Chapter 18, Problem 25P

Interpretation Introduction

Interpretation:

The reactions involved in the given synthesis are to be outlined, the structures of compounds A to E in the given sequence are to be drawn and the reactions involved in the given synthesis are to be shown.

Concept introduction:

Electrophiles are electron deficient species that have positive or partially positive charge. Lewis acids are electrophiles that accept electron pair.

Nucleophiles are electron rich species that have negative or partially negative charge. Lewis bases are nucleophiles that donate electron pair.

Free radical is an atom, molecule, or ion that has unpaired electrons, which makes it highly chemically reactive.

Substitution reaction: A reaction in which one of the hydrogen atoms of a hydrocarbon or a functional group is substituted by any other functional group is called substitution reaction.

Elimination reaction: A reaction in which two substituent groups are detached and a double bond is formed is called elimination reaction.

Addition reaction: It is the reaction in which unsaturated bonds are converted to saturated molecules by the addition of molecules.

Nucleophilic substitution reaction is a reaction in which an electron rich nucleophile attacks the positive or partial positive charge of an atom or a group of atoms to replace a leaving group.

${\text{S}}_{\text{N}}\text{2}$ reaction is the nucleophilic substitution reaction in which two components are involved in the rate determining step. ${\text{S}}_{\text{N}}\text{2}$ reaction occurs in one step.

${\text{S}}_{\text{N}}1$ reaction is the nucleophilic substitution reaction in which one component is involved in the rate determining step. ${\text{S}}_{\text{N}}1$ reaction occurs in two step.

The primary alkyl halides are sterically less hindered. Therefore, they are more prone to undergo ${\text{S}}_{\text{N}}\text{2}$ reaction.

The tertiary alkyl halides are sterically crowded and produce more stable carbocations than primary and secondary alkyl halides. Hence, they are most likely to undergo ${\text{S}}_{\text{N}}1$ reaction.

The ${\text{S}}_{\text{N}}1$ reactivity of the halides depends on the stability of the carbocation formed in the reaction. The stability order for the carbocation is tertiary > secondary > primary.

The compound $\beta -\text{dicarbonyl}$ can be converted into enolate ions in the presence of sodium ethoxide.

Alkylation in the $\beta -\text{dicarbonyl}$ compound is a ${\text{S}}_{\text{N}}2$ reaction.

LDA is lithium disopyramide. It is a strong base.

In an $\text{Sn2}$ reaction, one bond is broken and one bond is formed. In an $\text{Sn2}$ reaction, the nucleophile attacks the carbon atom with less steric hindrance.

Decarboxylation is the chemical reaction that transfers $\text{COOH}$ and liberates carbon dioxide.

Enantiomers are the stereoisomers whose molecules have a chiral center. These molecules are mirrors image of each other.

A molecule whose atoms are connected differently is called a constitutional isomer.

The molecules that are non-superimposable or not identical with their mirror images are known as chiral molecules.

A pair of two mirror images that are non-identical is known as enantiomers which are optically active.

The objects or molecules that are superimposable with their mirror images are achiral objects or molecules and these objects have a center of symmetry or plane of symmetry.

The achiral compounds in which plane of symmetry is present internally and consists of chiral centers are known as meso compounds, but they are optically inactive.

The stereoformula that is depicted in two dimensions, in which stereochemical information is not destroyed, is determined by Fisher Projection formula.

The stereoisomers which are non-superimposable on each other and not mirror images of each other are known as diastereomers.

Chiral molecules are capable of rotating plane polarized light