Examples: Aldehydes and ketones

Conditions for Alpha Substitution Add quickly

Conditions for Carbonyl Condensations

“Condensation” drives the overall reaction (notice equilibrium arrows)

Synthesis: Two products can be formed by the aldol

Symmetrical vs. Mixed Aldol

Example: Single product mixed Aldol No acidic protons

Example: Single product mixed Aldol These protons are more acidic, thus easier to remove

Watch out for the possibility of mixture of products In this case no mixture… why? – stability of pdt

Example: Mixed Claisen No acidic hydrogens

Example: Mixed Claisen-“like” A mixed aldol – Claisen type reaction

Example: Intramolecular Claisen

Intramolecular Claisen: Application to Synthesis The β-keto ester formed still has one acid hydrogen and thus can do additional chemistry. Remember, the β-keto ester formed can be hydrolyzed to the β-keto acid and these can spontaneously decarboxylate.

Review: Synthesis of an enamine

Enamine’s react similar to enolates

Example: Stork Reaction

Example: Robinson Annulation

Biological Claisen

Glucose Biosynthesis (Gluconeogenesis)