Reaction guide

Every key reaction drawn out — starting material, reagents over the arrow, product. Search by name or reagent, or filter by type. Part of the OChem study guide.

Markovnikov addition of H–X across C=C

Markovnikov addition of H–OH

Markovnikov alcohol, no rearrangement

Anti-Markovnikov, syn addition of H–OH

HalogenationAddition

Anti addition of two halogens (halonium ion)

Anti addition of X and OH

Anti-Markovnikov H–Br (radical)

Catalytic hydrogenationReduction

Syn addition of H–H → alkane

EpoxidationOxidation

Alkene → epoxide (syn)

Syn dihydroxylationOxidation

Adds two OH syn → cis diol

OzonolysisOxidation

Cleaves C=C into carbonyls

Markovnikov twice → geminal dihalide

Markovnikov → methyl ketone (via enol)

Anti-Markovnikov → aldehyde

Alkyne → cis (Z) alkene

Alkyne → trans (E) alkene

Extend the chain at a terminal alkyne

SN2 substitutionSubstitution

Backside attack, inversion

SN1 substitutionSubstitution

Via carbocation, racemization

E2 eliminationElimination

Anti-periplanar, one step, Zaitsev

E1 eliminationElimination

Via carbocation → Zaitsev alkene

Make OH a good leaving group

TosylationSubstitution

OH → tosylate (great leaving group)

E1 loss of water → alkene

1° alcohol → aldehyde (stops there)

1° alcohol → carboxylic acid

Anti opening → 1,2-diol

Aldehyde/ketone → alcohol

Even acids/esters → alcohol

Grignard additionOrganometallic

Adds R⁻ to a carbonyl (new C–C)

Stronger carbon nucleophile

Carbonyl → alkene

Protect a carbonyl as an acetal

Carbonyl + 1° amine → C=N imine

Carbonyl + 2° amine → enamine

Adds CN and OH across a carbonyl

Enolate + carbonyl → β-hydroxy carbonyl

Aldol + dehydration → enone/enal

Two esters → β-keto ester

Halogen on the α-carbon (via enol)

Acid + alcohol → ester (reversible)

Ester → carboxylate + alcohol

Acid chloride + amine → amide

Carbonyl + amine → amine

Puts a halogen on the ring (EAS)

NitrationAromatic

Installs –NO2 (EAS)

SulfonationAromatic

Installs –SO3H (reversible, EAS)

Adds an alkyl group (EAS)

Adds an acyl group (ketone)

Ar–NO2 → aniline

Brominates the allylic position

Substitutes an alkane C–H

Diels–AlderPericyclic

Concerted [4+2] → cyclohexene