Question

Which of the compound will not produce 3 -oxo butanal as the sole organic product with \(\mathrm{O}_{3}, \mathrm{Zn}\) ? (A) C=C1C=CCC=C1C (B) CC1CC1 (C) Cc1ccccc1 (D) Cc1ccc(C)cc1

Short answer

The compound that will not produce 3-oxo butanal as the sole organic product upon treatment with O₃ and Zn is (A) C=C1C=CCC=C1C.

Step-by-step solution

Understand the ozonolysis reaction

Ozonolysis is an oxidation reaction that involves cleaving double bonds (alkenes) by using ozone (O₃). The reaction proceeds through the formation of an ozonide intermediate, which is then reduced by Zn to form carbonyl compounds (typically aldehydes and/or ketones). This reaction can be used to identify the location and type of double bonds in an organic molecule. Therefore, we need to look for the compound that upon undergoing ozonolysis, will not produce 3-oxo butanal (a carbonyl compound) as the sole organic product.

Examine the given compound structures

Let's analyze the structure of the compounds given: (A) C=C1C=CCC=C1C (B) CC1CC1 (C) Cc1ccccc1 (D) Cc1ccc(C)cc1 Compound (A) contains two double bonds, one in a six-membered ring and one outside the ring. Compound (B) has no double bonds in its structure. Compound (C) consists of a six-membered ring with alternating single and double bonds (benzene ring) and one methyl group. Compound (D) has a six-membered ring with alternating single and double bonds (benzene ring) and two methyl groups attached to it.

Determine which compound will not produce 3-oxo butanal upon ozonolysis

As mentioned earlier, ozonolysis is specifically a reaction involving the cleavage of double bonds. We can immediately eliminate Compound (B) as it does not have any double bond and therefore will not undergo ozonolysis. For the remaining compounds, let's investigate their structures upon undergoing ozonolysis and check if 3-oxo butanal is formed. For Compound (A), ozonolysis will break the double bonds, forming two carbonyls. It will not form 3-oxo butanal as the sole organic product. For Compound (C), the ozonolysis of the double bonds in the benzene ring of the compound will lead to carbonyl groups, but it will not produce 3-oxo butanal as the organic product. For Compound (D), the ozonolysis of the double bonds in the benzene ring and the cleavage of one of the methyl groups will produce 3-oxo butanal as one of the products. From the analysis and the comparison of the structures, we can conclude that Compound (A) is the one that will not produce 3-oxo butanal as the sole organic product upon undergoing ozonolysis with O₃ and Zn.

Key concepts

Alkene Chemistry

Alkenes are hydrocarbons containing one or more carbon-carbon double bonds. These unsaturated molecules are primarily known for their versatility in organic reactions, especially in ozonolysis. The presence of double bonds allows alkenes to participate in addition reactions, where atoms or groups are added, and in oxidation processes, where these bonds are cleaved to form different compounds.
In the context of ozonolysis, the double bond serves as the reaction site where ozone can break the bond to form ozonides. These are then further reduced, often with zinc, to form carbonyl compounds, such as aldehydes and ketones. This property of alkenes is crucial in organic synthesis and analysis, allowing chemists to identify the location of double bonds and produce valuable intermediates for further chemical reactions. Understanding alkene chemistry is fundamental for those preparing for competitive exams like JEE Advanced.

Organic Reaction Mechanisms

Organic reaction mechanisms describe the step-by-step process through which an organic reaction occurs. In ozonolysis, the mechanism begins with the reaction of ozone with the carbon-carbon double bond of an alkene. This interaction forms a cyclic ozone intermediate, known as an ozonide.
Subsequently, a reductive workup stage follows, typically involving zinc or another reducing agent, breaking down the ozonide into two separate carbonyl compounds. Throughout this mechanism, several intermediates and transition states occur, detailing the pathway from reactants to the final products.
This detailed understanding of the mechanism helps predict the outcome of the reactions, crucial for problem-solving in exams like JEE Advanced. Being familiar with these processes teaches students how changes in conditions or substrates might alter the products formed.

Carbonyl Compounds

Carbonyl compounds, which include aldehydes and ketones, are typically the end products of an ozonolysis reaction. These organic molecules contain a carbon atom double-bonded to an oxygen atom, known as the carbonyl group, which is highly reactive and forms the basis for many organic synthesis pathways.

• Aldehydes have at least one hydrogen atom attached to the carbonyl carbon.
• Ketones have two alkyl or aryl groups attached to the carbonyl carbon.

The importance of carbonyl compounds lies in their reactivity, which makes them key intermediates in various chemical reactions. In the context of JEE Advanced preparation, recognizing the formation and reactivity of these compounds can help students to solve complex chemistry problems related to ozonolysis and other transformation reactions.

JEE Advanced Preparation

Preparing for the JEE Advanced exam requires a thorough understanding of both theoretical concepts and their practical applications, particularly in organic chemistry. Topics such as ozonolysis are typical as they encompass various key areas of organic chemistry including alkene reactions, reaction mechanisms, and the formation of carbonyl products.

• Recognize and predict the outcome of different organic reactions.
• Understand the mechanism behind reactions to solve complex problems.
• Familiarize oneself with common transformations of functional groups.

By mastering these aspects, students can effectively tackle organic chemistry questions in the JEE Advanced exam. Additionally, practicing various problem types ensures that candidates are well-prepared to apply their knowledge in real exam scenarios, enhancing both accuracy and confidence.