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Aldehid dan Keton
• Pyridoxal phosphate (PLP) is common coenzyme
• Hydrocortisone is steroid hormone secreted by adrenal glands
• Penicillin G : an antibiotic
Carbonyl Compounds
Nomenclature of Aldehydes
Naming Aldehydes and Ketones
Nomenclature of Ketones
Naming Aldehydes and Ketones
Some common names accepted by IUPAC
Boiling Points• More polar, so higher boiling point than
comparable alkane or ether.
• Cannot H-bond to each other, so lower boiling point than comparable alcohol.
Carbonyl Structure
• Carbon is sp2 hybridized.
• C=O bond is shorter, stronger, and more polar than C=C bond in alkenes.
Preparation of Aldehydes and Ketones• Aldehydes from oxidation of primary alcohols using
pyridinium chlorochromate (PCC)
• Aldehydes from reduction of carboxylic esters using diisobutylaluminum hydride (DIBAH)
Aldehydes and ketones react with nucleophiles to formaddition products: nucleophile addition reactions
Tetrahedral intermediate
Acid catalyst
All carboxylic acid derivatives react by the same generalmechanism
The tetrahedral intermediate eliminates the weakest base
Nucleophilic Addition Reactions of Aldehydes and Ketones
Nucleophilic Addition of H2O: Hydration
Aldehydes and ketones react reversibly with water to give 1,1-diols, or geminal (gem) diols
• Equilibrium favors carbonyl compound for steric reasons with the exception of formaldehyde
Formation of a New Carbon–Carbon Bond Using Grignard Reagents
Reduction by Hydride Ion
Aldehydes and ketones react with a primary amine toform an imine
This is a nucleophilic addition–elimination reactionThe pH of the reaction must be controlled
Aldehydes and ketones react with secondary amines toform enamines
Water adds to an aldehyde or ketone to form a hydrate
Addition of an Alcohol to an Aldehyde or a Ketone
Addition of Sulfur Nucleophiles
Oxidation of Aldehydes
Tollens Test
R C
O
H + 2 + 3 + 2+ 4+Ag(NH3)2+ OH
_ H2O2 Ag R C
O
O_
NH3 H2O
R C
O
H + 2 + 3 + 2+ 4+Ag(NH3)2+ OH
_ H2O2 Ag R C
O
O_
NH3 H2O
silver mirror
The reactivity of carbonyl compounds resides in thepolarity of the carbonyl group in a nucleophilic acyl substitution reaction
The -Hydrogen is Acidic
the anion is stabilized by resonance
Keto–Enol Tautomerism
The enol tautomer can be stabilized by intramolecularhydrogen bonding
One molecule of a carbonyl compound acts as a nucleophile and the other carbonyl compound acts as anelectrophile
Ketones are less susceptible than aldehydes to attack by nucleophiles
An aldol addition product loses water to form an aldol condensation product
The Mixed Aldol Addition