Chapter 21, Problem 21.51P

Interpretation Introduction

(a)

Interpretation:

The all stereoisomers formed in the given reaction are to be drawn.

Concept introduction:

The Wittig reaction utilizes carbon nucleophile from the Wittig reagent to yield alkenes. When a carbonyl compound is treated with a Wittig reagent, the $\text{C}=\text{O}$ bond of carbonyl is replaced by $\text{C}=\text{C}$, with by-product triphenylphosphine oxide $\left({\text{Ph}}_{\text{3}}\text{P}=\text{O}\right)$.

Interpretation Introduction

(b)

Interpretation:

The all stereoisomers formed in the given reaction are to be drawn.

Concept introduction:

The treatment of carbonyl compounds (aldehyde/ketone), with $\text{NaCN}$, and strong acid $\left(\text{HCl}\right)$ adds $\text{HCN}$ across the $\text{C}-\text{O}\text{π}$ bond. The overall reaction yields cyanohydrin. The formation of cyanohydrin involves two-step mechanism that is nucleophilic attack of cyanide ion followed by protonation.

Interpretation Introduction

(c)

Interpretation:

The all stereoisomers formed in the given reaction are to be drawn.

Concept introduction:

The hydride reduction or the nucleophilic addition of carbanions to carbonyl compounds (aldehyde/ketone), both involve two-step mechanism that is nucleophilic attack of hydride ion or carbanion followed by protonation.

Interpretation Introduction

(d)

Interpretation:

The all stereoisomers formed in the given reaction are to be drawn.

Concept introduction:

Cyclic hemiacetals are the compounds in which one $\text{C}$ atom of the ring is bonded to $\text{OH}$ group and $\text{OR}$ group. The $\text{OR}$ group is the part of ring. Cyclic hemiacetals yield acetals when they are treated with an alcohol and an acid. The reaction converts $\text{OH}$ group into $\text{OR}$ group.