A general and efficient method to convert selenides into selenones by using HOF·CH3CN

Article abstract of DOI:10.1002/ejoc.201300694

A general route for the preparation of selenones (R₂SeO ₂) is presented. This task is achieved through the quick and high-yielding reaction of selenides (R₂Se) with HOF·CH ₃CN. The reaction tolerates some elusiv

Full text of DOI:10.1002/ejoc.201300694

SHORT COMMUNICATION
DOI: 10.1002/ejoc.201300694
A General and Efficient Method To Convert Selenides into Selenones by Using
HOF·CH3CN
Shay Potash[a] and Shlomo Rozen*[a]
Keywords: Fluorine / Selenium / Selenones / Oxygenation / Hypofluorous acid
A general route for the preparation of selenones (R2SeO2) is
presented. This task is achieved through the quick and high-
yielding reaction of selenides (R2Se) with HOF·CH3CN. The
reaction tolerates some elusive electron-deficient and steri-
cally hindered selenides. Some mechanistic aspects are also
investigated and discussed.
second sluggish oxidation step to selenone, probably be-
cause of the dominant preference of selenium for the SeIV
oxidation state.[1b] Also, the decreased electron density on
the selenium atom of selenoxides renders it less susceptible
to further electrophilic oxygenation.[1b,10,11] This trend is
quite different from homologous organosulfur chemistry.[3a]
For rare cases in which selenones have been available, they
were found to be useful intermediates in biologically impor-
tant processes[12] and especially in some challenging substi-
tution reactions, in which the selenones were usually not
isolated.[13] This was attributed to the selenonyl anionic
Introduction
Over the past four decades, organoselenium chemistry
has been proven highly valuable in the field of organic syn-
thesis. The versatility of reactants and reagents based on
this third chalcogen has led to a rapid development in this
area, and organoselenium compounds have been broadly
adopted in many useful reactions.[1,2] Today, many of these
transformations revolve around the oxidation of selenides 1
(Scheme 1) to the corresponding monoxides, that is, selen-
oxides 3, which can be used as intermediates in facile elimi-
nations,[3] which were shown by Sharpless to proceed with
syn stereospecificity.[4] Selenoxides have been also used in
Pummerer-type[5] and [2,3] sigmatropic rearrangements[6]
for the preparation of chiral alcohols,[7] in catalytic green
chemistry,[8] and more.
–
group (RSeO2 ), which is an excellent leaving group in SN-
type displacements.[1b,1c,2c,14] It has been suggested that the
selenonyl moiety can be replaced with almost any kind of
nucleophile.[1c] The persisting problem, however, was the
synthetic barrier that hampered their preparation, which
thus prevented further development of their chemistry. We
present in this work the first general method to form selen-
ones that is very efficient and yet mild enough to keep this
sensitive moiety intact. The method is based on the reaction
of selenides with the acetonitrile complex of hypofluorous
acid, HOF·CH3CN.
Scheme 1. Organoselenium derivatives.
HOF·CH3CN is easily prepared by passing dilute fluor-
ine through aqueous acetonitrile.[15] Its forceful oxygen-
transfer ability is derived from its highly electrophilic oxy-
gen atom. Over the years, it has been successfully employed
for the oxygenation of many sulfur-containing compounds,
such as episulfides and very electron-deficient sulfides, thio-
phenes,[16] and oligothiophenes.[17] Oxygen-transfer reac-
tions using the HOF·CH3CN complex are by no means lim-
ited to organosulfur derivatives, as other difficult oxygen-
ations on a nitrogen atom of various families of compounds
have also been performed.[18,19] In addition “impossible”
epoxidations have been carried out,[20] tertiary hydroxyl-
ations have been achieved,[21] and many other diverse trans-
formations that could not be otherwise completed were ac-
complished.[22] We found that this outstanding oxygen-
transfer reagent can also play an important role in the syn-
Contrary to the developed selenoxide chemistry, hexava-
lent selenones 2 have received much less attention, as there
is no general method for their preparation.[9] It has been
established that only the most vigorous conditions and
strong oxidizing agents can lead to selenones.[1b] It seems
that the thermal instability of the fast-formed selenoxide
intermediates and the sensitivity of many selenones to chro-
matographic procedures have impeded many selenone prep-
arations. These works established the notion that the first
oxidation of selenide to selenoxide is fast, opposed to the
[a] School of Chemistry, Tel-Aviv University,
Tel-Aviv 69978, Israel
E-mail: rozens@post.tau.ac.il
Homepage: http://www.tau.ac.il/chemistry/rozen/
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201300694.
