Geminal halide hydrolysis

Geminal halide hydrolysis is an organic reaction. The reactants are geminal dihalides with a water molecule or a hydroxide ion. The reaction yields ketones from secondary halides^[1][2] or aldehydes from primary halides.^[3][4]

Reaction mechanism

The first part of the reaction mechanism consists of an ordinary nucleophilic aliphatic substitution to produce a gem-halohydrin:

RCH(Cl)₂ + KOH ${\textstyle \longrightarrow }$ RCH(OH)Cl + KCl

The remaining halide is a good leaving group and this enables the newly created hydroxy group to convert into a carbonyl group by expelling the halide:

RCH(OH)Cl ${\textstyle \longrightarrow }$Rearrangement gives R-CHO + HCl

Variations

Other functional groups can undergo similar hydrolysis reactions. For instance, geminal trihalides (e.g. benzotrichloride) can be partially hydrolyzed to acyl halides (e.g. benzoyl chloride) in a similar way.^[5] Further hydrolysis yields carboxylic acids.

See also

• Stephen aldehyde synthesis

References

1. Marvel, C. S.; Sperry, W. M. (1928). "Benzophenone". Organic Syntheses. 8: 26. doi:10.15227/orgsyn.008.0026.
2. Pond, F. J.; O. P., Maxwell; G. M., Norman (1899). "The Action of Sodium Methylate Upon Dibromides of Propenyl-Compounds and of Unsaturated Ketones". Journal of the American Chemical Society. 22 (11): 955–967. doi:10.1021/ja02061a002.
3. Bill, J. C.; Tarbell, D. S. (1954). "o-Phthalaldehyde". Organic Syntheses. 34: 82. doi:10.15227/orgsyn.034.0082.
4. Buck, Johannes S.; Zimmermann, F. J. (1938). "Protocatechualdehyde". Organic Syntheses. 18: 75. doi:10.15227/orgsyn.018.0075.
5. Rossberg, Manfred; Lendle, Wilhelm; Pfleiderer, Gerhard; Tögel, Adolf; Dreher, Eberhard-Ludwig; Langer, Ernst; Rassaerts, Heinz; Kleinschmidt, Peter; Strack, Heinz; Cook, Richard; Beck, Uwe; Lipper, Karl-August; Torkelson, Theodore R.; Löser, Eckhard; Beutel, Klaus K.; Mann, Trevor (2006). "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry: 139. doi:10.1002/14356007.a06_233.pub2. ISBN 3527306730.