Kharasch addition
Encyclopedia
The Kharasch addition is an organic reaction
and a metal-catalysed free radical addition
of CXCl3 compounds (X = Cl, Br, H) to alkene
s. The reaction was invented by Morris S. Kharasch
in the 1940s.
The basic reaction scheme runs as follows:
and proceeds through the CXCl2 free radical. Examples of organohalides are carbon tetrachloride
and chloroform
. The addition is an anti-Markovnikov addition
. Early work linked the addition to olefin polymerization and is therefore considered a first step into what was to become atom transfer radical polymerization.
An example of Karasch addition is the synthesis of 1,1,3-trichloro-n-nonane from 1-octene
, chloroform and ferric chloride.
Organic reaction
Organic reactions are chemical reactions involving organic compounds. The basic organic chemistry reaction types are addition reactions, elimination reactions, substitution reactions, pericyclic reactions, rearrangement reactions, photochemical reactions and redox reactions. In organic synthesis,...
and a metal-catalysed free radical addition
Free radical addition
Free radical addition is an addition reaction in organic chemistry involving free radicals. The addition may occur between a radical and a non-radical, or between two radicals....
of CXCl3 compounds (X = Cl, Br, H) to alkene
Alkene
In organic chemistry, an alkene, olefin, or olefine is an unsaturated chemical compound containing at least one carbon-to-carbon double bond...
s. The reaction was invented by Morris S. Kharasch
Morris S. Kharasch
Morris Selig Kharasch was a pioneering organic chemist best known for his work with free radical additions and polymerizations. He defined the peroxide effect, explaining how an anti-Markovnikov orientation could be achieved via free radical addition. Kharasch was born in Russian Empire in 1895...
in the 1940s.
The basic reaction scheme runs as follows:
- RR'CH=CH2 + CXCl3 → RR'CHX-CHCl2X
and proceeds through the CXCl2 free radical. Examples of organohalides are carbon tetrachloride
Carbon tetrachloride
Carbon tetrachloride, also known by many other names is the organic compound with the formula CCl4. It was formerly widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent...
and chloroform
Chloroform
Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes. The colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered somewhat hazardous...
. The addition is an anti-Markovnikov addition
Markovnikov's rule
In organic chemistry, Markovnikov's rule or Markownikoff's rule is an observation based on Zaitsev's rule. It was formulated by the Russian chemist Vladimir Vasilevich Markovnikov in 1870....
. Early work linked the addition to olefin polymerization and is therefore considered a first step into what was to become atom transfer radical polymerization.
An example of Karasch addition is the synthesis of 1,1,3-trichloro-n-nonane from 1-octene
1-Octene
1-Octene is an organic compound with a formula CH2CHC6H13. The alkene is classified as a higher olefin and alpha-olefin, meaning that the double bond is located at the alpha position, endowing this compound with higher reactivity and thus useful chemical properties. 1-Octene is one of the...
, chloroform and ferric chloride.