Design of fluoroketones as efficient reagents for epoxidation reactions in hexafluoropropan-2-ol

Article abstract of DOI:10.1016/S0040-4020(02)00252-1

Comparative studies on mediated epoxidation reaction using Oxone as primary oxidant and various fluoroketones as reagents, revealed that ketone 3 is very efficient, in particular when used in hexafluoroisopropanol (HFIP) as solvent. It does not suffer from Baeyer-Villiger reaction and can be used in a catalytic amount (1-5mol%) with only 1.5equiv. of Oxone. The reaction gave good yields of epoxides for a number of olefin substrates, included low reactive ones.

Full text of DOI:10.1016/S0040-4020(02)00252-1

TETRAHEDRON
Pergamon
Tetrahedron 58 /2002) 3993±3998
Design of ¯uoroketones as ef®cient reagents for epoxidation
reactions in hexa¯uoropropan-2-ol
p
Julien Legros, Benoit Crousse, Dani eÁ le Bonnet-Delpon and Jean-Pierre B e gu eÂ
p
Laboratoire BioCIS associ e au CNRS, Centre d'Etudes Pharmaceutiques, rue J.B. Cl e ment, F-92296 Chatenay-Malabry, France
This paper is dedicated to Professor Takeshi Nakai on the occasion of his 60th birthday
Received 25 October 2001; revised 20 December 2001; accepted 16 January 2002
w
AbstractÐComparative studies on mediated epoxidation reaction using Oxone as primary oxidant and various ¯uoroketones as reagents,
revealed that ketone 3 is very ef®cient, in particular when used in hexa¯uoroisopropanol /HFIP) as solvent. It does not suffer from Baeyer±
Villiger reaction and can be used in a catalytic amount /1±5 mol%) with only 1.5 equiv. of Oxone . The reaction gave good yields of
epoxides for a number of ole®n substrates, included low reactive ones. q 2002 Published by Elsevier Science Ltd.
w
4
d
1
. Introduction
be used in large excess. Hexa¯uoroacetone was used until
recently only under hard conditions /90% H O at re¯ux of
2
2
5
c,d
Fluoro analogs of acetone have been shown to be precursors
of very ef®cient epoxidation reagents. For instance,
tri¯uoroacetone is precursor of the methyl/tri¯uoromethyl)-
dioxirane which is the most powerful dioxirane known.
This latter is generated from ketone with Oxone and can
be used in situ, or isolated. Hexa¯uoroacetone acts
differently: in presence of concentrated hydrogen peroxide,
it provides 2-hydroperoxyhexa¯uoropropan-2-ol /HPHI)
which is the oxidizing intermediate in epoxidation reaction.
In both cases, the epoxidation reaction occurs through a
catalytic cycle /Scheme 1).
the solvent). Consequently, great efforts have been
focused to improve the use of ¯uoroketones as catalysts in
epoxidation reaction with Oxone or H O , and great
2 2
improvements have been achieved. We report here our
comprehensive investigations on the design of new ¯uori-
nated ketones in order to obtain the following improve-
ments: easy handling, stability towards competitive
oxidation process /Baeyer±Villiger reaction), ef®ciency in
w6
7
1
w2
3
4
5
w
Oxone -mediated epoxidation, recovering andꢀor use in
catalytic conditions.
Despite of their high oxidizing power, these reagents and
methods present some drawback. Both starting ketones are
expensive andꢀor volatile /bp CF COCH : 228C). Tri¯uoro-
2. Results and discussion
Our ®rst approach to improve tri¯uoroacetone and hexa-
¯uoroacetone catalysis in epoxidation reaction, was to
3
3
acetone undergoes a Baeyer±Villiger oxidation and has to
Scheme 1. Cycles of epoxidation reaction with oxidizing reagents derived from tri- and hexa¯uoroacetone.
w
Keywords: epoxidation; ¯uoroketones; Oxone ; hydrogen peroxide; HFIP; ¯uorous chain.
Corresponding authors. Tel.: 133-1-46-83-57-39; fax: 133-1-46-83-57-40; e-mail: benoit.crousse@cep.u-psud.fr; daniele.bonnet-delpon@cep.u-psud.fr
p
0040±4020ꢀ02ꢀ$ - see front matter q 2002 Published by Elsevier Science Ltd.
