Franchimont condensation

The Franchimont condensation (also called Franchimont reaction ) is a chemical reaction from the field of organic chemistry . It was discovered in 1872 by the Dutch chemist Antoine Paul Nicolas Franchimont (1844-1919) and named after him. In the Franchimont condensation, two α-bromocarboxylic acid molecules are linked together to form a new carbon-carbon bond.

Overview reaction

This reaction is the condensation of two α-bromocarboxylic acid molecules:

By reacting the α-bromocarboxylic acid with sodium cyanide and subsequent hydrolysis , the desired 1,2-dicarboxylic acid is finally formed.

Reaction mechanism

The Franchimont condensation is a carboxylic acid - dimerization . Instead of sodium cyanide, potassium cyanide can also be used. With this method it is also possible to cyclize dicarboxylic acid esters within the molecule (intramolecular).

First the α-bromocarboxylic acid is treated with sodium cyanide, the bromide ion is split off. An intermediate product is created. This is followed by the substitution reaction with a second α-bromocarboxylic acid, where another bromide ion is split off again. After hydrolysis and subsequent decarboxylation , a 1,2- dicarboxylic acid is finally formed via an enol through a 1,3-proton shift .

Individual evidence

↑ APN Eranchimont: About the dibenzyldicarboxylic acid . In: Reports of the German Chemical Society . tape 5 , no. 2 , July 1, 1872, p. 1048-1050 , doi : 10.1002 / cber.187200502138 .
↑ ^a ^b Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents. (3 volumes). John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 1113.
^ ^A ^b H. Krauch, W. Kunz: Name reactions of organic chemistry. Dr. Alfred Hüthig Verlag, Heidelberg 1961, p. 164.
^ Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents. (3 volumes). John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 1114.

[1] APN Eranchimont: About the dibenzyldicarboxylic acid . In: Reports of the German Chemical Society . tape 5 , no. 2 , July 1, 1872, p. 1048-1050 , doi : 10.1002 / cber.187200502138 .

[Wang-2] Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents. (3 volumes). John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 1113.

[Krauch-3] A ^b H. Krauch, W. Kunz: Name reactions of organic chemistry. Dr. Alfred Hüthig Verlag, Heidelberg 1961, p. 164.

[4] Z. Wang (Ed.): Comprehensive Organic Name Reactions and Reagents. (3 volumes). John Wiley & Sons, Hoboken, NJ 2009, ISBN 978-0-471-70450-8 , p. 1114.