5574
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 5574–5579

A General and Efficient Method To Convert Selenides into Selenones
thesis of selenones. Notably, a theoretical study predicted Table 1. Oxidation of selenides.
that contrary to other reagents, which form considerable
amounts of side reactions, HOF·CH3CN should smoothly
convert selenides into selenones.[23]
Results and Discussion
It was reported that diphenyl selenide (1a) reacts with a
10-fold excess amount of hypochlorite to produce diphenyl
selenone (2a) in 79% yield.[24] This result, however, could
not be replicated by others.[25] We treated 1a at 0 °C for
3 min with HOF·CH3CN (2.4 equiv., slight excess, as each
equivalent is a source of one oxygen atom) to form Ph2SeO2
(2a) in quantitative yield. Dialkyl selenones are somewhat
different, as the fully oxidized products, as well as the inter-
mediate selenoxides, are sensitive to thermal eliminations
and nucleophilic substitutions. The preparation of dibutyl
selenone (2b), for example, has been previously achieved in
two steps through the ozonolysis of dibutyl selenoxide (3b),
which in its turn was prepared by separate oxidation of
1b.[26] The mild conditions by which the HOF·CH3CN oxi-
dation proceeds eliminates any side reaction, and when 1b
served as the reactant, 2b was formed quantitatively after
5 min. Despite the fact that electron-rich aromatics are
known to be oxidized by HOF·CH3CN,[22b] the selenium
atom reacts much faster and both mildly activated bis(4-
methylphenyl) selenide (1c)[27] and electron-rich bis(4-meth-
oxyphenyl) selenide (1d)[28] were treated with a slight excess
amount of HOF·CH3CN to form the desired selenones
without any ring over-oxidations (Table 1).
Alkyl aryl selenides were also treated with HOF·CH3CN.
These substrates appear to be a different case from the oxi- 10-fold excess amount of H2O2 for 2 h, monoxide 3g was
dation standpoint, as the intermediates – alkyl aryl sele- formed exclusively.[30] Hypofluorous acid, which is a small
noxides of type 3e–f – are known to rapidly decompose molecule, has an advantage in the oxidation of such com-
through a syn elimination mechanism.[29] The reaction of pounds, and its reaction with 1g was complete within
butyl phenyl selenide (1e) with HOF·CH3CN, however, re- 10 min at 0 °C to afford selenone 2g in 85% yield. Even
sulted in clean oxidation to form selenone 2e in almost when the HOF·CH3CN complex was added to dineopentyl
quantitative yield after 3 min. The oxidation process of selenide (1h), with its two bulky alkyl substituents, the result
phenethyl phenyl selenide (1f) is even more sensitive to high again was that selenone 2h was formed in 91% yield
temperatures and long reaction times, as intermediate sele- (Table 1).
noxide 3f was found to be very unstable with a half-life of
The oxygenation of 1i bearing two electron-withdrawing
only 9 min at 38 °C.[29] This fact has prevented the prior nitrophenyl groups was previously attempted. In all cases,
preparation of 2f, but under treatment of 1f with a slight only the selenoxide 3i was formed, with no evidence of the
excess of HOF·CH3CN, selenone 2f was obtained in 90% corresponding selenone.[31] Here, the strong electrophilic
yield after 3 min. This molecule seems to be more stable properties of hypofluorous acid were able to overcome the
than the selenoxide, and no signs of any decomposition reduced susceptibility of the selenium atom in intermediate
were observed after the reaction (Table 1).
3i toward further electrophilic oxygenation, and so, sele-
In the past, sterically hindered and electron-depleted none 2i was obtained in 87% yield, although in this case,
selenides were too great of a challenge for contemporary the reaction was somewhat slower and required 15 min to
oxidants, so they were never oxidized to the corresponding complete (Table 1).
dioxides. This resulted from the fact that oxidation of selen-
Other electron-deficient selenides include polyfluorinated
oxides was known to be sensitive to steric hindrance[1b] and and perfluorinated selenides of type 1j–l. The oxygenation
to electron-withdrawing substituents, which reduce the elec- of this class of materials has attracted some attention, and
tron density around the selenium atom to the point at which attempts to oxygenate them were undertaken by using vari-
it is no longer susceptible to orthodox electrophilic oxygen- ous oxidizing agents, including neat and uncomplexed
ations. Thus, for example, when sterically congested di- HOF. Most of these reactions failed, and the reactions with
mesityl selenide (1g) was allowed to react with more than a HOF ended in explosions, from which selenoxides could, in
Eur. J. Org. Chem. 2013, 5574–5579
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5575

S. Potash, S. Rozen
SHORT COMMUNICATION
some cases, be isolated.[32] Unlike the explosive nature of led to a mixture of the sulfone and the starting material.[16a]
pure uncomplexed HOF and its troublesome preparation On the basis of sulfur chemistry precedence, selenides
and handling, the acetonitrile complex of HOF is much eas- should have been oxidized rapidly to selenones without
ier to prepare, and it should not be isolated prior to its use, forming considerable amounts of selenoxides. Selenium
thus enabling mild and tunable reactions without the risk chemistry, however, is quite different, and the selenoxide-
of explosions. The first attempt at the transformation of a to-selenone oxidation proceeds with more difficulties than
perfluorinated selenide into a selenone was performed with the parallel reactions leading to sulfones. Thus, when
pentafluorophenyl phenyl selenide (1j). First, an excess weakly nucleophilic bis(4-nitrophenyl) selenide (1i) was
amount of meta-chloroperoxybenzoic acid (mCPBA) was treated with approximately 1 equiv. of HOF·CH3CN
used with a prolonged reaction time, but only the selenoxide (enough to transfer only one oxygen atom), selenoxide 3i
3j was formed. A parallel reaction with dimethyldioxirane was formed almost exclusively, which points to a distinctive
(DMDO) resulted in unidentified products. When, however, two-step reaction.
