Chapter 19, Problem 19.71P

Interpretation Introduction

(a)

Interpretation:

Synthetic approach for the synthesis of following using propanal and any other ketone or aldehyde as only starting material containing carbon is to be proposed.

Concept introduction:

The relative position of the heteroatom in the target compound is 1, 2. The retrosynthetic approach suggests that is it contains cyanohydrin intermediate. This can be produced from propanal. LiAlH₄ is a reducing agent capable of reducing this to an amine. The overall synthesis will be substituted followed by reduction which will give the desired product.

Interpretation Introduction

(b)

Interpretation:

Synthetic approach for the synthesis of following using propanal and any other ketone or aldehyde as only starting material containing carbon is to be proposed.

Concept introduction:

The product has 1, 3-positioning of heteroatom. The retrosynthesis approach suggests the that an aldol to be a key intermediate. OH group in this aldol can be substituted by Br which further can be converted to thioether by a substitution reaction.

Interpretation Introduction

(c)

Interpretation:

Synthetic approach for synthesis of following using propanal and any other ketone or aldehyde as only starting material containing carbon is to be proposed.

Concept introduction:

The product has 1, 3-positioning of heteroatom. Retrosynthesis suggest that it contain α,β -unsaturated aldehyde as a key intermediate.

Interpretation Introduction

(d)

Interpretation:

Synthetic approach for synthesis of following using propanal and any other ketone or aldehyde as only starting material containing carbon is to be proposed.

Concept introduction:

The product has 1, 5-positioning of heteroatom. Retrosynthesis approach suggest the that it has α,β-unsaturated ketone as an key intermediate. It also suggests cyclohexanone to be a starting material along with propanal.