L.8 & L.9 Aldehydes & Ketones 1 &2 Flashcards
Name the 5 steps to IUPAC Naming conventions
5 Steps
- ID the longest carbon chain (Parent Chain)
- Number the chain, highest priority functional group receives the lowest possible number. This group = suffix.
- Name the substituents with a prefix. Multiple substituents of a single type receive another prefix denoting how many are present (di-, tri-, tetra- ) (-**yl instead of -ane)
- Assign a number to each substituent
- Complete name by alphabetizing the substituents and separating numbers from each other by commons and from words by hyphens.
Alkanes, Alkenes & Alkynes Ending Naming form
- Alkane single -ANE
- Alkene Double -ENE
- ALKYNE Triple -YNE
Alkane Formula & 8 Octanes Names
CnH(2n + 2)
- Methane
- Ethane
- Propane
- Butane
- Pentane
- Hexane
- Heptane
- Octane
Alcohols
General Form
Pka
Group
Suffix
Prefix
Priority
- ROH
- pKa = 16
- Group = hydroxyl (-OH)
- Suffix = -ol
- Prefix = Hydroxy-
- Higher priority than double or triple bonds and alkanes
- Diols = Two hydroxyls, geminal same carbon -or- vicinal if on adjacent
Order of Highest Priority Group (1-10)
Will be the most oxidized
Carbon Chain = -yl
Double bond higher than triple bond
- Carboxylic Acid
- Anhydride
- Ester
- Amide
- Aldehyde
- Ketone
- Alcohols
- Alkene
- Alkyne
- Alkane
Carbonyl Group
A carbon double bonded to an oxygen
Aldehydes
Pka
Group
Suffix
Prefix
Chain Terminating
Pka = 17
Group = Carbonyl
Suffix = -al
Prefix = oxo-
(Methanal, Ethanal, Propanal)
Ketones
Pka
Group
Suffix
Prefix
Non-terminal carbon
Pka = 18-21
Group = Carbonyl
Suffix = -one
Prefix = keto-
(2-propanone = dimethylkentone = Acetone)
Three physical properties of aldehydes and ketones
- The dipole of the carbonyl is stronger than the dipole of oxygen because of the double bond on the carbonyl
- Increase intermolecular attraction in solution compared to parent alkanes
- Still less polar than alcohols because alcohols are Hydrogen bonding
How to form an Aldehyde (3)
- Primary Alcohol
- PCC (Mild)
- If any stronger it turns into a carboxylic acid
How to form a Ketone (3)
- Secondary Alcohol
- Sodium dichromate/ K or Na & PCC
- It always stops at ketone
4 Steps to general nucleophilic addition to a carbonyl mechanism
- Nucleophile attacks Carbonyl Carbon (electrophile)
- Break pi bond of the carbonyl
- Pi bond electrons move to oxygen
- Forms tetrahedral molecule
If no good leaving group (aldehydes and ketones) the carbonyl will remain open and is protonated to form an alcohol
If there is a good leaving group (carboxylic acids and derivatives) then the carbonyl will reform and kick off the leaving group.
When a carbonyl is opened by an attack ask,
Can I reform it?
What Groups allow for reformation?
Aldehydes & Ketones = NO REFORMATION
Carboxylic Acids & Derrivatives = YES
In the presence of H2O, how do aldehydes and ketones react?
React to from geminal diols
(Hydration)
- Slowly
- Can Increase rate by adding catalytic acid or base
- Oxygen in water is nucleophile and attacks carbon.
In the presence of Alcohol, how to aldehydes and ketones react?
One Equivalent of alcohols gives
- semiacetal or simiketal
Two Equivalents of alcohol gives
- Acetal or Ketal
- Nu substitution SN1
- Catalyzed by anhydrous Acid
- Inert and used as protecting groups
- Reverted with aqueous acid and heat.
(oxygen in alcohol attacks carbonyl, double bond electrons go onto the oxygen making it negative, oxygen grabs the hydrogen from the attached alcohol molecule. Finish with OH & OR on the molecule.)
How are Cyanohydrins formed?
HCN (CYANIDE)
- Triple bond
- Electronegative nitrogen
- pKa = 9.2
