A pre-laboratory discussion on basic information regarding aldehydes and ketones.

1. Aldehydes and
Ketones
Activity No. 5

2. Aldehydes and Ketones
Aldehydes and ketones are subclasses of organic compounds that
contain a carbonyl group.

3. Aldehydes and Ketones
An aldehyde contains at least one H atom bonded to the carbonyl
carbon, whereas a ketone has two alkyl or aryl groups bonded to
it.
An aldehyde is often written as RCHO. However, keep in mind that
the H atom is bonded to the carbon atom, not the oxygen.
Likewise, a ketone is written as RCOR, or if both alkyl groups are the
same, R2CO.
Each structure must contain a C=O for every atom to have an octet.

4. Aldehydes and Ketones
Two structural features determine the chemistry and properties of
aldehydes and ketones:
1) The carbonyl group is sp2 hybridized and trigonal planar,
making it relatively uncrowded.
2) The electronegative oxygen atom polarizes the carbonyl group,
making the carbonyl carbon electrophilic.

5. Aldehydes and Ketones
As a result, aldehydes and ketones react with nucleophiles.
As the number of R groups around the carbonyl carbon increases,
the reactivity of the carbonyl compound decreases, resulting in the
following order of reactivity:

6. Aldehydes and Ketones
To name an aldehyde using the IUPAC system:
1. If the CHO is bonded to a chain of carbons, find the longest chain
containing the CHO group, and change the –e ending of the
parent alkane to the suffix –al.
2. For cyclic aldehydes, add –carbaldehyde at the end.
3. Number the chain or ring to put the CHO group as C1 (for chain)
or CHO group connected to C1 (for ring), but omit this number
from the name. Apply all of the other usual rules of nomenclature

7. Aldehydes and Ketones
Examples: Give the IUPAC name for each compound.

8. Aldehydes and Ketones
A common name for an aldehyde is formed by taking the common
parent name and adding the suffix –aldehyde.

9. Aldehydes and Ketones
Greek letters are used to designate the location of substituents in
common names. The carbon adjacent to the CHO group is the α
carbon, and so forth down the chain.

10. Aldehydes and Ketones
To name an acyclic ketone using IUPAC rules:
1. Find the longest chain containing the carbonyl group,and change
the –e ending of the parent alkane to the suffix –one.
2. Number the carbon chain to give the carbonyl carbon the lower
number. Apply all of the other usual rules of nomenclature.
With cyclic ketones, numbering always begins at the carbonyl
carbon, but the “1” is usually omitted from the name. The ring is then
numbered clockwise or counterclockwise to give the first substituent
the lower number.

11. Aldehydes and Ketones
Examples: Give the IUPAC name for each compound.

12. Aldehydes and Ketones
Most common names for ketones are formed by naming both alkyl
groups on the carbonyl carbon, arranging them alphabetically, and
adding the word ketone.
Example:

13. Aldehydes and Ketones
Three widely used common names for some simple ketones do not
follow this convention:

14. Aldehydes and Ketones
Give the IUPAC name for this aldehyde:
2,5,6-trimethyloctanal

15. Aldehydes and Ketones
Give the IUPAC name for this aldehyde:
(CH3)3CC(CH3)2CH2CHO
3,3,4,4-tetramethylpentanal

16. Aldehydes and Ketones
Give the IUPAC name for this aldehyde:
3,3-dichlorocyclobutanecarbaldehyde

17. Aldehydes and Ketones
Give the structure corresponding to each IUPAC name:
2-isobutyl-3-isopropylhexanal

18. Aldehydes and Ketones
Give the structure corresponding to each IUPAC name:
1-methylcyclopropanecarbaldehyde

19. Aldehydes and Ketones
Give the structure corresponding to each IUPAC name:
3,6-diethylnonanal

20. Aldehydes and Ketones
Give the IUPAC name of each ketone:
5-ethyl-4-methyl-3-octanone

21. Aldehydes and Ketones
Give the IUPAC name of each ketone:
(CH3)3CCOC(CH3)3
2,2,4,4-tetramethyl-3-pentanone or di(tert-butyl) ketone

22. Aldehydes and Ketones
Give the IUPAC name of each ketone:
3-(tert-butyl)-2-methylcyclopentanone

23. Aldehydes and Ketones
Draw (and name) a tertiary alcohol with butane as its parent
hydrocarbon and having the formula:
C5H12O
2-methyl-2-butanol