L.8 & L.9 Aldehydes & Ketones 1 &2 Flashcards Preview

Kaplan Organic Chemistry > L.8 & L.9 Aldehydes & Ketones 1 &2 > Flashcards

Flashcards in L.8 & L.9 Aldehydes & Ketones 1 &2 Deck (20)
Loading flashcards...
1

Name the 5 steps to IUPAC Naming conventions

5 Steps

 

  1. ID the longest carbon chain (Parent Chain)
  2. Number the chain, highest priority functional group receives the lowest possible number. This group = suffix.
  3. 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)
  4. Assign a number to each substituent 
  5. Complete name by alphabetizing the substituents and separating numbers from each other by commons and from words by hyphens.

 

2

Alkanes, Alkenes & Alkynes Ending Naming form

  • Alkane single -ANE
  • Alkene Double -ENE
  • ALKYNE Triple -YNE

3

Alkane Formula & 8 Octanes Names

CnH(2n + 2)

  • Methane
  • Ethane
  • Propane
  • Butane
  • Pentane 
  • Hexane
  • Heptane 
  • Octane

4

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

5

Order of Highest Priority Group (1-10)

Will be the most oxidized

Carbon Chain = -yl

Double bond higher than triple bond

  1. Carboxylic Acid
  2. Anhydride
  3. Ester
  4. Amide
  5. Aldehyde
  6. Ketone
  7. Alcohols
  8. Alkene
  9. Alkyne
  10. Alkane 

 

6

Carbonyl Group

A carbon double bonded to an oxygen

7

Aldehydes 

Pka

Group

Suffix

Prefix

 

Chain Terminating

Pka = 17 

Group = Carbonyl

Suffix = -al

Prefix = oxo-

(Methanal, Ethanal, Propanal) 

8

Ketones

Pka

Group

Suffix

Prefix

 

Non-terminal carbon

Pka = 18-21

Group = Carbonyl

Suffix = -one

Prefix = keto- 

(2-propanone = dimethylkentone = Acetone)

9

Three physical properties of aldehydes and ketones

  1. The dipole of the carbonyl is stronger than the dipole of oxygen because of the double bond on the carbonyl
  2. Increase intermolecular attraction in solution compared to parent alkanes
  3. Still less polar than alcohols because alcohols are Hydrogen bonding

10

How to form an Aldehyde (3)

  • Primary Alcohol
  • PCC (Mild)
  • If any stronger it turns into a carboxylic acid

11

How to form a Ketone (3)

 

  • Secondary Alcohol
  • Sodium dichromate/ K or Na & PCC
  • It always stops at ketone

12

4 Steps to general nucleophilic addition to a carbonyl mechanism

  1. Nucleophile attacks Carbonyl Carbon (electrophile)
  2. Break pi bond of the carbonyl
  3. Pi bond electrons move to oxygen
  4. 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. 

13

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

14

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.

15

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.)

 

16

Imines & Enamines

 

Nitrogen and nitrogen-based functional groups are good nucleophiles

  • Lone pair of electrons on nitrogen makes them good nucleophiles
  • React with carbonyls of aldehydes and ketones
  • Ammonia adds to a carbon atom and water is lost (condensation)
  • Nitrogen replaces the carbonyl oxygen (Substitution)

Hydroxylamine ---> Oxiamine

Hydrazine ---> Hydrazone

Semicarbazide ----> Semicarbazones

17

How are Cyanohydrins formed?

HCN (CYANIDE)

  • Triple bond
  • Electronegative nitrogen
  • pKa = 9.2

 

18

Reagents that oxidize Aldehydes

KMnO4 Potassium permanganate

CrO3 cromium trioxide

Ag2O silver 2oxide

H2O2 hydrogen peroxide

Ketones cannot be further oxidized (for secondary carbons)

19

Reagents that reduce aldehydes and Ketones

LiAlH4 Lithium aluminum hydride

NaBH4 Sodium borohydride

20