Chapter 12, Problem 75CP

Interpretation Introduction

Interpretation:

A separate synthesis for each of the given two compounds using a disubstituted alkene containing four carbon atoms as starting materials has to be given.

Concept introduction:

Hydrobromination:

A hydrobromination reaction is one of the electrophilic additions to alkenes to yield the corresponding bromo alkanes. In this reaction the bromine atom adds to the double bond carbon which is having lesser number of hydrogen or more substituted carbon (Markovnikov's rule).

Bromination of alkenes:

Alkene undergoes bromination which yields the dibromo compound (vicinal dibromides or 1,2-dibromides).

Hydroboration:

Hydroboration is the addition of a hydrogen-boron bond to the Carbon-Carbon, Carbon-Nitrogen, and Carbon-Oxygen double bonds and Carbon-Carbon triple bonds.

When alkene undergoes hydroboration using alkyl borane and hydrogen peroxide followed by hydrolysis which yields the alcohol. The formation of alcohol is depends on the less hindered carbon of the double bond.

Oxidation reaction:

Alcohol undergoes oxidation reaction using oxidising agent like ${\text{PCC or KMnO}}_{\text{4}}{\text{or K}}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$ which yields the corresponding carbonyl compounds. Primary alcohol undergoes oxidation reaction yields the corresponding aldehyde or acid, secondary alcohol undergoes oxidation reaction yields the corresponding ketone as the product. Tertiary alcohols do not undergo oxidation reaction.

The Grignard reaction:

Alkyl, vinyl, or aryl-magnesium halides ($\text{RMgX}$) is called as Grignard reagent.

Grignard reagent is reaction with carbonyl compound such as aldehyde or ketone, produces corresponding alcohol is the product and it is the one of the carbon – carbon bond forming reaction.