Synthesis of new sulfoxide-containing diselenides and unexpected cyclization reactions to 2,3-dihydro-1,4-benzoselenothiine 1-oxides

Article abstract of DOI:10.1002/ejoc.201000514

New chiral sulfoxide-containing diselenides were prepared and their corresponding selenium, electrophiles were used for the stereoselective functionalization of alkenes. The influence of solvents and different nucleophiles on the outcome of the selenenylation reaction was studied. Besides the successful selenenylation reactions, one selenium electrophile showed an unexpected reactivity in forming a six-membered heterocyclic system, upon reaction with, alkenes. A mechanism for the formation of these 2,3-dihydro-1,4-benzoselenothiine 1-oxides is proposed. 2010 Wiley-VCH Verlag GmbH & Co. KGaA.

Full text of DOI:10.1002/ejoc.201000514

FULL PAPER
DOI: 10.1002/ejoc.201000514
Synthesis of New Sulfoxide-Containing Diselenides and Unexpected
Cyclization Reactions to 2,3-Dihydro-1,4-benzoselenothiine 1-Oxides
Diana M. Freudendahl,[a] Michio Iwaoka,[b] and Thomas Wirth*[a]
Keywords: Selenium / Selenium electrophiles / Alkenes / Cyclization / Heterocycles / Stereoselective synthesis
New chiral sulfoxide-containing diselenides were prepared
and their corresponding selenium electrophiles were used for
the stereoselective functionalization of alkenes. The influ-
ence of solvents and different nucleophiles on the outcome
of the selenenylation reaction was studied. Besides the suc-
cessful selenenylation reactions, one selenium electrophile
showed an unexpected reactivity in forming a six-membered
heterocyclic system upon reaction with alkenes. A mecha-
nism for the formation of these 2,3-dihydro-1,4-benzoseleno-
thiine 1-oxides is proposed.
Introduction
Results and Discussion
The functionalization of activated C=C bonds with elec-
trophilic organoselenium compounds has been successfully
applied in various cases.[1] Furthermore, we and other re-
search groups have investigated stereoselective reactions of
alkenes with chiral selenium electrophiles.[2,3] Optically
active diselenides bearing a sulfoxide moiety as chiral centre
are easily accessible and the selenium electrophiles gener-
ated from these diselenides can add to alkenes with high
selectivities. A variety of nucleophiles have been used to
open the seleniranium intermediates 1 and the addition
products gave rise to many subsequent reactions
(Scheme 1).
The racemic bis[2-(tert-butylsulfinyl)phenyl] diselenide
(3) was synthesized from sulfoxide 2, after oxidation of the
corresponding sulfide with sodium periodate. We found
that the most effective method for the synthesis of tert-butyl
phenyl sulfide, described by Breau et al., was the use of tert-
butyl alcohol together with acetic acid, acetic anhydride
and perchloric acid.[4] The following oxidation to the sulf-
oxide 2 produced also the sulfone 6 as a side product and
6% of starting material were reisolated.[5] Diselenide 3 was
then synthesized by a standard procedure via ortho-lithi-
ation and addition of elemental selenium in tetrahydrofuran
followed by oxidative workup, in 39% yield.[6] Additionally,
bis[2-(tert-butylsulfonyl)phenyl] diselenide (5) was prepared
from tert-butyl phenyl sulfone (4) using the same reaction
conditions as mentioned above in 28% yield as shown in
Scheme 2.
Scheme 1. Selenenylation of alkenes.
Herein we report the synthesis of new optical active sulf-
oxide-containing diselenides and the addition reactions of
their corresponding selenium electrophiles to alkenes. Ad-
ditionally, we present the formation of a six-membered
heterocyclic ring system (2,3-dihydro-1,4-benzoselenothiine
1-oxides) via a new cyclization reaction and an interesting
dimerization product.
[a] School of Chemistry, Cardiff University,
Park Place, Cardiff, CF10 3AT, United Kingdom
Fax: +44-29-20876968
E-mail: wirth@cf.ac.uk
[b] Department of Chemistry, School of Science, Tokai University,
Kitakaname, Hiratsuka-shi
Kanagawa 259-1292, Japan
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201000514.
Scheme 2. Synthesis of racemic bis[2-(tert-butylsulfinyl)phenyl] di-
selenides and bis[2-(tert-butylsulfonyl)phenyl] diselenides.
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Sulfoxide-Containing Diselenides
The stereoselective oxidation of tert-butyl phenyl sulfide its synthesis as the reaction of 12 with (3-methoxyphenyl)-
what was attempted via modified Sharpless procedures for magnesium bromide led to a complex reaction mixture.
the asymmetric oxidation of sulfides to sulfoxides. A
method by Kagan et al.[7] described the use of Ti(O-iPr)4,
diethyl tartrate, water and tert-butyl hydroperoxide in
dichloromethane. Whereas the procedure is suitable for
small substituents on the phenyl sulfide moiety, it was not
possible to achieve a selective oxidation with tert-butyl
phenyl sulfide as starting material. A similar method pub-
lished by Jia et al. with (S)-BINOL as a ligand and toluene
as suitable solvent was not selective.[8] Using Kagan’s condi-
tions and (R)-TRIP [(R)-3,3Ј-bis(2,4,6-triisopropylphenyl)-
2,2Ј-dihydroxy-1,1Ј-dinaphthyl] as ligand did also not af-
ford an enantio-enriched sulfoxide.
However, enantiomerically pure sulfoxides can be ob-
tained from the cyclic chiral sulfite 11, which can be synthe-
sized in two steps from (S)-ethyl lactate.[9] (S)-tert-Butyl
phenyl sulfoxide (13) was ortho-lithiated with n-butyllithium
in THF and treated with selenium to afford the diselenide
14 in 39% yield after oxidative workup (Scheme 3).
Nevertheless it was possible to obtain racemic 7 in 24%
yield via the corresponding sulfoxide, obtained by oxidation
of tert-butyl 3-methoxyphenyl sulfide. However, it was not
possible to obtain crystals from this compound suitable for
X-ray crystal structure determination.
Therefore, the sulfone analog 9 of the diselenide was syn-
thesized albeit with very low yields (3%) and crystallized.[11]
During this reaction another diselenide 10 was formed
through lithiation in p-position to the methoxy substituent
in 8% yield, which could be separated and crystallized as
well.[11]
We compared these crystal structures[11] with the struc-
tural data of diselenide 16, which has been synthesized in
our group earlier and results in a high degree of stereoselec-
tivity (up to 99:1 dr) in the addition reaction to alkenes
(Table 1).[12]
Direct comparison between diselenide 14 and 16 reveals
that the oxygen attached to the chiral center has no interac-
tion with the selenium atoms in the solid state. The Se–Se
distance is almost identical for both compounds. The dihe-
dral angle C1–C2–SO in 14 is slightly larger than the C1–
C2–CO angle of 16 which is an effect of the bulkier tert-
butyl group. For the same reason, the C–Se–Se–C angle
seems to be larger. The downfield shift of 70 ppm observed
in the 77Se NMR can be assigned to the different elec-
tronical effects of the sulfur substituent. This can be backed
up, taking into account the chemical shifts of the sulfone-
substituted diselenides, which are shifted downfield by
about 100 ppm in comparison to the alcohol-substituted
diselenide 16. Although the Se–Se distance in all these di-
selenides is almost identical, there is a huge difference in
the C–Se–Se–C dihedral angles. Remarkably, this angle is
Scheme 3. Synthesis of (S)-bis[2-(tert-butylsulfinyl)phenyl] diselen-
ide.
It was possible to obtain X-ray structural analyzes of 14 almost identical for diselenides 10 and 16, but slightly
and 5. The synthesis of enantiomerically enriched diselenide forced open in diselenide 5. Again, out of steric effects it
15 was attempted analog to the preparation of diselenide can be presumed that this angle is even wider in diselenide
14. The coordinating and directing effect of the methoxy 9. The same reason seems to account for the dihedral angles
group in hydroxy diselenide 16 had a positive effect in the of C1C2SO in the sulfone-containing diselenides. In the
stereoselective outcome in the methoxyselenenylation of al- three diselenides, 5, 9, and 10, one oxygen of the sulfone
kenes.[10] The properties of the corresponding methoxy-sub- moieties is in coordinating distance to the adjacent sele-
stituted sulfinyl compound could be interesting. However, nium atom and in case of 9 even at the same distance than
the route used for diselenide 14 proved to be not suitable for the methoxy group. The second sulfoxide oxygen however
Table 1. Comparison of crystal structures of diselenides.
Se–O distance
4.65 Å
2.31 Å
2.79 Å
4.73 Å
2.32 Å
2.96 Å, 4.81 Å, 2.99 Å (OMe)
2.97 Å (OMe)
2.35 Å
2.78 Å, 4.72 Å
4.42 Å (OH),
2.97 Å (OMe)
2.33 Å
131° (CCCO)
77.5°
Se–Se bond length
2.23 Å
148.8°, 20.2° (CCSO)
78.9°
Dihedral angle C1C2XO 147° (CCSO)
152.5°, 24.7° (CCSO) 156.2°, 27.8° (CCSO)
96.2°
476 ppm
CSeSeC dihedral angle
89.5°
436 ppm
113.7°, 112.5°
465 ppm
77Se NMR
467 ppm
366 ppm
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D. M. Freudendahl, M. Iwaoka, T. Wirth
FULL PAPER
is in a similar distance as the oxygen atoms in diselenides Table 2. Selectivities of the methoxyselenenylation of 2Ј-chloro-
styrene with 20 in several solvents affording product 22a.
14 and 16.
Another chiral sulfoxide 19 (Scheme 4) was synthesized
by using the commercially available (–)-(1R)-menthyl (S)-p-
toluenesulfinate (17). The substitution of the menthyl group
can be performed with any Grignard reagent, but it has to
be taken into account that the next step requires a lithium
base for the ortho-deprotonation preventing the use of any
moieties with acidic protons. An ideal choice seemed to be
a (2,4,6-triisopropyl)phenyl group which can only be ortho-
lithiated at the desired position and only provides slightly
acidic protons. (R)-4-Methyl-1-[(2,4,6-triisopropylphenyl)-
sulfinyl]benzene (18) was obtained in 60% yield. The fol-
lowing ortho-lithiation was challenging. Using lithium di-
isopropylamide or LiTMP at –78 °C in tetrahydrofuran led
to the isolation of 19 in 6% yield (LiTMP 4% yield) and a
large amount of unidentified side products. Variation of the
reaction temperature (–78 °C, 0 °C, room temp., 40 °C), a
change of the lithium base (LDA, nBuLi, LiTMP) or the
use of different solvents (THF, cyclopentyl methyl ether) led
to complex reaction mixtures and did not enhance the yield.
Entry
Solvent
22a, yield [%]
22a, dr[a]
1
2
3
4
5
6
THF
29
29
36
41
41
48
4:1
4:1
5:1
5:1
11:1
7:1
CPME[b]
Et2O
Et2O/CH2Cl2 (4:1)
CH2Cl2
[c]
CHCl3
1
[a] Determined by H NMR spectroscopy. [b] CPME: cyclopentyl
methyl ether. [c] Reaction was carried out at –50 °C.
