Y13 Carbonyls Flashcards
What are the 2 carbonyls?
- Aldehydes
- Ketones
What are the reagents, conditions, and type of reaction for the conversion of an aldehyde to a carboxylic acid?
Reagents: K2Cr2O7/H2SO4
Conditions: Reflux
Type: Oxidation
(No H2O is formed)
Where is the pi bond positioned in a C=O bond?
Closer to the O
How do you test for carbonyls and what is the observation for a positive result?
Add Brady’s reagent, an orange ppt. forms if a carbonyl is present
What test can be done to tell if a carbonyl is an aldehyde or a ketone and what are the observations?
Add Tollen’s reagent, silver mirror forms if an aldehyde is present, ketone stays as it is
What is the method for complete identification of a carbonyl (without spectroscopy)?
- Add Brady’s reagent so an orange ppt. forms
- Filter and recrystallize
- Take the melting point and compare against a database
What are the reagents, conditions, and type of reaction for the conversion of a carbonyl to an alcohol?
Reagents: NaBH4
Conditions: Reflux
Type: Reduction
(2[H] for each carbonyl)
Why does carbon undergo attack from nucleophiles?
It is electron deficient
Describe the mechanism for step 1 of carbonyl –> alcohol
- O is more electronegative than C so C=O is a polar bond
- C is electron deficient
- H- acts a nucleophile so electron pair forms a bond with C
- Pi bond breaks
- Electron pair moves to O
Describe the mechanism for step 2 of carbonyl –> alcohol
- Negatively charged intermediate formed
- Pair of e- on O attracted to H of a H2O molecule
- O-H bond breaks
- Alcohol is formed
What kind of bond breaking is involved in the mechanism for carbonyl –> alcohol?
Heterolytic
What are the reagents, conditions, and type of reaction for the conversion of a carbonyl to a hydroxynitrile?
Reagents: NaCN/H2SO4
Conditions: Reflux
Type: Reduction
Why is the use of CN important in organic synthesis?
Carbon chain length is increased by 1
What are the reagents, conditions, and type of reaction for the conversion of a nitrile to an amine?
Reagents: H2
Conditions: Ni catalyst
Type: Addition
What are the reagents, conditions, and type of reaction for the conversion of a nitrile to a carboxylic acid?
Reagents: HCl (aq)
Conditions: Reflux
Type: Hydrolysis
