Q.How will you convert acetylene into n-butyl alcohol?

Step 1. Step 1: acetylene's terminal, weakly acidic C-H is removed by the strong base sodium amide, giving sodium acetylide: HC≡CH + NaNH2 gives HC≡C-Na+ + NH3.

Step 2. Step 2: sodium acetylide performs an SN2 alkylation on ethyl bromide, extending the two-carbon acetylide to a four-carbon terminal alkyne: HC≡C-Na + CH3CH2Br gives CH3CH2-C≡CH (but-1-yne) + NaBr.

Step 3. Step 3: hydroboration-oxidation of the terminal alkyne with a hindered borane such as disiamylborane, then H2O2/OH-, adds -OH anti-Markovnikov to the terminal carbon; the resulting enol tautomerises immediately to the terminal aldehyde, butanal, CH3CH2CH2CHO (this is the alkyne analogue of anti-Markovnikov alkene hydroboration). …

Build the carbon chain first via acetylide alkylation, then install the terminal oxygen via anti-Markovnikov hydroboration-oxidation of the resulting termi …

• Trying to build the 4-carbon chain by simply adding HBr/H2O directly to acetylene -- this only ever adds atoms across the SAME two carbons, and can never grow the chain from 2 carbons to 4; a carbanion alkylation step (sodium acetylide + ethyl bromide) is essential. …