1. Subject : Organic Chemistry
Module 1 : Name Reactions
Reformatskii Reaction
Author : Dr. M. T. Bachute
Dept. of Chemistry
K. B. P. Mahavidyalaya, Pandharpur
2. Reformatskii Reaction
Statement :
Aldehydes and ketones react with α-haloesters in
the presence of zinc metal in dry and inert
solvent like benzene, ether, toluene etc to form
β-hydroxyester.
4. Mechanism
For the reaction
Ph
H
O
+ Br
O
O
CH3
Benzaldehyde
i. Zn/benzene
Ph
OH
O
O
H
CH3
-bromoacetate hydroxyethyl- ethyl- - --phenylpropionate
ii. H 2O/H
+
5. Mechanism
Step I : Formation organo zinc compound
Br
O
O
C2H5
Zn
C6H6
Zn
O
O
C2H5
Br H2C O
O
C2H5
Br Zn
+
Organozinc compoundethyl
-
-
bromoacetate
Organozinc compound
6. Step II : Nucleophilic addition of organo zinc
compound to carbonyl group to form an
adduct.
Ph C
H
O
+ H2C O
O
C2H5
Br Zn
+
Organozinc compound
Ph C
H
OZnBr
CH2 C
O
O C2H5
AdductBenzadehyde
7. Mechanism
Step III : Hydrolysis of adduct
Ph C
H
OZnBr
CH2 C
O
O C2H5
Adduct
HCl/H 2O
Ph C
H
OH
CH2 C
O
O C2H5
-
Hydroxy ester
+ ZnBr.OH
ethyl
-
-
hydroxy
-
phenyl
-
-
propionate
8. Applications
1. To prepare β-hydroxy esters
2. To prepare β-hydroxy acids
3. To prepare α,β-unsaturated esters and acjds: β-
hydroxy esters and β-hydroxy acids can be
dehydrated to form α,β-unsaturated esters and
acids
e.g.Preparation of cinnamic acid
9. Preparation of ethyl cinnamate and
cinnamic acid
Explanation :
Ph
H
O
+ Br
O
O
CH3
Benzaldehyde
i. Zn/benzene
Ph
OH
O
O
H
CH3
-bromoacetate hydroxyethyl- ethyl- - --phenylpropionate
ii. H 2O/H
+
Con.H 2SO4
-H2O Ph
O
O
CH3
i. KOH,H 2O,Heat
ii.H 2O.H
+
Ph
O
O H
-
-
unsaturated ester
-
-
unsaturated acid
Ethyl cinnamate Cinnamic acid