Chapter 8, Problem 66PP

Interpretation Introduction

Interpretation:

All possible structural isomers should be drawn for the given molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{10}}$ and need to select the isomers, which cannot give products with stereo isomer in hydroboration-oxidation reaction.

Concept Introduction:

• Structural isomers: isomers that have same molecular formula and different structures are known as structural isomers.
• Hydroboration reaction: In this reaction water molecule is added across the double bond of the alkene in syn pathway. In hydroboration reaction, anti-Markovnikov’s product is favorable which means –OH group attached to less substituted carbon end of the alkene.
• Hydroboration reaction takes place in two steps; first step is syn addition of ${\text{BH}}_{\text{3}}$ and second step is attack of nucleophile (hydroxide ion produced from hydrogen peroxide and ${\text{BH}}_{\text{3}}$).

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.