11. Carbonyl alpha Substitution reactions and condensations
11. Carbonyl AlphaSubstitution Reactions and Condensations H O E + O E
The a position H E 0 OH H tOh Ht O E
The a Position H O OH . . E + OH E －H + O E + －H + H O O - E + O E O -
11.1 Keto-Enol p.345 Tautomerism OH H or oh H OH R R" R R R H2 R
11.1 Keto–Enol Tautomerism p.345 R R' OH R R R' O R H1 H2 R R' R OH H + or OHH O OH
Tautomers are not Resonance forms H H 且CC3≠ H C CH C C C HHH HHH 1-Butene 2-Butene a2004 Thomson/Brooks C
Tautomers Are Not Resonance Forms
Enols The enol tautomer is usually present to a very small extent and cannot be isolated However since it is formed rapidly, it can serve as a reaction intermediate
Enols: • The enol tautomer is usually present to a very small extent and cannot be isolated • However, since it is formed rapidly, it can serve as a reaction intermediate