Chemical manganese dioxide (CMD), an efficient activated manganese dioxide. Application to oxidation of benzylic and allylic alcohols

Article abstract of DOI:10.1055/s-1998-1583

Oxidation of benzylic and allylic alcohols with chemical manganese dioxide smoothly proceeded under mild reaction conditions to give the corresponding aldehydes and ketones, respectively, in high yields.

Full text of DOI:10.1055/s-1998-1583

January 1998
SYNLETT
35
Chemical Manganese Dioxide (CMD), an Efficient Activated Manganese Dioxide. Application
to Oxidation of Benzylic and Allylic Alcohols
*
*
Toyohiko Aoyama, Naoko Sonoda, Mariko Yamauchi, Kyoko Toriyama, Masahiro Anzai, Akira Ando, and Takayuki Shioiri
Faculty of Pharmaceutical Sciences, Nagoya City University, Tanabe-dori, Mizuho-ku, Nagoya 467, JAPAN
Fax: +81-52-834-4172; E-mail: shioiri@phar.nagoya-cu.ac.jp
Received 22 October 1997
Abstract: Oxidation of benzylic and allylic alcohols with chemical
manganese dioxide smoothly proceeded under mild reaction conditions
to give the corresponding aldehydes and ketones, respectively, in high
yields.
It is well-known that activated manganese dioxide (MnO ) is a useful
2
reagent both for selective oxidation of benzylic and allylic alcohols to
aldehydes and ketones, respectively, and for dehydrogenation of
1
heterocycles to heteroaromatics. Although several methods for
2
preparation of activated MnO have been reported, preparations are
2
very tedious and sometimes the oxidation efficiency lacks
reproducibility.
Commercially available activated MnO can also be used, but again its
2
activity varies widely. We have already reported that chemical
3
manganese dioxide (CMD), produced for dry battery manufacture, can
4
be efficiently used for oxidation of some allylic alcohols and for
5
dehydrogenation of heterocycles such as thiazolines,
2,3-
6
7
8
dihydrofurans, 3-pyrrolines, and 2-pyrrolines. Further investigations
along this line have revealed that CMD is widely applicable to the
selective oxidation of benzylic and allylic alcohols 1 to aldehydes and
ketones 2, respectively, as shown in Scheme 1.
Scheme 1
A typical experimental procedure is as follows: A mixture of piperonyl
alcohol 1a (152 mg, 1 mmol) and CMD (869 mg, 10 mmol) in
dichloromethane (10 ml) was stirred at room temperature for 24 h. The
mixture was filtered through a pad of celite and the filtrate was
concentrated in vacuo. The residue was purified by column
chromatography on silica gel (Fuji Davison, BW-820 MH, 15 g, hexane
: AcOEt = 10:1 to 5:1) to give piperonal 2a (143 mg, 95 %).
The results are summarized in Table. Various benzylic and allylic
alcohols 1 including functionalized ones smoothly underwent the
oxidation with CMD to give the corresponding aldehydes and ketones 2
in high yields. No isomerization of double bond was observed in the
oxidation of the cis- and trans-α,β-unsaturated alcohols 1h~k. As
2,9-11
compared with the reported procedure using activated MnO ,
the
2
efficiency of the method described here is either superior or comparable.
In the oxidation of 1,2,3,4-tetrahydro-1-naphthol, CMD proved to be
much superior to usual MnO commercially available from Aldrich,
2
Fluka, Merck, Nakarai, and Wako companies. Ten equivalents of CMD
was usually required for completion of the reaction smoothly.
Dichloromethane seemed to be the solvent of choice though benzene
could be used.
Incidentally, we found that the oxazolines 3a and 3b, bearing the aryl or
good yields, as shown in Scheme 2. 1,2,3,4-Tetrahydroisoquinoline 5
also afforded 3,4-dihydroisoquinoline 6 with a small amount of
isoquinoline 7 as a by-product.
vinilogous function at the C position on the oxazoline ring, were
2
smoothly dehydrogenated with CMD to give the oxazoles 4a and 4b, in

36
LETTERS
SYNLETT
References and Notes
1.
a) Pizey, J. S. Synthetic Reagents, Vol. II, Ellis Horwood Ltd.,
Chichester, 1974, Chapter 3. b) Fatiadi, A. J. Synthesis, 1976, 65
and 133. c) Cahiez, G.; Alami, M. Encyclopedia of Reagents for
Organic Synthesis, Vol. 5, Paquette, L. (ed), John Wiley & Sons,
Chichester, 1995, 3229.
2.
3.
Goldman, I. M. J. Org. Chem. 1969, 34, 1979. See Ref. 1 and
references cited therein.
a) Shioiri, T.; Aoyama, T.; Hamada, Y. Wako Junyaku Jiho, 1997,
65, 12. b) CMD is now available from Wako Pure Chemical
Industries, Ltd. (3-1-2 Dosho-machi, Chuo-ku, Osaka 541, Japan
Fax:+81-6-201-5964) as “manganese (IV) oxide, chemicals
treated”.
Scheme 2
4.
5.
Matsubara, J.; Nakao, K.; Hamada, Y.; Shioiri, T. Tetrahedron
Lett. 1992, 33, 4187.
The method described here is efficient and simple to conduct. Thus
commercially available chemical manganese dioxide in place of usual
3
a) Hamada, Y.; Shibata, M.; Sugiura, T.; Kato, S.; Shioiri, T. J.
Org. Chem. 1987, 52, 1252. b) Irako, N.; Hamada, Y.; Shioiri, T.
Tetrahedron, 1992, 48, 7251.
activated MnO will be widely used for selective oxidation of benzylic
2
and allylic alcohols to aldehydes and ketones.
6.
7.
8.
9.
Miwa, K.; Aoyama, T.; Shioiri, T. Synlett, 1994, 461.
Ogawa, H.; Aoyama, T.; Shioiri ,T. Heterocycles, 1996, 42, 75.
Yagi, T.; Aoyama, T.; Shioiri, T. Synlett, 1063.
Acknowledgment : We are grateful to Dr. A. Kozawa of International
Technology Exchange Society for helpful suggestions on the use of
manganese dioxide.
Papadopoulos, E. P.; Jarrar, A.; Issidorides, C. H. J. Org. Chem.
1966, 31, 615.
10. Harfenist, M.; Bavley, A.; Lazier, W. A. J. Org. Chem. 1954, 19,
1608.
11. Corey, E. J.; Gilman, N. W.; Ganem, B. E. J. Am. Chem. Soc.
1968, 90, 5616.