PII: S0040-4020/02)00252-1

3994
J. Legros et al. / Tetrahedron 58 ꢀ2002) 3993±3998
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Table 1. Epoxidation reaction with Oxone and ketone 1 or 2 in MeCN and in HFIP
w
Oxone /equiv.)
a
b
c
d
Entry
Ole®n
Ketone
Add. time /h)
Solvents
Time /h)
Ole®nꢀepoxide
Yield /%)
1
2
3
4
5
6
Cyclooctene
Dodecene
Cyclooctene
Dodecene
Dodecene
Dodecene
1
1
1
1
2
2
5
5
2.5
2.5
2.5
4
2
2
1
1
2
2
MeCNꢀH
MeCNꢀH
2
O
O
3
4
1
2
1
0
0:100
0:100
0:100
0:100
30:70
0:100
96
89
78
95
±
2
HFIPꢀH
HFIPꢀH
HFIPꢀH
HFIPꢀH
2
O
2
O
2
O
2
O
90
3
Ole®n /0.9 mmol), ¯uoroketone 1 or 2 /0.9 mmol), NaHCO /18 mmol, entry 1, 2; or 9 mmol, entry 3±5; or 14.4 mmol, entry 6) in a 3:1 mixture of HFIP /or
2
4
21
w
24
21
MeCN)ꢀaqueous EDTA /10 mol L ) /4 mL), and Oxone /4.5 mmol, 2.25 or 3.6 mmol) in aqueous EDTA /10 mol L ) /10 mL).
a
Per mol of ole®n.
After slow addition of Oxone .
b
c
d
w
Determinated by GC.
Yield of isolated product.
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ef®cient in the Oxone oxidation system and easier to
replace one tri¯uoromethyl group by a larger per¯uoroalkyl
group /Rf). Thus we envisaged to design and synthesize
highly ¯uorinated analogs of tri¯uoroacetone and
handle than tri¯uoroacetone. However, after completion of
the reaction ketone 1 was present only in traces, and the acid
C F CO H was recovered in the aqueous phase after acidi-
8
hexa¯uoroacetone. Ketone 1 /C F COCH , bp: 1208C)
3
7
15
7
15
2
9
and ketone 2 /CF COC F ), already described in literature,
®cation. This clearly shows that ketone 1 undergoes a
Baeyer±Villiger oxidation in Oxone system. Conversely,
3
8 17
w
were chosen as analogs of tri¯uoroacetone and hexa¯uoro-
acetone respectively. Potency of ketone 1 was evaluated in
the epoxidation reaction of cyclooctene and of the poor
reactive dodecene under the usual conditions of oxidation
the per¯uoroketone 2 is unlikely to undergo the Baeyer±
Villiger reaction due to the electronwithdrawing character
1
4,15
of ¯uorine atoms. However there are no precedent of use
of per¯uoroketones in epoxidation reaction with Oxone .
w
w 16
with Oxone . The reaction was conducted using 1 equiv. of
ketone 1 in MeCNꢀwater at 258C, in the presence of
9
Ketone 2 was prepared according to Chen's procedure and
w
NaHCO3 /20 equiv.); Oxone /5 equiv.), dissolved in
was obtained as the corresponding hydrate. Its ef®ciency
was investigated in the epoxidation of dodecene with
Oxone , under the improved conditions /HFIP) described
water, was added by a syringe pump over 2 h. Despite a
low solubility of 1 in MeCNꢀwater, conversion in epoxides
was complete and products were isolated in high yields
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for ketone 1 /Table 1, entries 5, 6). With 2.5 equiv. of
Oxone , a 70% conversion was obtained; 4 equiv. of
w
/
Table 1, entries 1, 2). Conditions of reaction could be
w
Oxone were required for a complete conversion into
improved by using hexa¯uoroisopropanol /HFIP) as solvent
instead of acetonitrile. Indeed ¯uorinated alcohols have
been shown to be very ef®cient and selective solvents in
oxirane. This clearly shows that the system per¯uoro-
ketoneꢀOxone can be used in epoxidation reaction, when
w
1
0
various oxidation reactions /oxidation of sul®des and of
and Baeyer±Villiger reac-
performed in HFIP, but is less ef®cient than the semi-
per¯uoroketoneꢀOxone . At this stage of this study, it can
1
thiols, epoxidation,
1
6a,7b,c,12
w
1
3
tion ). Moreover, in these solvents, both ¯uorinated
compounds and water are miscible.
be concluded that /i) oxidizing ef®ciency is retained by the
replacement of the CF group of the tri¯uoroacetone by a
3
longer Rf chain, although different reaction conditions do
not allow an accurate comparison; however the competitive
Baeyer±Villiger process could not be avoided, /ii) presence
of Rf chains on both sides of ketone seems to deactivate the
ketone as catalyst.
