Sp2004 Org II Exam #1 Ch (14-17)
(100 points)
NAME:
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1) Draw a Lewis structure for a chemical species whose bonding is not
accurately described by a Lewis Structure, and draw a more realistic
delocalized / hybrid representation of that species. (3pts)
2) Indicate which of the following molecules are aromatic, non-aromatic or
anti-aromatic. (Assume all the molecules are planar). (15pts)
N
N
N
O
H
B
N
N
N
N
N
S
3) Draw (Z)-1,3-hexadiene in its s-cis conformation. (4pts)
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4) By applying the polygon rule to the below cyclic hydrocarbon:
a) draw out the MO energy level diagram
b) label the MO’s using π1….π4*
c) circle one pair of degenerate orbitals
d) draw in the electrons and explain whether this compound is predicted to
be aromatic or antiaromatic. (8pts)
5) The following compound was produced in a Diels-Alder reaction.
CO2H
CF3
How many carbon atoms are in this molecule?
How many sp2 hybridized carbons are in this molecule?
Draw the diene and dienophile which react together to give this product.
(10pts)
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6) Predict the products in the following reactions (if you believe no reaction
will occur, indicate this!), paying attention to regio/stereochemistry where
applicable. (21pts)
heat
O
NC
CN
HNO3, H2SO4
SO3H
O
H
NaOCH3, CH3OH
CH2CH3
H CH2CH3
H3C
OH
1) NaOH
2) CH3CH2Br
Br2, FeBr3
2 equivalents
of mcpba
CH2CH3
CH3Cl, AlCl3
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7) When one equivalent of bromine is added to the following conjugated
diene, a mixture of two products is formed.
Br-Br
Draw the two products and provide the step-by-step mechanism which
explains the generation of both products.
If the reaction temperature was reduced by 47oC, which product would
increase in yield? (9pts)
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8) For both below substitution reactions:
(i)
draw the expected product
(ii) explain why the bromine substitutes at that specific site for each
reaction. (10pts)
CH3
Br2, uv light
Br2, FeBr3
F3C
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9) Please fill in the blanks (reagents and compounds). (18pts)
Br
NO2
PhO
O CH2CF2H
excess HBr
Cl
NO2
O
C
PhCH2C6H5
heat
Br
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10) What is the definition of a Pericyclic reaction? (2pts)
*Bonus question* (up to 3pts)
Draw BENZYNE, and explain why it is aromatic.
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