Syntheses and reactions of cyclic Se-alkoxy-Se-chloroselenuranes and alkoxyselenonium salts

Article abstract of DOI:10.1002/hc.1050

Several 1-chloro-2,1-oxaselenole selenuranes 3a-e and selenonium salts 4a-c and 5-chloro-5,11-epoxy-6,11-dihydrodibenzo[b,e]selenepines 12a and 12b and selenonium salts 13a-c-were synthesized, and their reactions with organometallic reagents were studied.

Full text of DOI:10.1002/hc.1050

Heteroatom Chemistry
Volume 12, Number 4, 2001
Syntheses and Reactions of Cyclic Se-Alkoxy-
Se-chloroselenuranes and Alkoxyselenonium
Salts
Tadashi Kataoka, Tatsunori Iwamura, Hisayoshi Tsutsui,
Yasuharu Kato, Yoshihiro Banno, Yasuko Aoyama,
and Hiroshi Shimizu
Gifu Pharmaceutical University, 6-1 Mitahora-higashi 5-chome, Gifu 502-8585, Japan;
kataoka@gifu-pu.ac.jp
Received 4 January, 2001; revised 5 February 2001
idation of the alkoxy moiety [5]. Kawashima and his
ABSTRACT: Several 1-chloro-2,1-oxaselenole sel-
coworkers reported that the thermolysis of tetra-
enuranes 3a–e and selenonium salts 4a–c and 5-chloro-
coordinate 1,2-oxaselenetanes containing a selenas-
5,11-epoxy-6,11-dihydrodibenzo[b,e]selenepines 12a
piro[4.5]ring system stereospecifically gave oxiranes
and 12b and selenonium salts 13a–c were synthesized,
and oxaselenoles [6]. However, the chemistry of al-
and their reactions with organometallic reagents were
koxyselenonium salts has been hardly studied. This
studied. ᭧ 2001 John Wiley & Sons, Inc. Heteroatom
article describes the syntheses and reactions of cy-
Chem 12:317–326, 2001
clic alkoxyselenuranes and alkoxyselenonium salts.
The 3H-2,1-benzoxaselenole selenuranes and se-
lenonium salts were synthesized as shown in
Scheme 1. o-(Phenylseleno)benzaldehyde (1) was
oxidized with silver oxide to give the benzoic acid 5.
INTRODUCTION
The chemistry of hypervalent molecules has been in-
tensively studied in recent years [1]. Hypervalent se-
lenium compounds, r-selenuranes with four carbon
ligands, have been isolated by Furukawa and his co-
workers [2], who also investigated the intermediates
of the reactions of selenonium salts with arylli-
thiums using 1H, 13C and 77Se NMR spectroscopy and
demonstrated that the intermediates were r-selen-
uranes [3]. r-Selenuranes with electronegative het-
eroatoms on the selenium atom can be isolated as
stable crystals [4]. We previously reported that the
thermal reaction of a 1-chloro-1-phenyl-3H-2,1-ben-
zoxaselenole afforded an aldehyde or a ketone by ox-
Esterification of 5, followed by the Grignard reac-
tion, afforded the alcohol 7. Alcohol 7 was chlori-
nated with N-chlorosuccinimide (NCS) to give 1-
chloro-3H-2,1-oxaselenole 3c. The selenurane 3c
was converted into oxaselenolium salt 4c. Other al-
koxyselenuranes 3a,b and selenonium salts 4a,b
were prepared by the known procedures [5]. Acylox-
yselenurane 3d was derived from carboxylic acid 5
by chlorination with NCS. Se-Methyl derivative 3e
was similarly prepared from o-(methylseleno)benzyl
alcohol 9, which was obtained by the reduction of
2,2Ј-dicarboxydiphenyl diselenide 8 with LiAlH4 fol-
lowed by alkylation with methyl iodide. The selen-
urane structures of 3a–d were characterized by the
1H and 77Se NMR spectra. Compounds 3a–e showed
downfield-shifted signals at d 8.72–9.04 due to H(7),
whereas the corresponding protons of selenonium
salts 4a–c appeared at d 8.11–8.25. The C(7)-H bond
Dedicated to Prof. Naoki Inamoto on the occasion of his 72nd
birthday.
Correspondence to: Tadashi Kataoka.
᭧ 2001 John Wiley & Sons, Inc.
317

318 Kataoka et al.
SCHEME 1
of the selenuranes is parallel to the apical Se–Cl bond
and the H(7) is affected by the anisotropic effect of
the chlorine atom. The 77Se-NMR spectra of selen-
uranes 3a–c exhibited the signals at d 797.2–815.7 in
contrast to those of selenonium salts 4a–c, which ex-
hibited them at d 983.3–1009.2. These spectroscopic
differences between selenuranes and selenonium
salts are in good agreement with other examples
[4,6,7].
11-Chloro-5,11-epoxy-6,11-dihydrodibenzo[b,e]
selenepines (12) and selenepinium salts (13) were
prepared by the procedures shown in Scheme 2. Al-
cohols 11a,b derived from 10 by reduction or the
Grignard reaction were chlorinated with NCS to give
chloroselenuranes 12a,b. The selenuranes 12a,b
were converted into selenonium salts 13a–c by the
treatment with AgBF4 or AgClO4. Selenuranes 12a,b
showed the characteristic downfield shift of H(4) at
d 8.68 and 8.55, respectively in their 1H NMR spectra.
The 77Se NMR signals of 12a,b appeared at d 719.7
and 726.7 in the higher field than those of the sele-
nonium salts of 13a,b at d 851.5 and 858.5,
respectively.
benzyl alcohols 2a,b, and reactions under reflux in
THF afforded benzophenone derivatives 14a,b and
benzyl ethers 15a,b in addition to 2a,b. The benzyl
alcohols 2a,b were presumably formed via the sin-
gle-electron transfer (SET) from the organometallic
reagent to the selenonium salt 4a,b [8] followed by
O–Se bond fission. The benzophenone derivatives
14a,b are formed by deprotonation of H(3) and sub-
sequent O–Se bond fission. This process corresponds
to the last step of the dimethyl sulfoxide oxidation
of alcohols [9] and is confirmed by the evidence that
the reaction of selenonium salt 4b with sodium hy-
dride gave benzophenone 14b in 32.5% yield. Benzyl
ethers 15a,b were presumably formed via the ligand
coupling reactions of the respective selenurane in-
termediates. 3,3-Dimethyl derivative 4c was used to
prevent oxidation triggered by deprotonation of
H(3). Reactions with phenyllithium or methylli-
thium at room temperature gave the SET reduction
product 7 only, and the reaction with methyllithium
at מ10ЊC gave a ligand coupling product 15c in 8%
yield.
From these results it was found that 2,1-oxase-
lenolium salts 4a–c readily underwent the SET re-
duction by the organometallic reagents. Therefore,
we next examined the reactions of 5,11-epoxy-6,11-
We conducted reactions of oxaselenolium salts
4a,b with organometallic reagents (Scheme 3 and
Table 1). Reactions at room temperature gave only

Syntheses and Reactions of Cyclic Se-Alkoxy-Se-chloroselenuranes and Alkoxyselenonium Salts 319
SCHEME 2
SCHEME 3
TABLE 1 Reactions of Selenonium Salts 4 with Organometallic Reagents
Products (% Yield)
Entry
Compound No.
R3M
PhLi
PhMgBr
PhLi
Temp.
Time
2
14
15
1
2
3
4
4a
4a
4b
4b
Reflux
Reflux
Reflux
Reflux
5 h
5 h
5 h
5 h
2a (41.8)
2a (83.3)
2b (22.4)
2b (37.7)
14a (3.1)
—
14b (7.1)
14b (5.4)
15a (13.0)
—
15b (7.2)
PhMgBr
15b ta
at ס trace (Ͻ1% yield).
dihydrodibenzo[b,e]selenepinium salts 13 with Gri-
gnard reagents (Scheme 4 and Table 2). Reactions of
13c with organolithiums gave complex mixtures of
products. Reactions with phenylmagnesium bro-
mide afforded a ring-opened product 16a, benzo
[c]furan derivative 17a, and dihydrodibenzoselene-
pinol 10b. Reaction at room temperature (entry 1)
gave 17a in greater yield than that at lower tempera-
ture (entry 2). When phenylmagnesium iodide was
used instead of the bromide, a SET reduction prod-
uct 10b was obtained in 56% yield (entry 3). Meth-
ylmagnesium iodide similarly caused the SET re-
duction to give 10b in 70.9% yield (entry 4). This
interesting difference between RMgI and RMgBr has
been reported in the reactions of cyclic selenonium
salts with organometallic reagents [8].

320 Kataoka et al.
SCHEME 4
TABLE 2 Reactions of Selenonium Salt 13c with Grignard
Reagents
than 12b might be that the selenium atom of 13b is
more positively charged than that of 12b.
Molar
Ratio
RMgX RMgX/13c
Products (% Yield)
EXPERIMENTAL
Entry
16
17
10b
Melting points were obtained with a Yanagimoto mi-
cro melting point apparatus and are uncorrected.
The IR spectra of solids (KBr) and liquids (NaCl)
were recorded on a JASCO IRA-100 spectrophotom-
eter. 1H NMR spectra were recorded on a JEOL GX-
270 (270 MHz) or a JEOL EX-400 (400 MHz) spec-
trometer with tetramethylsilane as an internal
standard. 13C NMR and 77Se NMR spectra were ob-
tained on a JEOL EX-400 spectrometer. The chemi-
cal shifts of 77Se signals were measured in ppm on
the d-scale downfield from dimethyl selenide as an
external standard. Mass spectra were recorded on a
JEOL JMS-SX102A spectrometer with a direct-in-
sertion probe at 70 eV. Elemental analyses of new
compounds were performed by use of a Yanaco CHN
Corder MT-5. All chromatographic isolations were
accomplished with BW-350 (Fuji Silysia) for column
chromatography or with Kieselgel 60 PF254 contain-
ing gypsum (Merck) for preparative thin-layer chro-
matography (TLC). CH2Cl2 was dried and freshly dis-
tilled over calcium chloride.
1
2
3
4
PhMgBr
PhMgBra
PhMgI
8
8
4
1.1
16a (45.6) 17a (31.6)
16a (38.4) 17a (1.7)
—
—
16a (14.7) 17a (24.8) 56.0
17b (3.1) 70.9
MeMgI
—
aTemp. מ78ЊC → r.t.
The probable mechanism of formation of prod-
ucts 16,17, and 10b is shown in Scheme 5. The Gri-
gnard reagents attack a selenium atom and form se-
lenurane 18, whose oxygen ligand and the benzylic
carbon couple with each other to give dihydro-
benzo[c]furan 17. If the nucleophilic attack of the
Grignard reagents at the selenium atom causes the
ligand exchange, selenonium salt 19 is formed. The
selenonium salt 19 reacts with another molecule of
RMgX to generate a selenurane-bearing four carbon-
ligands, 20, whose benzyl carbon combines with one
of the R ligands to give product 16. Products 16 and
17 might be formed by another pathway, that is, the
attack of RMgX and the alkoxide moiety, respec-
tively, on the benzylic carbon. However, we could not
determine how much the nucleophilic attack on the
benzylic carbon contributes to the reaction mecha-
nism. The SET from RMgX to selenonium ion 13c
brings about the O–Se bond cleavage to generate an
alkoxy radical, which abstracts a hydrogen from a
solvent or is reduced to an alkoxide ion and then
gives 10b.
Finally, we carried out the reaction of selenurane
12b and selenonium salt 13b with triethylamine
(Scheme 6). Since these compounds have no b-hy-
drogen to the selenonio moiety, their reactions with
a base did not cause b-elimination but rather the 1,2-
rearrangement of the alkoxy group. Both com-
pounds 12b and 13b afforded 5,10-epoxydihydrodi-
benzoselenepine 18 in 18% and 68% yields,
respectively. The reason why 13b gave a higher yield
1-Chloro-1-phenyl-3H-2,1-benzoxaselenole (3a)
Compound 3a was prepared by the known proce-
dure [5]. 1H NMR (CDCl3 d) 4.97 and 5.39 (each 1H,
d, J ס 14 Hz, 3-H), 7.37–7.48 (4H, m, ArH), 7.50–
7.57 (2H, m, ArH), 7.62–7.72 (2H, m, ArH), 8.96 (1H,
d, J ס 9 Hz, 7-H). 13C NMR (CDCl3 d) 74.2 (t), 123.1
(d), 127.7 (d ן 2), 129.3 (d), 129.5 (d ן 2), 131.2 (d),
131.4 (d), 132.5 (d), 133.4 (s), 141.5 (s), 143.8 (s).
77Se-NMR (CDCl3 d) 814.9.
1-Chloro-1,3-diphenyl-3H-2,1-benzoxaselenole
(3b)
Compound 3b was prepared by the known proce-
1
dure [5]. H NMR (CDCl3 d) 5.81 (1H, s, 3-H), 6.96
(1H, d, J ס 7 Hz, ArH), 7.17–7.31 (2H, m, ArH), 7.35–
7.75 (10H, m, ArH), 9.04 (1H, d, J ס 8 Hz, 7-H). 13
C

Syntheses and Reactions of Cyclic Se-Alkoxy-Se-chloroselenuranes and Alkoxyselenonium Salts 321
SCHEME 5
SCHEME 6
NMR (CDCl3 d) 87.3 (d), 126.1 (d), 128.3 (d ן 2),
128.4 (d ן 2), 129.3 (d ן 2), 129.5 (d), 130.0 (d ן
2), 130.2 (d), 131.4 (d), 131.6 (d), 133.0 (d), 134.1 (s),
139.7 (s), 141.8 (s), 146.7 (s). 77Se-NMR (CDCl3 d)
797.2.
mL), and the mixture was stirred for 12 hours at
room temperature. The precipitate was collected by
filtration and washed with hot acetonitrile several
times. The filtrate and the washings were combined
and concentrated. The residue was recrystallized
from acetonitrile-ether to give colorless prisms (11.2
1
g, 97.5%), m.p. 205–208ЊC (dec.). H NMR (CD3CN
1-Phenyl-3H-2,1-benzoxaselenolium Perchlorate
(4a)
d) 6.57 (1H, s, 3-H), 7.16 (1H, d, J ס 7 Hz, ArH), 7.2–
7.38 (2H, m, ArH), 7.38–7.52 (3H, m, ArH), 7.52–7.70
(4H, m, ArH), 7.70–7.87 (3H, m, ArH), 8.25 (1H, d, J
ס 7 Hz, ArH). 13C{1H} NMR (CD3CN d) 91.9, 126.4,
128.2, 128.5, 128.8, 129.3, 130.0, 130.4, 131.3, 133.7,
134.0, 134.1, 145.2. 77Se NMR (CDCl3 d) 983.3. IR
This compound was prepared by the known proce-
dure [5]. 1H NMR (CD3CN d) 5.62 and 5.76 (each 1H,
d, J ס 14 Hz, 3-H), 7.53 (2H, d, J ס 8 Hz, ArH), 7.61
(2H, t, J ס 8 Hz, ArH), 7.68–7.83 (3H, m, ArH), 7.88
(1H, t, J ס 7 Hz, ArH), 8.12 (1H, d, J ס 8 Hz, 7-H).
13C{1H}-NMR (CD3CN d) 79.2, 116.9, 123.7, 128.2,
129.2, 130.3, 130.7, 133.5, 134.1, 143.3. 77Se NMR
(CD3CN d) 1009.2.
מ
(KBr) cmמ1: 1200–1000 (ClO4 ). Anal. Calcd. for
C19H15ClO5Se: C, 52.13; H, 3.45. Found: C, 51.88; H,
3.44.
o-(Phenylseleno)benzoic Acid (5)
1,3-Diphenyl-3H-2,1-benzoxaselenolium
Perchlorate (4b)
Silver nitrate (14.4 g) was added to a solution of
NaOH (6.4 g) in 50% ethanol (240 mL). o-(Phenyl-
seleno)benzaldehyde [10] (1) (10.5 g, 40 mmol) was
added to the suspension, and the mixture was re-
Silver perchlorate (6.0 g, 29 mmol) was added to a
solution of 3b (9.8 g, 26 mmol) in dry CH2Cl2 (380

322 Kataoka et al.
fluxed for 4 hours. Hot water (480 mL) was added to
the mixture, and the whole was filtered through cel-
ite. The filtrate was acidified with 2 N HCl and ex-
tracted with CH2Cl2. The extracts were washed with
water, dried (MgSO4), and concentrated to dryness.
The residual solid was recrystallized from ethanol to
give colorless needles (10.3 g, 93%), m.p. 185–186ЊC
8 and 2 Hz, ArH), 7.48 (2H, m, ArH). 13C NMR (CDCl3
d) 30.4 (q ן 2), 74.4 (s), 125.7 (d), 126.4. (d), 127.6
(d), 127.8 (d), 129.4 (d ן 2), 131.0 (s), 131.9 (s), 133.9
(d), 134.7 (d ן 2), 147.2 (s). IR (film) cmמ1: 3370
(OH). HRMS Calcd for C15H16OSe: 292.0365. Found:
292.0343.
1
(reported [11] 190ЊC). H NMR (CD2Cl2 d) 5.32 (1H,
1-Chloro-3,3-dimethyl-1-phenyl-3H-2,1-
benzoxaselenole (3c)
s, OH), 6.94 (2H, d, J ס 8 Hz, ArH), 7.20–7.33 (4H,
m, ArH), 7.35–7.53 (6H, m, ArH), 7.65–7.75 (4H, m,
ArH), 8.15 (2H, d, J ס 7 Hz, ArH). 13C NMR (CD2Cl2
d) 125.3 (d), 128.9 (s), 129.5 (d), 129.7 (d), 130.2 (d
ן 2), 132.6 (d), 133.8 (d), 137.9 (d ן 2), 141.2 (s),
141.9 (s), 171.8 (s). IR (KBr) cmמ1: 3300–2400 (OH),
A solution of N-chlorosuccinimide (NCS) (850 mg,
6.5 mmol) in dry CH2Cl2 (50 mL) was added to a
solution of 7 (1.9 g, 6.5 mmol) in dry CH2Cl2 (20 mL).
The mixture was stirred for 30 minutes at room tem-
perature, concentrated to the amount of 20 mL, and
ether was added. The precipitate was collected by
filtration and recrystallized from CH2Cl2-ether to
give colorless prisms (1.10 g, 52%), m.p. 138–140ЊC
(dec.). 1H NMR (CDCl3 d) 1.07 (3H, s, CH3), 1.59 (3H,
s, CH3), 7.28 (1H, dd, J ס 7 and 2 Hz, ArH), 7.35–
7.47 (3H, m, ArH), 7.55 (2H, dd, J ס 8 and 1.5 Hz,
ArH), 7.65–7.78 (2H, m, ArH), 9.03 (1H, dd, J ס 8
and 1.5 Hz, 7-H). 13C NMR (CDCl3 d) 29.8 (q), 31.6
(q), 90.1 (s), 124.2. (d), 127.6 (d ן 2), 129.4 (d ן 2),
129.8 (d), 131.1 (d), 131.2 (s), 131.4 (d), 133.2 (d),
145.9 (s), 150.9 (s). 77Se NMR (CDCl3 d) 815.7. Anal.
Calcd. for C15H15ClOSe: C, 55.32; H, 4.64. Found: C,
55.10; H, 4.59.
ם
1670 (CסO). MS m/z: 278 (M , base). Anal. Calcd.
for C13H10O2Se: C, 56.30; H, 3.64. Found: C, 56.20; H,
3.64.
Ethyl o-(Phenylseleno)benzoate (6)
Carboxyclic acid 5 was added to thionyl chloride (1.3
g, 11 mmol), and the mixture was heated at 100ЊC
for 1 hour. Hydrogen chloride was removed from the
mixture under diminished pressure, and then a so-
lution of dry pyridine (4 mL) in dry ethanol (30 mL)
was gradually added to it. The reaction mixture was
stirred for 1 hour at room temperature and then di-
luted with ether (30 mL). The whole was washed
with 10% HCl, 10% NaOH, and water, successively,
dried (MgSO4), and concentrated to give a yellow oil
3,3-Dimethyl-1-phenyl-3H-2,1-
benzoxaselenolium Perchlorate (4c)
1
(2.2 g, quantitatively). H NMR (CDCl3 d) 1.44 (3H,
t, J ס 7 Hz, CH3), 4.44 (2H, q, J ס 7 Hz, CH2), 6.90
(1H, d, J ס 8 Hz, ArH), 7.10–7.25 (2H, m, ArH), 7.37–
7.53 (3H, m, ArH), 7.71 (2H, dd, J ס 8 and 2 Hz,
ArH), 8.06 (2H, dd, J ס 7 and 2 Hz, ArH). 13C NMR
(CDCl3 d) 14.4 (q), 61.4 (t), 116.7 (s), 124.7 (d), 127.4
(s), 128.9 (d), 129.1 (d), 129.7 (d ן 2), 131.3 (d),
132.5 (d), 137.5 (d ן 2), 140.3 (s), 166.8 (s). IR (film)
cmמ1: 1700 (CסO). HRMS Calcd for C15H14O2Se:
306.0158. Found: 306.0133.
Silver perchlorate (0.78 g, 3.8 mmol) was added to a
solution of 3c (1.1 g, 3.4 mmol) in dry CH2Cl2 (50
mL) at room temperature. The mixture was stirred
for 2 hours, and silver chloride was removed by fil-
tration. The filtrate was concentrated under reduced
pressure, and the residue was recrystallized from
ethyl acetate to give colorless prisms (0.95 g, 72%),
m.p. 193–195ЊC (dec.). 1H NMR (CD3CN d) 1.42 (3H,
s, CH3), 1.74 (3H, s, CH3), 7.53–7.67 (5H, m, ArH),
7.67–7.70 (1H, m, ArH), 7.83 (1H, td, J ס 7 and 1.5
Hz, ArH), 7.92 (1H, td, J ס 7 and 1.5 Hz, ArH), 8.11
(1H, dd, J ס 8 and 1 Hz, ArH). 13C NMR (CD3CN d)
30.6 (q), 30.9 (q), 100.2 (s), 126.1 (d), 129.4 (d), 130.1
(s), 130.3 (d ן 2), 131.6 (d ן 2), 132.5 (d), 135.3 (d),
135.4 (d), 138.8 (s), 151.0 (s). 77Se NMR (CDCl3 d)
1-Methyl-1-[(2-phenylseleno)phenyl]ethanol (7)
An ethereal solution of methylmagnesium bromide
(22.6 mL, 21.7 mmol) was added to a solution of 6
(2.2 g, 7.2 mmol) in dry THF (20 mL) under a nitro-
gen atmosphere. The mixture was stirred for 2 hours
at room temperature, cooled in an ice bath, and then
treated with a saturated NH4Cl solution. The aque-
ous mixture was extracted with ether. The extracts
were dried (MgSO4) and concentrated under re-
duced pressure to give a pale yellow oil (1.90 g, 90%).
1H NMR (CDCl3 d) 1.74 (6H, s, CH3), 2.91 (1H, s, OH),
6.99 (1H, td, J ס 7 and 1.5 Hz, ArH), 7.08–7.23 (2H,
m, ArH), 7.25–7.33 (3H, m, ArH), 7.38 (1H, dd, J ס
מ
987.1. IR (KBr) cmמ1: 900–1200 (ClO4 ). Anal. Calcd.
for C15H15ClO5Se: C, 46.23; H, 3.88. Found: C, 46.23;
H, 3.84.
1-Chloro-3-oxo-1-phenyl-2,1-oxaselenole (3d)
A solution of NCS (940 mg, 7.2 mmol) in dry CH2Cl2
(100 mL) was added to a solution of 5 (1.9 g, 6.5

Syntheses and Reactions of Cyclic Se-Alkoxy-Se-chloroselenuranes and Alkoxyselenonium Salts 323
mmol) in dry CH2Cl2 (50 mL). The mixture was
74.9 (t), 122.9 (d), 129.4 (d), 130.4 (d), 133.2 (d),
134.4 (s), 142.5 (s). Anal. Calcd. for C8H9ClOSe: C,
40.79; H, 3.85. Found: C, 40.73; H, 3.75.
stirred for 30 minutes at room temperature, concen-
trated to 50 mL, and ether was added. The precipi-
tate was collected by filtration and recrystallized
from CH2Cl2-ether to give colorless prisms (0.70 g,
11-Phenyl-6,11-dihydrodibenzo[b,e]selenepin-
11-ol (11a)
1
31%), m.p. 197–200ЊC (dec.). H NMR (DMSO-d6 d)
7.43–7.65 (5H, m, ArH), 8.04 (1H, t, J ס 7 Hz, ArH),
8.07–8.20 (2H, m, ArH), 8.72 (1H, d, J ס 8 Hz, 7-H).
13C NMR (DMSO-d6 d) 127.3. (d ן 2), 129.4 (d), 129.8
(d), 130.0 (d ן 2), 131.4 (s), 131.5 (d), 133.7 (d),
135.2 (d), 136.6 (s), 144.5 (s), 168.1 (s). Anal. Calcd.
for C13H9ClO2Se: C, 50.11; H, 2.91. Found: C, 49.89;
H, 3.01.
A solution of 6,11-dihydrodibenzo[b,e]selenepin-11-
one (10) [13] (4.0 g, 15 mmol) in dry benzene (40
mL) was added to an ethereal solution of phenyl-
magnesium bromide prepared from bromobenzene
(5.7 g, 36.3 mmol) and magnesium (1.1 g, 44 mmol).
The mixture was refluxed for 4.5 hours with stirring,
cooled in an ice bath and treated with a saturated
NH4Cl solution. The ether layer was separated and
the aqueous layer was extracted with CH2Cl2. The
ether layer and the extracts were combined, dried
(MgSO4), and concentrated under reduced pressure.
The residue was purified by column chromatogra-
phy on silica gel (hexane–CH2Cl2 ס 3:1) to give col-
orless prisms (from CH2Cl2-ether) (3.8 g, 74%), m.p.
o-(Methylseleno)benzyl Alcohol (9)
Diselenide 8 [12] (4.0 g, 10 mmol) was gradually
added to a suspension of LiAlH4 (0.95 g, 50 mmol)
in dry THF (50 mL) with cooling in an ice bath, and
the mixture was stirred for several hours at room
temperature. Then a solution of methyl iodide (2.8
g, 20 mmol) in dry THF (10 mL) was added to the
mixture. The whole was stirred overnight, and water
was added to it. The precipitate was filtered off and
washed with CH2Cl2. The filtrate was extracted with
CH2Cl2. The washings and the extracts were com-
bined, dried (MgSO4), and concentrated. The resid-
ual oil was purified by column chromatography on
silica gel (haxane–CH2Cl2 ס 2:1) to give a pale yellow
oil (2.4 g, 58%). 1H NMR (CDCl3 d) 2.30 (3H, s, CH3),
2.61 (1H, s, OH), 4.70 (2H, s, CH2), 7.15–7.28 (2H,
m, ArH), 7.30–7.38 (1H, m, ArH), 7.38–7.45 (1H, m,
ArH). 13C NMR (CDCl3 d) 7.30 (q), 64.9 (t), 126.5 (d),
128.0 (d), 128.3 (d), 130.6 (d), 131.4 (s), 140.9 (s). IR
(film) cmמ1: 3350 (OH). High-resolution mass spec-
trometry (HRMS) Calcd for C8H10OSe: 201.9896.
Found: 201.9871.
1
210–212ЊC. H NMR (CDCl3 d) 3.24 and 3.65 (each
1H, d, J ס 12 Hz, 6-H), 7.08 (1H, d, J ס 7 Hz, ArH),
7.13 (1H, dd, J ס 1.4, 8 Hz, ArH), 7.20–7.36 (9H, m,
ArH), 8.06 (1H, d, J ס 8 Hz, ArH), 8.11 (1H, d, J ס
8 Hz, ArH). 13C NMR (CDCl3 d) 27.3 (t), 79.1 (s), 125.7
(d), 127.9 (d), 126.7 (d), 127.1 (d ן 2), 127.6 (d),
127.9 (d), 128.3 (d), 128.4 (d), 128.9 (d ן 2), 129.4
(d), 129.8 (s), 130.9 (d), 132.5 (s), 140.7 (s), 144.2 (s
ם
ן 2). IR (KBr) cmמ1: 3140 (OH). MS m/z: 352 (M ),
195 (base). Anal. Calcd. for C20H16OSe: C, 68.38; H,
4.59. Found: C, 68.23; H, 4.57.
6,11-Dihydrodibenzo[b,e]selenepin-11-ol (11b)
Sodium borohydride (1.1 g, 30 mmol) was gradually
added to a solution of 10 (2.7 g, 10 mmol) in ethanol
(100 ml). The reaction mixture was stirred for 1 hour
at room temperature and added to water. The aque-
ous mixture was extracted with CH2Cl2, and the ex-
tracts were washed with water, dried (MgSO4), and
concentrated. Yellow crystals (2.7 g, 97%) were ob-
tained and used for preparation of 12b without fur-
1-Chloro-1-methyl-3H-2,1-benzoxaselenole (3e)
A solution of NCS (1.5 g, 12 mmol) in dry CH2Cl2 (60
mL) was added to a solution of 9 (2.4 g, 12 mmol) in
dry CH2Cl2 (30 mL). The mixture was stirred for 30
minutes at room temperature and then poured into
water. The CH2Cl2 layer was separated, and the aque-
ous layer was extracted with CH2Cl2. The CH2Cl2
layer and the extracts were combined, dried, and
concentrated to the amount of 20 mL, and then ether
was added. The precipitate was collected by filtration
and recrystallized from CH2Cl2-ether to give color-
less prisms (2.17 g, 77%), m.p. 114–117ЊC (dec.). 1H
NMR (CDCl3 d) 3.39 (3H, s, CH3), 5.48 and 5.57 (each
1H, d, J ס 14 Hz, CH2), 7.41 (1H, d, J ס 7 Hz, ArH),
7.52–7.62 (1H, m, ArH), 7.62–7.70 (1H, m, ArH), 8.76
(1H, d, J ס 8 Hz, 7-H). 13C NMR (CDCl3 d) 42.3 (q),
1
ther purification. H NMR (CDCl3 d) 2.90 (1H, brs,
OH), 3.85 and 4.48 (each 1H, d, J ס 12 Hz, 5-H), 6.00
(1H, s, 11-H), 6.95–7.57 (8H, m, ArH). IR (KBr)
ם
cmמ1: 3380 (OH). MS m/z: 276 (M ), 178 (base).
5-Chloro-5,11-epoxy-11-phenyl-6,11-
dihydrodibenzo[b,e]selenepine (12a)
A solution of NCS (380 mg, 2.85 mmol) in dry CH2Cl2
(50 mL) was added to a solution of 11a (1.0 g, 2.85
mmol) in dry CH2Cl2 (25 mL). The mixture was
stirred for 10 minutes at room temperature, concen-

324 Kataoka et al.
מ1
מ
trated to the amount of 10 mL, and ether was added.
The precipitate was collected by filtration and re-
crystallized from CH2Cl2-ether to give colorless
cm
:
900–1200 (BF4 ). Anal. Calcd. for
C20H15BF4OSe: C, 54.96; H, 3.46. Found: C, 54.77; H,
3.44.
1
prisms (883 mg, 80%), m.p. 238–240ЊC (dec.). H
NMR (CDCl3 d) 4.71 and 5.40 (each 1H, d, J ס 16
Hz, 6-H), 6.99 (1H, d, J ס 8 Hz, ArH), 7.12 (1H, dd,
J ס 1, 8 Hz, ArH), 7.18 (1H, dd, J ס 7, 8 Hz, ArH),
7.45–7.50 (3H, m, ArH), 7.53–7.60 (4H, m, ArH), 8.68
(1H, m, 4-H). 13C NMR (CDCl3 d) 50.1 (t), 93.3 (s),
124.8 (d), 126.5 (d), 127.5 (s), 127.7 (d), 128.7 (d),
129.0 (d), 129.3 (d ן 2), 129.4 (d ן 2), 129.8 (d),
130.1 (d), 131.2 (s), 131.5 (d), 132.2 (d), 136.9 (s),
138.5 (s), 149.6 (s). 77Se NMR (CDCl3 d) 719.7 MS m/
5,11-Epoxy-6,11-dihydrodibenzo[b,e]
selenepinium Tetrafluoroborate (13b)
Compound 12b (500 mg, 1.6 mmol) was similarly
treated with silver tetrafluoroborate (314 mg, 1.6
mmol) in CH2Cl2. Recrystallization from CH2Cl2-
ether gave colorless prisms (422 mg, 73%), m.p. 144–
1
1
146.5ЊC (dec.). H NMR H-NMR (DMSO-D6 d) 4.02
and 4.97 (each 1H, d, J ס 16 Hz, 6-H), 6.71 (1H, s,
11-H), 7.15 (1H, d, J ס 7 Hz, ArH), 7.32 (1H, m,
ArH), 7.37 (1H, m, ArH), 7.4–7.63 (3H, m, ArH), 7.64
(1H, d, J ס 6 Hz, ArH), 7.93 (1H, d, J ס 7 Hz, 4-H).
13C NMR (DMSO-D6 d) 42.87 (t), 85.5 (d), 122.6 (d),
125.7 (d), 126.0 (s), 127.6 (d), 128.3 (d), 129.5 (d ן
2), 130.2 (d), 132.1 (d), 133.7 (s), 134.9 (s), 147.1 (s).
77Se NMR (DMSO-D6 d) 858.5. IR (KBr) cmמ1: 900–
ם
z: 386 (M ), 321 (base). Anal. Calcd. for C20H15ClOSe:
C, 62.27; H, 3.92. Found: C, 61.99; H, 3.90.
5-Chloro-5,11-epoxy-6,11-
dihydrodibenzo[b,e]selenepine (12b)
Compound 11b (1.0 g, 3.6 mmol) was similarly
treated with NCS (485 mg, 3.6 mmol) in CH2Cl2. Re-
crystallization from CH2Cl2-ether gave colorless
prisms (1.0 g, 89%), m.p. 171–173ЊC (dec.). 1H NMR
(CDCl3 d) 4.64 and 5.06 (each 1H, d, J ס 16 Hz, 6-
H), 6.23 (1H, s, 11-H), 7.00 (1H, d, J ס 7 Hz), 7.26–
7.35 (3H, m, ArH), 7.41 (1H, m, ArH), 7.46–7.52 (2H,
m, ArH), 8.55 (1H, m, 4-H). 13C NMR (CDCl3 d) 122.4
(d), 125.5 (d), 127.5 (d), 128.0 (s), 129.5 (d), 129.6
(d), 129.9 (d), 130.3 (d), 132.1 (d), 134.0 (s), 134.3
(s), 147.8 (s). 77Se NMR (CDCl3 d) 726.7. MS m/z: 310
מ
1200 (BF4 ). Anal. Calcd. for C14H11BF4OSe: C, 46.58;
H, 3.07. Found: C, 46.30; H, 3.26.
5,11-Epoxy-6,11-dihydrodibenzo[b,e]
selenepinium Perchlorate (13c)
Silver perchlorate (1.55 g, 7.5 mmol) was added to a
solution of 12b (2.33 g, 7.5 mmol) in dry CH2Cl2 (95
ml) at room temperature. The mixture was stirred
for 4 hours, and then silver chloride was removed by
filtration. The filtrate was concentrated under re-
duced pressure. The residual solid was recrystallized
from CH2Cl2-ether to give colorless prisms (2.73 g,
97%), m.p. 178–179ЊC (dec.). IR (KBr) cmמ1: 1000–
ם
(M ), 275 (base). Anal. Calcd. for C14H11ClOSe: C,
54.30; H, 3.58. Found: C, 54.06; H, 3.50.
5,11-Epoxy-11-phenyl-6,11-dihydrodibenzo[b,e]
selenepinium Tetrafluoroborate (13a)
מ
1200 (ClO4 ). Anal. Calcd. for C14H11ClO4Se: C, 45.00;
H, 2.97. Found: C, 44.89; H, 3.02.
Silver tetrafluoroborate (252 mg, 1.3 mmol) was
added to a solution of 12a (500 mg, 1.3 mmol) in dry
CH2Cl2 (20 mL) at room temperature. The mixture
was stirred for 2 hours, and silver chloride was re-
moved by filtration. The filtrate was concentrated
under reduced pressure, and the residue was recrys-
tallized from CH2Cl2-ether to give colorless prisms
(560 mg, 99%), m.p. 188–190ЊC (dec.). 1H NMR
(DMSO-D6 d) 4.11 and 5.34 (each 1H, d, J ס 16 Hz,
6-H), 7.10 (2H, m, ArH), 7.22 (1H, dd, J ס 7, 8 Hz,
ArH), 7.36 (1H, dd, J ס 7, 8 Hz, ArH), 7.42 (1H, d, J
ס 8 Hz, ArH), 7.50–7.56 (3H, m, ArH), 7.57 (1H, d,
J ס 8 Hz, ArH), 7.58–7.70 (3H, m, ArH), 8.05 (1H, d,
J ס 7 Hz, 4-H). 13C NMR (DMSO-D6 d) 43.3 (t), 95.2
(s), 124.7 (d), 125.4 (s), 125.9 (d), 127.4 (d), 128.3 (d
ן 2), 128.9 (d), 129.0 (d ן 3), 129.5 (d), 129.8 (d),
129.9 (d), 131.1 (s), 132.1 (d), 135.5 (s), 136.5 (s),
147.8 (s). 77Se NMR (DMSO-D6 d) 851.5. IR (KBr)
Reactions of 4 with Organometallic Reagents
Phenylmagnesium bromide or phenyllithium (0.75
mmol) was added to a suspension of selenonium salt
4 (0.5 mmol) in dry THF at room temperature under
a nitrogen atmosphere. The mixture was refluxed for
5 hours with stirring and then cooled and treated
with 5% hydrochloric acid with cooling in an ice
bath. The whole was extracted with ether. The ex-
tracts were washed with water, dried (MgSO4), and
concentrated. The residue was separated by prepar-
ative TLC on silica gel (hexane–CH2Cl2 ס 5:1) and
the high polar fractions were separated again using
hexane–CH2Cl2 ס 1:1 as an eluant. Reaction condi-
tions and yields of products are shown in Table 1.
o-(Phenylseleno)benzaldehyde (14a): 1H NMR
(CDCl2 d) 7.01–7.85 (9H, m, ArH), 10.2 (1H, s, CHO).

Syntheses and Reactions of Cyclic Se-Alkoxy-Se-chloroselenuranes and Alkoxyselenonium Salts 325
ם
IR (NaCl) cmמ1: 1660 (CסO). MS (m/z): 262 (M ),
Reactions of 13c with Grignard Reagents
77 (base).
o-(Phenylseleno)benzophenone (14b): H NMR
An ethereal solution of a Grignard reagent was
added to a suspension of 13c (373 mg, 1 mmol) in
dry THF (5 mL) under a nitrogen atmosphere. The
mixture was stirred, cooled in an ice bath, and
treated with 5% hydrochloric acid. The whole was
extracted with ether. The extracts were dried
(MgSO4) and concentrated. The residue was sepa-
rated by preparative TLC on silica gel (hexane–
CH2Cl2 ס 2:1). Reaction conditions and yields of
products are listed in Table 2.
1
מ1
(CDCl3 d) 7.21–7.82 (14H, m, ArH). IR (film) cm
:
ם
1650 (CסO). MS (m/z) 338 (M ), 261 (base). This
sample was identical with an authentic sample [11].
o-(Phenylseleno)benzyl alcohol (2a): 1H NMR
(CDCl3, d) 2.08 (1H, s, OH), 4.76 (2H, s, CH2), 7.25–
7.37 (9H, m, ArH). IR (film) cmמ1: 3330 (OH). MS
ם
(m/z): 264 (M ), 105 (base). This sample was iden-
tical with an authentic sample [5].
Phenyl[o-(phenylseleno)phenyl]methanol (2b):
1H NMR (CDCl3 d) 2.50 (1H, s, OH), 6.30 (1H, s, CH),
7.12–7.53 (1H, m, ArH). IR (film) cmמ1: 3400 (OH).
o-Benzylphenyl[o-(phenylseleno)phenyl]metha-
nol (16a): m.p. 137–139ЊC (dec.). 1H NMR (CDCl3, d)
2.06 (1H, brs, OH), 3.94 and 4.09 (each 1H, d, 16Hz,
PhCH2), 6.38 (1H, s, CH), 7.04–7.39 (18H, m, ArH).
13C NMR (CDCl3, d) 38.7 (t), 71.7 (d), 126.1 (d), 126.7
(d), 127.3 (d), 127.5 (d), 127.7 (d ן 2), 127.8 (d),
128.4 (d), 128.4 (d), 128.9 (d), 129.3 (d), 130.5 (d),
131.1 (s), 131.2 (s), 132.7 (d), 134.8 (d), 138.7 (s),
140.4 (s), 140.5 (s), 144.1 (s). IR (KBr) cmמ1: 3550
ם
MS (m/z) 340 (M ), 181 (base). This sample was
identical with an authentic sample [5].
1
o-(Phenylseleno)benzyl phenyl ether (15a): H
NMR (CDCl3, d) 5.16 (2H, s, CH2), 6.91–6.97 (2H, m,
ם
ArH), 7.20–7.56 (12H, m, ArH). MS (m/z): 340 (M ),
245 (base).
␣-[o-(Phenylseleno)phenyl]benzyl phenyl ether
ם
(OH). MS (m/z): 430 (M ), 255 (base).