Under these new conditions, reaction was faster and only
2
required for a complete conversion of cyclooctene and
dodecene into corresponding epoxides /Table 1, entries 3,
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.5 equiv. of Oxone and 10 equiv. of NaHCO3 were
4
). This is another example of the improvement of the
oxidation processes in ¯uorinated alcohols. Besides an
enhanced solubility of the ketone in HFIP, an activation
of the O±O bond cleavage by strong hydrogen bonding
with HFIP, can also be evoked. Such an explanation has
previously been advanced for activation of hydrogen
We thus turned to a compromise to design more ef®cient
ketones. A ketone bearing an Rf group on one side, and, on
1
the other side, a per¯uorochain Rf /C F ) separated from
2
6 13
the carbonyl by a two-methylene spacer, was considered as
a good candidate. The ®rst Rf group should maintain the
1
1
0a,b
peroxide.
high oxidative potency; the presence of the two-methylene
spacer should minimize the deactivation due to the second
Rf2 chain; the electronwithdrawing effect of the Rf2
These ®rst experiments demonstrated that ketone 1 is very

J. Legros et al. / Tetrahedron 58 ꢀ2002) 3993±3998
3995
substituent was anticipated to disfavor the Baeyer±Villiger
/Scheme 2). Three ketones /3±5) were thus
1
4,15
process
prepared /Rf ˆCF , C F and C F ).
1
3
3
7
7 15
Ketones 3±5 were readily obtained following Guerrero's
procedure, from the commercial iodide 6 and the ethyl
1
7
Scheme 2. Design of ketones 3±5 and expected effects of the structure.
Table 2. Synthesis of ¯uoroketones 3±5
per¯uoroalkylcarboxylates /Table 2). The potency of
ketones 3±5, used stoichiometrically, was evaluated in the
w
epoxidation reaction of dodecene with Oxone , NaHCO , in
HFIPꢀwater at 258C /Table 3).
3
w
With 2.5 equiv. of Oxone , after 1 h of reaction, conversion
rate of dodecene to the corresponding epoxide was 100, 55
and 0% with ketones 3, 4 and 5, respectively, and these
ketones were found unchanged /.98% by GC analysis)
a
Entry
Rf
1
Fluoroketone
Yield /%)
when the reaction was stopped. Oxidative potency of ¯uoro-
ketones in the Oxone system clearly decreases with the Rf
w
1
1
2
3
CF
3
3
4
5
89
69
68
chain length. Such an in¯uence of the Rf length has already
7
C
C
3
F
F
7
b
7
15
been noticed in the oxidizing ¯uoroketoneꢀH O system.
2 2
a
Yield of isolated product.
Further investigations were then conducted with the most
ef®cient ketone 3. Considering its stability in the reaction
medium, ketone 3 could a priori be used in stoichiometric
amount and recovered, or be used in a catalytic amount. All
our attempts to recover the ketone 3 by technics of ¯uorous
Table 3. Epoxidation reaction of dodecene in HFIPꢀH
±5
2
O with ¯uoroketones
3
18
phase separation, by use of liquid±liquid extraction or by
1
9
separation over ¯uorous reverse phase silica gel, were not
very fruitful: less than 50% of ketone could be recovered.
Oxidation reactions were then investigated using ketone 3
catalytically. Reactions were performed in HFIP with
various ole®ns /Table 4).
Ketone
Time
Ole®nꢀ
epoxide
Recovered
ketone
Yield
/%)
a
b
c
d
/h)
/
%)
Cyclic, acyclic, trans-, cis-, disubstituted, trisubstituted and
even terminal ole®ns were all converted into epoxides in
good yields. First, with the use of HFIP as solvent,
3
4
5
1
1
1
0:100
45:55
100:0
.98
.98
.98
95
n.c.
