Synthesis of novel organoselenium as catalyst for Baeyer-Villiger oxidation with 30% H2O2

Article abstract of DOI:10.1016/j.tetlet.2005.10.055

A novel diselenide was synthesized in good yield via only four steps from phenol, and was employed as the catalyst for the Baeyer-Villiger oxidation with 30% H₂O₂ to obtain lactones in good yields.

Full text of DOI:10.1016/j.tetlet.2005.10.055

Tetrahedron
Letters
Tetrahedron Letters 46 (2005) 8665–8668
Synthesis of novel organoselenium as catalyst
for Baeyer–Villiger oxidation with 30% H2O2
Hayato Ichikawa,* Yoshihide Usami and Masao Arimoto
Osaka University of Pharmaceutical Sciences, 4-20-1 Nasahara, Takatsuki, Osaka 569-1094, Japan
Received 3 August 2005; revised 14 October 2005; accepted 17 October 2005
Abstract—A novel diselenide was synthesized in good yield via only four steps from phenol, and was employed as the catalyst for the
Baeyer–Villiger oxidation with 30% H2O2 to obtain lactones in good yields.
Ó 2005 Elsevier Ltd. All rights reserved.
The Baeyer–Villiger oxidation, which uses organic per-
oxy acids as oxidants, has been commonly employed
for the preparation of esters.1 In particular, the ease of
transformation from cyclic ketones to lactones makes
it an important method for the total syntheses of natural
products.2 However, such peroxy acids as trifluoroper-
acetic acid and m-chloroperbenzoic acid, which are the
most popular oxidants for the Baeyer–Villiger oxida-
tion, are explosive and therefore should be handled with
extreme care. Moreover, the storage of large amounts of
such peroxy acids is not desirable, and the generation of
much waste acid after the oxidation has hindered its use
in the industry. To overcome these problems, hydrogen
peroxide has been employed as an alternative.3
On the other hand, several selenium compounds are effi-
cient reagents for the oxidation of organic compounds.4
For example, the oxidation of olefin compounds with a
selenium dioxide takes place selectively at the allylic
position. Recently, Sheldon and co-workers reported
that organoselenium compounds bearing trifluoro-
methyl groups could catalyze the oxidation of olefins
and cyclic ketones with 60% hydrogen peroxide in
fluorous solvent to obtain epoxides and lactones, respec-
tively.4d–f The diselenides are reacted with excess
hydrogen peroxide to obtain peroxyseleninic acids that
serve as catalysts for the Baeyer–Villiger oxidation. In
this paper, we describe the synthesis of novel organic
selenium compounds that catalyze the Baeyer–Villiger
Figure 1. Catalytic cycle of seleninic acids with H2O2 in Baeyer–Villiger oxidation.
Keywords: Baeyer–Villiger oxidation; Diselenide; Seleninic acid; Hydrogen peroxide.
*
Corresponding author. Tel.: +81 72 690 1000; fax: +81 72 690 1005; e-mail: ichikawa@gly.oups.ac.jp
0040-4039/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2005.10.055