treated with HOF·CH3CN, 1j was transformed into the se-
Aside from electronic factors, spatial factors may also be
lenone 3j in excellent yield. Much like the case of the oxy- responsible for the deceleration of the second oxidation
genation of 1i, it took 15 min for the reaction to complete. step, as the nonbonding electron pairs of the large selenium
We turned our attention also to electron-deficient 1k and atom are fairly far from each other, and unlike the case of
found that it could be transformed into selenone 2k in very the sulfides, may allow the detachment of a second HOF
good yield. Lastly, 1l with its strongly electron-withdrawing molecule from the reagent’s cluster near the reaction center
perfluoroalkyl chain directly bonded to the selenium atom resulting in partially oxidized selenoxide. However, when
was treated with HOF·CH3CN to afford 2l in excellent yield molecules possessing a selenium atom with stronger nucleo-
as well (Table 1). All of the reported fluorine-containing se- philic character, as in the case of electron-rich bis(4-tolyl)
lenones were previously unknown. However, when bis(per- selenide (1c) and bis(4-methoxyphenyl) selenide (1d), were
fluorophenyl) selenide (1m, Scheme 2) was treated with treated with approximately 1 equiv. of HOF·CH3CN, mix-
HOF·CH3CN, the oxidation process stopped at the mon- tures of about 50% selenones 2c and 2d along with 50% of
oxide stage, as both the perfluoro substituents and the pola- the starting materials were obtained. No signs of sele-
rized Se–O bond reduced the electron density of the selen- noxides 3c and 3d were observed, as indicated by analysis
1
ium atom to the point that it could no longer act as a nu- of the crude reaction mixtures by H NMR spectroscopy,
cleophile. Thus, in this extreme case selenoxide 3m was ex- which points out that fast consecutive oxidation of the sele-
clusively obtained in quantitative yield (Scheme 2).
noxide to the selenone occurs, without the chance for the
HOF cluster to detach from the reaction center, and this
leaves only the doubly oxidized selenone along with unre-
acted selenide. When a less-reactive selenide, such as di-
phenyl selenide (1a), was treated with 1 equiv. of
HOF·CH3CN, selenone 2a was the major product, ac-
companied by the starting selenide, although this time small
amounts of selenoxide 3a were also detected (Scheme 2).
Conclusions
A very efficient and general method for the conversion
of selenides into selenones by using HOF·CH3CN is de-
scribed. For the first time, it is possible to prepare some
sterically hindered and electron-deficient selenones, such as
those possessing perfluorinated moieties. Mechanistic stud-
ies suggest some parallel behavior between the
HOF·CH3CN oxidation of sulfides and electron-rich sel-
enides, as in both cases the oxidation does not stop at the
monoxide, but rather proceeds to form the corresponding
dioxides. This feature is of synthetic value, as mixtures of
Scheme 2. Formation of selenones versus selenoxides by using an
insufficient amount of HOF·CH3CN.
It was of interest to examine some mechanistic aspects selenoxides and selenones are in many cases difficult to
of the oxidation of selenides by using HOF·CH3CN and separate, because they are prone to decomposition. In con-
compare them with the parallel sulfide-to-sulfone oxi- trast, the HOF·CH3CN oxygenation of electron-deficient
dation. Reactions of sulfides with HOF·CH3CN were found selenides displays a clear distinction between the two oxi-
to proceed generally directly to the sulfones, as clusters of dative steps, and in one extreme case (1m), the reaction
HOF molecules were grouped around the sulfur atom could not proceed to the selenone. These results also sup-
through hydrogen bonding skipping the formation of the port the notion that electrophilic oxygenations with
sulfoxide altogether. An insufficient amount of the reagent HOF·CH3CN are affected mainly by electronic factors
5576
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 5574–5579

A General and Efficient Method To Convert Selenides into Selenones
100%) was obtained. M.p. 132 °C (ref.[26] m.p. 91 °C). 1H NMR
(CDCl3): δ = 0.982 (t, J = 7.4 Hz, 6 H), 1.540 (sext, J = 7.4 Hz, 4
H), 1.985 (quint, J = 7.6 Hz, 4 H), 3.328 (t, J = 8.0 Hz, 4 H) ppm.
13C NMR (CDCl3): δ = 13.49, 22.16, 24.01, 57.13 ppm. HRMS
(ASAP): calcd. for C8H19O2Se [M + H] 227.0556; found 227.0556.