0
2
0
w
required amounts of Oxone could be decreased to
.5 equiv., instead of 5 equiv. And with the more reactive
1
Dodecene /1.8 mmol), ¯uoroketone /1.8 mmol), NaHCO
3
3
/18 mmol) in a
:1 mixture of HFIPꢀaqueous EDTA /10 mol L ) /16 mL), and Oxone
24
21
w
substrates /entries 1±3), the epoxidation was complete by
using only 1 mol% of ketone 3. With the poor reactive
ole®ns /entries 4±6) 5 mol% catalyst were required for a
complete reaction. As expected, in the case of limonene, the
epoxidation occurred selectively on the trisubstituted double
bond /entry 2), and a 1:1 mixture of stereoisomers was
obtained. In all cases, epoxides were isolated in high yields.
24
21
4.5 mmol) in aqueous EDTA /10 mol L ) /10 mL).
/
a
w
After addition of Oxone .
Measured by GC. No byproduct observed.
Measured by GC in the crude mixture.
Yield of isolated product.
b
c
d
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Table 4. Catalytic epoxidation reaction with Oxone and ketone 3 in HFIPꢀH
2
O
a
b
Entry
Ole®n
Cyclooctene
/S)-Limonene
Cyclohex-3-ene-1-methanol
trans-Stilbene
Dodec-1-ene
Ketone 3 /mol%)
Add. time /h)
Time /h)
Epoxide
Yield /%)
1
2
3
4
5
6
1
1
1
5
5
5
2
4
4
4
4
4
0.3
0.5
0.5
0.5
0.5
0.5
6
7a, b
8a, b
9
81
71
68
93
92
96
c
d
10
11
trans-Dec-4-ene
2
4
21
.8 mmol of ole®n in 4 mL /entry 1±3) or in 16 mL of HFIPꢀaqueous EDTA /10 mol L ).
1
a
w
After addition of Oxone .
Except where indicated, reaction afforded 100% conversion. Yield of isolated product.
b
c
d
1
1
0% of starting material recovered, 1:1, mixture of diastereoisomers.
.5:1 mixture of diastereoisomers, observed by GC, /not determined).

3
996
J. Legros et al. / Tetrahedron 58 ꢀ2002) 3993±3998
2
O ꢀMeCN oxidant system
Table 5. Epoxidation reaction with ketone 3 in H
2
a
Ole®n
Ketone 3 /mol%)
Solvent
MeCN
MeCNꢀHFIP
MeCNꢀHFIP
Time /h)
Ole®nꢀepoxide
Cyclooctene
Cyclooctene
Dodecene
10
1
10
6.5
16
24
50:50
0:100
80:20
21
Reactions were carried out with ole®n /1.8 mmol), ketone 3 /0.02±0.18 mmol), H
2
O
2
2 3
aq. 30% /7.2 mmol) and aqueous K CO solution /1.5 mol. L in
24
21
mol. L EDTA) in MeCN /2 mL, entry 1), or MeCNꢀHFIP /2 mL, entry 2±3) at 08C for 1 h, then rt.
Measured by GC.
10
a
For comparison, ketone 3 was also evaluated as promotor in
another oxidation system. Recently, a very ef®cient system
for epoxidation of ole®ns has been described with tri¯uoro-
acetone /10±30 mol%), with H O 30% /4 equiv.), in
capillary column /lˆ30 m). HFIP was used as provided,
without any puri®cation procedure.
2
2
7
a
MeCN as solvent, at pH 11. The ®rst step of the process
is supposed to be the formation of peroxyimidic acid result-
ing from the reaction between MeCN and H O , which
4.1. Preparation of ¯uoroketones 3±5
4.1.1. Per¯uorodecan-2-one 2 ꢀisolated as its hydrate
form). Colorless crystals: mp 388C; IR /neat) n
2
2
9
further generates the dioxirane by reacting with tri¯uoro-
acetone. This process was carried out with ketone 3 in
epoxidation reaction of cyclooctene and dodecene /Table
2
1 19
3198 cm ; F NMR d 2126.5 /m, 2F), 2123.0 /m, 2F),
2122.0 /m, 8F), 2120.8 /m, 2F), 281.6 /m, 3F,
CF /CF ) ), 281.2 /tt, J ˆ10, 1.9 Hz, 3F, CF );
1
5
). For cyclooctene, with 10% ketone, the conversion rate
H
NMR d 3.0 /s, OH); C NMR //CD ) CO) d 120.4 /q,
3
2 7
F±F
3
1
3
was only 50% in MeCN even after 24 h. By using HFIP as
co-solvent, the conversion could be increased to 100% with
only 1% of 3. Nevertheless, with a poor reactive substrate
3
2
1
JC±Fˆ290 Hz, CF C/OH) ), 122±100 /m, C F ), 91.9 /m,
3
2
8 17
C/OH) ).
