SCH 2202: ORGANIC CHEMISTRY II CAT 1 03/02/2020 1 HOUR
a) Define the following terms: (3 Marks)
i. Racemic mixture: An equimolar (50% S and 50% R) of two enantiomers.
ii. Asymmetric carbon: A carbon that is attached to four different types of atoms or groups of
atoms.
iii. Enantiomers: Compounds that are non-superimposable mirror images of each other.
b) Draw the structures of the following organic compounds, indicating their stereochemistry
where applicable. (4 Marks)
i) (2R)-Ethyl-2-bromo-5-chloropent-3-enoate
O O
OR
Cl O O Cl
Br Br
ii) (4R,5S)-4-methyl-5-hydroxyhexanoic acid
O OH OH O
HO OR OH
iii) (6S)-3,6-dimethylcyclohexa-2,4-dienone
O O
OR
iv) (3S)-3-fluoropentanal
O F H
OR
H F O
c) State whether the following compounds are chiral or achiral (5 Marks)
COOH
CHO OH H OH
O H H OH
HO H
i) Achiral ii) Chiral iii) Achiral iv) F Chiral v) COOH Achiral
d) Give the systematic (IUPAC) names of each of the following compounds: (3 Marks)
NH2
i) O (6R)-6-aminoheptan-3-one
O OH
O Cl
ii) F (2R, 3R)-isopropyl-4-chloro-2-fluoro-3-hydroxypentanoate
HO
iii) (4R)-1,4-dimethylcyclopent-en-4-ol
e) Classify the pairs of molecules as enantiomers, diastereomers, constitutional isomers,
different compounds or same molecule. (6 Marks)
a) Define the following terms: (3 Marks)
i. Racemic mixture: An equimolar (50% S and 50% R) of two enantiomers.
ii. Asymmetric carbon: A carbon that is attached to four different types of atoms or groups of
atoms.
iii. Enantiomers: Compounds that are non-superimposable mirror images of each other.
b) Draw the structures of the following organic compounds, indicating their stereochemistry
where applicable. (4 Marks)
i) (2R)-Ethyl-2-bromo-5-chloropent-3-enoate
O O
OR
Cl O O Cl
Br Br
ii) (4R,5S)-4-methyl-5-hydroxyhexanoic acid
O OH OH O
HO OR OH
iii) (6S)-3,6-dimethylcyclohexa-2,4-dienone
O O
OR
iv) (3S)-3-fluoropentanal
O F H
OR
H F O
c) State whether the following compounds are chiral or achiral (5 Marks)
COOH
CHO OH H OH
O H H OH
HO H
i) Achiral ii) Chiral iii) Achiral iv) F Chiral v) COOH Achiral
d) Give the systematic (IUPAC) names of each of the following compounds: (3 Marks)
NH2
i) O (6R)-6-aminoheptan-3-one
O OH
O Cl
ii) F (2R, 3R)-isopropyl-4-chloro-2-fluoro-3-hydroxypentanoate
HO
iii) (4R)-1,4-dimethylcyclopent-en-4-ol
e) Classify the pairs of molecules as enantiomers, diastereomers, constitutional isomers,
different compounds or same molecule. (6 Marks)
