Describe a sequence of reactions by which hept-1-yne can be straightforwardly prepared from hept-1-ene.
O 1) Br₂; 2) NaNH₂
O 1) Br₂; 2) NaNH₂, heat.
O 1) Br₂; 2) NaOH
O 1) HBr; 2) NaNH₂, heat.