2
/dodecene), only 20% conversion of ole®n into the corre-
sponding oxide was obtained, even with 10% catalyst. Thus,
4.1.2. Preparation of 3H,3H,4H,4H-per¯uorodecan-2-
one 3: typical procedure. t-BuLi /13.6 mL, 23.2 mmol,
1.7 M in hexane) was added at 2788C under argon to a
well-stirred solution of C F /CH ) I /10 g, 21.1 mmol) in
w
ketone 3 is much more ef®cient using Oxone as primary
oxidant.
6
13
2 2
a 3:2 mixture of hexaneꢀEt O /100 mL). After 5 min,
2
3. Conclusion
CF CO Et /4.5 g, 31.6 mmol) was added. The solution
3 2
was stirred for 30 min and was then allowed to warm to
08C. After 1 h, the solution was quenched with saturated
ammonium chloride solution, the layers were separated
The design of new models of ¯uoroketones as promotors for
epoxidation reactions allowed us to ®nd out the very power-
ful oxidizing ketone 3 in presence of Oxone . This ketone is
w
and the aqueous phase was extracted with Et
/3£50 mL). The combined organic phases were dried to
afford, after chromatography on silica gel /pentaneꢀEt O,
80:20), pure ketone 3 as a colorless liquid /8.32 g, 89%):
O
2
more reactive than per¯uoroketone 2, and more stable than
semi¯uoroketone 1 which suffers from Baeyer±Villiger
oxidation. Furthermore, when reaction was performed in
hexa¯uoroisopropanol as solvent, the ef®ciency of ketones
was highly improved. The new ¯uorinated ketone 3 is easily
prepared, ef®cient in catalytic amount /1±5 mol%) for
2
2
1 19
bp 95±968C; IR /neat) n 1772 cm ; F NMR d 2126.3
/m, 2F), 2123.6 /m, 2F), 2123.0 /m, 2F), 2122.0 /m, 2F),
2114.5 /m, 2F), 281.0 /t, JF±Fˆ10 Hz, 3F, CF
/Rf ), 279.3
2
); H NMR d 3.1 /t, Jˆ7.5 Hz, 2H), 2.6 /m, 2H);
3
w
1
Oxone mediated epoxidation of various ole®ns, even the
/s, 3F, CF
3
1
1
3
3
2
less reactive ones. This the smallest amount of ¯uoroketone
required for any reported system at the date of today. No
restricting conditions /temperature, control of pH) are
C NMR d 188.7 /q, JC±Fˆ37 Hz, CF
3
CO), 115.0 /q,
CO), 124.0±98.0 /m, Rf ), 27.9 /t,
), 24.4 /t, JC±Fˆ24 Hz, CH Rf ).
J
J
C±Fˆ291 Hz, CF
3
2
2
C±Fˆ3.5 Hz, CH CH
Rf
2
2
2
2
2
w
required and only 1.5 equiv. of Oxone are suf®cient for a
high yield of oxiranes.
4.1.3. 5H,5H,6H,6H-Per¯uorododecan-4-one 4. Starting
from C F CO Et /7 g, 28.9 mmol) and C F /CH ) I
3
7
2
6
13
2 2
/
5.5 g, 11.6 mmol), afforded pure ketone 4 as a colorless
2
1 19
4. Experimental
liquid /4.35 g, 69%): IR /neat) n 1766 cm ; F NMR d
126.9 /s, 2F, CF /Rf )), 2126.4 /m, 2F), 2123.8 /m, 2F),
2
2
1
1
9
1 13
F, H and C NMR were recorded on a Bruker AC-
2123.2 /m, 2F), 2122.2 /m, 2F), 2121.4 /q, JF±Fˆ8.7 Hz,
2F, CF CF /Rf
2.5 Hz, 3F, CF
200 MHz multinuclear spectrometer. Chemical shifts /d)
are given in ppm relative to CFCl for F NMR, and relative
2
3
1
)), 2114.6 /m, 2F), 281.2 /tt, JF±Fˆ9.3,
/Rf /Rf ));
3 2 3 1
1
9
)), 280.9 /t, JF±Fˆ9.0 Hz, CF
3
1
to TMS for H and C NMR. Except where indicated,
13
1
13
H NMR d 3.1 /t, Jˆ7.5 Hz, 2H), 2.5 /m, 2H); C NMR
2
CDCl was used as a solvent. IR spectra were recorded on
3
a Bruker Vector 22 spectrometer. GC analysis were
performed on HP 4890 apparatus equipped with a SE 30
d 191.6 /t, JC±Fˆ27.0 Hz, Rf
1
CO), 124±100 /m, Rf
Rf
1
, Rf
2
),
3
2
29.7 /t, JC±Fˆ3.5 Hz, CH
CH
), 24.7 /t, JC±Fˆ24 Hz,
2
2
2
CH Rf ).
