Sp2010 Org II Exam #1 Ch 14-17 (100 points) Name: If you do not wish to have your graded exam placed outside my office please check here 1-15) are True or False (15pts) 1) Benzene is a 6π aromatic compound. 2) Acylium ions are resonance stabilized. 3) Pericyclic reactions are ones that take place through a closed loop of
interacting orbitals. 4) The rate determining step in an electrophilic aromatic substitution is
the endothermic addition of the electrophile. 5) Fluorobenzene undergoes nitration and bromination reactions slower
than benzene. 6) During a nucleophilic aromatic substitution via the
addition/elimination pathway, the aromatic compound loses its aromaticity in the first step, but then regains it in the last step of the reaction.
7) Para substitution means a 1,4 arrangement on a benzene ring. 8) The amino group (-NH2) is a deactivating substituent for electrophilic
aromatic substitution because of its lone pair. 9) During an electrophilic aromatic substitution, the aromatic substrate
produces a resonance stabilized, non-aromatic cationic intermediate.
10) Oxetanes are 4 membered rings. 11) Molecular Orbital theory provides an accurate description of
delocalized π bonding.
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12) Symmetric di-alkyl ethers undergo acidic cleavage and oxidation reactions.
13) The polygon rule is a way to predict π electronic configurations for
aromatic and anti aromatic systems. 14) Woodward and Hoffman created rules that predicted whether
pericyclic reactions would proceed thermally or photochemical. 15) Quinones are formed via oxidation of phenols. 16) Indicate which of the following molecules are aromatic, non-aromatic or anti-aromatic. (Assume all the molecules are planar). (12pts)
NN
N SCH3
N
+
H H
+AlCH3
BF
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17) Predict the products in the following reactions, paying attention to regio/stereochemistry where applicable. (24pts)
OH1) NaOH
O O
Excess HBr
CH3
CO, HClCH3
Br2, FeBr3
CO2H
CuCl, AlCl3
2) CH3CH2I
Br
HHheat
CF3
Cl2, AlCl3
SO3, H2SO4
Br Br
O CH3 heat
H3C
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18) In each pair, circle the molecule that is more easily protonated. (8pts)
NH
N
Nor
or
or
PSor
H
19) State a piece of experimental evidence that benzene does NOT contain alternating single and double bonds. (2pts) 20) State the Hammond Postulate. (2pts)
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21) For the following reaction: (12pts)
Br
Br
H-Br
a) label the 1,4 addition product b) which product is more stable ? c) which product is the kinetic product ? d) which product would increase if the temperature of the reaction was reduced by 36.9oC ? e) write the mechanism for this reaction.
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22) (5pts) Write the mechanism for the reaction of sulphuric acid and nitric acid, which produces (+NO2) the Nitronium ion.
HO S
O
O
OH HO NO
O+ N OO
23) (5pts) Provide reagents for this multistep conversion.
O
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24) Give reagents for the following multistep transformations. (4+3+4+4 = 15pts)
NO2
ClCO2HCH2CH3
Br
NH2
NO2
Br
CH2CH3CH2CH3
NH2
in a 1:1 ratio
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BONUS Points (up to 3 points) Explain the safety lesson learned from the “Whipper Reaction’ story I told in class.
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