Chapter 5, Problem 5.13P

Draw structural formulas for these alkenes.

(a) trans-2-Methyl-3-hexene

(b) 2-Methyl-2-hexene

(c) 2-Methyl-1-butene

(d) 3-Ethyl-3-methyl-1-pentene

(e) 2,3-Dimethyl-2-butene

(f) cis-2-Pentene

(g) (Z)-1-Chloropropene

(h) 3-Methylcyclohexene

(i) 1-Isopropyl-4-methylcyclohexene

(j) (E)-2,6-Dimethyl-2,6-octadiene

(k) 3-Cyclopropyl-1-propene

(l) Cyclopropylethene

(m) 2-Chloropropene

(n) Tetrachloroethylene

(o) 1-Chlorocyclohexene

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is trans-2-methyl-3-hexene.

From the name, it is clear that,

• • The parent name is hexene thus the longest carbon chain has six carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the third carbon atom.
• • One methyl group is present at the second carbon atom.

• • Given compound is trans isomer and hence groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is 2-methyl-2-hexene.

From the name, it is clear that,

• • The parent name is hexene thus the longest carbon chain has six carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the second carbon atom.
• • One methyl group is present at the second carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Explanation of Solution

The given compound is 2-methyl-1-butene.

From the name, it is clear that,

• • The parent name is butene thus the longest carbon chain has four carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the first carbon atom.
• • One methyl group is present at the second carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is 3-ethyl-3-methyl-1-pentene.

From the name, it is clear that,

• • The parent name is pentene thus the longest carbon chain has five carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the first carbon atom.
• • One methyl group is present at the third carbon atom.
• • One ethyl group is present at the third carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is 2,3-dimethyl-2-butene.

From the name, it is clear that,

• • The parent name is butene thus the longest carbon chain has four carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the second carbon atom.
• • One methyl group is present at second and third carbon atoms.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is cis-2-pentene.

From the name, it is clear that,

• • The parent name is pentene thus the longest carbon chain has five carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the second carbon atom.

• • Given compound is cis isomer and hence carbon atoms present in the main chain are placed on same side of the carbon-carbon double bond.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Z configuration: The geometric isomers are given Z configuration if high priority groups are placed on same sides of the bond.

Explanation of Solution

The given compound is (Z)-1-chloropropene.

From the name, it is clear that,

• • The parent name is propene thus the longest carbon chain has three carbon atoms with a terminal carbon-carbon double bond.
• • One chloro group is present at the first carbon atom.

• • The given compound is (Z)-configuration and hence higher priority group are on same side of the double bond.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

Naming of Cycloalkene using IUPAC nomenclature:

Use the Cycloalkane name as the parent.

Cycloalkenes are named as alkyl-substituted cycloalkenes rather than as cycloalkyl-substituted alkenes.

Identify and number the substituents.

The group which has alphabetical priority should be numbered first and proceed around the ring in a direction in which the double bond gets the lowest possible number.

Explanation of Solution

The given compound is 3-methylcyclohexene.

From the name, it is clear that,

• • The parent name is cyclohexene so it is a six membered ring with a carbon-carbon double bond.
• • One methyl group is present at the third carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

Naming of Cycloalkene using IUPAC nomenclature:

Use the Cycloalkane name as the parent.

Cycloalkenes are named as alkyl-substituted cycloalkenes rather than as cycloalkyl-substituted alkenes.

Identify and number the substituents.

The group which has alphabetical priority should be numbered first and proceed around the ring in a direction in which the double bond gets the lowest possible number.

Explanation of Solution

The given compound is 1-isopropyl-4-methylcyclohexene.

From the structure, it is clear that,

• • The parent name is cyclohexene so it is a six membered ring with a carbon-carbon double bond.
• • One methyl group is present at the fourth carbon atom.
• • One isopropyl group is present at the first carbon atom

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Trans configuration: In trans configuration, groups present in the main chain are placed on opposite sides of the carbon-carbon double bond.

Cis configuration: In cis configuration, groups present in the main chain are placed on same sides of the carbon-carbon double bond.

Explanation of Solution

The given compound is (E)-2,6-dimethyl-2,6-octadiene.

From the name, it is clear that,

• • The parent name is octadiene thus the longest carbon chain has eight carbon atoms with two carbon-carbon double bond.
• • One carbon-carbon double bond is present at the second and sixth carbon atom.
• • One methyl group is present at the second and sixth carbon atom.

• • The given compound is (E)-configuration and hence higher priority group are on the opposite sides of the double bond at $C-2$ position.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Explanation of Solution

The given compound is 3-cyclopropyl-1-propene.

From the name, it is clear that,

• • The parent name is propene thus the longest carbon chain has three carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the first carbon atom.
• • One cyclopropyl group is present at the third carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Explanation of Solution

The given compound is cyclopropylethene.

From the name, it is clear that,

• • The parent name is ethene thus the longest carbon chain has two carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present.
• • One cyclopropyl group is present at the terminal carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Explanation of Solution

The given compound is 2-chloropropene.

From the name, it is clear that,

• • The parent name is propene thus the longest carbon chain has three carbon atoms with a carbon-carbon double bond.
• • One carbon-carbon double bond is present at the terminal carbon atom.
• • One chloro group is present at the second carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

IUPAC nomenclature:

• • Name the main chain: Find the longest carbon chain and name the chain according to the number of carbon atoms it contains; is also the root name.
• • Number the carbon atoms in the main chain: The carbons are numbered, in which the substituents must get lowest possible numbers.
• • Identify the substituents, and number each: The number at where substituents are present has to be noted. The substituents written as prefix.
• • Write the names as a single word: Use the hyphen to separate the numbers from the different prefix; commas to separate numbers. If two or more different substituents are present, arrange them in alphabetical order. If two or more identical substituents are present, use prefixes di-, tri-, tetra-, but this particular prefix should not be used for alphabetizing purpose.

Alkene: Unsaturated hydrocarbons having at least one double bond between two carbon atoms are known as alkenes.

The systematic name of alkenes are written by replacing “ane” of alkane with the suffix name “ene”. Numbering of the main chain should be in such away that alkene group must get lowest possible numbers.

Explanation of Solution

The given compound is tetrachloroethylene.

From the name, it is clear that,

• • The parent name is ethylene thus the longest carbon chain has two carbon atoms with a carbon-carbon double bond.
• • Two chloro groups are present at both first and second carbon atom.

Therefore,

Structural formula for the given alkene is,

Interpretation Introduction

Interpretation:

Structural formula for the given alkene has to be drawn.

Concept Introduction:

Naming of Cycloalkene using IUPAC nomenclature:

Use the Cycloalkane name as the parent.

Cycloalkenes are named as alkyl-substituted cycloalkenes rather than as cycloalkyl-substituted alkenes.

Identify and number the substituents.

The group which has alphabetical priority should be numbered first and proceed around the ring in a direction in which the double bond gets the lowest possible number.

Explanation of Solution

The given compound is 1-chlorocyclohexene.

From the name, it is clear that,

• • The parent name is cyclohexene so it is a six membered ring with a carbon-carbon double bond.
• • One chloro group is present at the first carbon atom.

Therefore,

Structural formula for the given alkene is,