2 2

J. Legros et al. / Tetrahedron 58 ꢀ2002) 3993±3998
3997
4.1.4. 9H,9H,10H,10H-Per¯uorohexadecan-8-one 5.
Starting from C F CO Et /8.3 g, 18.8 mmol) and
References
7
15
2
C F /CH ) I /3.56 g, 7.5 mmol), afforded, after crystalliza-
6
tion /Et Oꢀpetroleum ether), pure ketone 5 as a white solid
2
1. For reviews of dioxirane chemistry: /a) Adam, W.; Curci, R.;
Edwards, J. O. Acc. Chem. Res. 1989, 22, 205±211.
/b) Murray, R. W. Chem. Rev. 1989, 89, 1187±1201.
/c) Curci, R. Advances in Oxygenated Processes; Baumstark,
A. L., Ed.; JAI: Greenwich, 1990; Vol. 2, pp. 1±59 Chapter 1.
/d) Adam, W.; Hadjiarapoglou, L. P.; Curci, R.; Mello, R. In
Organic Peroxides, Ando, W., Ed.; Wiley: New York, 1992;
pp. 195±219 Chapter 4. /e) Adam, W.; Hadjiarapoglou, L. P.
Topics in Current Chemistry, Vol. 1645; Springer: Berlin,
13
2 2
2
1 19
/
2
/
2
3.8 g, 68%): mp 548C; IR /neat) n 1758 cm ; F NMR d
126.5 /m, 4F), 2124.0 /m, 2F), 2123.2 /m, 4F), 2122.4
m, 6F), 2121.8 /m, 2F), 2120.5 /m, 2F), 2114.8 /m, 2F),
1
81.2 /m, 6F, 2£CF ); H NMR d 3.2 /t, Jˆ7.5 Hz, 2H),
3
1
3
2
.5 /m, 2H); C NMR /CDCl , 578C) d 2191.0 /t,
3
2
JC±Fˆ27.0 Hz, Rf CO), 124±100 /Rf1, Rf2), 29.6
1
2
/
CH CH Rf ), 24.7 /t, J ˆ24 Hz, CH Rf ).
2
2
2
C±F
2
2
1
993 pp 45±62. /f) Curci, R.; Dinoi, A.; Rubino, M. F. Pure
Appl. Chem. 1995, 67, 811±822. /g) Denmark, S. E.; Wu, Z.
Synlett 1999, 847±859. /h) Denmark, S. E.; Wu, Z.; Grudden,
C. M.; Matsuhashi, H. J. Org. Chem. 1997, 62, 8288±8289.
4.2. Catalytic epoxidation of ole®n with ketone 3 and
Oxone in HFIP
w
/
i) Brown, D. S.; Marples, B. A.; Smith, P.; Walton, L.
Tetrahedron 1995, 51, 3587±3606.
4
.2.1. Epoxidation of trans-dec-4-ene: typical procedure.
w
2. Oxone is the trademark of 2KHSO ´KHSO ´K SO .
To a solution of trans-dec-4-ene /252 mg, 1.8 mmol) in
HFIP /2 mL), at 258C, ¯uoroketone 3 /40 mg, 0.09 mmol),
dissolved in HFIP /1 mL), was added. Then, NaHCO
5
4
2
4
3. /a) Yang, D.; Wong, M. K.; Yip, Y. C. J. Org. Chem. 1995, 60,
3887±3889. /b) Edwards, J. O.; Pater, R. H.; Curci, R.; Di
Furia, F. Photochem. Photobiol. 1979, 30, 63±70. /c) Gallopo,
A. R.; Edwards, J. O. J. Org. Chem. 1981, 46, 1684±1688.
/d) Cicala, G.; Curci, R.; Fiorentino, M.; Laricchiuta, O.