Bis(4-methylphenyl) Selenone (2c): Prepared from selenide 1c[27]
(166 mg, 0.64 mmol) as described in the general oxygenation pro-
cedure by using 2.4 equiv. of the oxidizing agent for 3 min. The
product was recrystallized from hexane/chloroform. A white solid
(185 mg, 100%) was obtained. M.p. 183 °C (ref.[35] m.p. 183.5 °C).
1H NMR (CDCl3): δ = 2.433 (s, 6 H), 7.386 (d, J = 8.6 Hz, 4 H),
7.854 (d, J = 8.4 Hz, 4 H) ppm. 13C NMR (CDCl3): δ = 21.79,
126.99, 130.90, 139.89, 145.18 ppm. HRMS (ASAP): calcd. for
C14H15O2Se [M + H] 291.0264; found 291.0269.
rather than steric ones, as the small size of the reagent has
the ability to reach even sterically hindered spaces.
Regarding the use of F2, which in the mind of many is
somewhat problematic, it should be remembered that dilute
fluorine (e.g., 10% F2 in N2) is less dangerous and easier to
work with than chlorine (it is also less toxic than Cl2[33]).
Dilute fluorine is commercially available, and the reactions
can be performed in standard glass vessels and only require
a simple soda–lime trap at the reaction outlet. Technical-
grade (Ͼ95%) F2 can be diluted on the spot to the desired
degree by using a simple vacuum line.[19a]
Experimental Section
General Experimental Procedures: 1H, 19F, and 13C NMR spectra
Bis(4-methoxyphenyl) Selenone (2d): Prepared from selenide 1d[28]
(199 mg, 0.68 mmol) as described in the general oxygenation pro-
cedure by using 2.4 equiv. of the oxidizing agent for 3 min. The
product was recrystallized from hexane/chloroform. A white solid
(218 mg, 99%) was obtained. M.p. 145–146 °C. 1H NMR (CDCl3):
δ = 3.860 (s, 6 H), 7.045 (d, J = 9.2 Hz, 4 H), 7.885 (d, J = 8.8 Hz,
4 H) ppm. 13C NMR (CDCl3): δ = 36.50, 116.11, 129.55, 134.69,
164.59 ppm. HRMS (ASAP): calcd. for C14H15O4Se [M + H]
323.0162; found 323.0172.
Butyl Phenyl Selenone (2e): Prepared from 1e[36] (151 mg,
0.71 mmol) as described in the general oxygenation procedure by
using 2.4 equiv. of the oxidizing agent for 3 min. The product was
precipitated from hexane. A white solid (173 mg, 100%) was ob-
tained. M.p. 56–60 °C. 1H NMR (CDCl3): δ = 0.822 (t, J = 7.4 Hz,
3 H), 1.389 (sext, J = 7.4 Hz, 2 H), 1.813 (quint, J = 8.0 Hz, 2 H),
3.432 (t, J = 8.0 Hz, 2 H), 7.54–7.58 (m, 2 H), 7.61–7.65 (m, 1 H),
7.87–7.89 (m, 2 H) ppm. 13C NMR (CDCl3): δ = 14.07, 22.49,
25.01, 60.41, 127.72, 130.98, 135.02, 141.74 ppm. HRMS (APPI):
calcd. for C10H15O2Se [M + H] 243.0264; found 243.0263.
were obtained at 400, 376, and 100 MHz, respectively, with Me4Si
as an internal standard for the H and 13C NMR spectra and with
1
9
CFCl3 as an internal standard for the F NMR spectra. MS data
were measured under ASAP or APPI conditions.
General Procedure for Working with Fluorine: Fluorine is a strong
oxidant and a corrosive material, so its reactions should be per-
formed in a well-ventilated area. It should be used only with an
appropriate vacuum line.[19a] For the occasional user, however, vari-
ous premixed mixtures of F2 in inert gases (N2 or He) are commer-
cially available, thereby simplifying the process. Unreacted fluorine
should be captured by a simple trap containing a base such as
soda–lime located at the outlet of the glass reactor. If elementary
precautions are taken, the work with fluorine is simple, and we
have never experienced any difficulties working with it.
General Procedure for Producing HOF·CH3CN: Mixtures of 10–
20% F2 in nitrogen were used throughout this work. The gas mix-
ture was prepared in a secondary container prior to the reaction
and passed at a rate of about 400 mLmin–1 through a cold (–15 °C)
mixture of CH3CN (10 mL) and H2O (1 mL) in a regular glass
reactor. The development of the oxidizing power was monitored by
treating aliquots with an acidic aqueous solution of KI. The liber-
ated iodine was then titrated with thiosulfate. Typical concentra-
tions of the oxidizing reagent were around 0.5–0.7 molL–1.
