Chapter 13, Problem 67IP

(a)

Interpretation Introduction

Interpretation:

The structure of the compound $\text{2}$ has to be provided.

Concept introduction:

Sharpless asymmetric epoxidation: An Alkene containing a Hydroxyl group in the allylic position is called as Allylic alcohols. Allylic position is the position next to $\text{C=C}$ bond.

Sharpless catalyst consists of Titanium tetraisopropoxide and one enantiomer of Diethyl tartrate ($\text{DET}$)

      

A chiral complex is formed with Titanium tetraisopropoxide and with either $\text{+DET}$ or $\text{-DET}$, and this complex serves as the chiral catalyst.

(b)

Interpretation Introduction

Interpretation:

The plausible mechanism for the transformation of $\text{2}\text{to}\text{3}$ and the expected configuration at each of the chiral centers in $\text{3}$ has to be proposed.

Concept introduction:

Ring-opening of epoxide:

The epoxide ring is highly strain and readily undergoes reaction with strong nucleophile result in the ring-opening reaction.

Base catalyzed ring opening of epoxide:

The nucleophile will attack at the less substituted position under basic conditions

(c)

Interpretation Introduction

Interpretation:

The structure of $\text{4}$ has to be drawn.

Concept introduction:

Protection of alcohols as TMS Ethers:

The use of TMSCl and a base is used to form TMS ethers. Primary, secondary and tertiary alcohols can be silylated using TMSCl

Methanesulfonates also can be used as a protecting group for alcohols.

(d)

Interpretation Introduction

Interpretation:

The plausible mechanism for the transformation of $\text{4}$ to $\text{5}$ has to be drawn.

Concept introduction:

Deprotonation: The reaction in which proton is removed from the compound using reagents is known as deprotonation.

Nucleophile: donates pair of electrons to positively charged substrate resulting in the formation of chemical bond.