Deck 5: Stereochemistry at Tetrahedral Centers

Question 1

Exhibit 5-3
Assign R,S configurations to each indicated chirality center in the molecules below.
​
Refer to Exhibit 5-3.The configuration of this carbon atom (A) is _____.

Answer 1

R

Question 2

_____ is the reason for "handedness" in molecules;the property of an object that causes it to be nonsuperimposable on its mirror image.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Answer 2

chirality

Question 3

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Answer 3

diastereomers

Question 4

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 5

Exhibit 5-3
Assign R,S configurations to each indicated chirality center in the molecules below.
​
Refer to Exhibit 5-3.The configuration of this carbon atom (B) is _____.

Question 6

_____ is an atom in a molecule that is bonded to four different atoms or groups of atoms.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Question 7

Exhibit 5-4
Consider the structure of streptimidone to answer the following question(s).
​
Refer to Exhibit 5-4.Will streptimidone have a meso stereoisomer? Explain your answer.

Question 8

The specific rotation of a compound is denoted by the symbol:

A)R
B)S
C)α
D)

Question 9

_____ are stereoisomers that are not mirror images.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Question 10

Exhibit 5-3
Assign R,S configurations to each indicated chirality center in the molecules below.
​
Refer to Exhibit 5-3.The configuration of this carbon atom (D) is _____.

Question 11

Exhibit 5-3
Assign R,S configurations to each indicated chirality center in the molecules below.
​
Refer to Exhibit 5-3.The configuration of this carbon atom (E) is _____.

Question 12

Exhibit 5-3
Assign R,S configurations to each indicated chirality center in the molecules below.
​
Refer to Exhibit 5-3.The configuration of this carbon atom (C) is _____.

Question 13

Exhibit 5-4
Consider the structure of streptimidone to answer the following question(s).
​
Refer to Exhibit 5-4.Based on the number of chirality centers,how many stereoisomers of streptimidone are possible?

Question 14

_____ is an sp³-hybridized atom that can become a chirality center by changing one of its attached groups.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Question 15

_____ are molecules which contain a plane of symmetry and chirality centers,but are achiral.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Question 16

____ are organic molecules which rotate the plane of polarization of plane-polarized light.

A)racemates
B)chirality center
C)chirality
D)diastereomers
E)enantiomers
F)meso compounds
G)optically active
H)prochirality center
I)optically inactive
J)achiral

Question 17

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 18

Exhibit 5-4
Consider the structure of streptimidone to answer the following question(s).
​
Refer to Exhibit 5-4.Assign R or S configuration to each chirality center indicated in streptimidone.

Question 19

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 20

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 21

(2R,3S)-Dibromobutane is:

A)optically active.
B)racemic.
C)dextrorotatory.
D)a meso compound.

Question 22

Exhibit 5-6
Refer to the structure below to answer the following question(s).
​
Refer to Exhibit 5-6.Draw the enantiomer of (S)-(−)-serine in a wedge-dash projection.

Question 23

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 24

Exhibit 5-7
A natural product having [α]_D = +40.3° has been isolated and purified.
Refer to Exhibit 5-7.Two structures have been proposed for this natural product.Circle the structure that is consistent with the information presented and briefly explain your choice.
​

Question 25

Explain why a work glove is chiral but disposable surgical gloves are not.

Question 26

Exhibit 5-7
A natural product having [α]_D = +40.3° has been isolated and purified.
Refer to Exhibit 5-7.This information indicates that the natural product:

A)is racemic.
B)does not rotate plane-polarized light.
C)is levorotatory.
D)is dextrorotatory.

Question 27

Draw a wedge-dash projection of (2R,3S)-dibromobutane.

Question 28

Draw a Newman projection of the most stable conformation of (2R,3S)-dibromobutane sighting down the C2−C3 bond.

Question 29

Exhibit 5-6
Refer to the structure below to answer the following question(s).
​
Refer to Exhibit 5-6.Give the complete name of the enantiomer of (S)-(−)-serine.

Question 30

Which of the following compounds will rotate the plane of polarized light?

A)
B)
C)
D)

Question 31

Which of the following objects is not chiral?

A)baseball glove
B)ballerina slipper
C)corkscrew
D)comb
E)All are chiral.

Question 32

Exhibit 5-6
Refer to the structure below to answer the following question(s).
​
Refer to Exhibit 5-6.(S)-(−)-Serine:

A)is dextrorotatory
B)rotates plane-polarized light in a counterclockwise direction
C)rotates plane-polarized light in a clockwise direction
D)is racemic

Question 33

In which of the following groups can the carbon atom be a chiral center?

A)
B)
C)
D)
E)The carbon atoms cannot be a chiral center in any of these groups.

Question 34

Acetoacetate synthase catalyzes the addition of pyruvate to β-ketobutyrate to yield α-aceto-α-hydroxybutyrate.If the addition occurs from the si face of β-ketobutyrate,what is the stereochemistry of the product?

Question 35

A white solid known to be enantiomerically pure is dissolved in water.This solution produced an observed optical rotation of +45.6°.The solution was allowed to stand and the optical rotation was measured repeatedly producing the data shown in the table.

Explain the pattern of observed rotation.

Question 36

Draw a structure for a singly substituted chiral chloroalkane that contains four carbon atoms.Indicate the chirality center with an asterisk (*).

Question 37

Exhibit 5-5
Label each pair of stereoisomers below as:
_____

A)enantiomers
B)diastereomers
C)identical
Place the letter of the correct answer in the blank to the left of the pair of stereoisomers.

Question 38

Which of the following would be has the highest priority according to the sequence rules?

A)-SH
B)-NH₂
C)-CH₃
D)-OH

Question 39

Estriol,a potent estrogenic hormone,has been isolated from the urine of pregnant women.When 40 mg of estriol is dissolved in 1.0 mL of dioxane and placed in a sample tube with 1 dm path length a rotation of +2.32° is observed.Calculate the specific rotation for estriol.

Question 40

Which of the following arranges the groups in order of decreasing priority according to the sequence rules?

A)CH₃ > CH₂CH₃ > CH₂OH > CO₂H
B)CH₃ > CH₂CH₃ > CO₂H >CH₂OH
C)CH₂OH > CO₂H > CH₂CH₃ > CH₃
D)CO₂H > CH₂OH > CH₂CH₃ > CH₃

Question 41

A compound with specific rotation,[α]_D = +35.4° reacts to form a single product.The product of the reaction shows no optical activity.This could mean that the product:

A)is a racemate.
B)does not have any chiral centers.
C)is a meso compound.
D)Any of the above are possible explanations.

Question 42

For which of the following generic substances is it not possible to isolate the enantiomers? (R₁,R₂ and R₃ represent different groups. )

A)
B)
C)
D)It is possible to isolate the enantiomers of all of these.
E)It is not possible to isolate the enantiomers of any of these.

Question 43

In muscles during strenuous exercise,under anaerobic conditions lactic acid builds up due to the following reaction. The carbon atom indicated by the asterisk is

A)chiral
B)achiral
C)prochiral
D)both achiral and prochiral