The influence of the solvent on the methoxyselenenyl-
ation was tested with 2Ј-chlorostyrene and racemic 20 and
21. The reactions were carried out at –78 °C and stopped
after 2 h. Interestingly, the colour of the selenium electro-
phile 21 is depending on the solvent (colour of RSeBr in all
solvents: orange; RSeOTf in THF: purple, in cyclopentyl
methyl ether (CPME): red and in CH2Cl2: green) and can
also be used as an indicator for the progress of the reaction.
This is not the case with 21 which always gives yellow mix-
tures. The best selectivity with 20 was found using dichloro-
methane. When the reactions were carried out in polar
ethers like tetrahydrofuran and cyclopentyl methyl ether
(CPME) the selectivities dropped significantly. The ob-
served diastereomeric ratio was decreased in chloroform,
however, this reaction showed the highest yield.
Surprisingly, 21 is less reactive and less selective in the
same reaction (Table 3). The highest diatereomeric ratio
was observed in tetrahydrofuran (3:1), but with low yield.
In chloroform the yield was better however, the diasterom-
eric ratio decreased to 2:1.
Table 3. Selectivities of the methoxyselenenylation of 2Ј-chloro-
styrene with 21 in several solvents affording product 23a.
Scheme 4. Synthesis of the chiral diselenide 19.
Entry
Solvent
23a, yield [%]
23a, dr[a]
As the product was isolated in a very low yield, the fol-
lowing methoxyselenenylation reactions were carried out
only with diselenides 3 and 7. A typical reaction proceeds
via the generation of selenenyl bromide by addition of ele-
mental bromine to the diselenide, exchange of the bromine
counter-anion with the less nucleophilic triflate and ad-
dition of the selenenyl cation onto the carbon–carbon
double bond. Attack of a nucleophile, in this case meth-
anol, led to product formation. The diastereomeric ratio of
the products derived from the racemic selenium electro-
1
2
3
4
5
6
THF
18
30
10
23
20
40
3:1
1:1
1:1
1:1
1:1
2:1
CPME[b]
Et2O
acetonitrile[c]
CH2Cl2
CHCl3
[d]
1
[a] Determined by H NMR spectroscopy. [b] CPME: cyclopentyl
methyl ether. [c] Reaction was carried out at –40 °C. [d] Reaction
was carried out at –50 °C.
Then the reactivity towards different substrates was in-
philes 20 and 21 determined by NMR indicates a reason- vestigated initially with diselenide 3. Monosubstituted
ably stereocontrol, which can be assumed as a synergetic double bonds (Table 4 entry 1 and 2) showed reasonable
effect of sulfoxide and the tert-butyl group (Table 2).
selectivities with a diastereomeric ratio of up to 6:1. But
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Sulfoxide-Containing Diselenides
only styrene gave a good yield in tetrahydrofuran. Methyl tion it is crucial that the temperature is increased to 0 °C.
cinnamate and 3-nitrostyrene seem to be not reactive To the best of our knowledge this is the first time that such
enough for the conditions of the methoxyselenenylation re- a reactivity has been observed (Scheme 5).
action. Substituents in the 2Ј-position of the aromatic sys-
tem seem to enhance the selectivity and led to reasonable
yields. More bulk on the double bond system leads to lower
yields, however the β-substitution enhances the selectivity.
Table 4. Reactivity of 21 towards different substrates.
Entry Alkene
Product Solvent
Yield [%] dr[a]
Scheme 5. Alkene addition to selenium electrophiles.
1
2
3
4
5
6
7
8
styrene
22b
22c
–
THF
THF
THF
52
32
0
6:1
5:1
–
2-vinylnaphthalene
methylcinnamate
3-nitrostyrene
2-chlorostyrene
α-methylstyrene
β-methylstyrene
In these cases the sulfoxide moiety seems to react as an
internal nucleophile. However, it was only possible to iso-
late products with α-substituted double bonds. β-Substitu-
tion in this reaction seems to result in to much strain during
the cyclization step (Table 6).
–
THF
0
–
22a
22d
22e
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
41
38
30
30
11:1
4:1
11:1
9:1
1-phenyl-1-cyclohexene 22f
Table 6. Cyclization reaction with different substrates.
1
[a] Determined by H NMR spectroscopy.
Alkene
Product
Solvent
Yield [%]
Styrene
25a
25b
–
25c
25d
–
THF
THF
THF
Et2O
CH2Cl2
THF
THF
10
16
–
9
12
–
2-Vinylnaphthalene
Methyl cinnamate
2-Chlorostyrene
α-Methylstyrene
β-Methylstyrene
1-Methyl-1-cyclohexene
–
–
The products obtained in this reaction could have dif-
ferent structures as NMR and mass spetrometric data can-
not distinguish between compounds 25 and 26. Without
reference spectra, the IR vibrations for both structures can
not be distinguished, as the S–O and the S=O absorbances
are in the same region according to literature.[13] Fortu-
nately, the X-ray structural analysis of 25b (Figure 1)
proved the presence of structures 25. According to the X-
ray crystal structure, the oxygen atom and the naphthyl ring
system are cis to each other, which indicates that the cleav-
age of the tert-butyl group has occurred after the sulfur–
carbon bond formation.
As was already observed during the solvent screening
with diselenide 7, the yields and selectivities are lower with
styrene leading to product 23b in 24% yield; dr 2:1 and with
β-methylstyrene resulting in 23c in 22% yield; dr 1:1.
In reactions of selenium electrophiles generated from dis-
elenide 3 we could also show that the diastereomeric ratio
of the products decreases with the size of the nucleophile,
at comparable yields (Table 5).
Table 5. Reactivity of 3 with 2-chlorostyrene and different nucleo-
philes.
Entry Nucleophile
Product Solvent
Yield [%] dr[a]
1
2
3
4
5
6
7
8
methanol
ethanol
2-propanol
22a
24a
24b
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
acetonitrile[b]
41
47
47
30
30
traces
35
11:1
8:1
8:1
6:1
3.5:1
–
tert-butyl alcohol 24c
benzyl alcohol
benzoic acid
TMSN3
24d
–
24e
–
6:1
–
NaN3
0
[a] Determined by 1H NMR spectroscopy. [b] Reaction was carried
out at –40 °C.
Figure 1. Crystal structure of 2-naphthyl-2,3-dihydro-1,4-benzo-
selenothiine 1-oxide (25b).
The mechanistic pathway outlined in Scheme 6 is sug-
gested for the product formation. After the formation of
the seleniranium cation the sulfur attacks the electrophilic
benzylic carbon atom in 27 to form intermediate 28. The
newly formed six membered ring system gets stabilized
upon cleavage of the tert-butyl group. Calculations of sim-
ilar structures (R = H, tert-butyl replaced by methyl) have
If the reaction of the selenium electrophile and the alkene shown that an oxygen involvement as shown in 29 is less
is carried out in the absence of an external nucleophile, the likely, as the energy of this structure is above the energy of
formation of different products was observed. For this reac- 28.[14,15]
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D. M. Freudendahl, M. Iwaoka, T. Wirth
FULL PAPER
solvents are indicated in the text. All experiments were performed
under an inert atmosphere of argon. THF and diethyl ether were
dried with sodium, dichloromethane was dried with CaH, cy-
clopentyl methyl ether, chloroform, methanol, ethanol, 2-propanol
and tert-butyl alcohol were dried with molecular sieves (4 Å). All
other purchased chemicals were used without further purification.
Isomers in NMR spectroscopic data are shown with an asterisk.
For the low resolution mass data only the main isotope peak of
the usual selenium isotope pattern is given.
GP 1. General Procedure for the Addition of Selenium Electrophiles
to Styrene: Bis[2-(tert-butylsulfinyl)phenyl] diselenide (3)
(0.1 mmol) was dissolved in dry solvent (4 mL) under argon, cooled
to –78 °C, and treated with bromine (0.1 mmol, 0.1 mL of a 1 
Scheme 6. Proposed mechanistic pathway.
Another reactivity was observed when the reaction mix-
ture was warmed to room temperature overnight instead of solution in CCl4). After 20 min silver triflate (solid) (54 mg,
0.21 mmol) was added and the mixture was stirred for 25 min at
–78 °C. The reaction mixture was treated with MeOH (0.10 mL)
and subsequently with the alkene (0.22 mmol). After the mixture
had been stirred for 2 h at –78 °C, it was warmed to 0 °C and fur-
ther stirred for 30 min. Then 2,4,6-collidine (0.10 mL) was added,
followed by water (4 mL). After extraction of the reaction mixture
with dichloromethane (3ϫ10 mL), drying of the combined organic
phases with MgSO4 and removal of the solvent under reduced pres-
sure. The residue was purified by column chromatography on silica
gel, yielding the addition products as colourless oils. The dia-
stereomers could not be separated by column chromatography
(ethyl acetate/hexane, 5:1).
warming it to 0 °C immediately and if the alkene was pres-
ent in excess. The observed dimer 30 formed in a 1:1 dia-
steromeric mixture in 30% yield via a cationic dimerization
and regenerates the double bond by deprotonation during
the workup. (Scheme 7).
GB 2. General Procedure for the Synthesis of 1,4-Benzselenathiine 1-
Oxides: Bis[2-(tert-butylsulfinyl)phenyl] diselenide (0.1 mmol) was
dissolved in dry tetrahydrofuran (4 mL) under argon, cooled to
–78 °C, and treated with bromine (0.1 mmol, 0.1 mL of a 1  solu-
tion in CCl4). After 20 min silver triflate (solid) (54 mg, 0.21 mmol)
was added and the mixture was stirred for 25 min at –78 °C. The
reaction mixture was treated with the alkene (0.22 mmol). After the
mixture had been stirred for 5 min at –78 °C, it was immediately
warmed to 0 °C and further stirred for 60 min. Then MeOH
(0.10 mL) was added and the mixture was stirred for additional
10 min at 0 °C. Then 2,4,6-collidine (0.10 mL) was added, followed
by water (4 mL). After extraction of the reaction mixture with
dichloromethane (3ϫ10 mL), drying of the combined organic
Scheme 7. Styrene as nucleophile.
Conclusions
Six new diselenides could be synthesized with either a
sulfone or sulfoxide moiety as a side chain. Crystal struc-
ture comparison and methoxyselenenylation reactions show
that the obtained diselenides can be easily converted into
selenium electrophiles. The sulfoxide-containing diselenide
shows, depending on the solvent, good diastereoselective in-
duction in the methoxyselenenylation of activated alkenes. phases with MgSO4 and removal of the solvent under reduced pres-
sure, the residue was purified by flash column chromatography
(ethyl acetate/hexanes, 1:5) on neutral Al2O3, yielding the addition
products as pale yellow oils.
