POTASSIUM PERMANGANATE–COPPER(II) SULFATE

1

Potassium Permanganate–Copper(II)
Sulfate

KMnO

4

CuSO

4

·

5H

2

O

(KMnO

4

)

[7722-64-7]

KMnO

4

(MW 158.04)

InChI = 1/K.Mn.4O/q+1;;;;;-1/rK.MnO4/c;2-1(3,4)5/q+1;-1
InChIKey = VZJVWSHVAAUDKD-QPPHZJHPAS
(CuSO

4

·5H

2

O)

[7758-99-8]

CuO

4

S

(MW 249.72)

InChI = 1/Cu.H2O4S.5H2O/c;1-5(2,3)4;;;;;/h;(H2,1,2,3,4);5*

1H2/q+2;;;;;;/p-2/fCu.O4S.5H2O/qm;-2;;;;;

InChIKey = JZCCFEFSEZPSOG-QLBZKNHHCL

(oxidant; capable of converting saturated primary alcohols into
carboxylic acids,

1

saturated secondary alcohols into ketones,

2

α

,β-unsaturated alcohols into α,β-unsaturated ketones,

3

dialkyl

and diaryl sulfides into sulfones,

4

diphenyl selenide into diphenyl

selenone,

4

α

,ω-diols into lactones,

1

alkenes into diketones

and α-hydroxy ketones,

5

ω

-hydroxy alkenes into ω-lactones,

6

1,5-dienes into 5-substituted butanolides,

7

and 

5

-unsaturated

steroids into the corresponding 5β,6β-epoxy steroids)

Physical Data:

mixture of high melting solids; see entries for

Potassium Permanganate and Copper(II) Sulfate.

Solubility:

sol cold H

2

O; insol CH

2

Cl

2

.

Form Supplied in:

KMnO

4

: purple solid. CuSO

4

·5H

2

O: blue

solid.

Handling, Storage, and Precautions:

oxidant; store in glass con-

tainers at rt.

Introduction. The use of KMnO

4

adsorbed on a solid sup-

port as a heterogeneous oxidant in nonaqueous solvents such as
CH

2

Cl

2

has two very practical advantages. First, in common with

most heterogeneous reactions, the product can be isolated simply
by filtering to remove the spent oxidant, followed by flash evapora-
tion of the solvent. Second, adsorption of potassium permanganate
onto a solid support remarkably improves its selectivity. Various
supports have been used (e.g. molecular sieves,

9

Alumina,

10,11

and silica

10

–

13

) with Copper(II) Sulfate being the most conve-

nient and versatile.

The water of hydration is important; without it very little or no

product is obtained.

2

While the role of water in controlling the

nature of the products is empirically well documented, a theo-
retical understanding of its function has been the subject of only
preliminary discussions.

11,14

Oxidation of Secondary Alcohols to Ketones. When potas-

sium permanganate (3 g) and copper(II) sulfate pentahydrate (2 g)
are ground together, a reagent capable of oxidizing both saturated
and α,β-unsaturated secondary alcohols into the corresponding
ketones is produced. When the alcohols (3 mmol) dissolved in
20 mL of CH

2

Cl

2

are added and the heterogeneous mixture re-

fluxed for several hours, ketones are formed in excellent yields;

3

however, primary alcohols, alkenes, and alcohols unsaturated at a
more remote position are not oxidized unless water or a base are
added.

Oxidation of Sulfides and Selenides. Under similar condi-

tions, sulfides and selenides are converted to sulfones and sele-
nones.

4

Oxidation of Primary Alcohols and α,ω-Diols.

If a base

(Cu(OH)

2

·CuCO

3

or KOH) is added, primary alcohols are oxi-

dized to the corresponding carboxylic acids in yields of 80–96%
and in a competition experiment it was found that primary al-
cohols are oxidized in preference to secondary alcohols.

1

Under

similar conditions, α,ω-diols are converted to lactones in good
yields (eq 1).

