Reactions of Enols, Enolates, Enones
(Carey, Chap. 18)

Reaction Product Notes
 
Keto-enol tautomerism
K usually << 1, but fast
 
alpha halogenation
via enol
alpha alkylation;
via enolate anion;
must use very strong base
(to get 100% enolate);
R'' must be 1o
 
beta-dicarbonyl alkylation;
alkoxide base strong enough;
R'' can be 1o or 2o
 
alpha alkylation via enamine;
R''X must be activated halide
(benzyl, allyl, alpha to C=O)
 
simple aldol condensation;
equilibrium;
K > 1 for aldehydes only
 
aldol with dehydration;
prep of conjugated enone
works with alde. or ketone
 
mixed aldol condensation;
R'' & R''' must have no
   alpha H's
 
mixed aldol condensation;
beta-dicarbonyl cpd gives
   enolate anion exclusively

 
 
intramolecular aldol;
5 or 6 memb. rings only
 
1,2-addition major;
NaBH4 gives both 1,2- &
   1,4-addition (mixtures)
 
1,2-addition major;
RMgX gives both 1,2- &
   1,4-addition (mixtures)
 
 
conjugate addition (1,4-) only
 
 
conjugate addition (1,4-) only
 
Michael reaction
(conjugate addition);
with beta dicarbonyl enolate
 
Robinson annelation:
Michael rxn to methyl vinyl
ketone, then intramolecular
aldol condensation.

schwartz@chem.fsu.edu