Organic Chemistry: A Guided Inquiry
2nd Edition
ISBN: 9780618974122
Author: Andrei Straumanis
Publisher: Cengage Learning
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Question
Chapter 12, Problem 11E
(a)
Interpretation Introduction
Interpretation: The structure and name of all the stereoisomers of 2,3-dichloropentane and 2,3-dichlorobutane needs to be determined.Also, the missing isomerof 2,3-dichlorobutane from the mentioned problem needs to be determined.
Concept Introduction:Number of stereoisomers (N) of a compound depends on the number of chiral centers. The formula is as follows:
Here, n is number of chiral carbon atoms in the molecule.
IUPAC nomenclatureis the method that is used to name the organic compounds in which the rules are governed by the International Union of Pure and Applied Chemistry.
Rules:
- Identify the parent chain from the given name of the compound that is written at the last.
- Find the position of the halogens present in the parent chain and attach those substituents in the corresponding position.
(b)
Interpretation Introduction
Interpretation: This is to be explained that how the number of stereoisomers of 2,3-dichloropentane is 4, but that of 2,3-dichlorobutane is 3.
Concept Introduction:If the different arrangement of atoms in a compound results in same formation of compound of same name thus, they are not condidered as stereiosiomers.
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Students have asked these similar questions
9.a. Circle all the appropriate terms.
t-Bu
The two molecules drawn above are
enantiomers
optically active
enantiomers
superimposable
9.b. Circle all the appropriate terms.
diastereomers
not optically active
H
optically active
Bull....
H₂CH...
Br
-CH3
The two molecules drawn above are
Me
H
diastereomers
not optically active
superimposable
Me
chiral
meso
not superimposable
H3C-
H
.......
chiral
meso
H
...III\CH3
Br
not superimposable
Cl
achiral
-t-Bu
identical
achiral
identical
3
pt. 4: Molecular Models: Stereoisomers
me:
4. Using the model of 2-bromobutane representing the R enantiomer from 4.,
switch any two groups on the chiral carbon. Compare this to your S
enantiomer from 4.
a. Are they the same or different?
b. Are they the same or enantiomers?
C. Now switch any pair of groups around the chiral carbon of the
"switched" model again! Compare the "double-switched" model with the
other unmodified S molecule from 4. Are they enantiomers or are they
identical?
С.
Shown below is the Fisher projection of (R)-2-bromo-(S)-3-chlorobutane.
ne mirror image of this stereoisomer and assign the RIS configurations of
iral carbons for both isomers.
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3. Complete the following 3 tasks for each molecule a-f.
i. Label each molecule as chiral, achiral, optically active,
ii.
iii.
optically inactive, and/or meso.
Label any stereocenters found in each molecule as R or S.
Identify the relationship between the molecule in the box
and molecules a-f. Are they identical molecules, resonance
structures, enantiomers, diastereomers, constitutional
isomers, or molecules with different molecular formulas? A
molecular model kit may help you compare structures.
a.
C.
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d.
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Chapter 12 Solutions
Organic Chemistry: A Guided Inquiry
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