Question

Draw the alkyne formed when 1,1-dichloro-4-methylpentane is treated with an excess of a strong base such as sodium amide. (Give the neutralized alkyne product, not the acetylide salt.)

Answer 1

Concepts and reason

Geminal dihalides are compounds containing carbon atoms with two halogens attached to it. Alkynes are compounds containing carbon-carbon triple bonds and are synthesized when geminal dihalide undergoes an elimination (dehydrohalogenation) reaction using a strong base such as sodamide $\left( {{\rm{NaN}}{{\rm{H}}_2}} \right).$

Fundamentals

Sodamide $\left( {{\rm{NaN}}{{\rm{H}}_2}} \right):$ The compound sodamide is an inorganic compound and it is a strong base.

It is used in elimination reactions such as dehydrohalogenation (removal of Hydrogen halide).

The reaction scheme for the dehydrohalogenation of dihaloalkane using sodamide is given below:

The reaction mechanism for the removal of hydrogen chloride is given below:

The reaction of sodamide with alkenyl chloride is given below:

Ans:

The alkyne formed when 1, 1-dichloro-4-methylpentane is treated with an excess of a strong base such as sodium amide is given below: