The major product formed in the following reaction is \(\; \mathrm{nBu_3SnH,\ AIBN,\ C_6H_6,\ heat}\)
Compound \(\mathbf{P}\) was prepared based on a four-component reaction at room temperature in methanol. The required starting materials for the synthesis are (structure of \(\mathbf{P}\) shown).
The topicity relationship of \(H_a\) and \(H_b\) in X, Y and Z (as drawn in the figure) are, respectively,
On irradiation using UV light (\(>300\) nm), compounds X and Y predominantly undergo which photochemical pathway? (Structures as shown in the figure)