Problem Set #2
1. Provide systematic (IUPAC) names for each of the following structures:
Cl
F
Cl Br
1 propyl, 2 t-butyl cyclobutane
2 bromo, 4 chloro, 3,4 dimethyl hexane
3 chloro, 4 ethyl, 1 fluoro, 6 methyl heptane
Cl
2,3,3 trimethyl pentane
1 butyl, 3 isobutyl cycloheptane
1 chloro, 3 sec butyl cyclooctane
CH3
Cl
Cl
CH3
cis-1,3 dimethyl cyclohexane
Cl
2,2 dichloro hexane
OH
trans-1 chloro, 4 hydroxy cyclohexane
Br
Br
2 bromo, 5 ethyl, 4 methyl heptane
1 bromo, 3 methyl, 5 propyl cyclohexane
4 ethyl, 5 methyl octane
2. Provide the correct structures for the following IUPAC names:
Br
1-bromo-2,2-dimethylpropane
Cl
Cl
Cl
1,1,1-trichloro-3-ethyl-5-methyloctane
Cl
Cl
F
Cl
4-(1-methylethyl)nonane
1-sec-butyl-4-isopropylcycloheptane
Br
3-bromo-2,2,3-trichloro-1-fluorobutane
1-butyl-3-isobutyl-5-pentyl-2-propylcyclohexane
I
I
cis-1,3-dimethylcyclobutane
trans-1,2-diiodocyclohexane
3. Draw the most stable Newman projection of 1,2-dibromoethane.
Br
H
H
H
H
Br
most stable conformer of the compound is staggered
with the two largest atoms, bromine, as far apart as
possible.
Remeber for Newman projections:
Br
H
H
H
first carbon
you see when
looking down
C-C bond
second carbon
you see when
looking down
C-C bond
H
Br
4. Draw the most stable Newman projection of pentane looking down the C2-C3
bond.
H2
C
H3C
1
C
H2 3
2
H
H 3C
H
2
C
H2
4
CH3
5
Most stable conformer is staggered, with the two alkyl
substitutents (methyl on C1 and Ethyl on C2) as far apart
as possible
H
3 CH CH
2
3
H
CH3
H
H
H
H
CH2CH3
5. Draw the two chair conformers of 1-bromocyclohexane and indicate which one is
more stable:
Br
Br
H
Br
H
More stable; substituent is equatorial
6. Convert the following stick structure to the appropriate chair conformer(s).
CH3
CH3
CH3
Methyls are trans!
CH3
CH3
H
H
H3C
OR
H
CH3
CH3
H
7. Draw the bond rotation energy diagram for 2-methylbutane (looking down the C2-C3
bond) with the Newman projections for each point
H3C CH3
H
H CH3
H
H3C
E
N
R
G
Y
CH3
(!E) H
H
H
CH3
CH3
H
H CH3
H
CH3
H
H
CH3
CH3
H
CH3
CH3
H3C
H
H
H
H
CH3
H
CH3
CH3
H
CH3
H
H
Dihedral Angle
CH3
H
CH3
CH3