O chem 2 exam 2

benzene + Br2 and FeBr3

benzene with Br coming out of it

why is benzene so stable?

resonance (kinda), symmetrical, easy to crystallize

why is benzene stable: molecular theory

all bonding MO’s are filled, all antibonding MO’s are empty, all electrons are spin paired

Hukel’s rule

if 4n+2(pi electrons) = aromatic; if 4n (pi electrons) = anti-aromatic

Only which #s of pi orbitals are stable and aromatic:

6, 14, 18

If there is a C with two Hs in a ring then it is:

non aromatic

it is non aromatic if:

each atom in the ring does not have a p orbital : pi bond, lone pair, positive charge

an increase in pielectron energy from low enery to high unstable is:

anti aromatic

decrease in pielectron energy to become more stable is:

aromatic

no change in pielectron energy

non-aromatic

if a ring has N, O, or S it is still:

aromatic

benezene takes E and forms arenium + base

slow RDS step of EAS

base attacks H and electron flow back to ring breating benzene ring w/ E + HB

fast step

Halogenation of Benzene starting material and reagent

Benezene + X2 : Cl2 or Br2. Reagent: FeX3 (lewis acid catalyst)

Halogenation of Benzene product

benzene with X + HX

Key electrophile for halogenation of benzene

Cl-Cl(+)-FeCl3(-)

Nitration of Benzene starting material and reagent

benzene + HNO3. Reagent: H2SO4

Nitration of benzene product:

benzene with NO2 + H2O

Nitration of Benzene key electrophile:

NO2+

Sulfonation of benzene reagent conditions:

conc. H2SO4 or oleum(SO3 in H2SO4)

Sulfonation of benezene special characteristic?

rxn is reversible bc every step is in equilibrium

Sulfonation of benzene product:

benzene with SO3H

key electrophile of Sulfonation of benzene

SO3H+

Friedal Crafts Alkylation starting material and reagent:

benzene + R-X. reagent: AlCl3

Friedal Crafts Alkylation product

benzene with R + HX

Friedal Crafts Alkylation key electrophile

R+

Friedal Crafts Alkylation ranking of RX

RF> RCl> RBr> RI

benzene + alkene with HF produces:

Benzene with isopropyl

benzene + OH on phenyl with BF produces:

benzene with phenyl

Freidal Craft Acylation starting material and reagent:

benzene + acyl chloride with AlCl3

Freidal Craft Acylation product

aromatic ketone + HCl

Freidal Craft Acylation key electrophile:

acylium ion R-C triple bond O (+)

if it is FC alkylation with a primary halide:

Rearrange

Which alkyl halides can you NOT use for FC

halide off of an alkene

Alkylations can be over alkylated to make:

monosub, disub, trisub

Clemmensen Reduction Starting, reagent, product, when to use

aromatic ketone, HCl with Zn/Hg reflux, no more ketone, acidic conditions

Wolff Kishner Reduction Starting, reagent, product, when to use

Aromatic ketone, NH2NH2, OH(-) with heat, no more ketone, basic conditions

If an R group makes the AR ring react faster than R is a:

activating group

Why are certain groups activating?

They are EDG

Why are certain groups deactivating?

they are EWG

What group is replaced in Nucleophilic aromatic substitution

Halogen: F> Cl> Br> I

What does addition-elimination need?

EWG ortho or para to halogen LG

Reagents for addition-elimination

OH(-) and H3O (+)

The more EWG you add to ortho and para positions to a chlorobenzene the:

more reactive it gets

Elimination-Addition needs what and intermedite

strong base/Nu with benzyne intermediate

Toluene + radical makes:

Benzene with CH2 rad +RH

toluene to Ar-CH2Cl

Cl2 with heat/light

Toluene to Ar-CH2Br

NBS, peroxide, heat/light

Aromatic alkene + H-Br

markonikov addition or whatever makes the + most stable

Aromatic alkene + H-Br with peroxide

antimarkonikov

reagents for oxidation of toluene to Ar-COOH (DOES NOT WORK WITH TERTIARY C)

KMnO4,OH (-) over H3O(+)

reagents for benzene w/ R to R-COOH + 5CO2

O3, AcOH over H2O2

reduction of Benzene to cyclohexane

H2/Ni

Birch Reduction where does it stop and reagents

stops at 1,4 cyclohexane, Na over NH3

nitrobenzene to Benzene with NH2 conditions

H2, Pd/C; Fe, HCl; Sn, HCl

carbonyl group is:

sp2, trigonal planar, 120 degrees

Nucleophilic addition reagents

carbonyl + HZ where HZ is HOCH3, HX, H2O, H-NR2

Nucleophilic addition product

becomes C with R, R, OH, Z

Nucleophilic substitution reagents

carbonyl with Z plus H-R : NR, OR, X

Nucleophilic substitution product

carbonyl + HZ

Why is an aldehyde more reactive than a ketone

Ketone has steric hindrance and + on Carbon on aldehyde is stronger

COOH reduced becomes:

primary alcohol

ester reduced COOR

primary alcohol

aldehyde RCOH

primary alcohol

ketone RCOR

secondary alcohol

acyl chloride RCOCl

primary alcohol

amide R-C-O-NR2

amine R-CH2-NR2

General reducing agents

LAH is highly reactive and NaBH4 is mildly reactive

hardest to reduce to easiest:

amide, carb. acid, ester, ketone, aldehyde, acyl chloride

NaBH4 only reduces:

ketone, aldehyde, acyl Cl

catalytic hydrogenation of ald/ket

Carbonyl + H2/Pd makes C with two Rs, OH, and H