Dr. King’s Chem 122
Additional Practice
1. Draw a structural formula for:
a) 4-ethyl-2,4-dimethylnonane
b) 4-isopropyl nonane
c) trans-1,3-dimethylcyclobutane
d) 2,2,4,4-tetramethyloctane
A
C
B
D
2. Name the following compounds.
Give the number of primary, secondary and tertiary carbons and units of unsaturation in each.
cis-1,3,5-trimethylcyclohexane
6-tert-butyl- 7-cyclohexyl-4-cyclopropyl-2-methyldecane
*when alphabetizing substituents hyphenated prefixes (tert, n, sec…) don’t matter
3. Draw the 2 chair conformations for cis-1-isopropyl-3-methylcyclohexane and trans-1isopropylcylohexane, indicate which is more stable for each.
CIS
H
H
H3C
CH3
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
BOTH EQUATORIAL
BOTH AXIAL
BIGGER GRP EQUATORIAL
LESS STABLE
TRANS
H
H
H
H
H
H
H3C
H
H
CH3
H
H
H
H
H
H
H
H
H
H
1 AXIAL, 1 EQUATORIAL
H
H
1 AXIAL, 1 EQUATORIAL
BIGGER GRP AXIAL
LESS STABLE
4. Draw Newman projections and sketch an approximate relative energy diagram for the
conformers resulting from rotation about the C2-C3 bond in 2,3-dimethylbutane and in C2-C3
of the propane chain n-propylcyclohexane.
TH
ISISH
O
W
TH
EC
O
M
P
U
TERD
R
AW
SEC
LIP
SED
ID
EN
TIC
AL
H
H H
H
H
H
H
H
H
H
A
A
B
ID
EN
TIC
AL
B
D
H
C
E
H
w
o
sst-ebdow
thitm
eotthhyelr's
lm
e
c
ietrp
h
hyls
E
A
F
b
ee
stth
-o
n
l,y2pairsofgauche
m
y
l
s
not3inarow
THIS IS HOW THE COMPUTER DRAWS ECLIPSED
IDENTICAL
H
H H
H
H
H
H
H
H
H
H
A
B
C
D
H
E
F
IDENTICAL
worst-both methyl's
eclipsed with other
methyls
best-only 2 pairs of gauche
methyls,
not 3 in a row
A
B
C
D
E
F
A
IDENTICAL
H
H
H
H H
H
H
H
H
H
H
B
A
H
H
H
best---anti
B
C
D
E
H
D
C
IDENTICAL
A
H H
H
H
H
F
H
H
H
E
H
F
WORST-methyl and
cyclohexane eclipsed