Additionally the new diselenides can be used to easily form
interesting six-membered heterocyclic ring systems (2,3-di-
hydro-1,4-benzoselenothiine 1-oxides). The formation of
these heterocycles seems to be a very selective process, with
oxygen and the aryl ring system on the same side. A pos-
Bis[2-(tert-Butylsulfinyl)phenyl] Diselenide (3): To a solution of tert-
butyl phenyl sulfoxide (13 mmol, 2.37 g) in 130 mL dry THF was
sible mechanism for the product formation could be pro- added slowly n-butyllithium (2.5  solution in hexane, 14.3 mmol,
5.72 mL) at –78 °C. The mixture was stirred for 1.5 h at this tem-
perature. Then selenium (14.3 mmol, 1.13 g) was added with vigor-
ous stirring at 0 °C. After 15 h stirring at room temperature the
mixture was quenched with 100 mL water and extracted with
dichloromethane (3ϫ100 mL). The combined organic phases were
dried with MgSO4 and the solvent was removed in vacuo. After
column chromatography (hexane/ethyl acetate, 4:1, 1:4) diselenide
3 was isolated with 39% yield (2.64 g) as yellow oil which crys-
tallized from diethyl ether upon standing. 1H NMR (400 MHz,
CDCl3): δ = 7.67–7.58 (t, J = 12 Hz, 4 H, ArH), 7.36–7.25 (d, J =
8 Hz, 4 H, ArH), 1.20 [d, J = 5.4 Hz, 18 H, C(CH3)3] ppm. 13C
NMR (126 MHz, CDCl3): δ = 140.8 (C), 140.8* (C), 132.7 (CH),
132.4 (CH), 132.2 (C), 132.2* (C), 127.7 (CH), 127.7* (CH), 127.5
(CH), 127.5* (CH), 58.6 [C(CH3)3], 58.6* [C(CH3)3], 23.3 [C(CH3)
3] ppm. 77Se NMR (57 MHz, CDCl3): δ = 438, 440 ppm. IR (film):
posed, according to the obtained crystal structure. Further
investigations in this research are under way.
Experimental Section
1
General: Melting points were obtained in open capillary tubes. H
NMR and 13C NMR spectra were recorded on a AV-400 Bruker
using the solvents indicated with 400 and 100 MHz, respectively,
also a DRX-500 Bruker was used in the some cases for 1H
(500 MHz) and 13C (125 MHz). Mass spectra (m/z) and HRMS
were recorded under the conditions of electron impact (EI) and
electrospray (ES) and chemical ionization (CI). All reactions were
monitored by thin-layer chromatography that was performed on
precoated sheets of silica gel 60, and flash column chromatography
was performed with silica gel 60 (Merck, 230–400 mesh). Eluting
ν = 2962, 2925, 2235, 1569, 1471, 1455, 1439, 1362, 1168, 1127,
˜
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Sulfoxide-Containing Diselenides
1045, 1018, 921, 755, 731 cm–1. MS (ES+): m/z (%) = [M + H]+:
544 (15), 523 (100), 497 (43), 462 (23), 449 (30), 423 (15), 391 (17),
279 (22), 260 (47), 235 (22), 205 (30), 187 (13). HRMS (ES+): [M
+ H]+ C20H27O2S276Se2 calcd. 514.9831; found 514.9829; m.p. 115–
116 °C (crystals from diethyl ether).
temperature the mixture was quenched with 90 mL water and ex-
tracted with dichloromethane (3ϫ90 mL). The combined organic
phases were dried with MgSO4 and the solvent was removed in
vacuo. After column chromatography (hexane/ethyl acetate, 4:1,
1:1) the products 9 and 10 were isolated as yellow amorphous solids
which were recrystallized from chloroform.
Bis[2-(tert-Butylsulfonyl)phenyl] Diselenide (5): To a solution of
tert-butyl phenyl sulfone (2.55 mmol, 505 mg) in 25 mL dry THF
was added slowly n-butyllithium (2.5  solution in hexane,
2.8 mmol, 1.12 mL) at –78 °C. The mixture was stirred for 1.5 h at
this temperature. Then selenium (2.8 mmol, 221 mg) was added
with vigorous stirring at 0 °C. After 15 h stirring at room tempera-
ture the mixture was quenched with 25 mL water and extracted
with dichloromethane (3ϫ25 mL). The combined organic phases
were dried with MgSO4 and the solvent was removed in vacuo.
After column chromatography (hexane/ethyl acetate, 4:1, 1:4) the
diselenide 5 was isolated with 28% yield (395 mg) as yellow oil
which crystallized from diethyl ether upon standing. 1H NMR
(500 MHz, CDCl3): δ = 7.76 (ddd, J = 1.7, J = 7.5, J = 18.5 Hz, 4
H, ArH), 7.33 (dt, J = 1.7, J = 7.5, J = 18.5 Hz, 1 H, 4 H, ArH),
1.38 [s, 18 H, C(CH3)3] ppm. 13C NMR (126 MHz, CDCl3): δ =
134.3 (CH), 133.9 (C), 133.7 (CH), 132.9 (C), 131.6 (CH), 126.8
(CH), 62.6 [C(CH3)3], 23.8 [C(CH3)3] ppm. 77Se NMR (57 MHz,
Bis[2-(tert-Butylsulfonyl)-6-methoxyphenyl] Diselenide (9): Yield 3%
(162 mg); yellow crystals. 1H NMR (400 MHz, CDCl3): δ = 7.52
4
3
3
(dd, J = 1.1, J = 7.9 Hz, 2 H, ArH), 7.38 (t, J = 8.1 Hz, 2 H,
ArH), 7.10 (dd, 4J = 0.9, 3J = 8.2 Hz, 2 H, ArH), 3.92 (s, 6 H,
OMe), 1.19 [s, 18 H, C(CH3)3] ppm. 13C NMR (500 MHz, CDCl3):
δ = 160.4 (C), 139.1 (C), 128.8 (CH), 125.4 (CH), 124.0 (C), 115.6
(CH), 61.4, 56.8, 24.0 [C(CH3)3] ppm. 77Se NMR (57 MHz,
CDCl ): δ = 465 ppm. IR (film): ν = 2972, 2926, 1570, 1458, 1432,
˜
3
1286, 1260, 1183, 1156, 1106, 1029, 841, 790, 723, 656 cm–1. MS
(ES+): m/z (%) = [M + H]+: 614 (80), 556 (10), 534 (10), 438 (8),
372 (3), 356 (7), 292 (13), 251 (100), 234 (55), 186 (25), 172 (10),
57 (65). HRMS (ES+): [M + H]+ calcd. for C22H30O6S276Se2:
605.9863; found 605.9866; m.p. (crystals from CHCl3): 253–256 °C.
Bis[2-(tert-Butylsulfonyl)-4-methoxyphenyl] Diselenide (10): Yield
8% (431 mg); yellow crystals. 1H NMR (400 MHz, CDCl3): δ =
3
4
7.69 (d, J = 8.9 Hz, 2 H, ArH), 7.38 (d, J = 2.8 Hz, 2 H, ArH),
6.99 (dd, 4J = 2.9, 3J = 8.9 Hz, 2 H, ArH), 3.82 (s, 6 H, OMe),
1.45 [s, 18 H, C(CH3)3] ppm. 13C NMR (500 MHz, CDCl3): δ =
159.0 (C), 134.5 (C), 133.3 (CH), 123.0 (C), 121.2 (CH), 118.8
(CH), 63.1, 56.3, 24.3 [C(CH3)3] ppm. 77Se NMR (57 MHz,
CDCl ): δ = 477 ppm. IR (film): ν = 2985, 1573, 1559, 1476, 1440,
˜
3
1421, 1395, 1364, 1293, 1278, 1252, 1193, 1139, 1114, 1086, 1039,
1021, 799, 761, 736, 707, 649, 634, 570 cm–1. MS (ES+): m/z (%)
= [M + NH4]+: 576 (8), 574 (11), 573 (37), 571 (100), 569 (89), 567
(50), 565 (14), 565 (4), 482 (2), 480 (5), 476 (3). HRMS: (ES+): [M
CDCl ): δ = 467 ppm. IR (film): ν = 2971, 1591, 1465, 1435, 1291,
˜
3
+
NH4]+ calcd. for C20H30O4S274Se76SeN: 512.9864; found
1259, 1230, 1145, 1037, 707, 653 cm–1. MS (ES+): m/z (%) = [M +
H]+: 614 (80), 556 (15), 438 (12), 372 (5), 308 (10), 292 (17), 251
(100), 234 (60), 186 (30), 171 (11), 77 (6), 57 (81). HRMS (ES+):
[M + H]+ calcd. for C22H30O6S276Se2: 605.9863; found 605.9866;
m.p. (foam): 85 °C; m.p. (crystals from CHCl3): 193–196 °C.
512.9864; m.p. 204–206 °C (crystals from diethyl ether).
Bis[2-(tert-Butylsulfinyl)-6-methoxyphenyl] Diselenide (7): To
a
solution of tert-butyl 3-methoxyphenyl sulfoxide (2.80 mmol,
600 mg) in 20 mL dry THF was added slowly n-butyllithium (2.5 
solution in hexane, 3.20 mmol, 1.28 mL) at –78 °C. The mixture
was stirred for 1.5 h at this temperature. Then selenium (2.85 mmol,
225 mg) was added with vigorous stirring at 0 °C. After 15 h stir-
ring at room temperature the mixture was quenched with 20 mL
water and extracted with dichloromethane (3ϫ20 mL). The com-
bined organic phases were dried with MgSO4 and the solvent was
removed in vacuo. After column chromatography (hexane/ethyl
acetate, 4:1, 1:1, then 1:2) the diselenide 7 was isolated with 24%
(S)-Bis[2-(tert-Butylsulfinyl)phenyl] Diselenide (14): To a solution of
(–)-(S)-tert-butyl phenyl sulfoxide (1.21 mmol, 220 mg) in 12 mL
dry THF was added slowly n-butyllithium (2.5  solution in hex-
ane, 1.24 mmol, 0.496 mL) at –78 °C. The mixture was stirred for
1.5 h at this temperature. Then selenium (1.24 mmol, 98.0 mg) was
added with vigorous stirring at 0 °C. After 15 h stirring at room
temperature the mixture was quenched with 10 mL water and ex-
tracted with dichloromethane (3ϫ10 mL). The combined organic
phases were dried with MgSO4 and the solvent was removed in
vacuo. After column chromatography (hexane/ethyl acetate, 4:1,
1:4) the diselenide 14 was isolated with 39% yield (245 mg) as yel-
low oil which crystallized from diethyl ether upon standing. 1H
NMR (500 MHz, CDCl3): δ = 7.64 (dd, 4J = 1.3, 3J = 7.7 Hz, 2
1
yield (391 mg) as yellow foam. H NMR (400 MHz, CDCl3): δ =
7.51 (t, J = 7.8 Hz, 2 H, ArH), 7.49 (t, J = 7.8 Hz, 2 H, ArH)*,
7.43 (dd, J = 1.1, J = 7.8 Hz, 2 H, ArH), 7.40 (dd, J = 1.1, J =
7.8 Hz, 2 H, ArH)*, 7.01 (dd, J = 1.0, J = 8.1 Hz, 2 H, ArH), 6.98
(dd, J = 0.94, J = 8.1 Hz, 2 H, ArH)*, 3.71 (s, 6 H, OMe), 3.70 (s,
6 H, OMe)*, 1.19 [s, 18 H, C(CH3)3], 1.12 [s, 18 H, C(CH3)3]* ppm.
13C NMR (500 MHz, CDCl3): δ = 159.9* (C), 159.7 (C), 146.4*
(C), 146.1 (C), 130.7* (CH), 130.5 (CH), 120.3 (C), 119.1* (CH),
119.0 (CH), 113.1* (CH), 113.0 (CH), 58.3*, 57.8, 56.5*, 56.4,
23.5* [C(CH3)3], 23.3 [C(CH3)3] ppm. 77Se NMR (57 MHz,
4
3
4
H, ArH), 7.61 (dd, J = 1.6, J = 7.5 Hz, 2 H, ArH), 7.32 (dt, J
= 1.4, 3J = 7.5 Hz, 2 H, ArH), 7.28 (dt, 4J = 1.7, J = 7.5 Hz, 1 H,
3
2 H, ArH), 1.20 [s, 9 H, C(CH3)3] ppm. 13C NMR (126 MHz,
CDCl3): δ = 140.9 (C), 132.4 (CH), 132.2 (CH), 131.3 (C), 127.7
(CH), 127.5 (CH), 58.6 [C(CH3)3], 23.3 [C(CH3)3] ppm. 77Se NMR
CDCl ): δ = 378 ppm. IR (film): ν = 2965, 2934, 1699, 1567, 1456,
˜
3
(57 MHz, CDCl ): δ = 436 ppm. IR (KBr): ν = 2960, 1568, 1440,
˜
3
1429, 1263, 1181, 1160, 1040, 785, 725 cm–1. MS (ES+): m/z (%) =
[M + H]+: 1180 (17), 583 (100), 503 (15), 291 (58), 235 (38). HRMS
(ES+): [M + H]+ calcd. for C22H31S2O474Se 76Se: 573.0075; found
573.0078.
1362, 1167, 1081, 1047, 1018, 756 cm–1. MS (ES+): m/z (%) = [M
+ H]+: 526 (30), 523 (100), 519 (50), 515 (3), 263 (17), 261 (100),
259 (44), 257 (17), 207 (17), 205 (95), 203 (42), 201 (17). HRMS
(ES+): [M + H]+ calcd. for C20H27O2S274Se76Se: 512.9864; found
512.9864. [α]2D0 = –65.45 (c = 0.1, CHCl2); m.p. 118.5–119.5 °C
(crystals from diethyl ether).
Bis[2-(tert-Butylsulfonyl)-6-methoxyphenyl] Diselenide (9) and Bis[2-
(tert-Butylsulfonyl)-4-methoxyphenyl] Diselenide (10): To a solution
of tert-butyl 3-methoxyphenyl sulfone (8.8 mmol, 2.0 g) in 90 mL
dry THF was added slowly n-butyllithium (2.5  solution in hex-
ane, 9.6 mmol, 3.84 mL) at –78 °C. The mixture was stirred for
1.5 h at this temperature. Then selenium (9.6 mmol, 758 mg) was
added with vigorous stirring at 0 °C. After 15 h stirring at room
(R)-4-Methyl-1-[(2,4,6-triisopropylphenyl)sulfinyl]benzene (18): To a
solution of (–)-(1R)-menthyl (S)-toluenesulfinate (1 mmol, 294 mg)
in 5 mL dry THF was added slowly (2,4,6-triisopropylphenyl)mag-
nesium bromide (1.5 mmol) at 0 °C. The mixture was stirred at 0 °C
for 3 h, quenched with 5 mL water and extracted with diethyl ether
Eur. J. Org. Chem. 2010, 3934–3944
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3939

D. M. Freudendahl, M. Iwaoka, T. Wirth
FULL PAPER
(3ϫ10 mL). The combined organic phases were dried with Na2SO4
and the solvent was removed in vacuo. After column chromatog-
raphy (petroleum ether/diethyl ether, 10:1) the product was isolated
with 60% yield (205 mg) as white solid. 1H NMR (500 MHz,
CDCl3): δ = 7.21 (m, 2 H, ArH), 7.15 (m, 2 H, ArH), 7.01 (s, 2 H,
ArH), 3.68 [m, 2 H, CH(CH3)3], 2.81 [m, 1 H, CH(CH3)3], 2.29 (s, 3
H, ArCH3), 1.19 [m, 36 H, CH(CH3)3] ppm. 13C NMR (125 MHz,
CDCl3): δ = 153.2, 151.2, 143.2, 139.3, 135.7, 129.5, 124.6, 123.4,
C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ = 143.7 (C), 138.1
(C), 134.1 (CH), 132.9 (C), 131.6 (C), 131.3 (CH), 129.6 (CH),
129.0 (CH), 127.4 (CH), 127.4 (CH), 127.2 (CH), 127.1 (CH), 78.8
(CHOCH3), 58.1 [C(CH3)3], 57.6 (OCH3), 35.8 (SeCH2CH), 23.3
[C(CH3)3] ppm.
Sulfoxide 22b: Synthesized according to GB 1; yield 51% (40 mg);
yellow foam; mixture of diastereomers 6:1 (solvent: THF). IR
(film): ν = 3056, 2934, 1643, 1570, 1443, 1267, 1151, 1102, 1030,
˜
34.4, 24.7, 23.7 ppm. IR (KBr): ν = 2956, 1598, 1560, 1492, 1458,
˜
958, 851, 738, 703, 640, 591 cm–1. MS (ES+): m/z (%) = [M +
NH4]+: 815 (20), 793 (25), 752 (3), 664 (5), 455 (13), 419 (19), 397
(100), 309 (14), 261 (10), 216 (18). HRMS (ES+): [M + NH4]+:
calcd. for C19H25O2S74Se: 391.0795; found 391.0800. [α]2D0 = –127.7
1423, 1382, 1362, 1301, 1083, 1042, 1025, 809 cm–1. MS (ES+): m/z
(%) = [M + H]+: 343 (100), 327 (83), 312 (3), 285.3 (2), 250 (3),
233 (5), 189 (8), 161 (5), 140 (18), 124 (10), 108 (15), 98 (6), 91
(10), 84 (10), 72 (10), 58 (10), 44 (10). HRMS (ES+): [M + H+]
calcd. for C22H30OS: 343.2090; found 343.2091.
1
(c = 0.44, CHCl2). Major isomer: H NMR (400 MHz, CDCl3): δ
= 7.72 (dd, J = 7.8, 1.4 Hz, 1 H, ArH), 7.48 (dd, J = 7.7, 1.0 Hz,
1 H, ArH), 7.36 (dt, J = 7.8, 7.6, 1.3 Hz, 1 H, ArH), 7.26 (m, 6 H,
ArH), 4.28 (dd, J = 8.3, 5.1 Hz, 1 H, CHOCH3), 3.29 (dd, J =
12.1, 8.3 Hz, 1 H, SeCH2CH), 3.14 (s, 3 H, OCH3), 3.01 (dd, J =
12.2, 5.0 Hz, 1 H, SeCH2CH), 1.15 [s, 9 H, C(CH3)3] ppm. 13C
NMR (125 MHz, CDCl3): δ = 142.4 (C), 139.4 (C), 132.9 (CH),
130.5 (CH), 127.6 (2CH), 127.2 (CH), 126.5 (2CH), 125.6 (2CH),
123.4 (C), 81.8 (CHOCH3), 57.2 [C(CH3)3], 55.1 (OCH3), 36.2
(SeCH2CH), 22.3 [C(CH3)3] ppm. Minor isomer: 1H NMR
(400 MHz, CDCl3): δ = 7.72 (dd, J = 7.8, 1.4 Hz, 1 H, ArH), 7.43
(dd, J = 7.8, 1.0 Hz, 1 H, ArH), 7.36 (dt, J = 7.8, 7.6, 1.3 Hz, 1 H,
ArH), 7.26 (m, 6 H, ArH), 4.26 (m, 1 H, CHOCH3), 3.22 (dd, J =
12.1, 9.2 Hz, 1 H, SeCH2CH), 3.17 (s, 3 H, OCH3), 3.04 (m, 1
H, SeCH2CH), 1.15 [s, 9 H, C(CH3)3] ppm. 13C NMR (125 MHz,
CDCl3): δ = 142.5 (C), 139.5 (C), 132.9 (CH), 130.6 (CH), 127.6
(2CH), 127.3 (CH), 126.6 (2CH), 125.6 (2CH), 123.4 (C), 81.8
(CHOCH3), 57.3 [C(CH3)3], 55.1 (OCH3), 36.2 (SeCH2CH), 22.3
[C(CH3)3] ppm.
Bis{5-methyl-2-[(2,4,6-triisopropylphenyl)sulfinyl]phenyl} Diselenide
(19): To a solution of diisopropylamine (2.58 mmol, 362 µL) in dry
THF (8 mL) under argon was added n-butyllithium (2.40 mmol,
960 µL, 2.5  solution in hexane) at 0 °C. After 15 min the solution
was cooled to –78 °C and (R)-4-methyl-1-(2,4,6-triisopropylphenyl-
sulfinyl)benzene (0.86 mmol, 292 mg) in dry THF (3 mL) was
added. This mixture was stirred at –78 °C for 90 min and then
warmed to 0 °C. After 10 min selenium was added with vigorous
stirring and the mixture was warmed to room temperature over-
night. To this mixture was added 1  hydrochloric acid (15 mL)
and the layers were separated. The aqueous layer was washed 3 x
with 10 mL diethyl ether and the combined organic layers were
treated with 100 mg potassium hydroxide and dried with Na2SO4.
