Geminal halide hydrolysis explained

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 $\backslash longrightarrow$ 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 $\backslash longrightarrow$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

Notes and References

1. Marvel. C. S.. Sperry. W. M.. Benzophenone. Organic Syntheses. 1928. 8. 26. 10.15227/orgsyn.008.0026.
2. Pond. F. J.. O. P.. Maxwell. G. M.. Norman. The Action of Sodium Methylate Upon Dibromides of Propenyl-Compounds and of Unsaturated Ketones. Journal of the American Chemical Society. 1899. 22. 11. 955–967. 10.1021/ja02061a002.
3. Bill. J. C.. Tarbell. D. S.. o-Phthalaldehyde. Organic Syntheses. 1954. 34. 82. 10.15227/orgsyn.034.0082.
4. Buck. Johannes S.. Zimmermann. F. J.. Protocatechualdehyde. Organic Syntheses. 1938. 18. 75. 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. Chlorinated Hydrocarbons. Ullmann's Encyclopedia of Industrial Chemistry. 2006. 139. 10.1002/14356007.a06_233.pub2. 3527306730.