Phenethyl Phenyl Selenone (2f): Prepared from 1f[29] (140 mg,
0.54 mmol) as described in the general oxygenation procedure by
using 2.4 equiv. of the oxidizing agent for 3 min. The product was
precipitated from hexane. A white solid (142 mg, 90%) was ob-
1
tained. M.p. 90 °C. H NMR (CDCl3): δ = 3.281 (t, J = 8.6 Hz, 2
H), 3.718 (t, J = 8.0 Hz, 2 H), 7.15–7.18 (m, 2 H), 7.20–7.29 (m, 3
H), 7.59–7.63 (m, 2 H), 7.68–7.72 (m, 1 H), 7.90–7.93 (m, 2 H)
ppm. 13C NMR (CDCl3): δ = 28.48, 60.53, 127.08, 127.51, 128.54,
129.09, 130.30, 134.31, 136.55, 141.57 ppm. HRMS (ASAP): calcd.
for C14H15O2Se [M + H] 291.0264; found 291.0274. C14H14O2Se
(293.22): calcd. C 57.35, H 4.81; found C 57.13, H 4.80.
General Procedure for Working with HOF·CH3CN: Selenide 1a–m
was dissolved in CH2Cl2, and the mixture was cooled to 0 °C. The
oxidizing agent was then added in one portion to the reaction ves-
sel. The reaction was monitored by GC or TLC and stopped after
a few minutes. The mixture was then poured into water and ex-
tracted with ethyl acetate. The organic layer was washed with water
until the aqueous phase was neutral and unreactive to KI. It was
then dried with MgSO4, and the solvent was evaporated. The crude
selenone product was usually purified by recrystallization.
Dimesityl Selenone (2g): Prepared from selenide 1g[30] (210 mg,
0.66 mmol) as described in the general oxygenation procedure by
using 2.4 equiv. of the oxidizing agent for 10 min. The product was
recrystallized from hexane/chloroform. A white solid (196 mg,
1
85%) was obtained. M.p. 158 °C (blackens). H NMR (CDCl3): δ
= 2.278 (s, 6 H), 2.559 (s, 12 H), 6.902 (s, 4 H) ppm. 13C NMR
(CDCl3): δ = 21.24, 21.73, 132.93, 139.10, 142.19, 143.96 ppm.
HRMS (APPI): calcd. for C18H22O2SeNa [M + Na] 369.0710;
found 369.0707.
Diphenyl Selenone (2a): Prepared from commercial selenide 1a
(233 mg, 1.42 mmol) as described in the general oxygenation pro-
cedure by using 2.4 equiv. of the oxidizing agent for 3 min. The
product was recrystallized from hexane/chloroform. A white solid
(302 mg, 100%) was obtained. M.p. 132 °C (ref.[25] m.p. 131–
Dineopentyl Selenone (2h): Prepared from selenide 1h[37] (201 mg,
0.91 mmol) as described in the general oxygenation procedure by
using 2.4 equiv. of the oxidizing agent for 10 min. The product was
recrystallized from hexane/chloroform. A white solid (210 mg,
1
132 °C). H NMR (CDCl3): δ = 7.56–7.60 (m, 4 H), 7.62–7.66 (m,
2 H), 7.95–7.98 (m, 4 H) ppm. 13C NMR (CDCl3): δ = 127.01,
130.34, 134.17, 142.64 ppm. HRMS (ASAP): calcd. for
C12H11O2Se [M + H] 262.9951; found 262.9960.
1
91%) was obtained. M.p. 118 °C. H NMR (CDCl3): δ = 1.294 (s,
Dibutyl Selenone (2b): Prepared from selenide 1b[34] (260 mg,
1.00 mmol) as described in the general oxygenation procedure by
using 2.4 equiv. of the oxidizing agent for 5 min. The product was
recrystallized from hexane/chloroform. A white solid (265 mg,
18 H), 3.280 (s, 4 H) ppm. 13C NMR (CDCl3): δ = 30.41, 33.97,
73.79 ppm. HRMS (ASAP): calcd. for C10H23O2Se [M + H]
251.0890; found 251.0875. C10H22O2Se (253.24): calcd. C 47.43, H
8.76; found C 47.17, H 8.70.
Eur. J. Org. Chem. 2013, 5574–5579
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5577

S. Potash, S. Rozen
SHORT COMMUNICATION
Bis(4-nitrophenyl) Selenone (2i): Prepared from selenide 1i[31b]
(140 mg, 0.43 mmol) as described in the general oxygenation pro-
cedure by using 2.4 equiv. of the oxidizing agent for 15 min. The
product was recrystallized from chloroform. An off-white solid
(134 mg, 87%) was obtained. M.p. 277–278 °C. 1H NMR ([D6]-
DMSO): δ = 8.363 (d, J = 9 Hz, 4 H), 8.510 (d, J = 9 Hz, 4 H)
[1]
[2]
a) T. G. Back (Ed.), Organoselenium Chemistry: A Practical Ap-
proach, Oxford University Press, Oxford, 1999; b) A. Krief in
Comprehensive Organometallic Chemistry II (Eds.: E. W. Abel,
F. G. A. Stone, G. Wilkinson), Pergamon, New York, 1995, vol.
11, pp. 515–569; c) T. Wirth in Comprehensive Organometallic
Chemistry III (Eds.: R. H. Crabtree, D. M. P. Mingos), Elsevier,
Oxford, 2006, vol. 9, pp. 457–499.
