Which of the following does not exhibit tautomerism?

Options

A.
B.
C.
D.

Answer

A

Explanation

For tautomerism to occur, at least one `alpha`-hydrogen should be presented on a saturated carbon next to the keto group. Since in option (a), `alpha`-hydrogens are not present on a saturated carbon and hence it does not show tautomerism. While all, other options contain `alpha`-hydrogens on saturated carbons next to the keto group and hence show tautomerism.