J. Org. Chem. 1982, 47, 2670±2673.
3
21
2
4
/
907 mg, 10.8 mmol) and aqueous EDTA /10 mol L )
/
A solution of Oxone /1.66 g, 2.7 mmol) in aqueous EDTA
1 mL) were added, and the mixture was vigorously stirred.
w
2
10 mol L ) /10 mL), was added, over 4 h via a syringe
4
21
/
pump, to the precedent solution. After the addition, the
reaction mixture was maintained under stirring for 0.5 h
4. /a) Adam, W.; Asensio, G.; Curci, R.; Gonz a lez-Nu nÄ ez, M. E.;
Mello, R. J. Am. Chem. Soc. 1992, 114, 8345±8349.
/b) Adam, W.; Curci, R.; Gonz a lez-Nu nÄ ez, M. E.; Mello, R.
J. Am. Chem. Soc. 1991, 113, 7654±7658. /c) Mello, R.;
Fiorentino, M.; Fusco, C.; Curci, R. J. Am. Chem. Soc.
1989, 111, 6749±6757. /d) Denmark, S. E.; Forbes, D. C.;
Hays, D. S.; DePue, J. S.; Wilde, R. G. J. Org. Chem. 1995,
60, 1391±1407.
/
reaction was monitored by GC), then poured into 70 mL
of water and extracted with Et O /3£30 mL). The combined
2
organic phases were washed with brine /40 mL), dried over
MgSO and solvents were evaporated, to afford, after chro-
4
matography on silica gel /petroleum etherꢀEt O, 70:30),
2
2
pure trans-4,5-epoxydecane 11 as a colorless liquid
1
1
270 mg, 96%). H NMR d 2.7±2.6 /m, 2H), 1.6±1.4 /m,
/
5. /a) Adam, W.; Degen, H. G.; Chantu, R. S. M. J. Org. Chem.
1999, 64, 1274±1277. /b) Iwahama, T.; Sakaguchi, S.; Ishii,
Y. Heterocycles 2000, 52, 693±705. /c) Biloski, A. J.; Heggs,
R. P.; Ganem, B. Synthesis 1980, 810±811. /d) Heggs, R. P.;
Ganem, B. J. Am. Chem. Soc. 1979, 101, 2484±2486. /e) For a
review of perhydrate chemistry, see: Ganeshpure, P. A.;
Adam, W. Synthesis 1996, 179±188.
8
H), 1.4±1.2 /m, 4H), 1.0±0.8 /m, 6H).
22 1
.2.2. 1,2-Epoxycyclooctane ꢀ6). H NMR d 3.0±2.8 /m,
4
2
H), 2.2±2.0 /m, 2H), 1.7±1.1 /m, 10H).
2
3 1
4
1
.2.3. 1,2-Epoxymenth-8-ene ꢀ7a/7b). H NMR d 4.7 /m,
H), 4.6 /br, s, 1H), 3.0±2.9 /br t, Jˆ3.0 Hz, 1Hꢀd,
6. /a) Legros, J.; Crousse, B.; Bourdon, J.; Bonnet-Delpon, D.;
B e gu e , J. P. Tetrahedron Lett. 2001, 42, 4463±4466. /b) Song,
C. E.; Lim, J. S.; Kim, S. C.; Lee, K. J.; Chi, D. Y. Chem.
Commun. 2000, 2415±2416.
Jˆ5.4 Hz), 2.1±1.4 /m, 7H), 1.7±1.65 /s, 3H), 1.32±1.31
/
s, 3H).
2
4
1
4
.2.4. 3,4-Epoxycyclohexan-1-methanol ꢀ8a/8b).
NMR d 3.5±3.3 /m, 2H), 3.2±3.1 /m, 2H), 2.3±0.9
m, 8H).
H
7. /a) Shu, L.; Shi, Y. J. Org. Chem. 2000, 65, 8807±8810.
/b) Van Vliet, M. C. A.; Arends, I. W. C. E.; Sheldon, R. A.
Chem. Commun. 1999, 263±264. /c) Van Vliet, M. C. A.;
Arends, I. W. C. E.; Sheldon, R. A. Synlett 2001, 1305±1307.
8. Kondo, A.; Iwatsuki, S. J. Fluorine Chem. 1984, 26, 59±67.
9. Chen, L. S.; Chen, G. J. J. Fluorine Chem. 1989, 42, 371±387.
0. /a) Ravikumar, K. S.; B e gu e , J. P.; Bonnet-Delpon, D.
