Chapter 5

How many stereogenic centers does this compound have?

0

How many stereogenic centers does this compound have?

1

How many stereogenic centers does this compound have?

2

Rank the following groups in order of decreasing priority using the Cahn Ingold Prelog rules. Assign number 1 to the highest priority, number 4 to the lowest priority. ___ -CH2CH3 ___ -CH3 ___ -H ___ -CH(CH3)2

2, 3, 4, 1

Rank the following groups in order of decreasing priority using the Cahn Ingold Prelog rules. Assign number 1 to the highest priority, number 4 to the lowest priority. ___ -COOH ___ -H ___ -NH2 ___ -OH

3, 4, 2, 1

How many stereogenic centers does this compound have?

4

The facts in Section 5.4A can be used to locate stereogenic centers in any molecule, no matter how complicated. Always look for carbons surrounded by four different groups. With this in mind, locate the stereogenic centers (by placing an asterisk on the structure) in aliskirin, a drug introduced in 2007 for the treatment of hypertension. How many stereogenic centers does Aliskiren have?

4

Rank the following groups in order of decreasing priority using the Cahn Ingold Prelog rules. Assign number 1 to the highest priority, number 4 to the lowest priority. ___ -H ___ -CH3 ___ -Cl ___ -CH2Cl

4, 3, 1, 2

How many stereogenic centers does this compound have?

7

How many stereogenic centers does this compound have?

8

Give the IUPAC name for the following compound: A. (1S,3S)-1-ethyl-3-methylcyclohexane B. (1R,3S)-1-ethyl-3-methylcyclohexane C. (1S,3R)-1-ethyl-3-methylcyclohexane D. (1R,3R)-1-ethyl-3-methylcyclohexane

A

Give the IUPAC name for the following compound: A. R-2,3-dimethylhexane B. S-2,3-dimethylhexane C. S-4,5-dimethylhexane D. R-4,5-dimethylhexane

A

What is the relationship between the following compounds? A. Diastereomers B. Constitutional isomers C. Enantiomers D. Identical

A

What is the relationship between the following two compounds? A. Constitutional isomers B. Stereoisomers C. Not isomers, different compounds D. Identical

A

What is the total number of possible stereoisomers for the following molecule? A. 8 B. 6 C. 4 D. 2

A

Which of the following compounds are chiral? A. II and III B. I and II C. I and IV D. III and IV

A

Which of the following compounds is a meso compound? A. (2R, 3S)-2,3-dichlorobutane B. (2R, 3S)-3-chloro-2-butanol C. (2R, 3R)-2,3-dichlorobutane D. (2R, 3R)-3-chloro-2-butanol

A

Which of the following is the correct definition for a pair of enantiomers? A. A pair of stereoisomers that are not superimposable mirror images of each other. B. A pair of stereoisomers that are not mirror images of each other. C. A pair of stereoisomers that have a plane of symmetry. D. A pair of stereoisomers that are superimposable mirror images of each other.

A

Which of the following is the definition for a pair of diastereomers? A. A pair of stereoisomers that are not mirror images of each other. B. A pair of stereoisomers with stereogenic centers but is not chiral. C. A pair of stereoisomers that are superimposable mirror images of each other. D. A pair of stereoisomers that are not superimposable mirror images of each other.

A

Which of the following structures has a different configuration from the other three? A. IV B. II C. I D. III

A

Which of the following structures has the R configuration? A. Only II B. I, II, and III C. Only I and II D. Only I

A

Draw both enantiomers of clopidogrel (trade name Plavix), a drug given to prevent the formation of blood clots in persons who have a history of stroke or coronary artery disease. Plavix is sold as a single enantiomer with the S configuration. Which enantiomer is Plavix? A or B?

B

Give the IUPAC name for the following compound: A. R-4-methylhexane B. S-3-methylhexane C. R-3-methylhexane D. S-4-methylhexane

B

Give the IUPAC name for the following compound: A. S-4-methylhexane B. R-3-methylhexane C. R-4-methylhexane D. S-3-methylhexane

B

How many chiral stereoisomers can be drawn for dimethycyclopropane? A. 1 B. 2 C. 4 D. 3

B

How many stereogenic centers are present in the following compound? A. 0 B. 1 C. 3 D. 2

B

What is the relationship between the following two compounds? A. Not isomers, different compounds B. Identical C. Constitutional isomers D. Stereoisomers

B

Which of the following compounds does not have a plane of symmetry? A. Only I, II, and IV B. Only II C. Only I and II D. Only III and IV

B

Which of the following statements is true? A. A chiral molecule usually contains a plane of symmetry. B. Enantiomers are mirror images that are not superimposable. C. A molecule that is superimposable on its mirror image is chiral. D. An achiral molecule does not contain a plane of symmetry.

B

How many stereogenic centers are present in the following compound? A. 0 B. 2 C. 3 D. 1

C

How many stereogenic centers are present in the following compound? A. 3 B. 1 C. 2 D. 4

C

How many stereogenic centers are present in the following compound? A. 3 B. 4 C. 2 D. 1

C

How many stereoisomers are possible for a molecule with formula CH3CHBrCH(OH)CH3? A. 2 B. 3 C. 4 D. 1

C

What is the relationship between the following compounds? A. Constitutional isomers B. Identical C. Enantiomers D. Diastereomers

C

Which of the following compounds can have a meso stereoisomer? A. III B. II C. IV D. I

C

Which of the following compounds has a plane of symmetry? A. II and III B. I and II C. III and IV D. II, III, and IV

C

Which of the following is the definition of chirality? A. The existence of a molecule that is superimposable on its mirror image. B. The existence of a molecule with a mirror image. C. The existence of a molecule that is not superimposable on its mirror image. D. The existence of a molecule with a carbon atom that has four different substituents.

C

Which of the following statements about constitutional isomers is not true? A. They have different IUPAC names. B. They have different physical properties. C. They always have the same functional groups. D. They have different chemical properties.

C

Which of the following statements is true? A. An achiral molecule must have one or more stereogenic centers. B. The presence of a plane of symmetry makes a molecule chiral. C. Stereoisomers that are not superimposable on their mirror image are enantiomers. D. All molecules that have stereogenic centers are chiral.

C

How many isomers (constitutional and stereoisomers) exist for dimethylcyclobutane? A. 3 B. 5 C. 4 D. 6

D

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system. A. I > II > IV > III B. I > II > III > IV C. II > I > III > IV D. II > I > IV > III

D

Rank the following groups in order of decreasing priority according to the Cahn-Ingold-Prelog system. A. I > II > IV > III B. IV > II > I > III C. III > II > I> IV D. IV > I > II > III

D

What is the relationship between the following compounds? A. Diastereomers B. Constitutional isomers C. Identical D. Enantiomers

D

What is the relationship between the following compounds? A. Enantiomers B. Diastereomers C. Constitutional isomers D. Identical

D

Which of the following molecules are chiral? A. I, IV B. I, II C. III, IV D. II, III

D

Which of the following molecules are chiral? I.2-Chlorobutane II.3-Bromopentane III.1-Bromo-2-methylpropene IV.2-Bromo-3-methylbutane A. III, IV B. I, II C. II, III D. I, IV

D

R or S isomer?

R

R or S isomer?

S