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thomas-riley
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Recall the many times we’ve synthesized these! I command thee.
• Oxidation of R-OH – (Periodinane, CrO3/Na2Cr2O7)
• Hydration of Alkynes (keto-enol tautomerism)– H3O+/HgSO4, BH3/H2O2,OH-, etc…
• Friedel-Crafts ACYLation of Aromatics – (acid halide + AlCl3)
REACTIONS OF ALDEHYDES/KETONES
• Oxidation of Aldehydes• Nucleophilic Additions (overview)– Hydride (H-) and Grignard (R-) as Nucleophiles– Water addition (hydrate/diol/geminal diol
formation)– Alcohol addition (acetal formation)– Amine addition (imine formation)
• Conjugate Nucleophilic Addition Reactions
Nucleophilic Addition Rxns
Slightly different mechanisms in acid or base. Neutral vs. Negatively charged Nucleophile
General picture (basic):
Reactivity Notes:
Less steric hindrance with aldehyde
Benzaldehyde less reactive due to resonance stabilization.
Basic vs. Acidic
BASIC: Strong nucleophile attacks, as in Nu-
ACIDIC:Carbonyl is converted to a stronger ELECTROPHILE as CABON BECOMES MORE POSITIVE.
Conjugate Nucleophilic Addition Rxns
THE DOUBLE BOND IS EFFECTIVELY “POLARIZED” INTO A NEGATIVE REGION THAT’S RESONANCE STABILIZED, AND A POSITIVE REGION AT THE BETA-CARBON.