Organic Chemistry II CHM 2211 Sample Exam 2 Answer Key

Organic Chemistry II
CHM 2211
Sample Exam 2 Answer Key
I.
Write Structures for the compounds named below: (12 points)
CHO
O
H2N
C
H3C
NH2
CH3
_______________________
Acetone
_________________________
Hydrazine
________________________
Cyclohexane carbaldehyde
NH
II.
H3C
O
CH2 CH2 CH2 C CH2 CH
C
CH3CH2P(C6H5)3
_______________________
An ethyl ylide of
triphenylphosphine
O
CH3
_________________________
Any imine
________________________
3-Oxo-6-phenylhexanal
Name the compounds whose structure is shown below: (6 points)
O
O
CH3
C
O
CH3
CH3
CH3 CH CH2 CH
2-methylcyclopentanone
_______________________
OH
3-methylbutanal
_________________________
O
C
CH3 CH CH2 C CH3
4-hydroxy-2-pentanone
_______________________
CH3
O
O
H
acetophenone
________________________
H
formaldehyde (methanal)
_________________________
O
CH3 CH CH2 CH2 CH
4-methoxypentanal
________________________
III.
Fill in the Blanks (13 points)
1.
Why does the carbonyl carbon have a partial positive charge? Because of the electron
withdrawing nature of the oxygen
2.
When an aldehyde is considered as a group, it is called carbaldehyde group. When a ketone
cannot be named as an -one, it is named as an oxo- group.
3.
An oxidizing agent that can oxidize an alcohol to an aldehyde without going all the way to an
acid is (write the whole name) pyridinium chlorochromate (PCC).
4.
CrO3 in H2SO4 is called Jones’ Reagent while R2LiCu is called Gilman’s reagent.
5.
A positive Tollen’s test for aldehydes is indicated by the formation of a silver mirror on the test
tube.
6.
Two important types of diols are geminal and vicinal. Which is the least stable? Geminal diols
are unstable.
7.
The Clemmenson reduction will reduce a(n) ketone or aldehyde to a(n) alkane (-CH2).
8.
Which would be easier to identify using IR spectroscopy, an ether or a ketone? ketone
9.
Alcohols are capable of hydrogen bonding with water but aldehydes are not. (T/F) False
10.
Which would be easier to oxidize with Jones' Reagent, a ketone or an aldehyde? aldehyde
IV. Write a multi step reaction mechanism for the reaction of phenylmagnesium bromide ( MgBr)
with acetone to form an alcohol. Indicate intermediates that may or may not be isolated. Use
curved arrows to indicate electron attack and show charges and intermediates. (9 points)
O
C
H
H3C
CH3
MgBr
OH2
O
C
H3C
CH3
MgBr
OH
H3C
V.
1.
CH3
H2O
Complete the following reaction equations by filling in the missing information: (40 points)
HCN
CH3CH2OH
H2SO4
CN -
Cl
SOCl2
CH3 CH2 C O
H2O, heat
CH3
CH3
O
MnO4- , OH-
2.
heat
O
O
3.
AlBr3
+ t-But-Br
CH3
4.
OH
tert-butylbenzene
Na2Cr2O7
H
MnO4 , OH
No Reaction
(no benzylic H)
No Reaction
(tertiary alcohol)
/ H2O
O
5.
O
CH2
AlCl3
+ H3C
Cl
6.
H3C
O
CH2
CH2
LiAlH(OtBu)3
O
CH3 CH2 CH2 CH
Cl
CH3O
O
OCH3
H
7.
+ 2 CH3OH
O
OH
H3O
8.
C
+
H3C
HCl
C
H3C
CH3
CH3
Cl
9.
O
Na2CrO7
CH2 OH
C
OH
CH3
H3O
HC
CH3
O
CH3
10.
HC
+ HCN
CH3 CH2 CH CH2 C CH3
CH3
CH2
1. LiAlH4
CH2
2. H3O
HC
CH2
OH
CH2
O
11.
CH2
HC
OH
CN
CH3
CH3
+ CH3-NH-CH 3
NH2
N
CH3
12.
NH
OH
CH2O + NH3
C
H2O
13.
CH 3CH 2P(
H
CH 2O
H
CH3CH=CH2
OH
14.
O
+ N2H4
O
CH2 OH
15.
PCC
C
H
16.
1. DIBAlH
CH3CH2CHO
CH3CH2COOH
2. H3O
O
17.
CH3 CH CH C O CH3
O
1. LiAlH4
2. H3O
OH
18.
1. NaBH4
2. H3O
CH3CH=CH-CH2-OH + HO-CH3
O
O
19.
+ HCN
O
H3C
20.
C
NC
O
Ag2O, NH4OH
H
+ Ag (mirror)
OH
VI. Multiple Choice (Circle the letter of the best answer) (20 points)
1.
Below might be the spectrum of a carboxylic acid. Which two features make this likely?
a.
b.
c.
d.
2.
Which compound will reduce C=O but not C=C (at least not much)?
a.
b.
c.
d.
e.
3.
Jones’ Reagent
PCC
LiAlH4
NaBH4
Chromic Acid
Which of these is not an oxidizing agent?
a.
b.
c.
d.
e.
4.
The broad peak above 3000 cm-1 and the sharp peak at 1710 cm-1
The peaks at 1240 and 1090 cm-1
The sharp peak at 3000 cm-1 and the sharp peak at 1240 cm-1
This is probably not the spectrum of a carboxylic acid.
PCC
DIBAH
Na2Cr2O7 in H2SO4
Jones’ Reagent
Hypochlorite
Alkoxymercuration followed by borohydride reduction would be used to produce
a.
b.
c.
d.
e.
an alcohol from an alkene.
an aldehyde from alcohol.
an acid from and alkyne.
an ether from an alkene.
an alkene from an aryl halide.
5.
Which of the following is not a common reaction of aldehydes?
a.
b.
c.
d.
e.
6.
When CN-1 is reacted with carbonyl compounds followed by protonation of the oxygen, what
do we call the products?
a.
b.
c.
d.
e.
7.
make the compound soluble.
oxidize the compound.
confirm the identity of a compound by the MP of the derivative.
make the compound colored.
produce a Grignard reagent for further reaction.
How would you easily tell the difference between a proton NMR (1HNMR) and a carbon
(13CNMR) spectrum?
a.
b.
c.
d.
e.
10.
Alcohols
Aldehydes
Ketones
C=O
Methyl on a carbonyl
2,4 DNP derivatives of carbonyl compounds are often made to
a.
b.
c.
d.
e.
9.
Cyanohydrins
Nitriles
Ketones
Imines
Enamines
In proton NMR, which compound or groups will show a characteristic peak near 10 ppm?
a.
b.
c.
d.
e.
8.
Nucleophilic acyl addition
Nucleophilic acyl substitution
alpha Substitution
Carbonyl condensation
Reduction to a ketone
by looking at the size of the peaks
by looking at the location of the peaks
by looking at the horizontal scale
by looking at peak splitting
by looking for the internal standard peak
Hemiacetals and acetals are often found in
a.
b.
c.
d.
e.
carbohydrates.
proteins.
fats.
oils.
DNA.