Chapter 7, Problem 55PP

Interpretation Introduction

Interpretation:

The pathway for the conversion of a starting material into products for each of the given reaction is to be provided.

Concept Introduction:

▸ Electrophiles are electron deficient species which has positive or partially positive charge. Lewis acids are electrophiles which accept electron pair.

▸ Nucleophiles are electron rich species which has negative or partially negative charge. Lewis bases are nucleophiles which 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.

▸ The reduction of alkenes with hydrogen gas in the presence of metal catalyst, calcium carbonate and quinoline is used to produce cis-alkene from the disubstituted alkynes.

▸ Hydrogenation of alkenes or alkynes is an addition reaction that leads to the formation of alkanes. It is performed in the presence of reducing agents such as ${\text{H}}_2/Ni$ and ${\text{LiAlH}}_{\text{4}}$.

▸ Sodium amide is a strong base and it helps in the formation of acetylide that can be converted into a bigger alkyne by adding alkylhalide.

▸ ${\text{H}}_2{\text{SO}}_4/{\text{180}}^{\circ }\text{C}$ acts as a dehydrating agent and the dehydration of alcohols leads to the formation of alkenes.

▸ Chair conformations: It is the most stable conformation, which accurately shows the spatial arrangement of atoms.

▸ Equatorial bonds are parallel to the average plane of the ring, while axial bonds are perpendicular to the average plane of the ring.

▸ The conformation having bonds at the equatorial positions are more stable than those with bonds at the axial position.

▸ On flipping the cyclohexane ring, axial bonds become equatorial bonds and equatorial bonds becomes axial bond.

▸ Bulkier group acquires equatorial positions to form stable conformer due to steric factors.

▸ In alkenes, if the higher priority group on both the carbon is on the same side, configuration is termed as Z-configuration.

▸ In alkenes, if the higher priority group on both the carbon is on the opposite side, configuration is termed as E-configuration.