After the solvent was removed in vacuo and column chromatog-
raphy (petroleum ether/diethyl ether, 2:1) diselenide 19 was ob-
1
tained with 6% yield (43 mg) as a yellow oil. H NMR (400 MHz,
CDCl3): δ = 7.54 (br. s, 2 H, ArH), 7.14 (d, J = 8 Hz, 2 H, ArH),
7.02 (m, 6 H, ArH), 3.72 [m, 4 H, CH(CH3)3], 2.83 [sep, J = 7 Hz,
2 H, CH(CH3)3], 2.27 (s, 6 H, ArCH3), 1.18 [d, J = 7 Hz, 18 H,
CH(CH3)3], 1.13 [d, J = 7 Hz, 18 H, CH(CH3)3] ppm. 13C NMR
(125 MHz, CDCl3): δ = 153.8, 151.5, 142.7, 141.2, 134.8, 134.5,
129.9, 128.3, 126.1, 123.3, 34.4, 29.2, 24.1, 23.7, 21.1 ppm. IR
Sulfoxide 22c: Synthesized according to GB 1; yield 32% (28 mg),
mixture of diastereomers 5:1 (solvent: THF). IR (film): ν = 2928,
˜
1711, 1598, 1445, 1366, 1262, 1153, 1095, 1045, 753 cm–1. MS
(ES+): m/z (%) = [M + H]+: 893 (34), 796 (4), 469 (5), 447 (100),
359 (12), 260 (7). HRMS (ES+): calcd. for C23H27O2S80Se:
447.0891; found 447.0886. Major isomer: 1H NMR (400 MHz,
CDCl3): δ = 7.88–7.69 (m, 5 H, ArH), 7.57 (dd, J = 7.7, 1.1 Hz, 1
H, ArH), 7.53–7.46 (m, 2 H, ArH), 7.46–7.37 (m, 2 H, ArH), 7.37–
7.27 (m, 1 H, ArH), 4.50 (dd, J = 7.9, 5.5 Hz, 1 H, CHOCH3),
3.45 (dd, J = 12.22, 8.01 Hz, 1 H, SeCH2CH), 3.25 (s, 3 H, OCH3),
3.15 (dd, J = 12.21, 5.46 Hz, 1 H, SeCH2CH), 1.21 [s, 9 H,
C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ = 143.6 (C), 137.8
(C), 133.9 (CH), 133.3 (C), 133.1 (CH), 131.6 (CH), 131.4 (CH),
128.6 (CH), 127.9 (CH), 127.7 (CH), 127.5 (CH), 127.5 (CH), 126.3
(2CH), 126.1 (CH), 123.9 (CH), 83.1 (CHOCH3), 58.2 [C(CH3)3],
57.2 (OCH3), 36.8 (SeCH2CH), 23.3 [C(CH3)3] ppm. Minor isomer:
1H NMR (400 MHz, CDCl3): δ = 7.88–7.69 (m, 5 H, ArH), 7.57
(dd, J = 7.7, 1.1 Hz, 1 H, ArH), 7.53–7.46 (m, 2 H, ArH), 7.46–
7.37 (m, 2 H, ArH), 7.37–7.27 (m, 1.2 H, ArH), 4.50 (m, 1 H,
CHOCH3), 3.39 (dd, J = 12.15, 9.17 Hz, 1 H, SeCH2CH), 3.29 (s,
3 H, OCH3), 3.18 (m, 1 H, SeCH2CH), 1.23 [s, 9 H, C(CH3)3] ppm.
13C NMR (125 MHz, CDCl3): δ = 143.4 (C), 137.9 (C), 133.9 (CH),
133.5 (C), 133.2 (CH), 132.1 (CH), 131.3 (CH), 128.5 (CH), 127.9
(CH), 127.7 (CH), 127.4 (CH), 127.2 (CH), 126.3 (2ϫ CH), 125.9
(CH), 123.9 (CH), 83.0 (CHOCH3), 58.2 [C(CH3)3], 57.0 (OCH3),
37.3 (SeCH2CH), 23.3 [C(CH3)3] ppm.
(film): ν = 2961, 2926, 2868, 1595, 1456, 1384, 1363, 1045, 1018,
˜
909, 732 cm–1. 77Se NMR (500 MHz, CDCl3): δ = 452.1 ppm. MS
(NES+): m/z (%) = [M + H]+: 921 (8), 843 (100), 523 (5), 391 (4).
HRMS (NES+): [M + H+] calcd. for C44H59O2S276Se2: 835.2335;
found 835.2336.
Sulfoxide 22a: Synthesized according to GB 1; yield 41% (35 mg),
mixture of diastereomers 11:1 (solvent: CH2Cl2). MS (ES+): m/z
(%) = [M + H]+: 861 (5), 431 (100), 342 (23), 204 (14). HRMS
(ES+): calcd. for C19H24O2ClS74Se: 425.0405; found 425.0410. IR
(film): ν = 3055, 2929, 2824, 1571, 1471, 1444, 1360, 1227, 1167,
˜
1105, 1047, 1022, 965, 757, 705, 666 cm–1 Major isomer: 1H NMR
(400 MHz, CDCl3): δ = 7.73 (dd, J = 7.83, 1.46 Hz, 1 H, ArH),
7.57 (dd, J = 7.63, 0.97 Hz, 1 H, ArH), 7.35–7.46 (m, 2 H, ArH),
7.22–7.33 (m, 2 H, ArH) 7.17 (d, J = 1.65 Hz, 1 H, ArH), 7.15 (d,
J = 1.45 Hz, 1 H, ArH), 4.83 (dd, J = 8.41, 3.77 Hz, 1 H,
CHOCH3), 3.24 (s, 3 H, OCH3), 3.10–3.23 (m, 2 H, SeCH2CH),
1.19 [s, 9 H, C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ =
143.5 (C), 138.1 (C), 134.1 (CH), 132.8 (C), 131.7 (C), 131.3 (CH),
129.5 (CH), 129.0 (CH), 127.4 (CH), 127.4 (CH), 127.3 (CH), 127.1
(CH), 79.3 (CHOCH3), 58.2 [C(CH3)3], 57.4 (OCH3), 35.6
(SeCH2CH), 23.3 [C(CH3)3] ppm. Minor isomer: 1H NMR
(400 MHz, CDCl3): δ = 7.77 (dd, J = 7.86, 1.43 Hz, 1 H, ArH),
7.53 (dd, J = 7.78, 0.95 Hz, 1 H, ArH), 7.35–7.46 (m, 2 H, ArH),
7.22–7.33 (m, 2 H, ArH), 7.19 (d, J = 3.77 Hz, 1 H, ArH), 7.13 (d,
J = 1.67 Hz, 1 H, ArH), 4.68 (dd, J = 9.33, 3.26 Hz, 1 H,
Sulfoxide 22d: Synthesized according to GB 1; yield 38% (31 mg);
mixture of diastereomers 4:1 (solvent: CH2Cl2). MS (ES+): m/z (%)
= [M + H]+: 821 (50), 433 (6), 411 (100), 379 (22), 323 (12), 260
CHOCH3), 3.24 (s, 3 H, OCH3), 3.10–3.23 (m, 1 H, SeCH2CH), (29), 204 (6). HRMS (ES+): C23H27O2S80Se: calcd. 411.0891; found
3.02 (dd, J = 12.40, 9.33 Hz, 1 H, SeCH2CH), 1.19 [s, 9 H,
411.0889. IR (film): ν = 3054, 2976, 2824, 1571, 1492, 1445, 1422,
˜
3940
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 3934–3944

Sulfoxide-Containing Diselenides
1
1362, 166, 1073, 1046, 1022, 868, 763, 701 cm–1 Major isomer: H
4.88 (dd, J = 3.5, J = 9.1 Hz, 1 H, CHOCH3), 3.86 (s, 3 H, OCH3),
3.20 (m, 4 H, OCH3 and SeCH2CH), 2.96 (dd, J = 3.5, J = 12.2 Hz,
NMR (400 MHz, CDCl3): δ = 7.72 (dd, J = 7.76, 0.97 Hz, 1 H,
ArH), 7.44 (d, J = 7.72 Hz, 1 H, ArH), 7.20–7.40 (m, 7 H, ArH), 1 H, 1 H, SeCH2CH), 1.15 [s, 9 H, C(CH3)3] ppm. 13C NMR
3.43 (d, J = 11.56 Hz, 1 H, SeCH2CH), 3.17 (d, J = 11.54 Hz, 1
H, SeCH2CH), 3.07 (s, 3 H, OCH3), 1.68 (s, 3 H, CH3), 1.16 [s, 9
H, C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ = 157.3 (C),
143.3 (C), 134.2 (CH), 132.3 (C), 131.4 (CH), 128.4 (2CH), 127.4
(63 MHz, CDCl3): δ = 159.2 (C), 146.8 (C), 138.2 (C), 132.7 (C),
129.5 (CH), 129.3 (CH), 128.9 (CH), 127.4 (CH), 127.2 (CH), 119.6
(2CH), 112.5 (CH), 79.9 (COCH3), 58.3 [C(CH3)3], 57.5 (OCH3),
56.3 (OCH3), 34.3 (ArSeCH), 23.6 [C(CH3)3] ppm; Isomer B: 1H
(CH), 127.2 (CH), 126.2 (2CH), 121.3 (CH), 78.9 (COCH3), 58.2 NMR (400 MHz, CDCl3): δ = 7.51 (d, J = 8.5 Hz, 1 H, ArH), 7.38
[C(CH3)3], 51.1 (OCH3), 44.2 (SeCH2CH), 24.2 (CCH3), 23.4
[C(CH3)3] ppm; Minor Isomer: H NMR (500 MHz, CDCl3): δ =
(dd, J = 1.7, J = 8.0 Hz, 1 H, ArH), 7.23 (m, 3 H, ArH), 7.13 (m,
1 H, ArH), 6.85 (dd, J = 2.9, J = 8.5 Hz, 1 H, ArH), 4.76 (dd, J
= 3.6, J = 8.8 Hz, 1 H, CHOCH3), 3.78 (s, 3 H, OCH3), 3.22 (s, 3
H, OCH3), 3.07 (dd, J = 8.8, J = 12.5 Hz, 1 H, SeCH2CH), 2.99
(dd, J = 3.6, J = 12.5 Hz, 1 H, SeCH2CH), 1.17 [s, 9 H, C(CH3)3]
ppm. 13C NMR (125 MHz, CDCl3): δ = 159.9 (C), 146.8 (C), 138.0
(C), 137.3 (C), 132.9 (CH), 129.6 (CH), 128.0 (CH), 127.3 (CH),
1
7.72 (dd, J = 7.76, 0.97 Hz, 1 H, ArH), 7.20–7.40 (m, 8 H, ArH),
3.37 (d, J = 11.61 Hz, 1 H, SeCH2CH), 3.19 (d, J = 11.63 Hz, 1
H, SeCH2CH), 3.09 (s, 3 H, OCH3), 1.68 (s, 3 H, CH3), 1.17 [s, 9
H, C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ = 157.3 (C),
143.7 (C), 134.0 (CH), 132.6 (C), 131.3 (CH), 128.4 (2CH), 127.5
(CH), 127.2 (CH), 126.1 (2CH), 121.3 (CH), 78.9 (COCH3), 58.1 127.1 (CH), 118.8 (2CH), 111.6 (CH), 79.4 (COCH3), 58.5
[C(CH3)3], 51.1 (OCH3), 44.2 (SeCH2CH), 24.2 (CCH3), 23.5 [C(CH3)3], 57.4 (OCH3), 55.7 (OCH3), 36.2 (ArSeCH), 23.5
[C(CH3)3] ppm.
[C(CH3)3] ppm.
