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

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Answer 1 · 2016-09-22T17:11:21

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

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.