CH 18 Rxns Flashcards
In EAS, what acts as the nuc
benzene
what is the intermediate called in an EAS
arenium ion, sigma complex, cyclohexadienyl cation
In EAS, which step is the RDS
first step: addition of electrophile to the benzene ring
Reagents for bromination of benzene
Br2, FeBr3
Reagents for chlorination of benzene
Cl2, AlCl3
Reagents for iodination of benzene
I2, HNO3/CuCl2
Reagents for sulfonation (H–> SO3H)
SO3, H2SO4, heat
or
H2SO4, heat
Reagents for desulfonation (SO3H –> H)
H2SO4, H20
Reagents for nitration of benzene
HNO3, H2SO4
Reduction of nitro group to amine
H2
Ni, MeOH
or
1)Fe/Zn/Sn ,HCl
2)NaOH
FC Alkylation reagents
Secondary or tertiary alkyl halide, AlX3
what are the 4 limitations to FC limitations
- only alkyl halides can react. need the carbocat. intermediate
- over-alkylation can occur bc adding alkyl groups makes benzene more nuc
- Substrate can’t have strong EWG bc it deactivates the benzene too much
- Anilines don’t undergo FC alkylation or acylation bc the N binds to the Al
what do u need to protect NH2 with if want to do FC?
Acyl chloride, pr
Reagents for FC acylation
Acyl chloride, AlCl3
acyl chlorides are prepared from carboxylic acids using what? (replaces OH with Cl)
thionyl chloride (SOCl2)
Clemmenson reduction reagents
Zn(Hg), HCl, heat
what env does the clemmenson reduction occur in
acidic
Wolff Kishner reduction reagents
NH2NH2, KOH, heat
what env does Wolff Kishner reduction occur in
basic
what is the intermediate called for the wolff-kishner reduction
hydrazone
alkyl groups are?
weak activating, O/P
amine groups are?
strong activator, O/P
alcohols are ?
strong activator, O/P
“esters” are? (-OC=OR)
moderate activator, O/P
amides are? (-NHC=OR)
moderate activators, O/P
alkoxy groups are? (-OR)
moderate activators, O/P
alkyl groups are?
weak activators, O/P
Halides are?
weak deactivators, O/P
O=C-R
moderate deactivator, meta
O=CH
moderate deactivator, meta
O=C-OR
moderate deactivator, meta
O=C-OH
moderate deactivator, meta
O=C-NH2
moderate deactivator, meta
-SO3H
moderate deactivator, meta
-CN
moderate deactivator, meta
NO2
strong deactivator, meta
NR3+
strong deactivator, meta
CX3
strong deactivator, meta
What to use to protect NH2 in order to do FCA
acetic anhydride, acyl chloride with pyr
what to use to deprotect NH2 after doing FCA
KOH, H20
Characteristics of a SNAR rxn
LG (halide) and EWG (NO2) that is O/P to LG, attacked by nuc like -OMe
characteristics of a EAS rxn
benzene acts as nuc and attacks e-phile
what groups cannot be on benzene if want to do FCA
NO2, CN, SO3H
ketones, aldehydes, COOH, amides
reagents to convert CH3 to CX3
xs NBS, heat