a) T. Wirth (Ed.), Organoselenium Chemistry: Synthesis and Re-
actions, Weinheim, Wiley-VCH, 2012; b) H. J. Reich in Oxi-
dation in Organic Chemistry, 1978, vol. 5, part C, pp. 1–130; c)
S. Patai, Z. Rappoport (Eds.), The Chemistry of Organic Selen-
ium and Tellurium Compounds, Wiley, New York, 1986; d) H. J.
Reich, Acc. Chem. Res. 1978, 11, 22; e) T. G. Back in Encyclo-
pedia of Inorganic Chemistry, Wiley, New York, 2006, DOI:
10.1002/0470862106.ia214.
a) H. J. Reich, Acc. Chem. Res. 1979, 12, 22; b) D. Liotta, Acc.
Chem. Res. 1984, 17, 28; c) K. B. Sharpless, R. F. Laurer, J.
Am. Chem. Soc. 1973, 95, 2697; d) K. B. Sharpless, R. F.
Laurer, A. Y. Teranishi, J. Am. Chem. Soc. 1973, 95, 6137.
K. B. Sharpless, M. W. Young, R. F. Lauer, Tetrahedron Lett.
1973, 14, 1979.
G. Galambos, V. Simonidesz, Tetrahedron Lett. 1982, 23, 4371.
a) H. J. Reich, S. Wollowitz, J. Am. Chem. Soc. 1982, 104, 7051;
b) H. J. Reich, K. E. Yelm, S. Wollowitz, J. Am. Chem. Soc.
1983, 105, 2503.
ppm. 13C NMR ([D6]DMSO):
δ = 126.44, 129.40, 147.04,
151.77 ppm. HRMS (ASAP): calcd. for C12H9N2O6Se [M + H]
352.9653; found 352.9655. C12H8N2O6Se (355.17): calcd. C 40.58,
H 2.27, N 7.89; found C 40.79, H 2.43, N 7.44.
Pentafluorophenyl Phenyl Selenone (2j): Prepared from selenide
1j[38] (261 mg, 0.81 mmol) as described in the general oxygenation
procedure by using 2.4 equiv. of the oxidizing agent for 15 min. The
product was recrystallized from hexane/diethyl ether. A white solid
(275 mg, 96%) was obtained. M.p. 104–105 °C. 1H NMR (CDCl3):
δ = 7.68–7.72 (m, 2 H), 7.77–7.79 (m, 1 H), 8.12–8.14 (m, 2 H)
ppm. 13C NMR (CDCl3): δ = 126.95 (s), 130.80 (s), 135.50 (s),
136.7–137.0 (m), 139.3–139.6 (m), 143.9–144.1 (m), 144.46 (s),
146.5–146.7 (m) ppm. 19F NMR (CDCl3): δ = –155.72 (t, J =
18.8 Hz), –141.46 (t, J = 19.9 Hz), –134.43 (d, J = 19.9 Hz) ppm.
HRMS (ASAP): calcd. for C12H6F5O2Se [M + H] 352.9480; found
352.9472. C12H5F5O2Se (355.12): calcd. C 40.59, H 1.42, F 26.75;
found C 40.52, H 1.23, F 26.63.
[3]
[4]
[5]
[6]
Bis(2,2,2-trifluoroethyl) Selenone (2k): Prepared from selenide 1k[39]
(108 mg, 0.44 mmol) as described in the general oxygenation pro-
cedure by using 4 equiv. of the oxidizing agent for 10 min. The
product was recrystallized from chloroform. An off-white solid
(121 mg, 100%) was obtained. M.p. 239 °C (sublimes). 1H NMR
([D6]acetone): δ = 4.99 (d, J = 10 Hz, 4 H) ppm. 13C NMR ([D6]-
acetone): δ = 58.74 (q, J = 127 Hz), 122.17 (q, J = 1110 Hz) ppm.
19F NMR (CDCl3): δ = 58.71 (s) ppm. HRMS (ASAP): calcd. for
C4H5F6O2Se [M + H] 274.9386; found 274.9389. C4H4F6O2Se
(277.02): calcd. C 17.34, H 1.46, F 41.15; found C 17.56, H 1.44,
F 40.72.
[7]
[8]
[9]
a) N. Komatsu, Y. Nishibayashi, S. Uemura, Tetrahedron Lett.
1993, 34, 2339; b) Y. Nishibayashi, J. D. Singh, S. Fukuzawa,
S. Uemura, J. Org. Chem. 1995, 60, 4114.
D. M. Freudendahl, S. Santoro, S. A. Shahzad, C. Santi, T.
Wirth, Angew. Chem. 2009, 121, 8559; Angew. Chem. Int. Ed.