Sulfoxide 22e: Synthesized according to GB 1; yield 30% (27 mg);
mixture of diastereomers 11:1 (solvent: CH2Cl2). MS (ES+): m/z
(%) = [M + H]+: 821 (2), 411 (100), 323 (25), 204 (16). HRMS:
2-(tert-Butylsulfinyl)-6-methoxyphenyl
2-Methoxy-2-phenylethyl
Selenide (23b): Synthesized according to GB 1; yield 24% (20 mg),
mixture of diastereomers 2:1 (solvent: chloroform, –50 °C). MS
(ES+): m/z (%) = [M + H]+: 490 (100) [M + Na + acetonitrile+],
calcd. for C H O S74Se 405.0951; found 405.0960. IR (film): ν =
˜
20 27
2
2975, 2927, 1445, 1125, 1080, 1045, 1022, 755, 702 cm–1 Minor 449 (80) [M + Na+], 427 (75), 425 (40), 380 (15), 339 (30), 276 (35),
isomer is indicated by:*. 1H NMR (500 MHz, CDCl3): δ = 7.84
(dd, J = 1.4, J = 7.9 Hz, 1 H, ArH), 7.81 (dd, J = 1.4, J = 7.9 Hz,
1 H, ArH)*, 7.61 (m, 1 H, ArH)*, 7.59 (dd, J = 1.1, J = 7.7 Hz, 1
H, ArH), 7.47 (dt, J = 1.3, J = 7.6 Hz, 1 H, ArH), 7.36 (m, 3 H,
130 (25), 85 (38). HRMS: [M + H]+ C20H27O3S 80Se calcd.
427.0846; found 427.0865. IR: ν = 2936, 1568, 1492, 1455, 1429,
˜
1360, 1286, 1260, 1169, 1149, 1104, 1040, 1026, 957, 833, 786, 768,
1
702 cm–1 Isomer is indicated by:*. H NMR (400 MHz, CDCl3): δ
ArH), 7.29 (m, 3 H, ArH), 4.41 (d, J = 4.7 Hz, 1 H, SeCHCH), = 7.47 (m, 2 H, ArH), 7.35 (m, 1 H, ArH), 7.28 (m, 3 H, ArH),
4.32 (d, J = 4.3 Hz, 1 H, SeCHCH)*, 3.52 (dq, J = 4.7, J = 7.0 Hz, 7.22 (m, 1 H, ArH) 6.97 (dd, J = 2.6, J = 6.7 Hz, 1 H, ArH), 6.94
1 H, 1 H, SeCHCH), 3.29 (s, 3 H, OCH3)*, 3.28 (s, 3 H, OCH3), (dd, J = 3.0, J = 6.2 Hz, 1 H, ArH)*, 4.39 (dd, J = 5.3, J = 8.3 Hz,
1.31 (d, J = 7.0 Hz, 3 H, CH3), 1.21 [s, 9 H, C(CH3)3]*, 1.21 [s, 9
H, C(CH3)3] ppm. 13C NMR (500 MHz, CDCl3): δ = 144.8 (C),
139.1 (C), 135.5 (CH), 135.5* (CH), 131.2 (C), 131.0* (C), 128.3
(2CH), 128.2* (2CH), 127.9 (CH), 127.8 (CH), 127.6 (CH), 127.0
(2CH), 126.9* (2CH), 86.2 (COCH3), 58.3 [C(CH3)3], 57.4 (OCH3),
48.6 (SeCHCH) 23.4 [C(CH3)3], 16.6 (SeCHCH3) ppm.
1 H, CHOCH3), 4.18 (dd, J = 4.2, J = 9.4 Hz, 1 H, CHOCH3)*,
3.95 (s, 3 H, OCH3), 3.88 (s, 3 H, OCH3)*, 3.32 (dd, J = 8.4, J =
12.0 Hz, 1 H, SeCH2CH), 3.22 (s, 3 H, OCH3)*, 3.19 (s, 3 H,
OCH3), 3.13 (dd, J = 4.6, J = 7.6 Hz, 1 H, SeCH2CH)*, 3.04 (dd,
J = 4.2, J = 12.2 Hz, 1 H, 1 H, SeCH2CH)*, 2.89 (dd, J = 5.3, J
= 12.0 Hz, 1 H, SeCH2CH), 1.22 [s, 9 H, C(CH3)3]*, 1.20 [s, 9 H,
C(CH3)3] ppm. 13C NMR (63 MHz, CDCl3): δ = 159.1 (C), 140.8
(C), 129.4 (2CH), 128.5 (CH), 128.1 (CH), 127.9* (CH), 126.6
(CH), 126.4 (CH), 119.6 (C), 112.6 (CH), 112.5* (CH), 83.8
(CHOCH3), 58.2 [C(CH3)3], 57.1* (OCH3), 56.9 (OCH3), 56.2
(OCH3), 56.2* (OCH3), 36.0 (SeCH2CH), 23.5 [C(CH3)3] ppm.
Sulfoxide 22f: Synthesized according to GB 1; yield 30% (27 mg);
mixture of diastereomers 9:1 (solvent: CH2Cl2). MS: m/z (%) =
(ES+) m/z (%) [M + H]+: 901 (50), 580 (16), 451 (100), 419 (66), 363
(14), 260 (7). HRMS: calcd. for C20H27O2S80Se: 451.1204; found
451.1197. IR (film): ν = 2935, 2857, 1445, 1361, 1209, 1151, 1065,
˜
1
1047, 1020, 880, 758, 699 cm–1. H NMR (500 MHz, CDCl3): δ = 2-(tert-Butylsulfinyl)-6-methoxyphenyl 2-Methoxy-2-phenylpropyl
7.72 (dd, J = 1.4, J = 7.9 Hz, 1 H, ArH), 7.33 (m, 6 H, ArH), 7.40– Selenide (23c): Synthesized according to GB 1; yield 22% (19 mg);
7.29 (m, 6 H, ArH)*, 7.12 (dt, J = 1.5, J = 7.5 Hz, 1 H, ArH), 6.85
(dd, J = 1.0, J = 7.8 Hz, 1 H, ArH), 3.66 (s, 1 H, ArSeCH), 3.60
mixture of diastereomers 1:1 (solvent: chloroform, –50 °C). MS
(ES+): m/z (%) = [M + H]+: 504 (12), 463 (100) [M + Na]+, 449
(s, 1 H, ArSeCH)*, 2.88 (s, 3 H, OCH3), 2.86 (s, 3 H, OCH3)*, (5), 415 (10). HRMS: [M + Na]+ calcd. C21H28O3SNa80Se:
2.16 (dd, J = 3.4, J = 9.6 Hz, 2 H), 1.73–1.66 (m, 3 H)*, 1.69 (m, 463.0822 found 463.0831. IR: ν = 3059, 1568, 1493, 1455, 1429,
˜
3 H), 1.60 (m, 3 H), 1.12 [s, 9 H, C(CH3)3] ppm. 13C NMR 1362, 1286, 1261, 1167, 1149, 1092, 1072, 1040, 1026, 911, 834,
1
(500 MHz, CDCl3): δ = 144.7 (C), 143.7 (C), 135.8 (CH), 131.0
(CH), 130.9 (CH), 128.1 (2CH), 127.6 (CH), 127.5 (CH), 127.2
(CH), 126.8 (2CH), 79.1 (COCH3), 58.5 [C(CH3)3], 58.3 (OCH3),
786, 766, 701 cm–1 Isomer is indicated by:*. H NMR (250 MHz,
CDCl3): δ = 7.20–7.50 (m, 7 H, ArH), 6.94 (dd, J = 2.6, J = 6.8 Hz,
1 H, ArH), 6.87 (dd, J = 2.7, J = 6.7 Hz, 1 H, ArH)*, 3.91 (s, 3
50.1 (ArSeCH), 27.9 (CH2), 26.0 (CH2), 23.5 [C(CH3)3], 21.3 H, OCH3), 3.84 (s, 3 H, OCH3)*, 3.45 (d, J = 11.0 Hz, 1 H,
(CH2), 20.7 (CH2) ppm.
SeCHCH)*, 3.32 (d, J = 11.5 Hz, 1 H, SeCHCH), 3.20 (d, J =
11.5 Hz, 1 H, SeCHCH), 3.13 (m, 1 H, SeCHCH)*, 3.11 (s, 3 H,
OCH3)*, 3.07 (s, 3 H, OCH3), 1.72 (s, 3 H, CH3), 1.72 (s, 3 H,
CH3)*, 1.19 [s, 9 H, C(CH3)3]*, 1.18 [s, 9 H, C(CH3)3] ppm. 13C
NMR (63 MHz, CDCl3): δ = 159.1, 143.5, 143.5, 129.4, 129.2,
128.2, 128.2, 127.3, 127.3, 126.1, 126.0, 119.6, 119.5, 112.5, 112.4,
79.0, 79.0, 58.2, 56.2, 56.1, 50.9, 42.5, 42.0, 30.3, 23.5, 23.4 ppm.
2-(tert-Butylsulfinyl)-6-methoxyphenyl 2-(2-Chlorophenyl)-2-meth-
oxyethyl Selenide (23a): Synthesized according to GB 1; yield 40%
(37 mg); mixture of diastereomers 2:1 (solvent: chloroform,
–50 °C). MS (ES+): m/z (%) = 524 (100) [[M + MeCNNa]+], 483
(68) [M + Na]+. HRMS: calcd. C20H26O335ClS80Se: 461.0456 found
461.0468. IR: ν = 2934, 1568, 1455, 1428, 1361, 1285, 1260, 1169,
˜
1149, 1104, 1040, 1026, 834, 786, 759, 732, 706 cm–1 Isomer A: 1H
Sulfoxide 24a: Synthesized according to GB 1; yield 47% (45 mg);
NMR (250 MHz, CDCl3): δ = 7.40 (m, 3 H, ArH), 7.22 (m, 1 H, mixture of diastereomers 8:1 (solvent: CH2Cl2). MS (ES+): m/z (%)
ArH), 7.18 (m, 1 H, ArH), 7.10 (m, 1 H, ArH) 6.87 (m, 1 H, ArH),
= [M + H]+: 445 (100), 391 (28), 343 (25), 261 (8), 204 (16). HRMS:
Eur. J. Org. Chem. 2010, 3934–3944
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3941

D. M. Freudendahl, M. Iwaoka, T. Wirth
FULL PAPER
calcd. for C H O ClS74Se 439.0561; found 439.0569. IR (film): ν
(CH), 75.6 [OC(CH3)3], 70.6 (SeCH2CH), 58.7 [C(CH3)3], 37.6 (Ar-
SeCH), 29.0 [OC(CH3)3], 23.8 [C(CH3)3] ppm.
