br, Cl

Step 3: The Reactant

Is it a strong Nucleo­phile?
Small (not "­bul­ky") nucleophilic.
Able to perform backside attack in SN2 reaction.
Is it a strong base?
If there is no protic solvent, will attack Beta-c­arb­on-­hyd­rogens to form carboc­ations in E2 reaction.

Step 4: The Substrate

Is the alpha carbon Primary (1o)?
Can only go through an SN2 reaction.
Is the alpha carbon Secondary (2o)?
Favors either SN2 or E2 reaction.
Is the alpha carbon Tertiary (3o)?
Favors an E1 or E2 reaction through alkene stability.