Kharasch addition

The Kharasch addition is an organic reaction and a metal-catalysed free radical addition of CXCl₃ compounds (X = Cl, Br, H) to alkenes.[1] The reaction was discovered by Morris S. Kharasch in the 1940s.[2][3][4]

The basic reaction scheme runs as follows:

R₂C=CH₂ + R'X → R₂CX-CH₂R':

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 [5] 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](FeCl2)].[6]

References

1. Name reactions: a collection of detailed reaction mechanisms, Jie Jack Li Springer; 2nd edition (September 17, 2003) 3540402039
2. Kharasch, M.; Jensen, E.; Urry, W. (1945). "Addition of Carbon Tetrachloride and Chloroform to Olefins". Science. 102 (2640): 128. Bibcode:1945Sci...102..128K. doi:10.1126/science.102.2640.128. PMID 17777366.
3. Kharasch, M. S.; Jensen, E. V.; Urry, W. H. (1947). "Reactions of Atoms and Free Radicals in Solution. X. The Addition of Polyhalomethanes to Olefins". Journal of the American Chemical Society. 69 (5): 1100. doi:10.1021/ja01197a035.
4. Kharasch, M. S.; Kuderna, B. M.; Urry, W. (1948). "Reactions of atoms and free radicals in solution; the additions of bromodichloromethane and dibromodichloromethane to olefins; the preparation of 2-alkenals". Journal of Organic Chemistry. 13 (6): 895–902. doi:10.1021/jo01164a020. PMID 18106035.
5. Kharasch, M. S.; Urry, W. H.; Jensen, E. V. (1945). "Addition of Derivatives of Chlorinated Acetic Acids to Olefins". Journal of the American Chemical Society. 67 (9): 1626. doi:10.1021/ja01225a517.
6. Organic Syntheses, Coll. Vol. 5, p.1076 (1973); Vol. 45, p.104 (1965). link