A1256655549WLpPz - PowerPoint PPT Presentation

Title: A1256655549WLpPz


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ALDEHYDES AND KETONES I
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CHAPTER 16
CHEMISTRY OF THE CO GROUP
Sections 16.1 and 16.2 Nomenclature of
Aldehydes and Ketones
Learn on your own.
Sections 16.3-16.5 Review and Overview
Read on your own
Section 16.6 Cyanide addition
Lecture
Section 16.7 Addition of Organometallics
Totally review
Section 16.8
Read on your own
Bisulfite Addtion
Sections 16.9-16.11
Lecture
Jump to Sections 16.15-16.19
Lecture
Go Back to Sections 16.12-16-14
Lecture
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STRUCTURE
Aldehyde
Ketone
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NOMENCLATURE
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IUPAC Nomenclature of Ketones

• Choose the longest continuous carbon chain that
  contains the carbonyl carbon
• Number from the end of the chain closest to the
  carbonyl carbon
• Ketone ending is -one

Do the ketones section of Organic Nomenclature
program!
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EXAMPLES
2-Pentanone
4-Ethyl-3-hexanone
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3-Isopropylcyclopentanone or 3-(1-Methylethyl)cy
clopentanone
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Common, or Trivial, Names
KETONES

• Name each group attached to the carbonyl group as
  an alkyl group
• Combine into a name, according to the pattern
• alkyl alkyl ketone
• NOTE This is not all one word!

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Example of Common Names
Methyl propyl ketone
Diethyl ketone
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SPECIAL CASES
diphenyl ketone
dimethyl ketone
benzophenone
acetone
A common laboratory solvent and cleaning agent
methyl phenyl ketone
KNOW THESE
acetophenone
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IUPAC Nomenclature of Aldehydes

• Choose the longest continuous carbon chain that
  contains the carbonyl carbon
• Number from the end of the chain closest to the
  carbonyl carbon (carbon 1!)
• Aldehyde ending is -al

Do the aldehydes section of Organic
Nomenclature program.
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EXAMPLES
aldehyde group is
always carbon 1
pentanal
1
3
2
4
2-chloro-3-methylbutanal
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Common Names of the Aldehydes
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SPECIAL CASES
formaldehyde
benzaldehyde
KNOW THESE
acetaldehyde
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Forming Common Names of Aldehydes
USE OF GREEK LETTERS
.
w is always the end of the chain, no matter how
long
a-chlorocaproaldehyde
w-chlorocaproaldehyde
( a-chlorohexanal )
( w-chlorohexanal )
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REACTIVITY OF THE CO GROUP
NUCLEOPHILIC ADDITION
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GENERALIZED CHEMISTRY
THE CARBONYL GROUP
nucleophilic at oxygen
H or E
electrophiles add here
nucleophiles attack here
Nu
electrophilic at carbon
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STEREOCHEMISTRY
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THE CARBONYL GROUP IS PLANAR (SP2
HYBRIDIZED)
Nu
.
.
..
C
O
..
Nu
nucleophiles can attack from either top or bottom
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LUMO OF FORMALDEHYDE
sCH
sCO
p
(LUMO)
nO
H
H
p
sCO
sCH
..
Nu
nucleophiles add to the larger lobe (on carbon)

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NUCLEOPHILIC ADDITION TO CO
MECHANISMS
IN ACID AND IN BASE
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Nucleophilic Addition to Carbonyl
Basic or Neutral Solution
an alkoxide ion
-
or on adding acid
Good nucleophiles and strong bases (usually
charged)
BASIC SOLUTION
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Nucleophilic Addition to Carbonyl
Acid Catalyzed
more reactive to addition than the un- protonated
precursor
()
Acid catalysis speeds the rate of addition of
weak nucleophiles and weak bases (usually
uncharged).
ACIDIC SOLUTION
stronger acid protonates the nucleophile
pH 5-6
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CYANOHYDRINS
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Addition of Cyanide
C N
Buffered to pH 6-8
a cyanohydrin
In acid solution there would be little CN-, and
HCN (g) would be a problem (poison).
A cyanohydrin
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CYANIDE ION BONDS TO HEMOGLOBIN
..
Cyanide bonds (irreversibly) to the site (Fe II)
where oxygen usually bonds.
CYANIDE IS IS A POISON
..
You die of suffocation - lack of oxygen.
HCN is a gas that you can easily breathe into
your lungs.
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SYNTHESIS OF a-HYDROXYACIDS
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SYNTHESIS OF AN a-HYDROXYACID
NaCN
a cyanohydrin
pH 8
1) NaOH/H2O/D
acetophenone
2) H3O
Aldehydes also work unless they are
benzaldehydes, which give a different reaction
(benzoin condensation).
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HYDROLYSIS OF THE NITRILE GROUP
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SYNTHESIS OF NITRILES (AND CYANOHYDRINS)
REVIEW
CO NaCN C-OH
CN
cyanohydrin
acetone
R-X NaCN R-CN NaX
SN2
nitrile
.. both can be hydrolyzed
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HYDROLYSIS OF THE CYANO GROUP (NITRILES)
METHOD ONE strong base H2O heat
gas
..

..
-


..
H3O
neutralize
OVER ALL
..

R-CN
..
..
R-COOH
Nitriles are hydrolyzed to carboxylic acids.
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HYDROLYSIS OF THE CYANO GROUP (NITRILES)
METHOD TWO strong acid H2O heat
..

H2SO4

..
H2O/D
..
OVER ALL
no mechanism at this time
R-CN
R-COOH
Nitriles are hydrolyzed to carboxylic acids.
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ORGANOMETALLICS
REVIEW FROM CHAPTER 15
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Synthesis of Alcohols
Addition of Organometallic Reagents
ether
(R-Li)
R -
workup step
alcohol
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Summary of Reactions of Organometallics with
Carbonyl Compounds
All review to you

• Organometallics with ketones yield
• tertiary alcohols
• Organometallics with aldehydes yield
• secondary alcohols
• Organometallics with formaldehyde yield
• primary alcohols.
• Organometallics with carbon dioxide yield
• carboxylic acids.

etc.