Question

An alkene with the molecular formula C8H16 undergoes ozonolysis to yield a mixture of (CH3)2C=O and (CH3)3CCHO. The alkene is:

a. 2,2-Dimethyl-2-hexene.

b. 2,3-Dimethyl-2-hexene.

c. 2,4-Dimethyl-2-hexene.

d. 2,4,4-Trimethyl-2-pentene.

e. more than one of these choices is a possible answer.

Answer 1

The alkene with the molecular formula C8H16 that yields (CH3)2C=O and (CH3)3CCHO upon ozonolysis is 2,3-Dimethyl-2-hexene. So the correct option is b.

Step-by-step explanation:

The student's question asks about the identity of an alkene with the molecular formula C8H16 that, following ozonolysis, yields a mixture of (CH3)2C=O (acetone) and (CH3)3CCHO (2,2-dimethylpropanal). Ozonolysis is a reaction used to cleave double bonds in alkenes to form carbonyl compounds, giving insight into the placement of the double bond within the organic molecule.

To determine which alkene would yield these products upon ozonolysis, we must consider the structure of the products formed. Acetone ((CH3)2C=O) has a carbonyl group flanked by two methyl groups, indicating that the original double bond was between two carbon atoms, each of which had two methyl substituents. Meanwhile, 2,2-dimethylpropanal ((CH3)3CCHO) has a carbonyl group adjacent to a quaternary carbon (a carbon attached to four other carbons), which suggests the original double bond was adjacent to a quaternary carbon.

Taking these observations into account, the alkene in question must be 2,3-Dimethyl-2-hexene (option b). This is the only alkene that, when cleaved, would produce the given fragments with the correct substitution. Each side of the double bond must have the appropriate substituents to form the products upon ozonolysis.

Answer 2

2,4,4-trimethyl-2-pentene yields mixture of
`(CH_(3))_(2)C=O` and
`(CH_(3))_(3)CHO`

Step-by-step explanation:

In ozonolysis (hydrolysis step involve a reducing agent such as Zn,
`Me_(2)S` etc.), a pi bond is broken to form ketone/aldehyde.

Ketone is formed from di-substituted side of double bond and aldehyde is formed from mono-substituted side of double bond.

Ozoznolysis involves two consecutive steps : (1) formation of ozonide, (2) hydrolysis of ozonide.

Hydrolysis can be done with/without using reducing agent. Carboxylic acid/carbon dioxide/ketone is produced when hydrolysis is done without using reducing agent.

Here, 2,4,4-trimethyl-2-pentene yields mixture of
`(CH_(3))_(2)C=O` and
`(CH_(3))_(3)CHO`

Reaction steps are shown below.