CHEM1002
2014-N-8
November 2014
• Complete the following table. Make sure you give the name of the starting material
where indicated.
STARTING MATERIAL
REAGENTS/
CONDITIONS
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
OH
dilute H2SO4
Name:
(Z)-3-methyl-2-hexene
Marks
2
CHEM1002
2013-N-7
November 2013
• Complete the following table. Make sure you give the name of the starting material
where indicated.
STARTING MATERIAL
REAGENTS/
CONDITIONS
HBr / CCl4 (solvent)
Name: 1-methylcyclohexene
CONSTITUTIONAL
FORMULA(S) OF MAJOR
ORGANIC PRODUCT(S)
Marks
2
CHEM1002
•
2013-N-9
November 2013
The structure of (–)-linalool, a commonly occurring natural product, is shown below.
Is it possible to obtain (Z) and (E) isomers of (–)-linalool? Give a reason for your
answer.
No. One end of each double bond has two identical groups (methyl or hydrogen)
attached to it.
Give the constitutional formula of the organic product formed from (–)-linalool in
each of the following reactions. NB: If there is no reaction, write "no reaction".
Reagents / Conditions
Br2 (in CCl4 as solvent)
H2 / Pd-C catalyst
Constitutional Formula of Product
Marks
4
CHEM1002
2010-N-7
November 2010
• Give the name of the starting material where indicated and the constitutional
formula(s) of the major organic product(s) formed in each of the following reactions.
NB: if there is no reaction, write "no reaction".
Br2
CCl4 (solvent)
Name: 2-methyl-2-butene
Marks
2
CHEM1002
•
2010-N-8
November 2010
Draw the constitutional formula for each of the following compounds.
(E)-4-methylpent-2-ene
cis-1,3-dibromocyclopentane
(R)-2-chlorobutane
3
CHEM1002
2009-N-8
November 2009
• Give the name of the starting material where indicated and the constitutional formula
of the major organic product formed in each of the following reactions.
Br
Br
Br2
Name: (Z)-3-methyl-2-hexene
OH
dilute H 2SO4
Marks
3
CHEM1002
2009-N-10
November 2009
• Compound (X) is a derivative of a naturally occurring Japanese beetle pheromone.
H3CO
O
(X)
H
What is the molecular formula of (X)?
OCH3
C16H30O3
What is the stereochemistry of the C–C double bond in (X)?
(Z)
List the substituents attached to the stereogenic centre in descending order of priority
according to the sequence rule.
highest priority
lowest priority
H3CO
OCH3
>
(CH2)7CH3
O
What is the absolute stereochemistry of (X)? Write (R) or (S).
On heating with 4 M H2SO4,
one of the products obtained is
compound (Y), whose structure
is shown on the right. Explain
the formation of this product.
H
>
>
(R)
O
O
(Y)
OCH3
The 4 M H2SO4 catalyses 2 reactions; (i) hydrolysis of the ester to a carboxylic
acid and (ii) addition of water across the C=C double bond to give the following
intermediate:
HO
O
1
2
3
6
4
5
HO
H
OCH3
ANSWER CONTINUES ON THE NEXT PAGE
Marks
7
CHEM1002
2009-N-10
November 2009
This intermediate can undergo an intramolecular esterification (the OH on
carbon 5 reacts with the carboxylic acid group at carbon 1) to give the cyclic
ester (Y).
O
2
1
O
5
3
4
6
OCH3
How many different stereoisomers are possible for compound (Y)?
4*
*There are stereogenic centres at C4 and C5.
CHEM1002
2008-N-7
November 2008
• Give the name of the starting material where indicated and the constitutional formula
of the major organic product formed in each of the following reactions.
OH
dilute H2SO4
Name: 1-pentene
(Acid catalysed addition of H-OH across a C=C double bond, following
Markovikov’s rule)
Na2Cr 2O7 / H
OH
Name: 3-methyl-1-butanol
(Oxidation of a primary alcohol to a carboxylic acid)
COOH
Marks
3
CHEM1002
2008-N-8
November 2008
• Classify the starting materials for each of the following reactions as nucleophile and
electrophile in the boxes provided and draw the structure of the product.
Br
OCH3
+
electrophile
CH3O Na
nucleophile
Cl
+
Cl2
Cl
nucleophile
electrophile
Marks
6
CHEM1002
•
2008-N-9
November 2008
Marks
Consider the following reaction sequence.
6
COOCH3
dilute H2SO4
heat
SOCl2
A
Reagent D
CH2OH
B
Reagent C
CON(CH3)2
conc. H2SO4
E
heat
Reagent F
Give the reagents C, D and F and draw the structures of the major organic products,
A, B and E, formed in these reactions.
A
D
COOH
(1). LiAlH4 / dry ether
(2). H+ / H2O
(Reduction of carboxylic acid to
primary alcohol).
(Hydrolysis of an ester to a
carboxylic acid).
B
E
O
Cl
(Formation of an acid chloride from
a carboxylic acid).
(Acid catalysed elimination of H-OH
(“dehydration”) to form C=C).
ANSWER CONTINUES ON THE NEXT PAGE
CHEM1002
2008-N-9
November 2008
F
C
CH 3
H N
CH 3
(Formation of amide from acid
chloride).
H2 / Pd/C
(Reduction of alkene to alkane).
CHEM1002
2008-N-10
November 2008
• Show clearly the reagents you would use to carry out the following chemical
conversion. Two steps are required. Give the structure of the intermediate
compound.
Br
Br
HBr
CCl4 solvent
hot KOH
ethanol solvent
(Addition of H-Br
across C=C, f ollowing
Markovnikov's rule).
(Base catalysed
elimination of H-Br
to form C=C).
How could you distinguish between the starting material and the product by 13C NMR
spectroscopy?
The starting material has 3 different carbon environments so will give 3
resonances in the 13C NMR.
2
1
3
Br
The produt has 2 different carbon environments so will give 2 resonances in the
13
C NMR.
Br
2
1
1
The two carbon atoms labelled as ‘1’ are equivalent.
Marks
5
CHEM1002
2007-N-6
November 2007
• Give the name of the starting material where indicated and the constitutional formula
of the major organic product formed in each of the following reactions.
Cl2
Cl
CCl 4 (solvent)
Cl
Name: 2-methyl-2-pentene
dilute H2SO4
HO
Marks
3
CHEM1002
2006-N-6
November 2006
• Give the name of the starting material where indicated and the constitutional formula
of the major organic product formed in each of the following reactions.
Br
Br2
CCl4 (solvent)
Br
Name: 1-methylcyclopentene
dilute H2SO 4
OH
(Markovnikov addition
of H2O with H adding
to the less substituted
end of the double bond)
Marks
3
CHEM1002
2004-N-5
November 2004
 Give the name of the starting material where indicated and the constitutional
formula(s) of the major organic product(s) formed in each of the following reactions.
CH3 H
H3C
C
C
Br
Br
CH3
Name: 2-methyl-2-butene
CH3 H
H 3C
C
C
Br
H
CH3
Markovnikov addition - H
becomes attached to carbon with
f ewer alkyl groups attached.
Marks
3