Exam 2 Reactions (Chapters 14 & 15)

Electrophilic Aromatic Substitution

Create super electrophile, nucleophilic attack by benzene, regenerate aromaticity

EAS Halogenation

Create super electrophile (Br2 bonds to FeBr3 or Cl2 bonds to AlCl3), nucleophilic attack by benzene (DB bonds to Br or Cl), regenerate aromaticity (BrFeBr3 or ClAlCl3 bonds to H and bond breaks to regenerate aromaticity)

Friedel-Crafts Alkylation (methyl and ethyl)

Create super electrophile (methyl/ethyl halide bonds to AlCl3 or FeBr3), nucleophilic attack by benzene (DB bonds to methyl or ethyl), regenerate aromaticity (BrFeBr3 or ClAlCl3 bonds to H and bond breaks to regenerate aromaticity)

Friedel-Crafts Alkylation (secondary and tertiary)

Create super electrophile (halide bonds to AlCl3 or FeBr3 then carbon group leaves to create carbocation), nucleophilic attack by benzene (DB bonds to carbocation), regenerate aromaticity (BrFeBr3 or ClAlCl3 bonds to H and bond breaks to regenerate aromaticity)

Friedel-Crafts Alkylation (primary other than ethyl)

Create super electrophile ( halide bonds to AlCl3 or FeBr3 then carbon leaves to form carbocation and rearrangement for stability occurs), nucleophilic attack by benzene (DB bonds to methyl or ethyl, regenerate aromaticity (BrFeBr3 or ClAlCl3 bonds to H and bond breaks to regenerate aromaticity)

Friedel-Crafts Acylation

create super electrophile (halogen bonds to compound, lone pairs move down and halogen leaves to create acylium ion), nucleophilic attack by benzene (stabilizes charge on oxygen), regenerate aromaticity

EAS Nitration

create super electrophile (OH of HNO3 steals H from H2SO4, OH2 group then leaves and nitronium ion is created), nucleophilic attack by benzene (bonds to nitrogen, kicking one DB electrons onto oxygen), regenerate aromaticity

EAS Sulfonation

H2SO4 fuming contains super electrophile SO3 gas, nucleophilic attack by benzene (onto sulfur, electrons go onto oxygen), regenerate aromaticity (H2O takes H), proton transfer (add H to negatively charged O from H3O)

Reverse EAS Sulfonation (Desulfonation)

proton transfer (H2O takes H from OH), destroy aromaticity (DB takes H), regenerate aromaticity (DB between S and O reforms, bond breaks to create DB on ring)

Clemmensen Reduction

(Acyl to Alkyl reagents) Zn(Hg), HCl, heat

Side-Chain Oxidation Book method

(Alkyl to Carboxyl reagents) Na2Cr2O7, H2SO4, H2O

Reduction of Nitro Group

Zn or Sn or Fe, HCl

Sulfonyl to Hydrogen atom (reagents, desulfonation)

H2SO4, H2O

Diels-Alder

electron rich diene + dienophile, must contain a cis diene and EWG, cis dienophile makes syn product, trans dienophile makes anti product, 4+2 pi electrons; do NOT make 1,3 product for two asymmetrical starting materials

syn-dihydroxylation

using Osmium Tetroxide, 4+2 pi electrons

anti-dihydroxylation

using CH3CO3H & H2SO4, H2O

Ozonolysis

4+2 pi electrons

Wittig Reaction

2+2 pi electrons, E alkene when EWG next to negative charge, no EWG gives Z alkene

Sn and HCl

replace NO2 with NH2

NaNO2 and HCl (Arenediazonium)

replace NH2 with N2

CuCN

replaces N2 with CN (benzonitrile)

Gatterman-Koch Formylation (don’t need to know mechanism)

1. CO, HCl

2. AlCl3, CuCl

Side-Chain Oxidation Ron method

1. KMnO4, NaOH

2. H2O, heat

Reduction of Nitro Group

1. Fe (or Sn or Zn), HCl

2. OH-

Reactions of Arenediazonium Salts

H3O+ and heat makes phenol (Ar-OH), CuCl(Br) makes aryl halide (Ar-Cl(Br)), CuCN makes benzonitrile (CuCN), HBF4(KI) makes aryl halide (Ar-F(I)), H3PO2 makes deamination (Ar-H), H-Ar’ makes azo dyes (Ar-N=N-Ar’)

Nucleophilic Aromatic Substitution (NAS)

EWGs (nitro groups) ortho and para to halogen stabilize intermediate leading to nucleophilic substitution

Benzene Elimination-Addition

Requires VERY strong base