Question

Question: Show how you might synthesize the following compounds, using acetylene and any suitable alkyl halides as your starting materials. If the compound given cannot be synthesized by this method, explain why. (a) hex-1-yne (b) hex-2-yne (c) hex-3-yne (d) 4-methylhex-2-yne (e) 5-methylhex-2-yne (f) cyclodecyne.

Short answer

Answer

a.

b.

c.

d.

e.

f.

Step-by-step solution

SN2 Reaction

A substitution reaction in which the elimination of the leaving group and the addition of nucleophile takes place simultaneously is known as reaction. This reaction happens when the nucleophile easily attacks the less hindered central atom.

Synthesis of the compound using acetylene and suitable alkyl halide

(a) The compound hex-1-yne can be synthesized by using acetylene and butyl bromide

(b) The compound hex-2-yne can be synthesized using acetylene, propyl bromide, and methyl iodide.

(c) The compound hex-2-yne can be synthesized using acetylene and ethyl bromide.

d) By this substitution reaction, the product 4-methylhex-2-yne will be much less as the substrate is a alkyl halide. So a strong base is needed to attack the alkyl halide. Hence this product can not be synthesized.

(e) 5-methylhex-2-yne can be synthesized by using acetylene, methyl iodide, and 1-bromo-2-methyl propane

(f) The compound cyclodecyne can be synthesized using acetylene and alkyl halide and intramolecular cyclization of the large ring.