Oxidation of Alkenes. The presence of a small additional

amount of moisture along with some t-butyl alcohol introduces
a modification to the reactivity of the reagent by formation of
an ‘omega’ phase

15

surrounding the solid support. Under such

conditions alkenes are oxidized to α-diketones and/or α-hydroxy
ketones. For example, when 200

␮

L of water was added to a

finely ground mixture of potassium permanganate (4.0 g) and
copper(II) sulfate pentahydrate (2.0 g) followed by cyclooctene
(4 mmol) in CH

2

Cl

2

(15 mL) and t-butyl alcohol (1.0 mL), α-

hydroxycyclooctanone was obtained in 50% yield after refluxing
for 30 min. Under similar conditions, but with the addition of
Cu(OAc)

2

·H

2

O (1.0 g), 1,2-cyclooctadione was obtained in 48%

yield (eq 2).

HO

HO

O

O

(1)

83%

O

O

O

OH

(2)

50%

48%

With some alkenes, epoxides are obtained instead of ketones.

For example, 

5

-unsaturated steroids are readily converted into

the corresponding 5β,6β-epoxides in 90–95% yield (eq 3).

5,8

O

AcO

H

H

H

O

AcO

H

H

H

(3)

O

90%

Oxidation of ω-Hydroxy Alkenes and 1,5-Dienes. When the

omega phase is produced by adding 400

␮

L of water to powdered

KMnO

4

(8 g) and CuSO

4

·5H

2

O (4 g), ω-hydroxy alkenes are

oxidized with the loss of one or more carbons (eq 4).

6

OH

R

2

R

1

O

R

2

R

1

O

52–84%

(4)

Under similar conditions, 1,5-dienes are converted to 5-sub-

stituted butanolides,

7

as opposed to 2,5-bis(hydroxymethyl)tetra-

Avoid Skin Contact with All Reagents

2

POTASSIUM PERMANGANATE–COPPER(II) SULFATE

hydrofurans which are formed in the corresponding aqueous re-
actions (eq 5).

16

O

O

OH

O

OH

KMnO

4

, CuSO

4

CH

2

Cl

2

HO

(5)

KMnO

4

H

2

O

1.

Jefford, C. W.; Wang, Y., J. Chem. Soc., Chem. Commun. 1988, 634.

2.

Menger, F. M.; Lee, C., J. Org. Chem. 1979, 44, 3446.

3.

Noureldin, N. A.; Lee, D. G., Tetrahedron Lett. 1981, 22, 4889.

4.

Noureldin, N. A.; McConnell, W. B.; Lee, D. G., Can. J. Chem. 1984,
62

, 2113.

5.

Baskaran, S.; Das, J.; Chandrasekaran, S., J. Org. Chem. 1989, 54, 5182.

6.

Baskaran, S.; Islam, I.; Vankar, P. S.; Chandrasekaran, S., J. Chem. Soc.,
Chem. Commun. 1990

, 1670.

7.

Baskaran, S.; Islam, I.; Vankar, P. S.; Chandrasekaran, S., J. Chem. Soc.,
Chem. Commun. 1992

, 626.

8.

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1992, 57, 1928.

9.

Regen, S. L.; Koteel, C., J. Am. Chem. Soc. 1977, 99, 3837.

10.

Quici, S.; Regen, S. L., J. Org. Chem. 1979, 44, 3436.

11.

Lee, D. G.; Chen, T.; Wang, Z., J. Org. Chem. 1993, 58, 2918.

12.

Ferreira, J. T. B.; Cruz, W. O.; Vieira, P. C.; Yonashiro, M., J. Org. Chem.
1987, 52, 3698.

13.

Clark, J. H.; Cork, D. G., J. Chem. Soc., Chem. Commun. 1982, 635.

14.

Lee, D. G.; Noureldin, N. A., J. Am. Chem. Soc. 1983, 105, 3188.

15.

Liotta, C. L.; Burgess, E. M.; Ray, C. C.; Black, E. D.; Fiar, B. E. In
Phase-Transfer Catalysis; New Chemistry, Catalysts, and Applications

;

Starks, C. M., Ed.; American Chemical Society: Washington, 1987; p
15.

16.

Walba, D. M.; Przybyla, C. A.; Walker, C. B., J. Am. Chem. Soc. 1990,
112

, 5624 and references therein.

Donald G. Lee

The University of Regina, Regina, Saskatchewan, Canada

A list of General Abbreviations appears on the front Endpapers