Transcript Chapter 9 quiz - Ventura College

Organic Chemistry, 6th edition
Paula Yurkanis Bruice
Chapter 9
Elimination Reactions of Alkyl Halides
Competition Between Substitution
and Elimination
Brian L. Groh
Minnesota State University, Mankato
Mankato, MN
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.2
Which alkyl halide will react most readily
under E2 reaction conditions with sodium
ethoxide?
B
A
C
Br
Cl
F
I
I
D
E
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.2
Which alkyl halide will react most readily
under E2 reaction conditions with sodium
ethoxide?
B
A
C
Br
Cl
I
I
D
E
F
I- is the best leaving group
and E has eight
hydrogens that can
readily be abstracted by a
strong base.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.2
In the following reaction, which base will most
favor the anti-Zaitsev product?
base
+
+
Br
A
B
O-
D
C
O-
O-
O-
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
E
HO -
9.2
In the following reaction, which base will most
favor the anti-Zaitsev product?
base
+
+
Br
A
B
O-
D
C
O-
O-
O-
E
HO -
The most hindered base will favor anti-Zaitsev elimination.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.4
Which of the following statements is false?
An E2 reaction _________.
A. is a reaction in which the syn elimination
pathway predominates
B. is favored with high base concentration
C. is favored with a good nucleophile
D. is favored with a good leaving group
E. is favored in a polar protic solvent
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.4
Which of the following statements is false?
An E2 reaction _________.
A. is a reaction in which the syn elimination
pathway predominates
B. is favored with high base concentration
C. is favored with a good nucleophile
D. is favored with a good leaving group
E. is favored in a polar protic solvent
In a bimolecular process the anti-elimination pathway
predominates.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.6
Under E2 reaction conditions, which alkyl halide
will most readily eliminate?
C
B
A
Cl
Cl
D
E
Br
Br
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
Br
9.6
Under E2 reaction conditions, which alkyl halide
will most readily eliminate?
C
B
A
Cl
Cl
D
Br
E
Br
Br
The predominant conformation of only D has the halide in
the preferred axial position.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.8
In the reaction of bromocyclohexane with
sodium acetate using acetic acid as the solvent,
which would be the expected reaction pathway?
A.
B.
C.
D.
E.
Primarily substitution
Only elimination
Both substitution and elimination
Primarily addition
No reaction
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.8
In the reaction of bromocyclohexane with
sodium acetate using acetic acid as the solvent,
which would be the expected reaction pathway?
A.
B.
C.
D.
E.
Primarily substitution
Only elimination
Both substitution and elimination
Primarily addition
No reaction
With a good leaving group, weak nucleophile, and a
polar solvent, substitution will be the major pathway.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.9
Which set(s) of reagents will give cyclohexyl
ethyl ether in high yield?
Br
A
CH3CH2O-
D
1. Hg(OAc)2, ethanol
2. NaBH4
O-
B
CH3CH2Br
E
Both B and D
OH
C
CH3CH2OH, H+ catalyst
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.
9.9
Which set(s) of reagents will give cyclohexyl
ethyl ether in high yield?
Br
A
CH3CH2O-
D
1. Hg(OAc)2, ethanol
2. NaBH4
O-
B
CH3CH2Br
E
OH
C
CH3CH2OH, H+ catalyst
Both B and D
A will eliminate while C
will give a mixture of
ethers.
Bruice: Organic Chemistry, © 2011 Pearson Education, Inc.