nucleophilic substitution + elimination rxns

SN2 substrate

CH₃ > primary > secondary

SN2 nucleophile/base

strong nucleophile

SN2 solvent

polar aprotic

E2 substrate

tertiary > secondary > primary

E2 nuceophile/base

strong base

E2 solvent

polar aprotic*

+ strong/bulky bases such as t-BuO^-, DBN, DBU, + LDA

SN1 substrate

tertiary > secondary

SN1 nucleophile/base

weak nucleophile

SN1 solvent

polar protic

E1 substrate

tertiary > secondary

E1 nucleophile/base

weak base

E1 solvent

polar protic

SN2 summary

• substrate: CH₃ + least substituted

• nucleophile/base: strong nucleophile

• solvent: polar aprotic

E2 summary

• substrate: most substituted > primary

• nucleophile/base: strong base

• solvent: polar aprotic*

SN1 summary

• substrate: most substituted

• nucleophile/base: weak nucleophile

• solvent: polar protic

E1 summary

• substrate: most substituted

• nucleophile/base: weak base

• solvent: polar protic

strong nucleophile

• negatively charged

• not sterically hindered (easy access to nucleus)

• high polarizability (electron cloud !!)

• low electronegativity

weak nucleophile

• neutral

• sterically hindered

• high electronegativity

strong base

• conjugate base of strong acid (low pKa)

• highly reactive

• negatively charged

weak base

• conjugate base of weak acid

• less reactive

• neutral