Draw the displayed formula for the major product/s formed when Compound F 4-Methyl-1-pentyne reacts with each of the following, applying Markovnikov’s rule where applicable:

Question

(a) Draw the displayed formula for the major product/s formed when Compound F 4-Methyl-1-pentyne reacts with each of the following, applying Markovnikov’s rule where applicable:

(i)           H₂O, H₂SO₄ and Hg²⁺ ions

(ii)         1 mole of HCl(g)

(iii)        dilute KMnO₄

Answer 1

reacts with

4-methyl-1-pentyne

(i) H₂O, H₂SO₄ and Hg²⁺ ions to give

Markovnikov addition of H₂O across the alkyne π bond

(OH on more substituted side) followed by rearrangement

of the initially formed enol to a more stable ketone.

(ii) 1 mole of HCl to give

Markovnikov addition of HCl across the alkyne π bond

(Cl on more substituted side).

(iii) dilute KMnO₄ to give