Chapter 28, Problem 28.33AP

Interpretation Introduction

(a)

Interpretation:

The following reactions by giving the major organic product(s), including stereochemistry is to be completed.

Concept introduction:

Cycloaddition reaction can be referred as a reaction of two different π-electron systems to form a ring product. Notably, in this reaction two new sigma bonds are formed in product with the disappearance of two fewer π-bonds. In other words, cyclo addition reaction can be best described as the reaction of number of electrons involved. In [4+2] cycloaddition one component is having four electrons and other component is having two electrons.

Interpretation Introduction

(b)

Interpretation:

The following reactions by giving the major organic product(s), including stereochemistry is to be completed.

Concept introduction:

Sigmatropic reaction can be described as the migration of allylic sigma bond at one end of the π-electron system to the other end of the π-electron system as an uncatalyzed intramolecular reaction. In some cases, Lewis acid catalysts can also be applied. Though, the position of π-bond is changed in Sigmatropic reaction, the total number of π-bonds remain unchanged. The sigma bond can be cleaved at the middle or at the end of the π-system. The formation of sigma bond at 3, 3-position of a 1, 5-diene is called as cope rearrangement.

Interpretation Introduction

(c)

Interpretation:

The following reactions by giving the major organic product(s), including stereochemistry is to be completed.

Concept introduction:

Cycloaddition reaction can be referred as a reaction of two different π-electron systems to form a ring product. Notably, in this reaction two new sigma bonds are formed in product with the disappearance of two fewer π-bonds. In other words, cyclo addition reaction can be best described as the reaction of number of electrons involved.

Interpretation Introduction

(d)

Interpretation:

The following reactions by giving the major organic product(s), including stereochemistry is to be completed.

Concept introduction:

Generally, [3, 3] sigmatropic reactions of 1, 5-diences are called as cope reactions. When the diene is having the oxygen at C3 or C4 position the sigmatropic reaction is called as oxy cope reaction. Notably, when the alkoxide fragment is involved it is referred as anionic oxy cope reaction. Moreover, the enhanced increase in rate of sigmatropic reaction and the decreased in the reaction temperature is observed as compared to parent alcohols.