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H. Ichikawa et al. / Tetrahedron Letters 46 (2005) 8665–8668
Table 1. The diselenides catalyzed Baeyer–Villiger oxidation with 30%
H2O2
was deprotonated by reacting with N-ethyldiisopropyl-
amine, followed by reacting with trifluoromethanesul-
fonic anhydride at À40 °C in dichloromethane under
nitrogen to obtain diselenide bearing bistriflate 3
(Scheme 1).5
Novel diselenide 3 and other diselenides were used as the
catalyst for the Baeyer–Villiger oxidation of 4-phenyl-
cyclohexanone with 30% hydrogen peroxide (Table 1).
As a result, only diselenide 3 catalyzed the oxidation
to obtain the corresponding lactone in 85% yield,
whereas the other diselenides did not promote any oxi-
dation.6 In addition, when the trifluoromethanesulfonic
acid (TfOH) was added as an additive to the oxidation
of 4-phenylcyclohexanone with catalyst 2 and hydrogen
peroxide, the starting material was almost recovered
(entry 6). Thus, it seems that the diselenide 3 bearing
the trifluoromethanesulfonate (TfO) group at o-position
is very important for catalyst.
Entry
Catalyst
Yielda (%)
1
2
None
PhSeSePh
0
0
3
4
5
0
0
This oxidation catalyzed by diselenide proceeded via
seleninic acid. Thus, the oxidation of ketone was carried
out with seleninic acid as the catalyst under the same
conditions as those used for the case of diselenide.
Seleninic acid was isolated from the diselenide and
30% hydrogen peroxide. When the oxidation of 4-phenyl-
cyclohexanone was carried out with seleninic acid as
the catalyst, the corresponding lactone was obtained in
a similar yield (Scheme 2).
85
6
2, TsOH (0.1 equiv)
12b
a Isolated yield.
b The starting material was recovered in 75%.
The Baeyer–Villiger oxidation catalyzed by diselenide 3
with 30% hydrogen peroxide was applied to various
ketones (Table 2). The oxidation of 4-phenylcyclohexa-
none proceeded in 77% and 84% yields for 8 and 16 h,
respectively (entries 1 and 2). Reducing the amount of
catalyst led to a lower product yield (entry 4). Other
cyclic ketones were also transformed into the corre-
sponding lactones in good yields.
oxidation with 30% hydrogen peroxide in dichloro-
methane (Fig. 1).
Novel organoselenium catalysts were synthesized in only
four steps from phenol in good yields. After phenol was
protected by MOM ether, ortho-lithiation of the ether
with n-BuLi generated lithium salt as a white suspen-
sion. The addition of selenium powder, followed by bub-
bling air, produced diselenide 1. Without purification of
1, deprotection of the MOM ether proceeded with 1 M
HCl in methanol with heating to reflux. Bisphenol 2
The oxidation of aromatic aldehyde is also catalyzed by
deselenide.4b 2,5-Dimethoxybenzaldehyde was reacted
with 30% hydrogen peroxide and 0.05 equiv of 3 to
produce 2,5-dimethoxyphenol in 99% yields (Scheme
3). The time to accomplish the oxidation of the aldehyde
was only 3 h when catalyst 3 was used, though the
Scheme 1.

