Favorskii Rearrangement

Favorskii rearrangement [fa′vȯr·skē ‚rē·ə′rānj·mənt]

(organic chemistry)

A reaction in which α-halogenated ketones undergo rearrangement in the presence of bases, with loss of the halogen and formation of carboxylic acids or their derivatives with the same number of carbon atoms.

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Favorskii Rearrangement 

a reaction for the synthesis of tertiary acetylenic alcohols through the condensation of hydrocarbons of the acetylene series with ketones in the presence of anhydrous, powdered potassium hydroxide. For example, acetylene reacts with acetone to form methyl butynol (2-methyl-3-butyn-2-ol):

HC≡CH + CH₃COCH₃ → (CH₃)₂C(OH)C≡CH

The reaction occurs in ether, benzene, and other organic solvents on cooling and mixing. Great practical value is attached to, for example, dimethylvinylethynyl carbinol:

(CH₃)₂C(OH)C≡C—CH=CH₂

which is synthesized from vinylacetylene and acetone; copolymerization of dimethylvinylethynyl carbinol with methyl metha-crylate and/or butyl methacrylate yields carbinol resins, which are used in the manufacture of varnishes and glues. The reaction was discovered by A. E. Favorskii in 1900.