˜
20 26
2
= 2973, 2926, 1572, 1471, 1442, 1362, 1168, 1119, 1096, 1048, 1023,
1
908, 756, 733, 591 cm–1 Minor isomer is indicated by:*. H NMR
Sulfoxide 24d: Synthesized according to GB 1: Reaction in dry
dichloromethane at –78 °C; yield 30% (32 mg); dr: 3.5:1. MS
(ES+): m/z (%) = [M + H]+: 1013 (15), 507 (100), 391 (12), 342
(22), 204 (13). HRMS: calcd. for C25H28O2ClS74Se 425.0418; found
(400 MHz, CDCl3): δ = 7.81 (dd, J = 1.4, J = 7.9 Hz, 1 H, ArH)*,
7.77 (dd, J = 1.5, J = 7.8 Hz, 1 H, ArH), 7.62 (dd, J = 1.2, J =
7.7 Hz, 1 H, ArH), 7.58 (dd, J = 1.1, J = 7.8 Hz, 1 H, ArH)*, 7.51
(m, 1 H, ArH)*, 7.49 (dd, J = 1.6, J = 8.0 Hz, 1 H, ArH), 7.41 (dt,
J = 1.3, J = 7.6 Hz, 1 H, ArH), 7.34 (dt, J = 1.5, J = 7.5 Hz, 1 H,
ArH), 7.28 (m, 2 H, ArH), 7.19 (m, 1 H, ArH), 4.97 (dd, J = 3.6,
J = 8.7 Hz, 1 H, CHOCH3), 4.84 (dd, J = 3.3, J = 9.3 Hz, 1 H,
CHOCH3)*, 3.41 (m, 2 H, CH2CH3), 3.23 (m, 1 H, SeCH2CH),
3.15 (dd, J = 3.7, J = 12.5 Hz, 1 H, SeCH2CH), 3.08 (dd, J = 9.3,
J = 12.4 Hz, 1 H, SeCH2CH)*, 1.23 [s, 9 H, C(CH3)3], 1.18 (t, J =
7.0 Hz, 1 H, CH2CH3) ppm. 13C NMR (400 MHz, CDCl3): δ =
143.2 (C), 138.6 (C), 134.0 (CH), 132.6 (C), 131.9 (C), 131.9* (C),
131.2 (CH), 129.5* (CH), 129.4 (CH), 128.9 (CH), 127.4 (CH),
127.3 (CH), 127.3* (CH), 127.2 (CH), 127.2 (CH), 77.5
(SeCH2CH), 65.3* (OCH2CH3), 65.1 (OCH2CH3), 58.2 [C(CH3)3],
35.9* (ArSeCH), 35.7 (ArSeCH), 23.3 [C(CH3)3], 23.2* [C(CH3)3],
15.2* (OCH2CH3), 15.1 (OCH2CH3) ppm.
501.0717. IR: ν = 3060, 3029, 2973, 2925, 2864, 1570, 1471, 1441,
˜
1361, 1167, 1089, 1047, 1024, 755 cm–1 Minor isomer is indicated
by:*. 1H NMR (400 MHz, CDCl3): δ = 7.72 (dd, J = 1.3, J =
7.9 Hz, 1 H, ArH)*, 7.67 (dd, J = 1.4, J = 7.8 Hz, 1 H, ArH), 7.50
(td, J = 2.6, J = 8.4 Hz, 1 H, ArH), 7.46 (dd, J = 1.1, J = 7.8 Hz,
1 H, ArH)*, 7.42 (dd, J = 1.1, J = 7.8 Hz, 1 H, ArH), 7.36 (m, 1
H, ArH)*, 7.31 (m, 1 H, ArH), 7.20 (m, 8 H, ArH), 5.00 (dd, J =
3.5, J = 8.7 Hz, 1 H, CHOCH2Ar), 4.96 (m, 1 H, CHOCH2Ar)*,
4.34 (m, 2H CHOCH2Ar), 3.22 (dd, J = 8.7, J = 12.6 Hz, 1 H,
SeCH2CH), 3.08 (dd, J = 3.6, J = 12.6 Hz, 1 H, SeCH2CH), 1.14
{s, 9 H, [C(CH3)3]} ppm. 13C NMR (400 MHz, CDCl3): δ = 143.2,
138.0, 137.5, 134.0, 132.8, 131.7, 131.3*, 131.2, 129.6*, 129.6,
129.1, 128.3, 128.0, 127.9, 127.9*, 127.8, 127.7*, 127.4, 127.4,
127.3, 127.3*, 127.3*, 71.6, 71.3, 58.2, 35.9*, 35.5, 23.3 ppm.
Sulfoxide 24b: Synthesized according to GB 1; yield 47% (46 mg);
mixture of diastereomers 8:1 (solvent: CH2Cl2). MS (ES+): m/z (%)
2-Azido-2-(2-chlorophenyl)ethyl 2-(tert-Butylsulfinyl)phenyl Selenide
(24e): Synthesized according to GB 1; yield 35% (33 mg); mixture
= [M + H]+: 481 (7), 459 (100), 391 (28), 343 (13), 199 (14). HRMS: of diastereomers 6:1 (solvent: CH2Cl2). MS (ES+): m/z (%) = [M
calcd. for C H O ClS74Se 453.0718; found 453.0722. IR (film): ν
+ H]+: 442 (100), 368 (20), 343 (40), 261 (2), 205 (21). HRMS:
calcd. for C H ClN OS76Se 438.0281; found 438.0281. IR: ν =
˜
21 28
2
= 2971, 2928, 1572, 1470, 1443, 1378, 1363, 1329, 1166, 1120, 1087,
˜
18 21
3
1
1048, 1023, 941, 756, 705 cm–1 Minor isomer is indicated by:*. H
2963, 2925, 2107, 1472, 1443, 1249, 1046, 1021, 756 cm–1 Minor
isomer is indicated by:*. 1H NMR (400 MHz, CDCl3): δ = 7.82
(dd, J = 1.4, J = 7.9 Hz, 1 H, ArH)*, 7.79 (dd, J = 1.4, J = 7.8 Hz,
1 H, ArH), 7.61 (dd, J = 1.1, J = 7.7 Hz, 1 H, ArH), 7.57 (dd, J
= 1.1, J = 7.7 Hz, 1 H, ArH)*, 7.46 (tt, J = 1.9, J = 3.4 Hz, 2 H,
NMR (400 MHz, CDCl3): δ = 7.80 (dd, J = 1.5, J = 7.9 Hz, 1 H,
ArH)*, 7.77 (dd, J = 1.5, J = 7.8 Hz, 1 H, ArH), 7.62 (dd, J = 1.2,
J = 7.7 Hz, 1 H, ArH), 7.58 (dd, J = 1.2, J = 7.8 Hz, 1 H, ArH)*,
7.54 (dd, J = 1.6, J = 8.1 Hz, 1 H, ArH), 7.40 (dt, J = 1.3, J =
7.6 Hz, 1 H, ArH), 7.33 (dt, J = 1.5, J = 7.5 Hz, 1 H, ArH), 7.28 ArH), 7.38 (dd, J = 1.4, J = 7.5 Hz, 1 H, ArH), 7.30 (m, 2 H,
(m, 2 H, ArH), 7.19 (m, 1 H, ArH), 5.11 (dd, J = 3.4, J = 9.0 Hz, ArH), 7.23 (dd, J = 1.7, J = 7.6 Hz, 1 H, ArH), 7.21 (m, 1 H,
1 H, SeCH2CH), 5.00 (m, 1 H, SeCH2CH)*, 3.51 [sept., J = 6.1 Hz, ArH)*, 5.22 (dd, J = 4.6, J = 8.5 Hz, 1 H, CHN3), 3.31 (dd, J =
1 H, CHOCH(CH3)2], 3.24 (dd, J = 9.1, J = 12.4 Hz, 1 H, 4.6, J = 12.7 Hz, 1 H, SeCH2CH)*, 3.25 (dd, J = 4.6, J = 12.8 Hz,
SeCH2CH), 3.24 (dd, J = 9.1, J = 12.4 Hz, 1 H, SeCH2CH)*, 3.10 1 H, SeCH2CH), 3.18 (dd, J = 8.5, J = 12.8 Hz, 1 H, SeCH2CH),
(dd, J = 3.5, J = 12.3 Hz, 1 H, SeCH2CH), 1.23 [s, 9 H, C(CH3)3],
1.23 [s, 9 H, C(CH3)3]*, 1.19 [d, J = 6.3 Hz, 1 H, CHOCH-
3.09 (dd, J = 9.1, J = 12.6 Hz, 1 H, SeCH2CH)*, 1.22 [s, 9 H,
C(CH3)3] ppm. 13C NMR (400 MHz, CDCl3): δ = 136.1 (C), 134.6
(CH3)2], 1.08 [d, J = 6.4 Hz, 1 H, CHOCH(CH3)2]*, 1.07 [d, J = (C), 134.3 (C), 132.5 (CH), 131.5, 130.1 (C), 129.9 (CH), 129.7
6.2 Hz, 1 H, CHOCH(CH3)2] ppm. 13C NMR (400 MHz, CDCl3): (CH), 128.1 (CH), 127.8 (CH), 127.6 (CH), 127.5 (CH), 62.1
δ = 143.4 (C), 140.0 (C), 134.2 (CH), 134.0* (CH), 132.8 (C), 132.8 (SeCH2CHN3), 58.4 [C(CH3)3], 34.3 (ArSeCH2), 23.3 [C(CH3)3]
(C), 131.7 (CH), 129.8 (CH), 129.3 (CH), 128.0 (CH), 127.8 (CH), ppm.
127.7 (CH), 127.6 (CH), 127.6* (CH), 75.4 (SeCH2CH), 71.2*
Selenathiine 1-Oxide 25a: Synthesized according to GB 2; yield
[OCH(CH3)2], 70.9 [OCH(CH3)2], 58.7 [C(CH3)3], 36.6 (ArSeCH),
10% (6 mg). MS (ES+): m/z (%) = [M + H]+: 617 (10), 421 (10), 331
23.8 [C(CH3)3], 23.6* [C(CH3)3], 22.0* [OCH(CH3)2], 21.9
(15), 309 (100), 205 (6). HRMS: calcd. for C14H13OS76Se 304.9874,
[OCH(CH3)2] ppm.
found 304.9880. [α]2D0 = +48.0 (c = 0.1, CH2Cl2). 1H NMR
(500 MHz, CDCl3): δ = 7.57 (dd, J = 7.8, 0.9 Hz, 1 H, ArH), 7.47
(dd, J = 7.7, 1.4 Hz, 1 H, ArH), 7.37 (dt, J = 7.7, 7.6, 1.5 Hz, 1 H,
ArH), 7.29–7.23 (m, 4 H, ArH), 7.09 (dd, J = 7.6, 1.8 Hz, 2 H,
ArH), 4.51 (dd, J = 8.1, 6.2 Hz, 1 H, SeCH2CHS), 3.88 (dd, J =
Sulfoxide 24c: Synthesized according to GB 1; yield 30% (30 mg);
mixture of diastereomers 6:1 (solvent: CH2Cl2). MS (ES+): m/z (%)
= [M + H]+: 945 (38), 495 (7), 473 (100), 417 (44), 343 (21), 260
(16), 205 (12). HRMS: calcd. for C22H30O2ClS74Se 467.0874; found
11.7, 8.2 Hz, 1 H, SeCH2CHS), 3.33 (dd, J = 11.7, 6.1 Hz, 1 H,
467.0877. IR (film): ν = 2972, 1470, 1443, 1365, 1187, 1082, 1047,
˜
SeCH2CHS) ppm. 13C NMR (126 MHz, CDCl3): δ = 139.5 (C),
134.7 (CH), 131.6 (CH), 131.1 (CH), 130.1 (CH), 128.6 (CH), 128.4
(CH and C), 128.2 (2CH), 127.2 (C), 126.7 (CH), 61.3
1022, 755 cm–1 Minor isomer is indicated by:*. 1H NMR
(400 MHz, CDCl3): δ = 7.79 (dd, J = 1.5, J = 7.9 Hz, 1 H, ArH)*,
7.76 (m, 2 H, ArH), 7.63 (m, 2 H, ArH), 7.58 (dd, J = 1.2, J =
7.7 Hz, 1 H, ArH)*, 7.39 (dt, J = 1.4, J = 7.6 Hz, 1 H, ArH), 7.33
(dt, J = 1.5, J = 7.5 Hz, 1 H, ArH), 7.27 (m, 2 H, ArH), 7.16 (m,
1 H, ArH), 5.21 (dd, J = 3.5, J = 8.9 Hz, 1 H, CHOCH3), 5.14
(dd, J = 3.3, J = 9.1 Hz, 1 H, CHOCH3)*, 3.24 (dd, J = 8.9, J =
12.3 Hz, 1 H, SeCH2CH), 3.19 (m, 1 H, SeCH2CH)*, 3.03 (dd, J
= 3.6, J = 12.3 Hz, 1 H, SeCH2CH), 1.23 [s, 9 H, C(CH3)3], 1.12
(SeCH CHS), 16.7 (SeCH CHS) ppm. IR (film): ν = 3057, 2928,
˜
2
2
1575, 1494, 1452, 1425, 1251, 1093, 1063, 1049, 1030, 754, 728, 698
cm–1.
