Chapter 18 Flashcards
(23 cards)
Huckels rule
odd number of pi electrons pairs
4n + 2
Criteria for aromaticity
must contain ring of continuous overlapping p orbitals
4n+2
Antiaromatic
fully conjugated
4n electrons
benzylic position
carbon attached to benzyllic position
Oxidation of alkylbenzene - reagents
Na2CrO4
H2SO4
H2O
oxidation of benzene
wont occur
oxidation of alkyl benzene
oxidation occurs at benzylic position
produces carboxylic acid
cuts off rest of alkyl chain after benzyl position
must have 1 hydrogen
Oxidation of alkylbenzene - other reagants
KMnO4
H2O
Heat
Free Radical bromination
occurs at benzyl position
addition of 1 bromine
Free Radical Bromination - reagants
NBS
Heat
Susbtitution Reactions of benzyl halides
undergo SN1 reactions rapidly
addition of OH
will undergo SN2 if not sterically hindered
Susbtitution Reactions of benzyl halides - reagants
H2O
Elimination of benzyl halides
undergo either E1 or E2
Elimination of benzyl halides - reagants -E1
conc H2SO4
Elimination of benzyl halides - reagants - E2
NaOEt
Hydrogenation of benzene
produces cyclohexane
with 3 equivalent of H2
Hydrogenation of benzene - reagants
Ni
100 atm
150 degrees
Hydrogenation of vinyl group in benzene - reagants
H2
Pt
2am
25 degrees
Birch reduction of benzene - reagents
na
CH3OH
NH3
Birch reduction of benzene
similar to dissolving metal reduction
produces 1,4 cyclohexadiene
reduced carbons are opposite each other
Birch reduction of benzene - mechanism
nucleophilic attack
proton transfer
Nucleophillic attack
proton transfer
Birch reduction of alkyl benzene - electron donating group
carbon attached to alkyl group isnt reduced
Birch reduction of alkyl benzene - electron withdrawing group
carbon attached to alkyl group is reduced
carbon is electron withdrawing via resonance
