ORGANIC CHEMISTRY 354
CARBONYL CONDENSATION REACTIONS
ALDOL CONDENSATION
CLAISEN CONDENSATION
- CARBONYLS:
- NUCLEOPHILIC ADDITION
- NUCLEOPHILIC ACYL SUBSTITUTION
- ALPHA-SUBSTITUTION
- CAN MORE THAN ONE OF THESE REACTIONS TAKE PLACE AT THE SAME TIME????
- ALDOL CONDENSATION
- IN THE ALDOL:
- THE ENOLATE BEHAVES AS A NUCLEOPHILE;
- ANOTHER ALDEHYDE BEHAVES AS AN ELECTROPHILE.
- THE REACTION IS AN EQUILIBRIUM REACTION
- ONLY NEED CATALYTIC AMOUNTS OF BASE
- MONOSUBSTITUTED ALDEHYDES FAVOR PRODUCT
- DISUBSTITUDED ALDEHYDES FAVOR REACTANT
- KETONES FAVOR REACTANT
- EXAMPLES
- SOMETIMES A SIDE-PRODUCT OF ALPHA-SUBSTITUTIONS
- MINIMIZE BY RAPID FORMATION OF 1 EQUIVALENT OF ENOLATE AT LOW TEMPERATURE.
- BETA-HYDROXY ALDEHYDES AND KETONES READILY
DEHYDRATE TO FORM CONJUGATED
PRODUCTS.
- MIXED ALDOLS
- INTRAMOLECULAR ALDOLS
- CLAISEN CONDENSATION
- MIXED CLAISENS
- INTRAMOLECULAR CLAISENS
- MICHAEL REACTION
- NUCLEOPHILE: (NEEDS AN ACIDIC HYDROGEN) BETA-DIKETONE; BETA-KETO ESTER; MALONIC ESTER; BETA-KETO NITRILE;
NITRO COMPOUNDS.
- ACCEPTOR: ALPHA,BETA-UNSATURATED ALDEHYDE, ESTER, KETONE, NITRILE.
- EXAMPLE
- GO TO ULTRAVIOLET SPECTROSCOPY
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