Selenathiine Oxide 25b: Synthesized according to GB 2; yield 16%
(11 mg). MS (ES+): m/z (%) = [M + H]+: 717 (55), 471 (10), 380
(10), 359 (100). HRMS: calcd. for C18H15OClS80Se 359.0003; found
[s, 9 H, C(CH3)3] ppm. 13C NMR (400 MHz, CDCl3): δ = 142.5 359.0001. IR (film): ν = 3055, 2926, 1443, 1425, 1051, 1031, 909,
˜
1
(C), 133.7 (CH), 133.4 (C), 133.3 (C), 131.7 (CH), 131.5 (C), 129.6 856, 819, 751, 728 cm–1. H NMR (500 MHz, CDCl3): δ = 7.73–
(CH), 129.0 (CH), 128.7 (CH), 127.8 (CH), 127.5 (CH), 127.4
7.63 (m, 3 H, ArH), 7.55–7.50 (m, 2 H, ArH), 7.41–7.37 (m, 2 H,
3942
www.eurjoc.org
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 3934–3944

Sulfoxide-Containing Diselenides
ArH), 7.30 (t, J = 7.8, 1.3 Hz, 1 H, ArH), 7.20–7.18 (m, 1 H, ArH),
7.18–7.13 (m, 1 H, ArH), 7.12–7.09 (m, 1 H, ArH), 4.61–4.56 (m,
1 H, SeCH2CHS), 3.92 (dd, J = 11.7, 8.4 Hz, 1 H, SeCH2CHS),
3.31 (dd, J = 11.7, 6.03 Hz, 1 H, SeCH2CHS) ppm. 13C NMR
(125 MHz, CDCl3): δ = 139.6 (C), 133.1 (C), 133.0 (CH), 132.3
(CH), 131.7 (CH), 131.1 (CH), 130.3 (CH), 128.2 (CH), 128.1
SeCH2CHCHCHAr), 3.30 (m, 2 H, SeCH2CHCHCHAr), 1.12 [s,
9 H, C(CH3)3] ppm. 13C NMR (125 MHz, CDCl3): δ = 143.4 (C),
143.4* (C), 142.7 (C), 142.6* (C), 136.9 (C), 136.8* (C), 133.7,
133.6*, 131.8, 131.8*, 131.7, 131.4, 131.4*, 131.1, 130.9, 128.7,
128.7*, 128.4, 127.6, 127.6*, 127.5, 127.4*, 127.0, 126.9*, 126.3,
126.3*, 122.5, 58.2 [C(CH3)3], 58.1* [C(CH3)3], 49.1 (SeCH2CH),
(CH), 127.7 (CH), 127.6 (CH), 127.3 (C), 126.7 (CH), 126.5 (CH), 49.0* (SeCH2CH), 35.9 (SeCH2CH), 35.8* (SeCH2CH), 23.3
126.4 (CH), 125.7 (CH), 61.5 (SeCH2CHS), 16.8 (SeCH2CHS)
[C(CH3)3] ppm.
ppm. 77Se NMR (57 MHz, CDCl3): δ = 244 ppm.
Selenathiine Oxide 25c: Synthesized according to GB 2; yield 9%
(6 mg). MS (ES+): m/z (%) = [M + H]+: 717 (55), 471 (10), 380 (10),
359 (100). HRMS: calcd. for C14H11O35ClS78Se 339.9392; found
Acknowledgments
We thank Dr. B. Kariuki, Cardiff University, for the X-ray analyses
of 9, 10, 14 and 25b, the Engineering and Physical Sciences Re-
search Council (EPSRC) National Crystallography Service, South-
ampton, for the X-ray analysis of 5, the School of Chemistry,
Cardiff University for support and the EPSRC, National Mass
Spectrometry Service Centre, Swansea, for mass spectrometric
data.
339.9400. IR (film): ν = 3375, 3056, 2972, 2928, 1571, 1471, 1441,
˜
1
1363, 1164, 1092, 1047, 755 cm–1. H NMR (500 MHz, CDCl3): δ
= 7.60 (dd, J = 1.5, J = 7.7 Hz, 1 H, ArH), 7.49 (ddd, J = 5.1, J
= 6.2, J = 16.7 Hz, 1 H, ArH), 7.38 (dd, J = 1.5, J = 6.8 Hz, 1 H,
ArH), 7.34 (dd, J = 1.5, J = 7.7 Hz, 1 H, ArH), 7.25 (dd, J = 2.3,
J = 3.0 Hz, 1 H, ArH), 7.23 (m, 1 H, ArH), 4.79 (dd, J = 3.7, J =
11.9 Hz, 1 H, SeCH2CHS), 4.03 (t, J = 11.9 Hz, 1 H, SeCH2CHS),
3.04 (dd, J = 3.8, J = 11.7 Hz, 1 H, SeCH2CHS) ppm. 13C NMR
(125 MHz, CDCl3): δ = 138.8 (C), 134.1 (C), 132.7 (2CH), 132.6
(CH), 130.8 (CH), 129.8 (C), 129.7 (CH), 128.8 (CH), 127.5 (CH),
127.3 (C), 126.0 (CH), 56.2 (SeCH2CHS), 13.9 (SeCH2CHS) ppm.
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Selenathiine Oxide 25d: Synthesized according to GB 2; yield 12%
(8 mg). IR (film): ν = 3389, 2926, 1571, 1494, 1444, 1094, 1060,
˜
755, 697 cm–1. MS (ES+): m/z (%) = [M + H]+: 645 (25), 490 (8),
338 (7), 323 (100). HRMS: calcd. for C15H15OS80Se 323.0003;
found 323.0002. 1H NMR (400 MHz, CDCl3): δ = 7.81 (dd, J =
7.7, 1.5 Hz, 1 H, ArH), 7.69–7.65 (m, 2 H, ArH), 7.59 (dd, J = 7.6,
1.1 Hz, 1 H, ArH), 7.51–7.29 (m, 5 H, ArH), 3.58 (d, J = 12.3 Hz,
1 H, SeCH2CHS), 3.17 (d, J = 12.3 Hz, 1 H, SeCH2CHS), 1.46 (s,
3 H, CH3) ppm. 13C NMR (125 MHz, CDCl3): δ = 141.2 (C), 131.7
(CH), 130.5 (CH), 128.9 (2CH), 128.4 (CH), 128.1 (CH), 127.6 (C),
127.5 (CH), 126.7 (C), 126.5 (2CH), 64.2 (SeCH2CS), 30.6 (CH3),
20.1 (SeCH2CS) ppm.
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2-(tert-Butylsulfinyl)phenyl (E)-2,4-diphenylbut-3-enyl Selenide (30):
Bis[2-(tert-butylsulfinyl)phenyl] diselenide (1 mmol) was dissolved
in dry tetrahydrofuran (40 mL) under argon, cooled to –78 °C, and
treated with bromine (1 mmol, 1 mL of a 1  solution in CCl4).
After 20 min silver triflate (solid) (540 mg, 2.1 mmol) was added
and the mixture was stirred for 25 min at –78 °C. The reaction mix-
ture was treated with the alkene (2.2 mmol). The mixture was fur-
ther stirred at –78 °C and warmed to –10 °C overnight. Then
MeOH (1 mL) was added and the mixture was stirred for ad-
ditional 60 min at 0 °C. Then 2,4,6-collidine (1 mL) was added, fol-
lowed by water (40 mL). After extraction of the reaction mixture
with dichloromethane (3ϫ50 mL), drying of the combined organic
phases with MgSO4 and removal of the solvent under reduced pres-
sure, the residue was purified by flash column chromatography on
silica gel, yielding the addition products as pale yellow oils. The
diastereomers could not be separated by flash chromatography
(ethyl acetate/hexanes, 1:5); yield 30% (309 mg), pale yellow grease.
MS (ES+): m/z (%) = [M + H]+: 969 (5), 937 (15), 501 (22), 469
(100), 413 (27), 365 (5), 309 (7), 251 (7), 207 (20). HRMS: calcd.
for C H OS74Se 463.1158; found 463.1163. IR (film): ν = 3057,
˜
26 29
3026, 2966, 2926, 1599, 1569, 1494, 1443, 1426, 1362, 1326, 1217,
1148, 1091, 965, 749, 699 cm–1. Mixture of diastereomers (1:1): 1H
NMR (500 MHz, CDCl3): δ = 7.73 (ddd, J = 1.4, J = 3.7, J =
7.8 Hz, 1 H, ArH), 7.45 (td, J = 1.2, J = 7.6 Hz, 1 H, ArH), 7.35
(m, 1 H, ArH), 7.20 (m, 11 H, ArH), 6.37 (dd, J = 15.9, J =
20.4 Hz, 1 H, SeCH2CHCHCHAr), 6.27 (ddd, J = 1.9, J = 7.6, J
= 15.8 Hz, 1 H, SeCH2CHCHCHAr), 3.69 (p, J = 7.4 Hz, 1 H,
Eur. J. Org. Chem. 2010, 3934–3944
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
3943

D. M. Freudendahl, M. Iwaoka, T. Wirth
FULL PAPER
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[11] CCDC-768926 (for 5), -769238 (for 9), -769239 (for 10),
-769236 (for 14), and -769237 (for 25b) contain the supplemen-
tary crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge Crystallographic
Data Centre via www.ccdc.cam.ac.uk/data_request/cif.
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[14] Ab initio calculations were performed by using Gaussian 03
program (rev. B.04).[15] All possible rotational isomers were
tested as initial structures of comp A and comp B, and the
geometries were fully optimized at HF/6-31+G(d) level. For
each calculation, the structures were converged to four dif-
ferent stable structures, among which only the relevant ones
are shown here. The transition structures with one imaginary
vibration were characterized by frequency calculation at the
same calculation level. The energies are not corrected with
zero-point energies.
Received: April 14, 2010
Published Online: May 27, 2010
3944
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 3934–3944