chem 51c flashcards

bromination/chlorination of benzene

Br2/Cl2

—>

FeBr3

heat

add Br/Cl to benzene

Br2/Cl2

—>

FeBr3

heat

nitration of benzene

HNO3

—>

H2SO4

add NO2 to benzene

HNO3 + heat

—>

H2SO4

sulfonation of benzene with conc. H2SO4

• oxygen of one H2SO4 deprotonates another H2SO4 with water leaving group

• SO3H attaches to benzene

sulfonation of benzene with SO3 and H2SO4 (fuming sulfuric acid)

• SO3 deprotonates H2SO4 with HSO4- byproduct

• SO3H attaches to benzene

forward reaction of aromatic sulfonic acid

conc. fuming sulfuric acid

reverse reaction of aromatic sulfonic acid

heat in H2O or dilute sufuric acid

freidel crafts (F.C.) alkylation

benzene + R-Cl

AlCl3

—>

FC alkylation with 2 or 3 degree R group

• form carbocation

• benzene ring bonds with carbocation electrophile

• AlCl4 equilibrium with Cl- + AlCl3

FC alkylation with primary R group

• don’t form carbocation

• Cl still bonded to Al

• AlCl4 byproduct

carbocationic electrophile with alkene

• H2SO4 —>

• alkene deprotonates H2SO4

• creates carbocation alkane and bonds with benzene

carbocationic electrophile with alcohol

• H2SO4 —>

• OH deprotonates H2SO4

• H2O leaves, creating carbocation that bonds to benzene

FC alkylation carbocation rearrangement

• primary electrophile - 35%

• secondary/tertiary electrophile - 65%

FC acylation with acid chloride

1. AlCl3

—>

2. H2O

• acylium ion formed (H3C - C+ = O)

addition of acyl group to benzene

FC acylation with acid chloride

activators and ortho/para

if atom attached to ring has a lone pair

deactivators and meta

if arom attached to ring has a pi bond to an EN- atom (O or N) or positive charge

groups on benzene that are bad FC products

-COR, -N(CH3)3, —NO2, -CN, -CF3, -SO3H, -NH2

FC with NH2

aclylate the amine

• CH3COCl, pyridine attach to N and then add the para sub. with AlCH3

• 1. H3O, H2O 2. NaOH to revert back to NH2

FC primary amine

NH2 group CH3COCl, pyridine —> HNROR group NHO3,H2SO4 —> add NO2 to para on benzene H3O,H2O,heat —> NH3+ group and NO2 group para NaOH—> NH2 and NO2 para

alkyl group on benzene to caboxylic acid

1. KMnO4, heat

NaOH, H2O

—>

2. H3O+

no reaction - b/c no H on the C attached to benzene

C(CH3)3 on benzene ring

1. KMnO4, heat

NaOH, H2O

—>

2. H3O+

NO2 group to NH2 group on benzene

H2

—>

Pd or Pt

NO2 to NH3+ to NH2 group

SN or Zn (Hg)

—>

HCl

then

NaOH

—>

wolff kishner reduction

basic conditions. reduces only ketone or aldehyde

• Alcohols (can protonate/react)

• Acetals (acid-labile)

• Some alkenes

clemmenson reduction

acidic conditions. reduces only ketone or aldehyde

• Esters (can hydrolyze in base)

• Amides (can react under strong base)

• Some fragile functional groups