Chapter 21, Problem 21.21P

Interpretation Introduction

(a)

Interpretation:

The starting materials that are needed to prepare the given alkene by Wittig reaction are to be predicted, and the preferred route is to be identified, if there are two possible routes.

Concept introduction:

One should follow the two steps retrosynthesis to find out the starting materials that are needed to prepare the given alkene. The first step is cleaving of $\text{C}=\text{C}$ into two components, carbonyl and Wittig reagent. The second step is selection of preferred pathway. While selection one should consider that pathway in which Wittig reagent is derived from an unhindered alkyl halide, like ${\text{CH}}_{\text{3}}\text{X}$ or ${\text{RCH}}_{\text{2}}\text{X}$.

Interpretation Introduction

(b)

Interpretation:

The starting materials that are needed to prepare the given alkene by Wittig reaction are to be predicted, and the preferred route is to be identified, if there are two possible routes.

Concept introduction:

One should follow the two steps retrosynthesis to find out the starting materials that are needed to prepare the given alkene. The first step is cleaving of $\text{C}=\text{C}$ into two components, carbonyl and Wittig reagent. The second step is selection of preferred pathway. While selection one should consider that pathway in which Wittig reagent is derived from an unhindered alkyl halide, like ${\text{CH}}_{\text{3}}\text{X}$ or ${\text{RCH}}_{\text{2}}\text{X}$.

Interpretation Introduction

(c)

Interpretation:

The starting materials that are needed to prepare the given alkene by Wittig reaction are to be predicted, and the preferred route is to be identified, if there are two possible routes.

Concept introduction:

One should follow the two steps retrosynthesis to find out the starting materials that are needed to prepare the given alkene. The first step is cleaving of $\text{C}=\text{C}$ into two components, carbonyl and Wittig reagent. The second step is selection of preferred pathway. While selection one should consider that pathway in which Wittig reagent is derived from an unhindered alkyl halide, like ${\text{CH}}_{\text{3}}\text{X}$ or ${\text{RCH}}_{\text{2}}\text{X}$.