Tetrahedron Lett. 1998, 39, 3141±3144. /b) Ravikumar,
K. S.; Zhang, Y. M.; B e gu e , J. P.; Bonnet-Delpon, D. Eur.
J. Org. Chem. 1998, 2937±2940. /c) Ravikumar, K. S.;
Barbier, F.; B e gu e , J. P.; Bonnet-Delpon, D. J. Fluorine
Chem. 1999, 95, 123±125.
/
2
5 1
4
3
.2.5. trans-Stilbene oxide ꢀ9). H NMR d 7.4 /s, 10H),
.9 /s, 2H).
1
2
2 1
4
1
1
.2.6. 1,2-Epoxydodecane ꢀ10). H NMR d 2.9 /br m,
H), 2.8 /dd, Jˆ5.1, 4.0 Hz, 1H), 2.5 /dd, Jˆ2.7, 5 Hz,
H), 1.6±1.2 /m, 18H), 0.9 /t, Jˆ6.0 Hz, 3H).
1
1. Kesavan, V.; Bonnet-Delpon, D.; B e gu e , J. P. Synthesis 2000,
223±225.
Acknowledgements
1
2. /a) For the ®rst examples of HFIP used as co-solvent in
catalyzed hydrogen peroxide epoxidation, see: Shryne, T. M.
US 4024165 /1977) /Shell), Romanelli, M. G. EP 0096130
/1983) /Exxon). /b) Ravikumar, K. S.; Barbier, F.; B e gu e ,
J. P.; Bonnet-Delpon, D. Tetrahedron 1998, 54, 7457±7464.
/c) Neimann, K.; Neumann, R. Org. Lett. 2000, 2, 2861±2863.
We thank Central Glass Co., Ltd for kindly providing HFIP.
We also thank the European Contract of Research Training
Network /`Fluorous Phase' HPRN CT 2000-00002) and the
European Union /COST-Action `Fluorous Medium'
D12ꢀ98ꢀ0012).

3998
J. Legros et al. / Tetrahedron 58 ꢀ2002) 3993±3998
/
d) Van Vliet, M. C. A.; Arends, I. W. C. E.; Sheldon, R. A.
Synlett 2001, 248±250.
3. Berkessel, A.; Andreae, M. R. M. Tetrahedron Lett. 2001, 42,
293±2295.
20. Same reaction performed in tri¯uoroethanol gave similar
results, but in a longer reaction time. In MeOH, no reaction
occurred. It has to be noted that when supplied in bulk the
price of HFIP can be reasonable.
1
1
2
4. For reviews of the Baeyer±Villiger oxidation, see: /a) Krow,
G. R. Org. React. 1993, 43, 251±379. /b) Renz, M.; Meunier,
B. Eur. J. Org. Chem. 1999, 737±750.
21. Venturello, C.; D'Aloisio, R. J. Org. Chem. 1988, 53, 1553±
1557.
22. Rocha Gonsalves, A. M. d'A.; Pereira, M. M.; Serra, A. C.;
Johnstone, R. A. W.; Nunes, M. L. P. G. J. Chem. Soc., Perkin
Trans. 1 1994, 2053±2057.
1
1
1
1
5. Kitazume, T.; Kataoka, J. J. Fluorine Chem. 1996, 80, 157±
158.
w
6. Epoxidation reaction with hexa¯uoroacetoneꢀOxone has
been reported to be unsuccessful: Ref. 4d.
7. Villuendas, I.; Parilla, A.; Guerrero, A. Tetrahedron 1994, 50,
23. Carman, R. M.; Klika, K. D. Aust. J. Chem. 1991, 44, 1803±
1808.
24. Chini, M.; Crotti, P.; Flippin, L. A.; Macchia, F.; Pineschi, M.
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12673±12684.
8. /a) Horv a th, I. T.; R a bai, J. Science 1994, 266, 72. /b) For a
review on extraction with ¯uorinated solvents, see: Curran,
D. P. Angew. Chem., Int. Ed. Engl. 1998, 37, 1175±1196.
9. For a review on ¯uorous reverse phase silica gel, see: Curran,
D. P. Synlett 2001, 1488±1496.
25. Battioni, P.; Renaud, J. P.; Bartoli, J. F.; Reina-Artiles, M.;
Fort, M.; Mansuy, D. J. Am. Chem. Soc. 1988, 110, 8462±
8470.
1