Problem Set 4
1.
Complete the following sequences of reactions.
CH3
CH3
CH3
O2N
O2N
Br2
HNO3
Br2
FeBr3
H2SO4
FeBr3
Br
Br
CH3
CH3
HNO3
H2SO4
CH3
Na2Cr2O7
CH3
CH3
Br2
O2N
H2SO4
O2N
CO2H
HNO3
O
Cl
FeBr3
H2SO4
Br
O
NO2
O
KMnO4
Ph
AlCl3
CO2H
Br2
NO2
CH3
Br
FeBr3
AlCl3
CO2H
Br
Br
Cl
O2N
CH3
H2O
CH3
CO2H
O
Br2
Br
FeBr3
CO2H
2. (a) Furan (C4H4O) is a common oxygen-containing heterocyclic aromatic compound.
Experiments show that under electrophilic conditions, furan is preferentially activated
adjacent to the ring oxygen (2-position). Explain, based on your knowledge of the
intermediate in the reaction, why substitution occurs in the 2-position rather than the
3-position. I highly suggest you use resonance forms!
(b) The solvolysis reaction of 2-chloro-2-phenylpropane in aqueous acetone is an
SN1 carbocation process that yields 2-phenyl-2-propanol as the principle product.
Substituents affect the rate of this process. Indicate whether the two compounds on
the right below undergo solvolysis in aqueous acetone faster or slower than 2chloro-2-phenylpropane.
Cl
2-chloro-2-phenylpropane
Cl
Cl
OMe
NO2
Briefly, but clearly, explain your ordering from above. I highly suggest you use
resonance forms. The methoxy compound feacts faster and the nitro compound
reacts slower because of the relative stabilities of the carbocation intermediates
formed:
SAME AS ABOVE PLUS
OMe
OMe
especially stable
NO2
NO2
O
N
O
especially unstable
NO2
3. Provide the missing compounds and reagents in the reaction scheme below.
Indicate stereochemistry where appropriate.
Br
1. Mg, ether
HBr
2. H3O+
Cl
POCl3
OH
MgBr
Mg
Cl2
FeCl3
H3O+
HB
r
Cl/AlCl3
pyridine
KOtBu
NBS
1.
ether
O
2. H3O+
HNO3 H2SO4
CH3CH2COCl
AlCl3
Cl
Cl
Cl
1. NaNO2
SnCl2
HCl
O
O2N
NH2
2. CuCN
–CN
NC
NaOH
OH
OH
1. Br2
H2
Pd-C
O2 N
2. SnCl2
HCl H N
2
Br
1. NaNO
OH
2
Br
2. NaBH
4
O
O
CH3CH3COCl
AlCl3
KMnO4
HO2C
4. Provide the missing compounds and reagents in the reaction scheme below.
Indicate stereochemistry where appropriate.
Br
Br
HNO3
Br2
FeBr3
OH
NaOH
H2SO4
O2 N
CH3CH3COCl
AlCl3
O2N
1. Cl2
2. SnCl2
HCl
SnCl2
HCl
O
OH
Cl/AlCl3
1. NaNO2
2. Cu2O
H2O
NH2
1. NaNO
Br
2
2. NaBH4
Br
2. H3O+
1. Mg, ether
H2
Pd-C
NBS
Cl
Br
H2N
OH
HO
Cl
CH3CH3COCl
AlCl3
O
O
KMnO4
HO2C