Question

6.) Synthesis: Show how the following synthetic conversions may be carried out. Include structures of all intermediate compounds as well as all reagents used in the conversions. (NO ELECTRON PUSHING MECHANISM SHOULD BE SHOWN HERE!!!) H H a.) H H HzC CH2CH3

Answer 1

Answer:

a)

HEH n Buli + H =e CHỦ → H =CH₂ n Beli CH₃CH₂ cl - CH₂ CH₂ CH3 o= CH3 | Pa/Bason the CH₂ CH₂ & (These two are same).

b)

3 Ala

Explanation and mechanisms:

a)

Mechanism:

n Ba- H₃CH₂C-=-CH₂ Pd/Baso (Lindlar's catalyst Reduces alkyne to give cis alkene) CH, HCH,

nBu-Li acts as a base and abstracts a proton generating a negative charge on the acetylene molecule. That negative charge will attack CH_{​​​​3}​​​​Cl to give "intermediate compound-a". Which on reaction with nBuLi followed by reaction with CH3CH2Cl to give "intermediate compound-b". Compound-b on reduction with Lindlar catalyst gives our product.

b)

Mechanism:

Mechanismy teaz isala, Ta-ala, -HC Alaz (Frieded crafts Ti-aia alkylation T ca) a-Alaz (Friedelcraft accylation) a -HU , А 2а

First the benzene ring will undergo Friedel crafts alkylation to give "compound-a" which undergoes Friedlec acylation to give our product.

para * On tho » Electron donating group Increases the electron density on "Ortho" & "parca" positions.

This increase in electron density on ortho and para position is the reason for Friedel crafts acylation.

* Ethyl Para position is only available for the Frieded crafts acylation) Ortho positions are hindered from the reaction because of the bulky "ethyl" group) group