sn1 sn2 e1 e2 reagents

nanh2

strong base, strong nucleophile

NaOH / KOH

strong base, strong nucleophile

NaOCH₃ / KOCH₃

strong base, strong nucleophile

NaOEt / KOEt

strong base, strong nucleophile

RO^-

strong base, strong nucleophile

OH^-

strong base, strong nucleophile

NaCN / CN^-

strong nucleophile, weak base

NaI / I^-

strong nucleophile, weak base

NaBr / Br^-

Strong nucleophile, weak base

NaSH / HS⁻

strong nucleophile, weak base

RS⁻

strong nucleophile: sulfur is big, attacks carbon well

weak base: the negative charge is more stable on sulfur (since bigger atom spread charge) than on oxygen, so it is less eager to grab H

CH₃COO⁻ / RCOO⁻

strong nucleophile, weak base

H₂O

weak nucleophile, weak base

CH₃OH

weak nucleophile, weak base

EtOH

weak nucleophile, weak base

ROH

weak nucleophile, weak base

RCOOH

weak nucleophile, weak base

KOtBu / t-BuO⁻

strong bulky base, poor nucleophile

DBU

strong bulky base, poor nucleophile

DBN

strong bulky base, poor nucleophile

LDA

strong bulky base, poor nucleophile

Hünig’s base

strong bulky base, poor nucleophile

in general how to know if strong/weak base

strong bases are usually (-) charged and unstable/happy to grab H⁺; weak bases are usually neutral or resonance-stabilized. think OH⁻, RO⁻, NH₂⁻ = strong bases, while H₂O, ROH, RCOOH = weak bases.

How do I know how many E2 alkene products form?

Find the carbon with the leaving group → check the 2 adjacent β-carbons.

If removing H from either side gives the same alkene → 1 product

If it gives different double-bond locations → 2 products

NaNH₂ (2 eq.)

strong base used for double E2 elimination of a vicinal or geminal dihalide → alkyne.

2 equivalents = remove 2 HX → make a triple bond.

⁻OC(CH₃)₃

or KOtBu / t-BuO⁻
strong bulky base, poor nucleophile

E1 product?

2 prod (trans, cis)

Major = Zaitsev (more substituted ). Because E1 forms a carbocation, always check for 1,2-hydride/alkyl rearrangement first before drawing the alkene.

sn1 properties

3>2>1
protic reagent
racemic
carbocation

sn2 properties

1>2>3
aprotic
inversion (1 prod)

KOH

strong base, strong nucleophile → SN2 or E2
KOH gives OH⁻

Why 3° SN1 faster than 1° SN1?

SN1 forms a carbocation first.

3° carbocation is more stable than 1°, so 3° reacts faster.

What does heat (Δ) usually favor in SN1/SN2/E1/E2?

Heat favors elimination over substitution.

Think: Δ → E1/E2 more likely, especially if elimination is already possible.

What makes something work best as a base and not as a nucleophile?

It is usually a strong, bulky/sterically hindered base.
Bulky = hard to attack carbon → poor nucleophile, but it can still grab H⁺ → base/E2.

when does e2 favor hoffman

E2 favors the Hofmann product = less substituted alkene when you use a bulky base.