1.
The final product of the given reaction is:

A molecule with a methyl group, a COOCH3\text{COOCH}_3 group, and a CH2\text{CH}_2 chain leading to a COCH3\text{COCH}_3 group undergoes:
1. DIBAL-H\text{DIBAL-H}
2. KOH,Δ\text{KOH}, \Delta