Potassium Hydroxide-Carbon Tetrachloride

KOH-CCl4
(KOH)

[1310-58-3]  · HKO  · Potassium Hydroxide-Carbon Tetrachloride  · (MW 56.11) (CCl4)

[56-23-5]  · CCl4  · Potassium Hydroxide-Carbon Tetrachloride  · (MW 153.81)

(ketones, alcohols, and sulfones react with CCl4/KOH, usually in t-BuOH, to give a variety of products1)

Physical Data: see entry for Potassium Hydroxide.

Reactions with Ketones.

Reactions of ketones with CCl4-KOH in t-BuOH generally fall into four categories.1,2

  • 1)Ketones with a- and a-hydrogens were transformed into carboxylic acids, resulting from Favorskii rearrangement of an intermediate a-chloro ketone (eq 1).1,2

  • 2)Hindered ketones with a- but no a-hydrogens were a-chlorinated but do not undergo any further reaction, e.g. the reaction with ketone (1) to give the a-chloro ketone (2) (eq 2).2

  • 3)Some ketones with a- but no a-hydrogens were a-chlorinated and then converted to the a-hydroxy derivative (eq 3).2

  • 4)Some ketones with a- but no a-hydrogens were a-chlorinated and subsequently cleaved into carboxylic acids,1,2 e.g. pinacolone gave Pivalic Acid in 80% yield (eq 4).

    Another example was the reaction with estrone and estrone 3-methyl ether (3a,b) which gave the a,a-dichloro derivatives (4) that were rapidly cleaved to the 16,16-dichlorodoisynolic acids (5) (eq 5).2

    Reactions with Alcohols.

    Primary and secondary alcohols were oxidized to aldehydes and ketones respectively upon reaction with CCl4-KOH in t-BuOH. Both initial products further react to form other products. Stable aldehydes (e.g. pivalaldehyde) and stable ketones (e.g. benzophenone) could be isolated. Tertiary alcohols were unreactive.1

    Reactions with Sulfones.

    Based on their structure and the outcome of the reaction, sulfone reactions can be classified into three categories.1

  • 1)Aryl alkyl sulfones were mono-, di-, and trichlorinated (eq 6). Intermediate trichloromethyl sulfones may be cleaved to aryl sulfonic acids under the reaction conditions (eq 7).1

  • 2)Dibenzyl sulfones were converted to stilbenes. This was explained by the initial formation of a-chloro sulfones, then a 1,3-elimination of HCl, followed by extrusion of SO2 to form the alkene; a sequence known as the Ramberg-Bäcklund reaction (eq 8).1

    Treatment of the cyclic sulfone (6) with KOH-CCl4 and t-BuOH at 50 °C overnight resulted in a similar Ramberg-Bäcklund reaction to give a mixture of the hydroindenones (7) and (8) (eq 9).3

    The conjugated triene (10) was similarly obtained from the diallyl sulfone (9) by KOH-CCl4 at rt (eq 10).4

    Di-primary alkyl sulfones (11) gave, unexpectedly, the cis-dialkylethylenesulfonic acid K salts (12) (eq 11). Symmetrical sulfones gave single isomeric cis products while unsymmetrical sulfones gave two isomeric cis products.5,6

  • 3)Di-s-alkyl sulfones were converted into alkenes and alkene-dichlorocarbene adducts (1,1-dichlorocyclopropanes).1

    Dichlorocyclopropanation of Alkenes.

    The generation of dichlorocarbene in the reaction of KOH-CCl4 with sulfones in t-BuOH was used as a tool for dichlorocyclopropanation of alkenes in yields ranging from 45-93%, e.g. the reaction of 1,1-diphenylethylene with KOH, CCl4, t-BuOH, and Me2SO2 to give 1,1-dichloro-2,2-diphenylcyclopropane in 93% yield (eq 12).7


    1. Meyers, C. Y.; Malte, A. M.; Matthews, W. S. JACS 1969, 91, 7510.
    2. Meyers, C. Y.; Kolb, V. M. JOC 1978, 43, 1985 and references therein.
    3. Kattenberg, J.; de Waard, E. R.; Huisman, H. O. TL 1973, 1481.
    4. Büchi, G.; Freidinger, R. M. JACS 1974, 96, 3332.
    5. Meyers, C. Y.; Ho, L. L. TL 1972, 4319.
    6. For mechanisms and related studies, see: (a) Meyers, C. Y.; Ho, L. L.; McCollum, G. J.; Branca, J. TL 1973, 1843. (b) Meyers, C. Y.; Matthews, W. S.; McCollum, G. J.; Branca, J. C. TL 1974, 1105.
    7. Poon, C.-D.; Yuen, P.-W.; Man, T.-O.; Li, C.-S.; Chan, T.-L. JCS(P1) 1984, 1561.

    Ahmed F. Abdel-Magid

    The R. W. Johnson Pharmaceutical Research Institute, Spring House, PA, USA



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