Chapter 18: Enols and Enolates |
MECHANISM OF ACID
CATALYSED TAUTOMERISATION |
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Step 1: First, an acid-base reaction. The Lewis basic O atom of the carbonyl is protonated by the acid catalyst giving an oxonium ion. |
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Step 2: Another acid-base reaction. Removal of an α-hydrogen by a water molecule functioning as a base allows formation of the C=C and neutralises the positive charge on the O giving the enol and regenerates the catalyst. |
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© Dr. Ian Hunt, Department of Chemistry |