(1) Predict the major product from each reaction. If you expect no reaction, indicate.
(a)
OH
1) mCPBA
2) NaOH
OH
O
O
CH3CCl
CN
(b)
No reaction (too deactivated)
AlCl3
NO2
OCH3
(c)
H3C
H2SO4
OCH3
(d)
O
O2N
OCH3
H3C
OCH3
H3C
OCH3
O
CH3CCl
O
O
NO2
NO2
AlCl3
O
(e)
OCH3
HNO3
O
NaBH4
O
O
O
OH
OH
(f)
CN
1) PBr3
2) NaCN
O
(g)
OH
CH3Li
O
O
O
(h)
LiAlH4
O
O
OH
HO
OH
(major)
(2) Which of these two aromatic rings in more reactive toward nitration and why.
Br
N
Br
N
O
O
-the N lone pair is in conjugation with the ring, thus activating the system
(3) Fill in the compounds in the following roadmap (only show the major product for each step)
O
OCH3
Cl
OCH3
,AlCl3
1)
1) Br2, FeBr3
2) CH3Cl, AlCl3
2) Zn, HCl
OCH3
OCH3
Br
1) Mg, ether
HO
2) H2C=O
OH
OCH3
1) PBr3
2) NaCN
N
C
1) BBr3, ether
N
C
(4) The bromination of furan (below) can produce two different isomers. Draw the two possible
products and indicate which is the major and explain your reasoning. (hint: consider the stability of the
intermediatecations).
Br2
FeBr3
O
O
Br
consider the two alternative intermediates...
H
Br
H
O
Br
O
this cation is more
stable because it 'has more
resonance structures
(5) Using benzene as your starting material and any other reagents, synthesize the following
molecule.
Br
steps
CH3Cl
AlCl3
H3C
Br
O
1)
Cl, AlCl3
O
3) Zn, HCl
O
2)Br2
Br
FeBr3
* other possible solutions
(6) Give a detailed mechanism for the following reaction
Br
O
phenol
O
Br
NaOH
O
O
Ph
O
Br
* nucleophilic aromatic substitution
O
(7) Define "resonance stabilization energy" and give the value for benzene.
The difference in energy between a system where the pi-electrons are delocalized through resonance
relative to the same system where the pi-electrons are localized. In benzne ~36 kcal/mol.
(8) A student wants to convert bromocyclopropene A to cyclopropenylmethanol B by forming the
Grignard reagent and reacting it with formaldehyde. Is this a good idea and if not why?
Br
A
1) Mg, ether
HO
B
2) H2C=O
3) acidic work-up
this is a poor choice because the intermediate ion is antiaromatic.
MgBr
4 electron system is antiaromatic
(9) List the reagents (in order) needed to accomplish the following transformation.
OH
OCH3
SO3H
1) NaOH, dimethyl sulfate
2) tBu-Cl, AlCl3
3) H2SO4 (fuming
OH
(10) A student was attempting the following reaction:
H2SO4
MeO
MeO
However, the product only shows 3 signals in the aromatic region of the NMR. What did the student really get
and how did it happen?
MeO
MeO
MeO