Q16E - Organic Chemistry (Mcmurry)

Question

How would you prepare the following substances, starting from any

compounds having four carbons or fewer?

Step-by-Step Solution

Answer

Definition of Simmons-smith reaction

This is the reaction which is used for converting an alkene into three membered cyclopropane ring. With the help of ${\mathrm{CH}}_2{\mathrm{I}}_2$ with zinc or copper metal, cyclopropane ring is formed.

Draw the structure of compound

Black sphere represent Carbon atom

Grey sphere represent Hydrogen atom

Red sphere represent oxygen atom

By considering above representation the structure of the given compound is drawn

Formation of given aldehyde

Synthesis of 1-cyclopropane propane-2-ol 

With the use of the Bromopropene we can synthesize the required product.

1. Simmons-smith reaction- used for conversion of alkene into three membered cyclopropane ring
2. Addition of acetylene - addition of acetylene to introduce triple bond.
3. Conversion of triple bond into double bond with the help of Lindlar’s catalyst
4. Finally Mercuric acetate, $\mathrm{Hg}{\left(\mathrm{OAc}\right)}_2$ with Sodium borohydride, ${\mathrm{NaBH}}_4$ added for conversion of alkene into alcohol.

Definition of Mercuric sulphate catalyzed reaction

This reaction is used for transformation of alkyne functional group into ketone in the presence of Mercuric sulphate in acidic medium $\left({\mathrm{HgSO}}_4,\mathrm{H}{3_{\mathrm{O}}}^{+}\right)$.

Draw the structure of compound

Black sphere represent Carbon atom.

Grey sphere represent Hydrogen atom.

Red sphere represent oxygen atom.

By considering  above representation  the structure of the given compound is drawn.

Formation of given ketone

Synthesis of Hex-2-one-5-ene

With the use of the bromobutene, we can synthesize the required product.

1. Addition of acetylene - addition of acetylene to introduce triple bond into bromobutene.
2. Reaction of Mercuric sulphate ${\mathrm{HgSO}}_4$ with ${\mathrm{H}}_3{\mathrm{O}}^{+}$ used for conversion of alkene into ketone.