2009, 48, 8409.
A. Krief, W. Dumont, J. N. Denis, G. Evard, B. Norberg, J.
Chem. Soc., Chem. Commun. 1985, 569.
J. Nakayama, Bull. Chem. Soc. Jpn. 2000, 73, 1.
Compared to sulfoxides, selenoxides are characterized with re-
duced d–p π bonding, as indicated by the greater polarity and
basicity of selenoxides, as well as by lower stretching force con-
stants. See ref.[2b] and the references cited therein.
a) C. E. Wheelock, M. E. Colvin, I. Uemura, M. M. Olmstead,
J. R. Sanborn, Y. Nakagawa, A. D. Jones, B. D. Hammock, J.
Med. Chem. 2002, 45, 5576; b) S. A. Mousa, L. O’Connor,
T. G. Rossman, E. Block, Carcinogenesis 2007, 28, 962; c) Y.
Ma, R. Liu, X. Gong, Z. Li, Q. Huang, H. Wang, G. Song, J.
Agric. Food Chem. 2006, 54, 7724; d) M. A. Abbady, S. H.
Abdel-Hafez, Phosphorus Sulfur Silicon Relat. Elem. 2000, 160,
121.
A. Toshimitsu, S. Uemura in Organoselenium Chemistry: A
Practical Approach (Ed.: T. G. Back), Oxford University Press,
Oxford, 1999, p. 241.
The PhSeO2 group is a much better leaving group than iodide;
see: H. J. Reich, Proceedings of the 4th International Symposium
on Organic Selenium and Tellurium Compounds (Eds.: E. J.
Berry, W. R. McWhinnie), Birmingham, UK, 1983, p. 268.
S. Rozen, M. Brand, Angew. Chem. 1986, 98, 565; Angew.
Chem. Int. Ed. Engl. 1986, 25, 554.
[10]
[11]
Perfluorooctyl Phenyl Selenone (2l): Prepared from selenide 1l[40]
(210 mg, 0.36 mmol) as described in the general oxygenation pro-
cedure by using 4 equiv. of the oxidizing agent for 20 min. The
product was recrystallized from hexane. A white solid (202 mg,
[12]
1
91%) was obtained. M.p. 70–71 °C. H NMR (CDCl3): δ = 7.77–
7.81 (m, 2 H), 7.88–7.92 (m, 1 H), 8.09–8.12 (m, 2 H) ppm. 13C
NMR (CDCl3): δ = 128.54, 131.05, 136.33, 138.65 ppm. 19F NMR
(CDCl3): δ = –124.84 (s), –121.43 (s), –120.57 (s), –120.40 (s),
–120.19 (s), –117.59 (s), –102.12 (s), –79.46 (s) ppm. HRMS
(ASAP): calcd. for C14H6F17O2Se [M + H] 604.9288; found
604.9276. C14H5F17O2Se (607.12): calcd. C 27.70, H 0.83, F 53.20;
found C 27.61, H 0.72, F 52.99.
[13]
[14]
Bis(pentafluorophenyl) Selenoxide (3m): Prepared from selenide
1m[41] (214 mg, 0.52 mmol) as described in the general oxygenation
procedure by using 2.2 equiv. of the oxidizing agent for 10 min. A
white solid (220 mg, 100%) was obtained. M.p. 154 °C. 19F NMR
(CDCl3): δ = –156.7, –144.6, –136.5 ppm. HRMS (APPI): calcd.
for C10HF10OSe 430.9033 [M + H]; found 430.9029.
[15]
[16]
a) S. Rozen, Y. Bareket, J. Org. Chem. 1997, 62, 1457; b) A. E.
Feiring, E. R. Wonchoba, S. Rozen, J. Fluorine Chem. 1999,
93, 93; c) S. Rozen, Eur. J. Org. Chem. 2005, 2433; d) T. Harel,
E. Amir, S. Rozen, Org. Lett. 2006, 8, 1213; e) R. Beckerbauer,
B. E. Smart, Y. Bareket, S. Rozen, J. Org. Chem. 1995, 60, 6186;
f) N. Shefer, M. Carmeli, S. Rozen, Tetrahedron Lett. 2007, 48,
8178; g) S. Rozen, Y. Bareket, J. Chem. Soc., Chem. Commun.
1994, 1959.
Supporting Information (see footnote on the first page of this arti-
cle): Copies of the 1H, 13C, and 19F NMR spectra, HRMS data,
and elemental analysis report.
[17]
a) S. Potash, S. Rozen, Chem. Eur. J. 2013, 19, 5289; b) E.
Amir, S. Rozen, Angew. Chem. 2005, 117, 7540; Angew. Chem.
Int. Ed. 2005, 44, 7374; c) S. Potash, S. Rozen, J. Org. Chem.
