Q13P - Organic Chemistry (Mcmurry)

Question

Beginning with acetylene and any alkyl halide needed, how would you synthesize the following compounds?

(a) Decane

(b) 2,2-Dimethylhexane

(c) Hexanal 

(d) 2-Heptanone

Step-by-Step Solution

Answer

The transformations in the given question follow the following mechanistic pathway.

Definition of Synthesis

The process of synthesis is a laboratory method of obtaining a particular compound with the help of other compounds and reagents

Formation of Decane

Conversion of acetylene into octane requires the following steps.

• Firstly an acidic proton is abstracted from acetylene with the help of a base $\left({\mathrm{NaNH}}_2\right)$. The anion formed attacks the bromooctane to form decyne.
• ${\mathrm{H}}_2/\mathrm{Pd}$ catalyst is used to reduce the alkyne into alkane.

Formation of 2,2-dimethylhexane

Conversion of acetylene into octane requires to two chemical reactions:

• Firstly an acidic proton is abstracted from acetylene with the help of a base $\left({\mathrm{NaNH}}_2\right)$. The anion formed attacks the alkyl halide to increase the number of carbons in the chain.
• ${\mathrm{H}}_2/\mathrm{Pd}$ catalyst is used to reduce the alkyne into alkane.

The complete mechanism is given below.

Formation of Hexanal

Conversion of acetylene into octane requires to two chemical reactions:

• Firstly an acidic proton is abstracted from acetylene with the help of a base $\left({\mathrm{NaNH}}_2\right)$. The anion formed attacks the alkyl halide to increase the number of carbons in the chain.
• Hydroboration-oxidation reaction  converts hex-1-yne  into hexanal

Finally, formation of the product takes place.

The complete reaction mechanism is given below.

Formation of 2-Heptanone

Conversion of acetylene into octane requires to two chemical reactions:

• Firstly an acidic proton is abstracted from acetylene with the help of a base $\left({\mathrm{NaNH}}_2\right)$. The anion formed attacks the alkyl halide to increase the number of carbons in the chain.
• Oxymercuration-demercuration reaction converts hept-1-yne into 2-heptanone.

The complete reaction mechanism is given below.