H. Ichikawa et al. / Tetrahedron Letters 46 (2005) 8665–8668
8667
Scheme 2.
Table 2. Baeyer–Villiger oxidation with 30% H2O2 for various ketones
was washed with brine and dried over MgSO4. After
filtration and evaporation of the solvent, the residue
was purified by column chromatography on silica gel.
In conclusion, the synthesis of novel diselenide was
achieved in good yield via only four steps from phenol.
It was clarified that diselenide 3 is an excellent catalyst
for the Baeyer–Villiger oxidation without fluorous
solvent. Further studies of the epoxidation and regio-
selectivity of the oxidation with 3, and the synthesis of
asymmetric and reusable organoselenium catalysts are
ongoing.
Entry Ketone
Catalyst (mol %) Time (h) Yield (%)
1
2
3
4
5
8
16
24
22
77
84
85
32
5
5
0.5
Acknowledgements
We gratefully acknowledge Mr. Katsuhiko Minoura
and Ms. Mihoyo Fujitake (Osaka University of Phar-
maceutical Sciences), for the measurements of 77Se
NMR and HRMS, respectively.
5
6
5
5
17
17
90
99
References and notes
1. Krow, G. R. In Comprehensive Organic Synthesis; Trost, B.,
Fleming, I., Eds.; Pergamon Press: New York, 1991; Vol. 7,
p 671.
7
8
5
5
22
65
41
59
2. Last decadeÕs work: (a) Lebreton, J.; Alphand, V.; Furstoss,
R. Tetrahedron 1997, 53, 145; (b) Schultz, A. G.; Pettus, L.
J. Org. Chem. 1997, 62, 6855; (c) Mal, D.; Bandhyopa-
dhyay, M.; Datta, K.; Murty, K. V. S. N. Tetrahedron 1998,
54, 7525; (d) Kraehenbuehl, K.; Picasso, S.; Vogel, P. Helv.
Chim. Acta 1998, 81, 1439; (e) Pankau, W. M.; Kreiser, W.
Helv. Chim. Acta 1998, 81, 1997; (f) Kim, D.; Shim, P. J.;
Lee, J.; Park, C. W.; Hong, S. W.; Kim, S. J. Org. Chem.
2000, 65, 4864; (g) Brown, R. C. D.; Bataille, C. J. R.;
Bruton, G.; Hinks, J. D.; Swain, N. A. J. Org. Chem. 2001,
66, 6719; (h) Tanaka, T.; Murakami, K.; Kanda, A.; Patra,
D.; Yamamoto, S.; Satoh, N.; Kim, S.-W.; Rahman, S. M.
A.; Ohno, H.; Iwata, C. J. Org. Chem. 2001, 66, 7107; (i) de
Faria, A. R.; Salvador, E. L.; Correia, C. R. D. J. Org.
Chem. 2002, 67, 3651; (j) Rigby, J. H.; Laxmisha, M. S.;
Hudson, A. R.; Heap, C. H.; Heeg, M. J. J. Org. Chem.
2004, 69, 6751.
3. (a) Heaney, H. Aldrichim. Acta 1993, 26, 35; (b) Strukul,
G.; In Adv. Catal. Des. Proc. Workshop; 2nd ed.; Graziani,
M., Rao, C. N. R., Eds.; 1993, 53; (c) ten Brink, G.-J.;
Arends, I. W. C. E.; Sheldon, R. A. Chem. Rev. 2004, 104,
4105, and reference cited therein.
4. (a) Grieco, P. A.; Yokoyama, Y.; Gilman, S.; Ohfune, Y. J.
Chem. Soc., Chem. Commun. 1977, 870; (b) Syper, L.
Synthesis 1989, 167; (c) Brzaszcz, M.; Kloc, K.; Maposah,
M.; Mlochowski, J. Synth. Commun. 2000, 30, 4425; (d) ten
Scheme 3.
diphenyl diselenide needed to oxidize the aldehyde for
20 h.4b
The typical procedure is as follows: Diselenide 3
dissolved in dichloromethane was added dropwise to
30% hydrogen peroxide at rt. After stirring for 0.5 h,
ketones were added to the reaction mixture. The result-
ing mixture was poured into saturated NH4Cl solution
and extracted with dichloromethane. The organic layer

8668
H. Ichikawa et al. / Tetrahedron Letters 46 (2005) 8665–8668
Brink, G.-J.; Fernandes, B. C. M.; van Vliet, M. C. A.;
JC–F = 316.3 Hz); 77Se NMR (95 MHz, CDCl3): d 420.7; IR
m 3090, 2350, 1917, 1790, 1563, 1457, 1040 cmÀ1; HRMS
calcd for (M+) C14H8F6O6S2Se2 609.7997, found 609.8001.
6. The oxidation of 4-phenylcyclohexanone with 12 equiv of
30% hydrogen peroxide and 0.5 equiv of diphenyl disele-
Arends, I. W. C. E.; Sheldon, R. A. J. Chem. Soc., Perkin
Trans. 1 2001, 224; (e) ten Brink, G.-J.; Vis, J.-M.; Arends,
I. W. C. E.; Sheldon, R. A. J. Org. Chem. 2001, 66, 2429;
(f) ten Brink, G.-J.; Vis, J.-M.; Arends, I. W. C. E.;
Sheldon, R. A. Tetrahedron 2002, 58, 3977; (g) Miyake, Y.;
Nishibayashi, Y.; Uemura, S. Bull. Chem. Soc. Jpn. 2002,
75, 2233.
nide as a catalyst for 24 h gave
a mixture of the
corresponding lactone (10%), the hydrolysis product of
the lactone (22%), the a,b-unsaturated ketone (trace) and
the recovered cyclohexanone (50%). When the catalytic
amount of 3 was used in the oxidation, the corresponding
lactone was only prepared and no side products were
obtained.
5. Bis(2-phenyltrifluoromethanesulfonate)diselenide 3; pale
1
yellow powder; mp 55 °C; H NMR (200 MHz, CDCl3): d
7.25–7.43 (m, 3H), 7.76–7.80 (m, 1H); 13C NMR (75 MHz,
CDCl3): d 148.8, 135.7, 130.0, 128.8, 123.5, 121.6, 118.3 (q,