Which sequence of reagents would be expected to accomplish the transformation of 1-butyne shown below?

Question

Quizplus · Accepted Answer

The starting material is an alkyne, and we want to convert it to an alcohol. This requires addition of water across the triple bond. Option A suggests adding H2SO4 and HgSO4 followed by Pt; this is not effective for adding water across a triple bond. Option B is close, but it only adds one equivalent of water across the triple bond (with HBr), and then proceeds to add a second equivalent of H2 across the double bond (with Pt and NaOH). Option E suggests adding an O atom to the molecule before adding water, which is not necessary. Option D calls for addition of HBr with peroxides, which would result in anti-Markovnikov addition of a Br atom across the triple bond (not what we want), followed by addition of water and then reaction with Pt; this is unnecessarily complicated. Option C suggests using Lindlar’s catalyst (Pd on CaCO3 poisoned with Pb) to add two equivalents of H2 across the triple bond, forming an alkene, and then using BH3-THF to add a BH2 group to the alkene. Finally, the product is oxidized with H2O2 and NaOH to form the alcohol.

Which Sequence of Reagents Would Be Expected to Accomplish the Transformation