An acid-catalyzed and a base-catalyzed rearrangement of a β , γ -unsaturated carbonyl compound to a more stable α , β -unsaturated carbonyl compound has to be proposed. Concept introduction: The carbon which is adjacent to the carbonyl group is known as α -carbon , followed next by β -carbon and γ -carbon . The α , β -unsaturated carbonyl compounds are a type of carbonyl compounds where there is a double bond between the α and β -carbon . The β , γ -unsaturated carbonyl compounds are those where there is a double bond between the β and γ carbon. The α , β -unsaturated carbonyl compounds are most stable than the β , γ -unsaturated carbonyl compounds and hence rearrangement takes place in presence of either an acid or a base.

Question

A b,g-unsaturated carbonyl compound rearranges to a more stable conjugated a,b-unsaturated compound in the presence of either acid or base. a. Propose a mechanism for the base-catalyzed rearrangement. b. Propose a mechanism for the acid-catalyzed rearrangement.

Answer 1

Question

Chapter 17, Problem 64P

(a)

Interpretation Introduction

Interpretation: An acid-catalyzed and a base-catalyzed rearrangement of a β,γ-unsaturated carbonyl compound to a more stable α,β-unsaturated carbonyl compound has to be proposed.

Concept introduction: The carbon which is adjacent to the carbonyl group is known as α-carbon, followed next by β-carbon and γ-carbon. The α,β-unsaturated carbonyl compounds are a type of carbonyl compounds where there is a double bond between the α and β-carbon. The β,γ-unsaturated carbonyl compounds are those where there is a double bond between the β and γ carbon. The α,β-unsaturated carbonyl compounds are most stable than the β,γ-unsaturated carbonyl compounds and hence rearrangement takes place in presence of either an acid or a base.

(b)

Interpretation Introduction

Interpretation: An acid-catalyzed and a base-catalyzed rearrangement of a β,γ-unsaturated carbonyl compound to a more stable α,β-unsaturated carbonyl compound has to be proposed.

Concept introduction: The carbon which is adjacent to the carbonyl group is known as α-carbon, followed next by β-carbon and γ-carbon. The α,β-unsaturated carbonyl compounds are a type of carbonyl compounds where there is a double bond between the α and β-carbon. The β,γ-unsaturated carbonyl compounds are those where there is a double bond between the β and γ carbon. The α,β-unsaturated carbonyl compounds are most stable than the β,γ-unsaturated carbonyl compounds and hence rearrangement takes place in presence of either an acid or a base.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Students have asked these similar questions

A b,g-unsaturated carbonyl compound rearranges to a more stable conjugated a,b-unsaturated compound in the presence of either acid or base. a. Propose a mechanism for the base-catalyzed rearrangement. b. Propose a mechanism for the acid-catalyzed rearrangement.

Draw the enol form of each keto tautomer in parts (a) and (b), and the keto form of each enol tautomer in parts (c) and (d).

Draw the product(s) that result from a rearrangement in the following reaction.