Question

Draw the products formed when each dihalide is treated with excess ${\mathbf{\text{NaNH}}}_{\mathbf{2}}$.

a.

b.

c.

d.

Short answer

The products formed after the treatment with ${\text{NaNH}}_2$ is shown below:

Step-by-step solution

Type of the base used

${\text{NaNH}}_2$is a strong base.

When used in excess, it tends to abstract all the $\text{β}$ protons since, in these substrates, two leaving groups are present. As a result, the elimination product formed gives an alkyne.

Removal of β hydrogens

Removal of excess $\text{β}$hydrogens gives the elimination product. Based on the steps, the products formed after the treatment with ${\text{NaNH}}_2$ is shown below:

Representation of the possible alkynes from a

Representation of the possible alkynes from b

Representation of the possible alkynes from c

Representation of the possible alkynes from d