Question

The reaction betwecn 1,3 -butadienc and cthenc gives cyclohexenc. It is known as (1) Dicls Alder reaction (2) Perkin's reaction (3) Sabatier Scnderns reaction (4) Ilydrogenation

Short answer

Diels-Alder reaction

Step-by-step solution

Understand the Chemical Compounds

The reaction involves 1,3-butadiene and ethene as reactants, forming cyclohexene as the product.

Identify the Reaction Type

The given reaction is a typical cycloaddition reaction where 1,3-butadiene reacts with ethene to form a six-membered ring, cyclohexene.

Recognize the Named Reaction

This type of cycloaddition reaction, specifically forming cyclohexene from 1,3-butadiene and ethene, is known as the Diels-Alder reaction.

Match to Provided Options

As identified, the Diels-Alder reaction matches the first option provided. Verify that it does not match Perkin's reaction, Sabatier-Scncdcrns reaction, or Hydrogenation.

Key concepts

Cycloaddition Reaction

Cycloaddition reactions are a type of pericyclic reaction where two or more unsaturated molecules (or parts of the same molecule) react to form a cyclic compound. This reaction is highly useful in organic synthesis because it allows for the construction of complex ring structures in a single step.
In the context of the Diels-Alder reaction, we see a [4+2] cycloaddition. This means four pi electrons from one reactant (like 1,3-butadiene) interact with two pi electrons from another reactant (like ethene) to form a six-membered ring. The new ring structure formed is cyclohexene.

• Cycloaddition reactions are types of pericyclic reactions.
• They involve the formation of rings through the interaction of multiple unsaturated molecules.
• The Diels-Alder reaction is a specific type of [4+2] cycloaddition reaction.

1,3-butadiene

1,3-butadiene is an important diene in organic chemistry. It's a molecule with four carbon atoms connected in a linear sequence with alternating double bonds (pi bonds) and single bonds (sigma bonds). The chemical structure of 1,3-butadiene is CH₂=CH-CH=CH₂.
It’s called a conjugated diene because the double bonds are separated by a single bond. This conjugation stabilizes the molecule and gives it unique reactivity properties. The 1,3-butadiene can participate in cycloaddition reactions such as the Diels-Alder reaction, where its four pi electrons are used to form a six-membered ring.

• 1,3-butadiene has a linear structure with alternating double and single bonds.
• It is a conjugated diene, which means its double bonds are separated by a single bond.
• Its conjugation offers unique stability and reactivity, making it an essential reactant in Diels-Alder cycloaddition reactions.

Cyclohexene

Cyclohexene is the six-membered ring product derived from the Diels-Alder cycloaddition reaction between 1,3-butadiene and ethene. Cyclohexene has a chemical structure of C₆H₁₀, consisting of a six-carbon ring with one double bond.
This compound is significant in organic chemistry due to its stability and versatility in further chemical transformations. It serves as a building block for various synthetic processes, offering a balance between reactivity due to the double bond and the stability from the ring structure.

• Cyclohexene is a six-membered ring compound with one double bond.
• It is formed through a Diels-Alder cycloaddition reaction involving 1,3-butadiene and ethene.
• This compound is crucial in synthetic chemistry for its balanced reactivity and stability.