Chapter 8, Problem 53P

(a)

Interpretation Introduction

Interpretation:The best method for synthesis of indicated ketone from appropriate alcohol should be outlined.

  

Concept introduction:Chromium reagents such as ${\text{CrO}}_{\text{3}}$ , pyridiniumchlorochromate or sodium and potassium chromate that has chromium present in high oxidation state $\text{Cr}\left(\text{VI}\right)$ are useful oxidizing reagent for primary or secondary alcohols. The tertiary alcohols have no hydrogen so it cannot be oxidized.

Aqueous sodium dichromate is the reagent added for oxidation of $2°$ alcohol to a ketone. The reagent is written as ${\text{NaCr}}_2{\text{O}}_{\text{7}}{\text{/H}}_{\text{2}}{\text{SO}}_{\text{4}}$ and has $\text{Cr}\left(\text{VI}\right)$ that transforms to $\text{Cr}\left(\text{III}\right)$ while it acts as oxidizing agent.

(b)

Interpretation Introduction

Interpretation:The best method for synthesis of indicated acid from appropriate alcohol should be devised.

  

Concept introduction:Chromium reagents such as ${\text{CrO}}_{\text{3}}$ , pyridiniumchlorochromateor sodium and potassium chromate that has chromium present in high oxidation state $\text{Cr}\left(\text{VI}\right)$ are useful oxidizing reagent for primary or secondary alcohols. The tertiary alcohols have no hydrogen so it cannot be oxidized.

Since aldehydes in water tend to remain in equilibrium with the diols, one of the two hydroxyl functional group presents may further react with chromium regent to form carboxylic acid as final oxidation product. This is known as overoxidation without the formation of intermediate oxidized product aldehyde. The regent for direct conversion of alcohol to acid is ${\text{K}}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$ , ${\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}$ and ${\text{H}}_{\text{2}}\text{O}$ .

(c)

Interpretation Introduction

Interpretation: The best method for synthesis of indicated aldehyde from appropriate alcohol should be devised.

  

Concept introduction:PCC is useful for selective oxidation of primary alcohol to corresponding aldehydes. The tertiary alcohols have no hydrogen so it cannot be oxidized. The structure of pyridinium chlorochromate is as follows:

  

(d)

Interpretation Introduction

Interpretation: The best method for synthesis of indicated ketone from appropriate alcohol should be outlined.

  

Concept introduction:Chromium reagents such as ${\text{CrO}}_{\text{3}}$ , pyridiniumchlorochromate or sodium and potassium chromate that has chromium present in high oxidation state $\text{Cr}\left(\text{VI}\right)$ are useful oxidizing reagent for primary or secondary alcohols. The tertiary alcohols have no hydrogen so it cannot be oxidized.

Aqueous sodium dichromate is the reagent added for oxidation of $2°$ alcohol to a ketone. The reagent is written as ${\text{NaCr}}_2{\text{O}}_{\text{7}}{\text{/H}}_{\text{2}}{\text{SO}}_{\text{4}}$ and has $\text{Cr}\left(\text{VI}\right)$ that transforms to $\text{Cr}\left(\text{III}\right)$ while it acts as oxidizing agent.

(e)

Interpretation Introduction

Interpretation: The best method for synthesis of indicated aldehyde from appropriate alcohol should be devised.

  

Concept introduction: PCC is pyridinium chlorochromate is useful for selective oxidation of primary alcohol to corresponding aldehydes. The tertiary alcohols have no hydrogen so it cannot be oxidized. The structure of pyridinium chlorochromate is as follows: