Preparation of novel chiral non-racemic diselenides and applications in asymmetric synthesis

Article abstract of DOI:10.1002/ejoc.201001272

New chiral non-racemic diselenides were prepared and their corresponding selenium electrophiles were used for thestereoselective functionalization of alkenes. The influence of different nucleophiles on the outcome of the selenenylation reaction was studie

Full text of DOI:10.1002/ejoc.201001272

FULL PAPER
DOI: 10.1002/ejoc.201001272
Preparation of Novel Chiral Non-Racemic Diselenides and Applications in
Asymmetric Synthesis
Liwei Zhao,[a,b] Zhong Li,[b] and Thomas Wirth*[a]
Keywords: Asymmetric synthesis / Addition reactions / Selenium electrophiles / Selenium / Alkenes
New chiral non-racemic diselenides were prepared and their
corresponding selenium electrophiles were used for the
stereoselective functionalization of alkenes. The influence of
different nucleophiles on the outcome of the selenenylation
reaction was studied.
Introduction
Results and Discussion
A common characteristic of the optically active diselen-
ides reported in the literature is the close proximity of an
electron rich heteroatom such as oxygen, nitrogen or sulfur.
It has been shown that selenium can interact with such
nearby heteroatoms. If the heteroatom is connected to an
adjacent benzylic position, intermediate species such as 2
(Figure 1) are generated. Increasing the distance between
the heteroatom and the selenium will result in different in-
teractions and in conformationally more flexible intermedi-
ates. The six-membered intermediates 3 lead to lower selec-
tivities in the corresponding selenenylation reactions as we
have reported earlier.[5] The success of larger ring intermedi-
ates in related electrophilic iodine-based reagents[6]
prompted us to investigate structures of type 4 forming
seven-membered intermediates as shown in Figure 1. We
have, however, no direct evidence for this interaction nor
have we prepared the corresponding compounds replacing
the oxygen atoms with methylene groups.
The stereoselective functionalization of non-activated
carbon-carbon double bonds is one of most interesting
topics in organic chemistry, and electrophilic selenenylation
reactions of alkenes have been successfully studied for sev-
eral years.[1] In a stereoselective approach to this reaction,
other research groups and we have investigated stereoselec-
tive reactions of alkenes with chiral selenium electro-
philes.[2,3] The general reaction is illustrated in Scheme 1. A
variety of nucleophiles have been used to open the selenir-
anium intermediates 1 and the addition products gave rise
to a lot of subsequent reactions (Scheme 1). However, many
of the reported chiral diselenides required a rather long syn-
thetic route for their preparations, sometimes accompanied
with low overall yields, or expensive reagents.
Scheme 1. Selenenylation of alkenes.
Recently, we have reported easily accessible optically
active diselenides bearing a sulfoxide moiety as the chiral
centre.[4] Herein, we describe a series of novel chiral diselen-
ides prepared from easily available, cheap starting materials
in a short and efficient synthesis and the addition reactions
of their corresponding selenium electrophiles to alkenes.
Figure 1. Interaction of heteroatoms with selenium electrophiles.
The key reaction for the formation of precursors 6 is the
Mitsunobu reaction of the corresponding phenols 5 with
(–)-ethyl lactate to generate the desired chiral products in
high yields. The ester moiety can be reduced by lithium alu-
minium hydride to produce alcohol 7 almost quantitatively,
which is then protected by a methyl group to yield the chiral
ether 8. After ortho-lithiation, selenium is introduced and
after an oxidative work-up, diselenides 9a, 9b and triselen-
ide 10 are formed. Triselenide 10 is reduced and reoxidized
[a] School of Chemistry, Cardiff University,
Park Place, Cardiff, CF10 3AT, U.K.
Fax: +44-29-20876968
E-mail: wirth@cf.ac.uk
[b] East China University of Science and Technology,
Shanghai, China
Supporting information for this article is available on the
WWW under http://dx.doi.org/10.1002/ejoc.201001272.
176
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 176–182

Preparation of Novel Chiral Non-Racemic Diselenides
to diselenide 9c (Scheme 2). It has already been observed in Table 1. Methoxyselenenylation of styrene using diselenides 9.
the past that sterically demanding compounds can produce
Entry
Diselenide
Yield [%]
dr[a]
mixtures of diselenides and triselenides.[7]
1
2
3
9a
9b
9c
12a: 40
12b: 72
12c: 68
92: 8
87.5:12.5
94.5:5.5[b]
1
[a] Determined with H NMR spectroscopy. [b] 96:4 dr after col-
umn determined by HPLC.
and others have investigated such a directing effect of a
methoxy-substituent in the second ortho-position to the se-
lenium electrophile and usually an increase in selectivity
was observed.[5,8] An explanation for this unusual drop in
selectivity cannot be given at present, especially as in com-
parison with 9c the selectivities should not be dependent on
the electronic properties of the selenium electrophiles.
Diselenide 9c as the most promising reagent in this series
was then used for several other selenenylation reactions as
shown in Scheme 4 and Table 2.
Scheme 2. Synthesis of new diselenides 9.
These three chiral diselenides 9 have then been used in
the methoxyselenenylation of styrene. After conversion of
the diselenides into the corresponding selenenyl triflates the
methoxyselenenylation of styrene was performed at –78 °C
as shown in Scheme 3. These reactions were complete after
2 h reaction time and the products isolated by flash
chromatography. The mixtures of diastereomers could not
be completely separated, but enriched by flash chromatog-
raphy. The diastereomeric ratios (dr) were determined by
Scheme 4. Selenenylation of styrene derivatives using selenium elec-
trophiles generated from diselenide 9c.
Table 2. Alkoxyselenenylation of styrene derivatives using diselen-
ide 9c.
Entry Ar, R1, R2
ROH
Yield [%] dr[a]
1
2
3
4
5
6
7
8
9
10
Ph, H, H
MeOH
MeOH
MeOH
MeOH
12c: 68
13a: 54
13b: 61
13c: 44
13d: 32
13e: 0
13f: 65
13g: 54
13h: 48
13i: 34
94.5:5.5[b]
2-Me-C6H4, H, H
2-Cl-C6H4, H, H
3-Me-C6H4, H, H
95.5:4.5[c]
91:9
1
integration of H NMR signals in the crude reaction mix-
91.5:8.5
67:33
–
75:25
92:8
78:22
60:40
ture. All these chiral diselenides gave the addition products
in good yields and with high selectivites as shown in
Table 1.
From these experiments, the C2-symmetric chiral diselen-
ide 9c showed the highest selectivity. Interestingly, the reac-
tion using the methoxy-substituted derivative 9b showed
lower selectivity than the unsubstituted compound 9a
4-MeO-C6H4, H, H MeOH
Ph, H, Me
Ph, Me, H
Ph, H, H
Ph, H, H
Ph, H, H
MeOH
MeOH
EtOH
iPrOH
tBuOH
1
[a] Determined with H NMR spectroscopy. [b] 96:4 dr after col-
umn determined by HPLC. [c] Ͼ97:3 dr after column determined
(Table 1, entries 1 and 2). This is noteworthy, because we by HPLC.
Scheme 3. Methoxyselenenylation of styrene with selenium electrophiles generated from diselenides 9.
Eur. J. Org. Chem. 2011, 176–182
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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177

L. Zhao, Z. Li, T. Wirth
FULL PAPER
1.27 (t, J = 7.1 Hz, 3 H, CHCH3), 4.24 (q, J = 7.1 Hz, 2 H,
CH3CH2), 4.77 (q, J = 6.8 Hz, 1 H, CH3CH), 6.91 (d, J = 8.8 Hz,
2 H, ArH), 6.99 (t, J = 7.0 Hz, 1 H, ArH), 7.30 (t, J = 7.8 Hz, 2
H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ = 14.6, 19.0, 61.7,
73.0, 115.5, 121.9, 129.2, 158.0, 172.7 ppm. HRMS: m/z calcd. for
The substitution pattern of the different styrene deriva-
tives has a large influence on the selectivity of the reaction.
Whereas substituents in ortho- and meta-position are toler-
ated, an electron-rich derivative with a methoxy moiety in
the para-position leads to a largely reduced selectivity in the
methoxyselenenylation reaction. The reduced selectivities
with bulkier nucleophiles are in line with previous experi-
ments. Unlike previous selenium electrophiles, the electro-
phile generated from 9c does not react with disubstituted
alkenes. No product formation was observed with β-methyl-
styrene (Table 2, entry 6) and also α-methylstyrene showed
only low selectivities (Table 2, entry 7). Also various
attempts to use the electrophile generated from 9c in cycli-
zation reactions failed, both in stoichiometric as well as in
catalytic reactions.[9] This seems to be an interesting feature
of these electrophiles, which has not yet been observed. It
C H O [M + H]+: 195.1016; found 195.1015. IR (neat): ν = 3097,
˜
11 15
3
3063, 3042, 2986, 2938, 2908, 2870, 1753, 1734, 1600, 1589 1495,
1446, 1376, 1344, 1274, 1241, 1196, 1154, 1135, 1098, 1050, 1020,
946, 885, 860, 802, 754, 690 cm–1.
(R)-Ethyl 2-(3-Methoxyphenoxy)propanoate (6b):[12] Similar reac-
tion as described for 6a using: 3-methoxyphenol (2.48 g, 20 mmol),
PPh3 (7.68 g, 30 mmol), ethyl (–)-lactate (3.54 mL, 30 mmol) in
THF (50 mL), diisopropyl azodicarboxylate (2.0 m in toluene,
30 mmol, 15 mL). Product 6b was isolated in 86% yield (1.76 g,
1
7.86 mmol) as a colorless oil. [α]2D5 = +25.7 (c = 1.13, CHCl3). H
NMR (CDCl3, 400 MHz): δ = 1.27 (t, J = 7.1 Hz, 3 H, CH2CH3),
1.63 (d, J = 6.8 Hz, 3 H, CHCH3), 3.79 (s, 3 H, OCH3), 4.24 (q, J
cannot be attributed to the steric congestion around the = 7.1 Hz, 2 H, CH3CH2), 4.75 (q, J = 6.8 Hz, 1 H, CH3CH), 3.45–
3.50 (m, 2 H, ArH), 6.55 (dd, J = 2.3, J = 8.2 Hz, 1 H, ArH), 7.18
(t, J = 8.2 Hz, 1 H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ =
14.6, 19.0, 55.6, 61.7, 72.9, 77.3, 77.6, 77.9, 102.0, 107.1, 107.8,
130.3, 159.3, 161.3, 172.5 ppm. HRMS: m/z calcd. for C12H17O4
selenium electrophile as other C2-symmetric compounds are
known to successfully react with substituted alkenes.[10] The
reason for their reactivity only towards terminal double
bonds will be investigated further.
[M + H]+: 225.1121; found 225.1118. IR (neat): ν = 3410, 2985,
˜
2942, 2927, 2838, 2360, 2341, 1754, 1733, 1603, 1492, 1454, 1379,
1284, 1268, 1200, 1154, 1094, 1049 cm–1.
Conclusions
(2R,2ЈR)-Diethyl 2,2Ј-(1,3-Phenylene)bis(oxy)dipropanoate (6c):[13]
Similar reaction as described for 6a using: resorcinol (2.2 g,
20 mmol), PPh3 (13.1 g, 50 mmol), ethyl (–)-lactate (5.9 mL,
50 mmol) in THF (100 mL), diisopropyl azodicarboxylate (2.0 m in
toluene, 50 mmol, 25 mL). Product 6c was isolated in 90% yield
(5.56 g, 17.94 mmol) as a colorless oil. [α]2D5 = +46.9 (c = 1.16,
In conclusion, we prepared three novel chiral diselenides
in an efficient synthesis using cheap starting materials. The
corresponding electrophiles have been investigated in
stereoselective selenenylation reactions, in which the C2-
symmetrical derivative showed the highest selectivities. Fur-
ther experiments to improve the stereoselectivity of these
and related processes and to gain additional insight into the
observed selectivities are in progress.
1
CHCl3). H NMR (CDCl3, 400 MHz): δ = 1.26 (t, J = 7.1 Hz, 6
H, CH2CH3), 1.60 (d, J = 6.8 Hz, 6 H, CHCH3), 4.22 (q, J =
7.2 Hz, 4 H, CH3CH2), 4.71 (q, J = 6.8 Hz, 2 H, CH3CH), 6.45–
6.50 (m, 3 H, ArH), 7.15 (t, J = 8.2 Hz, 1 H, ArH) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 14.5, 18.9, 61.7, 73.0, 103.4, 108.4, 130.4,
159.2, 172.5 ppm. HRMS: m/z calcd. for C16H23O6 [M + H]+:
311.1495; found 311.1485. IR (neat): ν = 2987, 2947, 2842, 2798,
˜
Experimental Section
1754, 1720, 1603, 1491, 1447, 1376, 1282, 1180, 1157, 1133, 1095,
1
1051, 1017, 858, 766, 685 cm–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.
Mass spectra (m/z) and HRMS were recorded under the conditions
of electron impact (EI) and electrospray (ES) and chemical ioniza-
tion (CI). All reactions were monitored by thin-layer chromatog-
raphy 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 solvents are indicated in the text.
All experiments were performed under an inert atmosphere of ar-
gon. Dichloromethane was dried with CaH2, methanol, ethanol, 2-
propanol and tert-butanol were dried with 4-Å molecular sieves. All
other purchased chemicals were used without further purification.
(R)-2-Phenoxypropan-1-ol (7a):[14] LiAlH4 (532 mg, 14 mmol) was
suspended in dry THF (15 mL), cooled to –78 °C, and 6a (1.70 g,
9.3 mmol) in dry THF (25 mL) was added slowly. After the ad-
dition, the mixture was warmed to 0 °C, kept at that temperature
for 2 h, and then stirred overnight at room temperature. The reac-
tion was quenched by 1 m HCl solution (20 mL) at 0 °C, and ex-
tracted with EtOAc (3ϫ50 mL). The combined organic phases
were dried with anhydrous MgSO4, and the solvent was removed
under reduced pressure to give 7a as a colorless oil in 96% yield
(1.37 g, 9.01 mmol). [α]2D5 = –49.0 (c = 1.35, CHCl3). 1H NMR
(CDCl3, 400 MHz): δ = 1.17 (d, J = 6.3 Hz, 3 H, CHCH3), 2.21 (s,
1 H, OH), 3.60–3.67 (m, 2 H, CH3CH2), 4.37–4.44 (m, 1 H,
CH3CH), 6.83–6.89 (m, 3 H, ArH), 7.14–7.24 (m, 2 H, ArH) ppm.
13C NMR (CDCl3, 100 MHz): δ = 16.3, 66.7, 75.1, 116.5, 121.6,
130.0, 158.1 ppm. HRMS: m/z calcd. for C9H12O2NH4 [M +
(R)-Ethyl 2-Phenoxypropanoate (6a):[11] To a solution of phenol
(0.94 g, 10 mmol), PPh3 (3.93 g, 15 mmol) and ethyl (–)-lactate
(1.77 mL, 15 mmol) in THF (25 mL), diisopropyl azodicarboxylate
(2.0 m in toluene, 15 mmol, 7.5 mL) was added slowly at 0 °C, then
the reaction mixture was warmed up to room temperature. After
stirring overnight, the resulting mixture was concentrated in vacuo,
and the residue was purified by flash column chromatography on
silica gel (hexane/EtOAc, 25:1) to give 6a in 91% yield (1.76 g,
NH ]+: 170.1176; found 170.1173. IR (neat): ν = 3390, 2980, 2933,
˜
4
2910, 1598, 1587, 1495, 1376, 1291, 1241, 1174, 1051, 932, 876,
752, 692 cm–1.
(R)-2-(3-Methoxyphenoxy)propan-1-ol (7b): Similar reaction as de-
scribed for 7a using: LiAlH4 (86 mg, 2.25 mmol) in dry THF
1
9.07 mmol) as a colorless oil. [α]2D5 = +39.8 (c = 0.96, CHCl3). H
NMR (CDCl3, 400 MHz): δ = 1.27 (t, J = 7.1 Hz, 3 H, CH2CH3), (10 mL), 6b (345 mg, 1.5 mmol) in dry THF (5 mL). Product 7b
178
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Preparation of Novel Chiral Non-Racemic Diselenides
was isolated in 96% yield (262 mg, 1.44 mmol) as a light gray oil. methyl iodide (2.27 g, 1 mL, 16 mmol). Product 8b was isolated in
1
[α]2D5 = –38.6 (c = 1.33, CHCl3). H NMR (CDCl3, 400 MHz): δ =
83% yield (840 mg, 3.31 mmol) as a light yellow oil. [α]2D5 = –16.3
1
1.09 (d, J = 6.2 Hz, 3 H, CHCH3), 2.07 (s, 1 H, OH), 3.53–3.60 (c = 1.20, CHCl3). H NMR (CDCl3, 400 MHz): δ = 1.17 (d, J =
(m, 5 H, OCH3, CH2OH), 4.27–4.34 (m, 1 H, CH3CH), 6.31–6.37 6.3 Hz, 1 H), 3.27 (s, 6 H), 3.33 (dd, J = 4.5, J = 10.1 Hz, 1 H),
(m, 3 H, ArH), 7.00 (t, J = 8.1 Hz, 1 H, ArH) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 16.3, 55.7, 66.5, 75.1, 103.0, 107.0, 108.5,
130.4, 159.4, 161.3 ppm. HRMS: m/z calcd. for C10H15O3 [M +
3.44 (dd, J = 5.7, J = 10.1 Hz, 1 H), 4.38 (sext, J = 6 Hz, 2 H),
6.38–6.41 (m, 3 H), 7.00 (t, J = 8.2 Hz, 1 H) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 17.2, 59.7, 73.2, 104.7, 108.8, 130.2,
159.5 ppm. HRMS: m/z calcd. for C14H23O4 [M + H]: 255.1591;
H]+: 183.1016; found 183.1014. IR (neat): ν = 3408, 2974, 2937,
˜
2883, 2836, 2360, 1738, 1602, 1492, 1454, 1378, 1334, 1285, 1265,
found 255.1588. IR (neat): ν = 2979, 2930, 2879, 2832, 2813, 1600,
˜
1200, 1154, 1048, 976, 900, 838, 764, 688 cm–1.
1589, 1489, 1452, 1375, 1354, 1331, 1283, 1263, 1203, 1183, 1143,
1113, 1008, 969, 906, 838, 765, 689 cm–1.
(2R,2ЈR)-2,2Ј-[1,3-Phenylenebis(oxy)]bis(propan-1-ol) (7c): Similar
reaction as described for 7a using: LiAlH4 (86 mg, 2.25 mmol) in
dry THF (10 mL), 6c (1.3 g, 4.2 mmol) in dry THF (8 mL). Prod-
uct 7c was isolated in 95% yield (900 mg, 3.98 mmol) as a colorless
(R)-2-[(1-Methoxypropan-2-yl)oxy]phenyl Diselenide (9a): To
a
solution of 8a (240 mg, 1.45 mmol) in dry THF (10 mL), n-butyl-
lithium (0.88 mL, 2.5 m solution in hexane, 2.18 mmol) was added
slowly at 0 °C. The mixture was stirred for 2.5 h at this temperature.
Then selenium powder (138 mg, 1.74 mmol) was added with vigor-
ous stirring at 0 °C. After 15 h stirring at room temperature the
mixture was quenched with 1 m HCl (15 mL) and extracted with
EtOAc (3ϫ25 mL). The combined organic phases were dried with
MgSO4 and the solvent was removed in vacuo. After column
chromatography (hexane/ethyl acetate, 8:1) the diselenide 9a was
1
oil. [α]2D5 = –59.0 (c = 0.40, CHCl3). H NMR (CDCl3, 400 MHz):
δ = 1.18 (d, J = 6.2 Hz, 6 H), 2.34 (s, 2 H), 3.59–3.67 (m, 4 H),
4.39 (d p, J = 4.0, J = 6.3 Hz, 2 H), 6.45–6.47 (m, 3 H), 7.06–7.10
(m, 1 H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 16.3, 66.6, 75.2,
104.9, 109.0, 130.5, 159.4 ppm. HRMS: m/z calcd. for C12H19O4
[M + H]: 227.1278; found 227.1279. IR (neat): ν = 3375, 2970,
˜
2934, 2865, 2373, 2343, 2328, 2313, 1600, 1589, 1488, 1447, 1373,
1282, 1268, 1181, 1157, 1051, 1000, 985 cm–1.
isolated as yellow oil in 50% yield (178 mg, 0.36 mmol). [α]D25
=
–25.7 (c = 0.60, CHCl3). 1H NMR (CDCl3, 400 MHz): δ = 1.32 (d,
J = 6.3 Hz, 6 H, CHCH3), 3.38 (s, 6 H, OCH3), 3.47 (dd, J = 4.7,
J = 10.3 Hz, 2 H, CH3OCHH), 3.60 (dd, J = 6.0, J = 10.3 Hz, 2
H, CH3OCHH), 4.50–4.58 (m, 2 H, CH3CH), 6.76–6.83 (m, 4 H,
ArH), 7.07–7.11 (m, 2 H, ArH), 7.43 (dd, J = 1.6, J = 7.8 Hz, 2
H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.8, 60.0, 75.5,
76.4, 113.9, 120.8, 122.8, 128.3, 130.6, 155.7 ppm. 77Se NMR
(57 MHz, CDCl3): δ = 327 ppm. HRMS: m/z calcd. for C20H26O4
74Se176Se1NH4 [M + NH4]+: 498.0586; found 498.0590. IR (neat):
(R)-1-(1-Methoxypropan-2-yloxy)benzene (8a):[15] Sodium hydride
(320 mg, 8 mmol, 60% in mineral oil) was washed with dry THF
(2ϫ12 mL), then dry THF (8 mL) was added. A solution of 7a
(600 mg, 4 mmol) in dry THF (4 mL) was added slowly at 0 °C,
and the reaction mixture stirred for 30 min. Methyl iodide (1.14 g,
0.5 mL, 8 mmol) was added and the reaction mixture was slowly
warmed up to room temperature and stirred overnight. The reac-
tion was quenched by the addition of saturated NaHCO3 and ex-
tracted with EtOAc (3ϫ30 mL). The combined organic phases
were dried with anhydrous MgSO4, and the solvent was removed
under reduced pressure to give a colorless oil in 84% yield (560 mg,
3.37 mmol). [α]2D5 = –9.6 (c = 1.35, CHCl3). 1H NMR (CDCl3,
400 MHz): δ = 1.17 (d, J = 6.3 Hz, 3 H, CHCH3), 3.27 (s, 3 H,
OCH3), 3.34 (dd, J = 4.5, J = 10.1 Hz, 1 H ppm. CH3OCHH),
3.45 (dd, 1 H, J = 5.8 Hz, J = 10.1 Hz, CH3OCHH), 4.34–4.46 (m,
1 H, CH3CH), 6.78–6.80 (m, 3 H, ArH), 7.10–7.15(m, 2 H, ArH)
ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.3, 59.8, 73.2, 76.3,
116.5, 121.3, 123.0, 158.2 ppm. HRMS: m/z calcd. for
C10H14O2NH4 [M + NH4]+: 184.1332; found 184.1330. IR (neat):
ν = 3400, 2980, 2925, 2911, 1574, 1465, 1441, 1270, 1233, 1110,
˜
1029, 976, 747 cm–1.
(R)-6-Methoxy-2-[(1-methoxypropan-2-yl)oxy]phenyl
Diselenide
(9b): Similar reaction as described for 9a using: 8b (540 mg,
2.76 mmol) in dry THF (12 mL); n-butyllithium (1.66 mL, 2.5 m
solution in hexane, 4.14 mmol); selenium powder (262 mg,
3.32 mmol). The diselenide 9b was isolated as yellow oil in 65%
yield (492 mg, 0.90 mmol). [α]2D5 = +5.53 (c = 3.0, CHCl3). 1H
NMR (CDCl3, 400 MHz): δ = 1.23 (d, J = 6.3 Hz, 1 H, CHCH3),
3.36–3.40 (m, 4 H, OCH3, CH3OCHH), 3.50 (dd, J = 5.5, J =
10.2 Hz, 1 H, CH3OCHH), 3.74 (s, 3 H, ArOCH3), 4.43 (sext, J =
6 Hz, 1 H, CH3CH), 6.52 (d, J = 8.1 Hz, 1 H, ArH), 6.59 (d, J =
8.2 Hz, 1 H, ArH), 7.21 (t, J = 8.3 Hz, 1 H, ArH) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 17.4, 56.5, 59.8, 75.3, 76.1, 104.5, 108.0,
112.2, 130.7, 159.6, 161.5 ppm. 77Se NMR (57 MHz, CDCl3): δ =
343 ppm. HRMS: m/z calcd. for C22H30O676SeNH4 [M + NH4]+:
ν = 3297, 2925, 2910, 1598, 1587, 1494, 1455, 1376, 1290, 1243,
˜
1202, 1152, 1115, 1026, 999, 971, 885, 752 cm–1.
(R)-1-Methoxy-3-(1-methoxypropan-2-yloxy)benzene (8b): Similar
reaction as described for 8a using: sodium hydride (528 mg,
13.2 mmol, 60% in mineral oil), 7b (1.2 g, 6.6 mmol) in dry THF
(8 mL), methyliodide (1.89 g, 0.83 mL, 13.2 mmol). Product 8b was
isolated in 82% yield (1.06 g, 5.41 mmol) as a colorless oil. [α]D25
=
560.0765; found 560.0767. IR (neat): ν = 3078, 2971, 2917, 2850,
˜
2753, 2524, 2360, 1571, 1463, 1246, 1091, 766, 713 cm–1.
1
–10.0 (c = 0.3, CHCl3). H NMR (CDCl3, 400 MHz): δ = 1.34 (d,
J = 6.3 Hz, 3 H, CHCH3), 3.44 (s, 3 H, OCH3), 3.50 (dd, J = 4.5,
J = 10.1 Hz, 1 H, CH3OCHH), 3.61 (dd, J = 5.7, J = 10.1 Hz, 1
H, CH3OCHH), 3.80 (s, 3 H, ArOCH3), 4.52–4.59 (m, 1 H,
CH3CH), 6.51–6.56 (m, 3 H, ArH), 7.17–7.21 (m, 1 H, ArH) ppm.
13C NMR (CDCl3, 100 MHz): δ = 17.2, 55.7, 59.8, 73.2, 76.2,
102.8, 107.0, 108.4, 130.3, 159.5, 161.2 ppm. HRMS: m/z calcd. for
2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl Diselenide (9c): Sim-
ilar reaction as described for 9a using: 8c (640 mg, 2.5 mmol) in
dry THF (8 mL); n-butyllithium (1.5 mL, 2.5 m solution in hexane,
3.75 mmol); selenium powder (237 mg, 3 mmol). The mixture of 10
and 9c was isolated and dissolved in absolute ethanol (10 mL), and
NaBH4 (81 mg, 2.13 mmol) was added. The red solution became
colorless, was stirred for 15 min and then the flask was opened
to air for 6 h. The solvent was removed in vacuo. After column
chromatography (hexane/ethyl acetate, 6:1) the diselenide 9c was
isolated as a red oil in 44% yield (364 mg, 0.55 mmol). [α]2D5 = –64.2
C H O [M + H]+: 197.1172; found 197.1170. IR (neat): ν = 2990,
˜
11 17
3
2931, 2879, 2835, 2360, 2328, 1601, 1491, 1453, 1375, 1285, 1265,
1202, 1147, 1113, 1041, 997, 982, 835, 763 cm–1.
1,3-Bis{[(R)-1-methoxypropan-2-yl]oxy}benzene (8c): Similar reac-
tion as described for 8a using: sodium hydride (640 mg, 16 mmol,
60% in mineral oil), 7c (0.9 g, 3.98 mmol) in dry THF (4 mL),
1
(c = 0.72, CHCl3). H NMR (CDCl3, 400 MHz): δ = 1.15 (d, J =
6.2 Hz, 1 H), 3.27–3.31 (m, 7 H), 3.41 (dd, J = 5.3, J = 10.1 Hz, 1
Eur. J. Org. Chem. 2011, 176–182
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
179

L. Zhao, Z. Li, T. Wirth
FULL PAPER
H), 4.32 (sext, J = 6 Hz, 2 H), 6.47 (d, J = 8.3 Hz, 2 H), 7.07 (t, J 126.7, 127.7, 128.3, 128.7, 141.7, 159.1 ppm. HRMS: m/z calcd. for
= 8.2 Hz, 1 H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.4, 59.8,
75.0, 75.2, 107.8, 113.8, 130.4, 159.8 ppm. 77Se NMR (57 MHz,
CDCl3): δ = 345 ppm. HRMS: m/z calcd. for C28H42O880Se2NH4
C
23H32O5SeNH4 [M + NH4]+: 480.1813; found 480.1817. IR
(neat): ν = 2979, 2930, 2878, 2817, 1579, 1492, 1455, 1375, 1352,
˜
1244, 1201, 1151, 1111, 1039, 955, 767, 703 cm–1.
[M + NH ]+: 684.1555; found 684.1554. IR (neat): ν = 2970, 2928,
˜
4
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)[2-methoxy-2-(o-
tolyl)ethyl]selane (13a): Colorless oil, 54 % yield (52 mg,
0.108 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.26 (d, J = 6.3 Hz,
6 H, CHCH3), 2.07 (s, 3 H, ArCH3), 3.08–3.10 (m, 2 H, ArSeCH2),
3.15 (s, 3 H, OCH3), 3.20 (s, 6 H, OCH3), 3.39 (dd, J = 4.7, J =
10.1 Hz, 1 H, CH3OCH2), 3.52 (dd, J = 5.9, J = 10.1 Hz, 1 H,
CH3OCH2), 4.38–4.48 (m, 3 H, CH3CH, CH3OCH), 6.50 (d, J =
8.3 Hz, 1 H, ArH), 7.00–7.15 (m, 4 H, ArH), 7.30 (d, J = 7.5 Hz,
1 H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.5 (CHCH3),
19.2 (ArCH3), 33.2 (ArSeCH2), 57.3 (CHOCH3), 59.6 (CH2OCH3),
74.9 [O(CH3)CH], 76.3 (CH3OCH2), 80.7 (CH3OCH), 107.8 (C),
111.2 (C), 126.1 (C), 127.6 (C), 129.3 (C), 130.7 (C), 136.1 (C),
140.1 (C), 159.7 (C) ppm. HRMS: m/z calcd. for C24H34O574SeNH4
2880, 2835, 2820, 1572, 1456, 1375, 1246, 1201, 1112, 1092, 1037,
956, 769 cm–1.
General Procedure for the Addition of Selenium Electrophiles to Sty-
rene: The diselenide 9 (0.1 mmol) was dissolved in dry dichloro-
methane (2.5 mL) under argon, cooled to –78 °C, and treated with
bromine (0.11 mmol, 0.11 mL of a 1 m solution in CCl4). After
20 min a solution of silver triflate (72 mg, 0.28 mmol) in dry meth-
anol (0.1 mL) was added and the mixture was stirred for 30 min
at –78 °C. The styrene derivative (0.4 mmol) was added. After the
mixture had been stirred for 2 h at –78 °C. Saturated aqueous
NaHCO3 (2 mL) was added followed by water (2 mL). After ex-
traction of the reaction mixture with dichloromethane (3ϫ10 mL),
the combined organic phases were dried with MgSO4 and the sol-
vent was removed under reduced pressure. The residue was purified
by column chromatography on silica gel, yielding the addition
products as colourless oils. The diastereomers could not be sepa-
rated by column chromatography (ethyl acetate/hexane, 1:15). All
spectroscopic data are given for the main diastereomers.
[M + NH ]+: 494.1969; found 494.1964. IR (neat): ν = 3392, 2974,
˜
4
2925, 2885, 2822, 2357, 2341, 1581, 1558, 1463, 1375, 1253, 1219,
1112, 1037 cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)[2-(2-chlorophenyl)-
2-methoxyethyl]selane (13b): Colorless oil, 61 % yield (63 mg,
0.125 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.27 (d, J = 6.3 Hz,
(2-Methoxy-2-phenylethyl)(2-{[(R)-1-methoxypropan-2-yl]oxy}- 1 H, CHCH3), 3.07 (dd, J = 9.2, J = 12.4 Hz, 1 H, ArSeCH), 3.16–
phenyl)selane (12a): Colorless oil, 40% yield, (30 mg, 0.079 mmol). 3.20 (m, 4 H, OCH3, ArSeCH), 3.23 (s, 6 H, OCH3), 3.39 (dd, J =
1H NMR (CDCl3, 400 MHz): δ = 1.28 (d, J = 6.3 Hz, 3 H, 4.8, J = 10.1 Hz, 2 H, CH3OCH2), 3.54 (dd, J = 5.8, J = 10.1 Hz,
CHCH3), 3.02 (dd, J = 4.9, J = 12.1 Hz, 1 H, ArSeCHH), 3.18–
3.23 (m, 4 H, OCH3, ArSeCHH), 3.23 (s, 3 H, OCH3), 3.42 (dd, J =
4.9, J = 10.1 Hz, 1 H, CH3OCHH), 3.55 (dd, J = 5.8, J = 10.1 Hz, 1
H, CH3OCHH), 4.30 (dd, J = 4.9, J = 8.7 Hz, 1 H, CH3OCH),
4.48 (sext, J = 5.9 Hz, 1 H, CH3CH), 6.78–6.82 (m, 2 H, ArH),
7.07–7.11 (m, 1 H, ArH), 7.21–7.31 (m, 6 H, ArH) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 17.6, 32.9, 57.5, 59.8, 74.7, 76.3, 83.6,
114.0, 122.1, 127.1, 127.7, 128.5, 129.0, 131.4, 141.7, 156.6 ppm.
2 H, CH3OCH2), 4.45 (sext, J = 6 Hz, 2 H, CH3CH), 4.67 (dd, J
= 3.7, J = 9.2 Hz, 1 H, CH3OCH), 6.48 (d, J = 8.3 Hz, 2 H, ArH),
7.05–7.12 (m, 2 H, ArH), 7.17–7.21 (m, 2 H, ArH), 7.41 (dd, J =
1.7, J = 7.6 Hz, 1 H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ
= 17.5, 32.6, 57.7, 59.6, 74.8, 76.2, 80.3, 107.7, 111.0, 127.4, 127.7,
129.0, 129.3, 129.8, 133.6, 139.5, 159.6 ppm. HRMS: m/z calcd. for
C23H31ClO574SeNH4 [M + NH4]+: 514.1423 found 514.1420. IR
(neat): ν = 3063, 2980, 2930, 2885, 2825, 1760, 1732, 1574, 1456,
˜
HRMS: m/z calcd. for C19H24O380Se [M + Na]+: 403.0788; found 1375, 1353, 1245, 1202, 1152, 1112, 1038, 968, 760, 735, 708 cm–1.
403.0772. IR (neat): ν = 3066, 2984, 2926, 2885, 2819, 1575, 1469,
˜
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)[2-methoxy-2-(m-
tolyl)ethyl]selane (13c): Colorless oil, 44 % yield (40 mg,
0.088 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.27 (d, J = 6.3 Hz,
6 H, CHCH3), 2.26 (s, 3 H, ArCH3), 3.05 (dd, J = 4.9, J = 12.1 Hz,
1441, 1271, 1238, 1107, 1034, 957, 747, 702 cm–1.
(2-Methoxy-2-phenylethyl)(2-methoxy-6-{[(R)-1-methoxypropan-2-
yl]oxy}phenyl)selane (12b): Colorless oil, 72 % yield (59 mg,
0.144 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.26 (d, J = 6.2 Hz, 1 H, ArSeCH), 3.20–3.26 (m, 7 H, OCH3, ArSeCH), 4.17 (dd, J =
3 H, CHCH3), 3.02 (dd, J = 5, J = 12.1 Hz, 1 H, ArSeCHH), 3.14 4.9, J = 8.9 Hz, 1 H, CH3OCH), 4.45 (sext, J = 6 Hz, 2 H,
(s, 3 H, OCH3), 3.24 (s, 3 H, OCH3), 3.20–3.27 (m, 1 H, Ar-
SeCHH), 3.41 (dd, J = 4.7, J = 10 Hz, 1 H, CH3OCHH), 3.54 (dd,
J = 5.9, J = 10 Hz, 1 H, CH3OCHH), 3.79 (s, 3 H, OCH3), 4.23
(dd, J = 4.9, J = 8.8 Hz, 1 H, CH3OCH), 4.46 (sext, J = 4.7 Hz, 1
H, CH3CH), 6.45 (d, J = 8.2 Hz, 1 H, ArH), 6.51 (d, J = 8.2 Hz,
CH3CH), 6.50 (d, J = 8.5 Hz, 2 H, ArH), 6.98–7.14 (m, 5 H) ppm.
13C NMR (CDCl3, 100 MHz): δ = 17.6, 21.9, 34.1, 57.4, 59.6, 74.8,
76.2, 84.2, 107.9, 111.2, 124.3, 127.7, 128.6, 128.9, 129.1, 138.2,
142.0, 159.5 ppm. HRMS: m/z calcd. for C24H34O580Se [M +
Na]+: 505.1469; found 505.1464. IR (neat): ν = 2979, 2927, 2881,
˜
1 H, ArH), 7.11 (t, J = 8.3 Hz, 1 H, ArH), 7.15–7.28 (m, 5 H, 2817, 2358, 2337, 1575, 1456, 1375, 1244, 1202, 1111, 1039, 966,
ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.5, 34.2, 56.5, 768, 709 cm–1.
57.4, 59.6, 74.8, 76.3, 84.2, 104.4, 107.7, 109.2, 127.1, 128.2, 128.7,
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)[2-methoxy-2-(4-
76-
129.5, 141.9, 159.4, 160.1 ppm. HRMS: m/z calcd. for C20H26O4
methoxyphenyl)ethyl]selane (13d): Colorless oil, 32% yield, (32 mg,
0.064 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.27 (d, J = 6.3 Hz,
6 H, CHCH3), 3.04 (dd, J = 5.3, J = 12.0 Hz, 1 H, ArSeCH), 3.11
(s, 3 H, OCH3) 3.21–3.27 (m, 7 H, OCH3, ArSeCH), 3.40 (dd, J =
4.9, J = 10.1 Hz, 2 H, CH3OCH2), 3.54 (dd, J = 5.7, J = 10.0 Hz,
SeNH4 [M + NH ]+: 424.1361; found 424.1362. IR (neat): ν =
˜
4
2971, 2932, 2880, 2830, 1582, 1464, 1246, 1097, 767, 702 cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)(2-methoxy-2-phen-
ylethyl)selane (12c): Colorless oil, 68% yield (64 mg, 0.137 mmol).
1H NMR (CDCl3, 400 MHz): δ = 1.27 (d, J = 6.3 Hz, 6 H, 2 H, CH3OCH2), 3.72 (s, 3 H, ArOCH3), 4.15 (dd, J = 5.3, J =
CHCH3), 3.06 (dd, J = 4.9, J = 12.2 Hz, 1 H, ArSeCH), 3.14 (s, 3
H, OCH3), 3.21–3.27 (m, 7 H, OCH3, ArSeCH), 3.40 (dd, J = 4.8,
J = 10.0 Hz, 2 H, CH2OCH3), 3.54 (dd, J = 5.8, J = 10.0 Hz, 2 H,
CH2OCH3), 6.50 (d, J = 8.3 Hz, 2 H, ArH), 7.07 (t, J = 8.3 Hz, 1
8.6 Hz, 1 H, CH3OCH), 4.45 (sext, J = 6 Hz, 2 H, CH3CH), 6.49
(d, J = 8.3 Hz, 2 H, ArH), 6.77 (d, J = 8.7 Hz, 1 H, ArH), 7.06 (t,
J = 8.3 Hz, 1 H, ArH), 7.15 (d, J = 8.6 Hz, 1 H, ArH) ppm. 13C
NMR (CDCl3, 100 MHz): δ = 17.6, 34.0, 55.7, 57.10, 59.7, 74.7,
H, ArH), 7.15–7.27 (m, 5 H, ArH) ppm. 13C NMR (CDCl3, 74.8, 83.7, 107.8, 111.1, 114.0, 128.4, 129.1, 134.0, 159.5 ppm.
100 MHz): δ = 17.2, 33.7, 57.0, 59.2, 74.4 75.9, 83.8, 107.5, 110.8,
HRMS: m/z calcd. for C24H34O680Se [M + Na]+: 521.1418; found
180
www.eurjoc.org
© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2011, 176–182

Preparation of Novel Chiral Non-Racemic Diselenides
521.1441. IR (neat): ν = 2974, 2923, 2870, 2833, 2816, 2358, 1610,
Supporting Information (see also the footnote on the first page of
this article): Supporting Information contains 1H and 13C NMR
spectra for all compounds.
˜
1575, 1511, 1456, 1245, 1110, 1036, 830, 766 cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)(2-methoxy-2-phen-
ylpropyl)selane (13f): Colorless oil, 65% yield (63 mg, 0.131 mmol).
1H NMR (CDCl3, 400 MHz): δ = 1.25 (d, J = 6.3 Hz, 1 H,
CHCH3), 3.05 (s, 3 H, OCH3), 3.20–3.32 (m, 7 H, OCH3, Ar-
SeCH), 3.40–3.45 (m, 4 H, CH3OCH2, ArSeCH), 3.54 (dd, J = 5.8,
J = 10.1 Hz, 2 H, CH3OCH2), 4.45 (sext, J = 6 Hz, 2 H, CH3CH),
6.48 (d, J = 8.3 Hz, 2 H, ArH), 7.06 (t, J = 8.2 Hz, 1 H, ArH),
7.15 (t, J = 7.3 Hz, 1 H, ArH), 7.24 (t, J = 7.5 Hz, 2 H, ArH),
7.34 (dd, J = 1.2, J = 8.4 Hz, 1 H, ArH) ppm. 13C NMR (CDCl3,
100 MHz): δ = 17.5, 24.5, 39.2, 51.3, 59.7, 74.6, 76.3, 79.6, 107.8,
111.7, 126.6, 127.4, 128.5, 129.2, 145.0, 159.6 ppm. HRMS: m/z
calcd. for C24H34O574SeNH4 [M + NH4]+: 494.1949 found
Acknowledgments
We thank the China Scholarship Council (CSC) (to L. Z.) and the
School of Chemistry, Cardiff University, for support. The EPSRC
National Mass Spectrometry Service Centre, Swansea, is thanked
for mass spectrometric data.
[1] a) G. Hölzle, W. Jenny, Helv. Chim. Acta 1958, 41, 593–603; b)
Organoselenium Chemistry (Ed.: T. G. Back), Oxford Univer-
sity Press, Oxford, 1999; c) Organoselenium Chemistry: Modern
Developments in Organic Synthesis (Ed.: T. Wirth), Top. Curr.
Chem. Springer, Berlin, vol. 208, 2000.
494.1968. IR (neat): ν = 3082, 3059, 2979, 2930, 2823, 1579, 1493,
˜
1456, 1373, 1244, 1201, 1153, 1113, 1039, 969, 868, 766, 902 cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)(2-ethoxy-2-phenyl-
ethyl)selane (13g): Light yellow oil, 54% yield (52 mg, 0.108 mmol).
1H NMR (CDCl3, 400 MHz): δ = 1.09 (t, J = 7.0 Hz, 3 H,
CH2CH3), 1.27 (d, J = 6.3 Hz, 6 H, CHCH3), 3.06 (dd, J = 4.8, J
= 12.1 Hz, 1 H, ArSeCH), 3.21–3.30 (m, 9 H, CH3CH2, OCH3,
ArSeCH), 3.40 (dd, J = 4.8, J = 10.0 Hz, 2 H, CH3OCH2), 3.54
(dd, J = 5.7, J = 10.0 Hz, 2 H, CH3OCH2), 4.29 (dd, J = 4.9, J =
8.9 Hz, 1 H, CH3OCH), 4.45 (sext, J = 6 Hz, 2 H, CH3CH), 6.50
(d, J = 8.3 Hz, 2 H, ArH), 7.07 (t, J = 8.3 Hz, 1 H, ArH), 7.14–
7.17 (m, 1 H, ArH), 7.23–7.24 (m, 4 H, ArH) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 15.7, 17.6, 34.4, 59.6, 65.0, 74.8, 76.2, 82.3,
107.8, 111.2, 127.0, 127.9, 128.6, 129.0, 142.8, 159.5 ppm. HRMS:
m/z calcd. for C24H34O574SeNH4 [M + NH4]+: 494.1969; found
[2] For reviews, see: a) M. Tiecco, Top. Curr. Chem. 2000, 208, 7;
b) T. Wirth, Angew. Chem. 2000, 112, 3890–3900; Angew.
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Intermediates in Organic Synthesis (Ed.: C. Paulmier), Perga-
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Selenium and Tellurium Compounds (Eds.: S. Patai, Z. Rappo-
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S. Patai, Z. Rappoport), John Wiley & Sons, New York, 1986;
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selenium Chemistry: A Practical Approach (Ed.: T. G. Back),
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Wirth, Tetrahedron 1999, 55, 1–28; i) D. M. Browne, T. Wirth,
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S. A. Shazhad, T. Wirth, Eur. J. Org. Chem. 2009, 1649–1664.
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61, 1875; b) R. Déziel, E. Malenfant, C. Thibault, Tetrahedron
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T. G. Back, B. P. Dyck, S. Nan, Tetrahedron 1999, 55, 3191; h)
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L. Testaferri, C. Santi, C. Tomassini, F. Marini, L. Bagnoli, A.
Temperini, Tetrahedron: Asymmetry 2000, 11, 4645.
494.1967. IR (neat): ν = 3088, 3055, 3034, 2976, 2928, 2877, 2814,
˜
2360, 1577, 1456, 1375, 1244, 1202, 1152, 1113, 1039, 970, 766, 702
cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)(2-isopropoxy-2-
phenylethyl)selane (13h): Colorless oil, 48 % yield (48 mg,
0.097 mmol). 1H NMR (CDCl3, 400 MHz): δ = 0.97 [d, J = 6.2 Hz,
3 H, CH(CH3)CH3], 1.07 [d, J = 6.0 Hz, 3 H, CH(CH3)CH3], 1.27
(d, J = 6.3 Hz, 6 H, CHCH3), 3.04 (dd, J = 4.6, J = 12.1 Hz, 1 H,
ArSeCH), 3.18–3.24 (m, 7 H, OCH3, ArSeCH), 3.40 (dd, J = 4.9,
J = 10.0 Hz, 2 H, CH3OCH2), 3.53 (dd, J = 5.7, J = 10.0 Hz, 2 H,
CH3OCH2), 4.40–4.47 (m, 3 H, CH3OCH, CH3CH), 6.49 (d, J =
8.3 Hz, 2 H, ArH), 7.05 (t, J = 8.3 Hz, 1 H, ArH), 7.13–7.27 (m,
5 H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ = 17.6, 21.9, 23.8,
34.9, 70.2, 74.8, 76.3, 80.0, 107.8, 111.5, 127.0, 127.8, 128.6, 129.0,
143.7, 159.5 ppm. HRMS: m/z calcd. for C25H36O580Se [M +
[4] D. M. Freudendahl, M. Iwaoka, T. Wirth, Eur. J. Org. Chem.
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anie.201003503.
Na]+: 519.1616; found 519.1639. IR (neat): ν = 3064, 3021, 2973,
˜
2929, 2874, 2820, 2358, 1575, 1455, 1375, 1244, 1202, 1114, 1039,
764, 702 cm–1.
(2,6-Bis{[(R)-1-methoxypropan-2-yl]oxy}phenyl)[2-(tert-butoxy)-2-
phenylethyl]selane (13i): Colorless oil, 34% yield (34 mg,
0.067 mmol). 1H NMR (CDCl3, 400 MHz): δ = 1.03 [s, 9 H,
O(CH3)3], 1.27 (d, J = 6.4 Hz, 1 H, CHCH3), 2.94–2.99 (m, 1 H,
ArSeCHH), 3.15–3.25 (m, 7 H, OCH3, ArSeCHH), 3.33–3.43 (2
H, CH3OCHH), 3.50–3.58 (m, 2 H, CH3OCHH), 3.39–4.47 (m, 2
H, CH3CH), 4.55–4.59 [m, 1 H, C(tBuO)CH], 6.48 (d, J = 8.3 Hz,
2 H, ArH), 7.02–7.14 (m, 3 H, ArH), 7.17–7.21 (m, 1 H, ArH),
7.28–7.31 (m, 2 H, ArH) ppm. 13C NMR (CDCl3, 100 MHz): δ =
17.6, 29.3, 36.4, 59.7, 74.8, 75.0, 75.3, 76.3, 107.9, 111.9, 126.7,
127.3, 128.4, 128.9, 146.4, 159.4 ppm. HRMS: m/z calcd. for
C26H38O574SeNH4 [M + NH4]+: 522.2282; found 522.2281. IR
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Received: September 10, 2010
Published Online: November 12, 2010
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Eur. J. Org. Chem. 2011, 176–182