Identify the major product of the following reaction sequence:

Step-by-step solution

The reaction sequence begins with the hydration of the alkyne group in 2-methyl-2-(prop-1-ynyl)cyclohexan-1-one using 1 % HgSO ₄ and dil. H ₂ SO ₄ . Due to significant steric hindrance from the adjacent quaternary carbon, the hydration regioselectively occurs at the less hindered carbon of the triple bond. This yields 2-methyl-2-(2-oxopropyl)cyclohexan-1-one, which is a 1,4-diketone intermediate. In the second step, the base ( OH ^- ) abstracts a proton from the terminal methyl group of the side chain to form an en