(15b): 1H NMR (CDCl3 d) 6.75 (1H, s, CH), 6.90–7.43
1-[o-(Phenylseleno)phenyl]-1,3-dihydrobenzo[c]
ם
(19H, m, ArH). MS (m/z) 416 (M ), 245 (base).
1
furan (17a): H NMR (CDCl3, d) 5.20 and 5.34 (each
1H, d, J ס 12 Hz, 3-H), 6.71 (1H, s, 1-H), 6.96–7.47
(13H, m, ArH). 13C NMR(CDCl3, d) 73.2 (t), 85.3 (d),
120.8 (d), 122.3 (d), 127.3 (d), 127.4 (d), 127.6 (d),
128.1 (d), 128.3 (d), 128.8 (d), 129.3 (d), 130.8 (s),
131.3 (s), 132.9 (d), 134.5 (d), 139.3 (s), 141.4 (s),
Reaction of 4b with Sodium Hydride
Selenonium salt 4b (110 mg, 0.25 mmol) was added
to a suspension of NaH (60% in mineral oil) (24 mg,
0.6 mmol) in dry THF (20 mL). The mixture was
stirred for 2 days at room temperature and treated
with water. The aqueous mixture was extracted with
ether, washed with water, dried (MgSO4), and con-
centrated. The residue was separated by preparative
TLC on silica gel (hexane:CH2Cl2 ס 2:1) to give 2b
(36 mg, 42.5%) and 14b (27.5 mg, 32.5%).
ם
143.4 (s). MS (m/z): 352 (M ), 178 (base).
1-[o-(Methylseleno)phenyl]-1,3-dihydrobenzo[c]
1
furan (17b): H NMR (CDCl3, d) 2.37 (3H, s, CH3),
5.23 and 5.35 (each 1H, d, J ס 12 Hz, 3-H), 6.64 (1H,
ם
s, 1-H), 7.09–8.17 (8H, m, ArH). MS (m/z): 290 (M ),
165 (base).
Reaction of 12b or 13b with Triethylamine
Reactions of 4c with Methyllithium
Reaction of 12b: Dry triethylamine (0.5 mL, 3.6
mmol) was added to a solution of 12b (250 mg, 0.65
mmol) in dry CH2Cl2 (10 mL). The mixture was
stirred at room temperature for 3.5 hours and then
concentrated to dryness. The residue was washed
with ether several times, and the washings were con-
centrated. The colorless solid was recrystallized
from CH2Cl2-hexane to give 6,11-epoxy-11-phenyl-
6,11-dihydrodibenzo[b,e]selenopine (18) as colorless
prisms (40 mg, 18%), m.p. 148–150ЊC. 1H NMR
(CDCl3 d) 6.89 (1H, s, 6-H), 6.94–7.14 (4H, m, ArH),
7.26–7.38 (3H, m, ArH), 7.41–7.50 (4H, m, ArH),
7.64–7.71 (2H, m, ArH). 13C NMR (CDCl3 d) 78.9 (d),
91.1 (s), 119.9 (d), 121.9 (d), 125.4 (d), 127.0 (d),
127.9 (d), 128.3 (d), 128.4 (d), 128.5 (d ן 2), 128.7
(s), 128.9 (d), 129.1 (d ן 2), 131.6 (d), 135.2 (s), 138.2
(s), 140.7 (s), 141.8 (s). 77Se NMR (CDCl3 d) 422.1.
An ethereal solution of methyllithium (1 M solution,
1.25 mL, 1.25 mmol) was added to a suspension of
selenonium salt 4c (98 mg, 0.25 mmol) in dry THF
(5 mL) at מ10ЊC under a nitrogen atmosphere. The
mixture was stirred overnight at that temperature
and then treated with 5% hydrochloric acid. The
whole was extracted with ether. The extracts were
washed with water, dried (MgSO4), and concen-
trated. The residue was separated by preparative
TLC on silica gel (hexane–CH2Cl2 ס 5:1), and the
high polar fractions were separated again using hex-
ane–CH2Cl2 ס 1:1 as an eluant. 2-(1-Methoxy-1-
methyl)ethyl-1-(phenylseleno)benzene (15c) (6 mg,
8%) and alcohol 7 (36 mg, 49%). 15c: 1H NMR
(CDCl3 d) 1.72 (6H, s, Mex2), 3.18 (3H, s, OMe), 6.98–
7.69 (9H, m, ArH). MS (m/z): 306 (Mם), 73 (base).

326 Kataoka et al.
ם
2340; (d) [10-Se-4(C2O2)]: Paetzold, R.; Lindner, U.
Z Anorg Chem 1967, 350, 295; (e) Horn, V.; Paetzold,
R. Z Anorg Chem 1973, 398, 186; (f) Reich, H. J Am
Chem Soc 1973, 95, 964; (g) Nakanishi, W.; Ikeda, Y.;
Iwamura, H. J Org Chem 1982, 47, 2275; (h) Ka-
washima, T.; Ohno, F.; Okazaki, R. J Am Chem Soc
1993, 115, 10434; (i) [10-Se-4(C3O)]: Kataoka, T.; Wa-
tanabe, S.; Yamamoto, K.; Yoshimatsu, M.; Tanabe,
G.; Muraoka, O. J Org Chem 1993, 63, 6382.
[5] Kataoka, T.; Shimizu, H.; Tomimatsu, K.; Tanaka, K.;
Hori, M.; Kido, M. Chem Pharm Bull 1990, 38, 874.
[6] (a) Kawashima, T.; Ohno, F.; Okazaki, R. J Am Chem
Soc 1993, 115, 10434; (b) Kawashima, T.; Ohno, F.;
Okazaki, R. Phosphorus Sulfur Silicon 1998, 136–
138, 501.
MS m/z: 350 (M ), 321 (base). Anal. Calcd. for
C20H14OSe: C, 68.77; H, 4.04. Found: C, 68.49; H,
4.01. Reaction of 13b: Compound 13b (500 mg, 1.1
mmol) was similarly treated with triethylamine (1
mL, 7.2 mmol), and 18 (272 mg, 68%) was obtained.
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