2011, 76, 7245; d) N. Shefer, S. Rozen, J. Org. Chem. 2011, 76,
4611.
Acknowledgments
This research was supported by the Israel Science Foundation
(grant 373/13).
5578
www.eurjoc.org
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2013, 5574–5579

A General and Efficient Method To Convert Selenides into Selenones
[18] a) S. Rozen, M. Carmeli, J. Am. Chem. Soc. 2003, 125, 8118;
b) S. Rozen, M. Kol, J. Org. Chem. 1992, 57, 7342; c) S. Rozen,
[29] H. J. Reich, S. Wollowitz, J. E. Trend, F. Chow, D. F. Wendel-
born, J. Org. Chem. 1978, 43, 1697.
A. Bar-Haim, E. Mishani, J. Org. Chem. 1994, 59, 1208; d) E. [30] N. Ghavale, P. P. Phadnis, A. Wadawale, V. K. Jain, Indian J.
Golan, S. Rozen, J. Org. Chem. 2003, 68, 9170.
[19] a) S. Dayan, M. Kol, S. Rozen, Synthesis 1999, 1427; b) S.
Rozen, S. Dayan, Angew. Chem. 1999, 111, 3679; Angew. Chem.
Int. Ed. 1999, 38, 3471; c) S. Rozen, M. Carmeli, J. Org. Chem.
2005, 70, 2131.
[20] a) S. Rozen, E. Golan, Eur. J. Org. Chem. 2003, 1915; b) E.
Golan, A. Hagooly, S. Rozen, Tetrahedron Lett. 2004, 45, 3397.
[21] S. Rozen, M. Brand, M. Kol, J. Am. Chem. Soc. 1989, 111,
8325.
[22] a) M. Carmeli, S. Rozen, J. Org. Chem. 2006, 71, 4585; b) M.
Kol, S. Rozen, J. Org. Chem. 1993, 58, 1593; c) S. Rozen, Acc.
Chem. Res. 1996, 29, 243; d) S. Rozen, Y. Bareket, M. Kol,
Tetrahedron 1993, 49, 8169.
[23] M. Srnec, M. Oncak, R. Zahradnik, J. Phys. Chem. A 2008,
112, 3631.
Chem. 2011, 50A, 22.
[31] The oxidation was preformed on compound 1f by using PhICl2
and tBuOCl and yielded only the selenoxide; see: a) M. Cin-
quini, S. Colonna, R. Giovini, Chem. Ind. (Chichester, U.K.)
1969, 1737; b) M. Kobayashi, H. Ohkubo, T. Shimizu, Bull.
Chem. Soc. Jpn. 1986, 59, 503.
[32] S. Gockel, A. Hass, V. Probst, R. Boese, I. Muller, J. Fluorine
Chem. 2000, 102, 301.
[33] American Environmental Group Ltd., AEGL (Acute Exposure
Guideline Level) (50) October 2, 2009.
[34] A. Krief, M. Trabelsi, W. Dumont, M. Derock, Synlett 2004,
1751.
[35] K. Dostal, Z. Zak, M. Cernik, Chem. Ber. 1971, 104, 2044.
[36] S. Narayanaperumal, E. E. Alberto, K. Gul, O. E. D. Rodrig-
ues, A. L. Braga, J. Org. Chem. 2010, 75, 3886.
[37] A. B. Pierini, A. B. Penenory, R. A. Rossi, J. Org. Chem. 1985,
50, 2739.
[24] J. M. Khurana, B. M. Kandpal, Y. K. Chauhan, Phosphorus
Sulfur Silicon Relat. Elem. 2003, 178, 1369.
[25] In a comparable experiment, only 39% of the desired product
formed; see: M. Oba, Y. Okada, M. Endo, K. Tanaka, K. Ni-
shiyama, S. Shimada, W. Ando, Inorg. Chem. 2010, 49, 10680.
[26] R. Paetzold, G. Bochmann, Z. Anorg. Allg. Chem. 1968, 360,
293.
[27] Y. Li, C. Nie, H. Wang, X. Li, F. Verpoort, C. Duan, Eur. J.
Org. Chem. 2011, 7331.
[38] G. G. Furin, A. I. Rezvukhin, M. A. Fedotov, G. G. Yakobson,
J. Fluorine Chem. 1983, 22, 231.
[39] K. K. Bhasin, V. Gupta, R. Khajuria, R. P. Sharma, Org. Prep.
Proced. Int. 1993, 25, 590.
[40] E. Magnier, E. Vit, C. Wakselman, Synlett 2001, 8, 1260.
[41] T. M. Klapötke, B. Krumm, K. Polborn, Eur. J. Inorg. Chem.
1999, 1359.
[28] V. P. Reddy, A. V. Kumar, K. R. Rao, J. Org. Chem. 2010, 75,
8720.
Received: May 11, 2013
Published Online: July 24, 2013
Eur. J. Org. Chem. 2013, 5574–5579
© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
5579