Major product of the following reaction is

A compound ‘$$\mathrm{A}$$’ on reaction with ‘$$\mathrm{X}$$’ and ‘$$\mathrm{Y}$$’ produces the same major product but different by product '$$a$$' and '$$b^{\prime}$$. Oxidation of '$$a$$' gives a substance produced by ants.

'X' and 'Y' respectively are

Two isomers 'A' and 'B' with molecular formula C₄H₈ give different products on oxidation with KMnO₄ in acidic medium. Isomer 'A' on reaction with KMnO₄/H⁺ results in effervescence of a gas and gives ketone. The compound 'A' is

What will be the major product of following sequence of reactions?