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18 Cards in this Set
- Front
- Back
Addition Reactions of Aldehydes
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1. hydration
2. acetal and ketal formations 3. rxn with cyanohydrins 4. condensation w/ ammonia derivatives. |
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Hydration of aldehydes and ketones
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1.in the presence of water, aldehydes and ketones form gem-diols, where H2O is the nucelophile
2. this slow rxn can be sped up by addition of an acid or base |
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Acetal & Ketal Formation
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1. hemiacteal is formed from an aldehyde/ketone and an alcohol.
2. acetals are formed when another alcohol is added to the hemiacetal 3. rxn catalyzed by anhydrous acid & convertred back w/aqueous acid |
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Formation of Cyanohydrins
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1.cyanide ion attacks the carbon atom on the carbonyl of an aldehyde or ketone
2. Cyanohydrins are unstable |
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Condensation with Ammonia Derivatives
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1.Ammonia and its derivatives are nucleophiles.
2. Simplest form: Imine 3. Rxn can proceed to more compounds after LG leaves tet. intermediate |
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Aldehydes oxidized to carboxylic acid
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Oxidation reagents used: KMnO4, CrO3, Ag2O, H2O2
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Aldehydes and Ketones oxidized to alcohols
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Use oxidation reagent LAH (or NaBH4 when milder conditions are needed)
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Two methods to reduce aldehydes and ketones to alkanes
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1. Wolff-Kishner Reduction
2. Clemmensen Reduction |
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Wolff-Kishner Reduction
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1. only good when product is stable under basic conditions
Aldehyde/Ketone + H2NNH2-> hydrazone + base/heat -> alkane |
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Clemmensen Reduction
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1. doesn't have base-resrtictions that Wolff-Kishner does
2. Aldehye /Ketone + Hg(Zn), HCl -> alkane |
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Wittig Reaction
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1. method of forming alkenes from aldehydes and ketones.
2. goes by formation of an ylide/ phosphorane |
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Aldol Condensation
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1. one aldehyde acts as a nucleophile (enol form) and the other as the target (keto form)
2. Higher temps and stronger bases are need to make a,b- unsaturated aldehydes (lose h2O) |
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Michael Rxn
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1. Nucelophilic Sn2 rxn between two a,b unsaturated carbonyl compounds
2. catalyzed by a base |
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Physical properties of Aldehydes and Ketones
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1. carbonyl group has a dipole moment, which elecated the bp, but it is NOT as strong as H-bonding
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Synthesis of Aldehydes and Ketones
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1. oxidation of alcohols
2. ozonolysis of alkenes 3. friedal-crafts acylation |
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Oxidation of Alcohols
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1. aldehydes are made from oxidized primary alcohols
2. ketones are made from oxidized secondary alcohols |
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Ozonolysis of Alkenes
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double bonds can be oxidatively cleaved by ozone to make aldehyes/ ketones
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Friedal-crafts acylation
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produces ketones from an acyl halide and an aromatic compound
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