Double Elimination Practice Problems

The double elimination of H―Cl from a dihaloalkane under basic conditions is an alternative method to synthesize alkynes. Suggest a mechanism for this reaction.

In the overnight reaction between fused KOH and 2,2-dichloro-1-phenylpropane at 200℃, a compound of formula C₉H₈ is obtained as the major product. Provide a structure for the major product and propose a mechanism for its formation.

The major product when 2,2-dichloropentane is heated overnight with NaNH₂ at 150 °C has a formula of C₅H₈. Draw the structure of the product and provide the mechanism of the reaction.

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.

2,2-dibromopentane → pent-1-yne

Show how the following synthetic transformation can be accomplished. Give the structures of all intermediates.
2,2-dibromopentane → pent-2-yne