What is a stepwise mechanism for the hydroxide ion base catalyzed tautomerization of acetone to the enol form?

1 Answer
Sep 22, 2016

#H_3C-C(=O)CH_3 + HO^(-) rightleftharpoons H_2C=C(O^-)(Na^+)CH_3#

Explanation:

Acetones can form equilibrium quantities of the enol:

#H_3C-C(=O)CH_3 rightleftharpoons H_2C=C(-OH)CH_3#

Of course, the equilibrium lies to the left as written, but given a strong base, the enolic hydrogen may be deporotonated to form the enolate:

#H_2C=C(-OH)CH_3 + ""^(-)OH rarr H_2C=C(-O^-)CH_3 + H_2O#

The enolate is itself in equilibrium with the carbanion:

#H_2C=C(-O^-)CH_3 rarr H_2^(-)C-C(=O)CH_3#

And the carbanion is used to make #C-C# bonds.