Chemistry - STRUCTURAL ISOMERISM Question with Solution | TestHub

The compound is cyclopent-3-en-1-one. Under OD⁻/D₂O, the ordinary alpha positions C-2 and C-5 (2H each, 4H) exchange first. In addition, each enol form is conjugated with the ring double bond (O-C=C-C=C), so the two vinylic carbons C-3 and C-4 act as gamma positions through these dienols and their hydrogens (1H each, 2H) also exchange on prolonged treatment. Total = 4 + 2 = 6.