1. Carbonyl compounds - reaction of the aldol type
Claisen condensation
reaction proceeds between aldehyd and an ester under base catalysis
the base is usually the alcoholate of alcohol bound in ester
after reaction when acidified very often observe formation of a,b-unsaturated ester
the more is the product after dehydratation conjugated, the more difficult is to isolate molecule with hydroxy group

2. Carbonyl compounds - reaction of the aldol type
PERKIN synthesis
Aromatic aldehydes and acetanhydride under base catalysis

3. Carbonyl compounds - reaction of the aldol type
Knoevenagel condensation
Reaction of aldehydes or ketones with compounds having acidic methylene
X, Y = CN, COOR, NO2, COR, CHO

4. Aldolisation and aldol condensation– catalysed by a base
Acidity constants of various compounds
compound
structure

5. Reactions of carbonyl compounds
Darzen reaction
Reaction of aldehydes with a-halogenesters

6. Reactions of carbonyl compounds
Mannich reaction
Reaction of aldehyde (ketone) in acidic medium with Mannich reagent ( formed from formaldehyde and sec. amine)
Mannich reagent
the starting compound has to have enolisable structure
Reaction leads to N,N-dialkylaminomethyl carbonyl compounds
Příprava N,N-dialkylaminomethylkarbonylových sloučenin

7. Reactions of carbonyl compounds without a-hydrogens
They cannot under treatment of base undergo aldolisation and aldol condensation
Cannizar reaction (disproporcionation):
from aldehyde alcohol and carboxylic acid are prepared
beside benzaldehyde react this way also alifatic compounds with fully substituted a-carbon atom and also other aromatic compounds:.

8. Reaction of carbonyl compounds
Wittig reaction
Introduction of double C=C bond instead C=O bond

9. Oxidation of carbonyl compounds
Aldehydes are easily oxidable to carboxylic acids even by gentle oxidation reagents
Proof of aldehyde group by Tollens reagent
Proof by Fehling reagent
before reaction Fehling I and Fehlingem II are mixed together
Fehling I = aqueous solution of CuSO Fehling II = aqueous solution of salt C4H4O6 Na K + NaOH

10. Oxidation of carbonyl compounds Baeyer – Villiger oxidation
oxidation of aldehydes and ketones by peroxyacids to esters
Ability of migration is dependent upon the type of substitution:
H Ph t-alkyl sek.alkyl prim.alkyl methyl
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11. Reactions at carbon atom in the neigbourhood of carbonyl
Hydrogen atoms in the neigbourhood of carbonyl are acidic aldolisation
and other reactions
Halogenation in acidic medium:
Because halogen by its acceptor effect makes hydrogen atom in the neigbourhood acidic, the halogenation to further steps is easier than to the first step, we are faced formation of more halogenated products.

12. Reactions at carbon atom in the neigbourhood of carbonyl
Haloform reaction
bromoform
Generally haloform is formed – compound with characteristic smell: chloroform - liquid
jodoform and bromoform - crystalinic

13. Nitrosation to a-position
Reactions at carbon atom in the neigbourhood of carbonyl
Nitrosation to a-position
treatment by alkaline nitrite
nitroso oximo (isonitroso) tautomerie
For the reaction is possible to use also aldehydes or ketones with a longer chain

14. Reactions at carbon atom in the neigbourhood of carbonyl
Methyl or methylene group next to carbonyl is sensitive to oxidation, leading to dialdehydes, diketones or aldehydketones
oxidation agent is SeO2
Conditions: dioxane (water), SeO2, 50 – 100 oC
1,2-diketones
R, R1 = Ph = benzil
= CH3 = diacetyl
1,2-aldoketones
1,2-dialdehydes
1,2-dioxoderivatives is possible to prepared by oxidation of acyloins by Cu2+ acetate

15. 1,3-diketones and 1,3-dioxo compounds
Claisenova kondenzace
Reaction of aldehydes and ketones with esters
Reaction of ketones with esters leads to
1,3-diketones
Reaction of aldehydes with esters leads to
1,3-ketoaldehydes
Condensation of esters leads to 1,3-ketoesters (b-ketoesters)
Catalyst are chosen according with acidity of substrates: alcoholates, sodium amide, or sodium

16. Acyloin condensation
reaction of aldehydes without a- hydrogen atoms (mostly aromatic)
during reaction are prepared acyloines (a-hydroxyketones)
benzoin condensation
catalyst is cyanide anion

17. 1,2-Dicarbonyl compounds
dialdehydes
methylglyoxal
diacetyl

18. 1,3-diketones and 1,3-dioxo compounds
Generaly the equilibrium between keto and enol form is shifted to more stabil keto form; at 1,3-dicarbonyl compounds we meet in dependence upon the solvent also enolform. Its existence is explained by possible formation of stabil cyclic structures.
H2O % %
Hexan % %

19. 1,3-diketones and 1,3-dioxo compounds
1,3-dioxo compounds can form by treatment of bases ambident anions. These react wíth an agents according its properties obeying Kornblum rules.
Polar solvent
SN2
SN1

20. Conjugated additions to a,b-unsaturated carbonyl compounds
Reactions proseed at systems, where carbonyl is member of the group –CHO, - COR, -COOR, CONH2 or where instead it is -CN, - NO2, -SOR or SO2R group.
These are nucleophilic additions, which may be sometimes, mainly at nitriles, complicated by 1,2-addition

21. Conjugated additions to a,b-unsaturated carbonyl compounds

22. Conjugated additions to a,b-unsaturated carbonyl compounds
1,4-addition proceeds with compounds with acidic hydrogen atom
Substrates are a,b-unsaturated ketones, esters, nitriles
Michael addition

23. Ketenes
very reactive carbonyl species (more reactive than aldehydes and ketones)
Csp Csp Osp2
Preparation :
„keten lamp “

24. Ketenes