Ochem Exam 2

Formation of epoxide

Formation of epoxide

MCPBA attacks electron-filled double bond.

Acid-catalyzed opening of epoxides in water

H⁺, H₂O; adds two OH groups on carbons.

Acid-catalyzed opening of epoxides in alcohols

H⁺, Alcohol; alkoxy group attacks more substituted side.

Acid-catalyzed opening of epoxides using HBr, HCl, or HI

Br/I/Cl attacks more substituted side; stereoinversion.

Base-catalyzed opening of epoxides with alkoxides or hydroxide

Alkoxy group bonds to less substituted side.

Base-catalyzed opening of epoxides with organometallics

R group binds to less substituted side.

Grignard reaction with epoxides

RMgX reacts with epoxide.

Electrophilic Aromatic Substitution: Halogenation

Br₂, FeBr₃ used for bromination.

Electrophilic Aromatic Substitution: Nitration

HNO₃, H₂SO₄ used; adds NO2 group.

Electrophilic Aromatic Substitution: Addition of amine to ring

HNO3, H2SO4, Zn/HCl used.

Electrophilic Aromatic Substitution: Sulfonation

SO₃, H₂SO₄ used; adds HSO3 group.

Desulfonylation of benzene

H2O, H⁺, heat used.

Electrophilic Aromatic Substitution: Iodination

I2 and HNO3 used.

Friedel-Crafts Alkylation

Alkyl chloride, AlCl₃ used.

Friedel-Crafts Acylation

Acyl chloride, AlCl₃/H2O used.

Protonation of Alkenes

HF forms cation attacking aromatic ring.

Limitations of alkylation

Rearrangements possible; limit to 2 carbons.

Clemmenson reaction

Acyl chloride + AlCl3, then ZnHg to remove carbonyl.

Wolf Kishner reaction

NH2NH2, NaOH used; removes carbonyl.

Nucleophilic Aromatic Substitution

F>Cl>Br>I; Nucleophile added.

Hydrogenation of benzene ring

3H2, pressure, Pd catalyst used.

Suzuki reaction

Aryl halide, boronic acid, Pd catalyst used.

Heck reaction

Aryl halide, alkene, Pd(OAc)₂, PPh₃, Et₃N used.

Adding alkyl to aromatic ring or alkene

(R_2CuLi)+ R-X used to replace leaving group.

Synthesizes ethers from alcohols and halides (Williamson Ether Synthesis)

Alkoxide ion, primary alkyl halide used.

Synthesizes ethers via alkene addition (Alkoxymercuration-Demercuration)

Alkene, Mercury(II) acetate, then reduction with NaBH₄.

Synthesizes phenyl ethers from phenols

NaOH forms phenoxide ion, reacts with alkyl halide.

Cleaves ethers into alkyl halides

HX in excess used; Ar-O-R turns into Ar-OH.

Aromatic ring to ring with two double bonds

Na NH3 (l)