Desulfurilative self-coupling reaction of 1,3-thiazolidine-2-thiones and intramolecular non-bonded S?S interaction in the crystallographic structure of the products

Article abstract of DOI:10.1016/S0022-328X(00)00460-5

An attempt at an asymmetric Pummerer-type reaction of trans-4-benzyloxythiane-1-oxide (1) with 3-trifluoroacetyl-4S-isopropyl-1,3-thiazolidine-2-thione (2) resulted in failure but an attractive desulfurilative self-coupling reaction of 4S-isopropyl-1,3-th

Full text of DOI:10.1016/S0022-328X(00)00460-5

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 611 (2000) 172–177
Desulfurilative self-coupling reaction of 1,3-thiazolidine-2-thiones
and intramolecular non-bonded S···S interaction in the
crystallographic structure of the products
Yoshimitsu Nagao a,*, Hiroaki Nishijima a, Hitoshi Iimori a, Hideki Ushirogochi a,
Shigeki Sano a, Motoo Shiro b
a Faculty of Pharmaceutical Sciences, The Uni6ersity of Tokushima, Sho-machi, Tokushima 770-8505, Japan
b Rigaku Corporation, 3-9-12 Matubara-cho, Akishima, Tokyo 196-8666, Japan
Received 30 March 2000; accepted 18 April 2000
Abstract
An attempt at an asymmetric Pummerer-type reaction of trans-4-benzyloxythiane-1-oxide (1) with 3-trifluoroacetyl-4S-isopro-
pyl-1,3-thiazolidine-2-thione (2) resulted in failure but an attractive desulfurilative self-coupling reaction of 4S-isopropyl-1,3-thia-
zolidine-2-thione (6) occurred to give 4S-isopropyl-3-(4S-isopropyl-1,3-thiazolin-2-yl)-1,3-thiazolidine-2-thione (5). The same
desulfurilative self-coupling reaction of compound 6 or 11 efficiently proceeded by treatment of diphenyl sulfoxide (7a) or methyl
phenyl sulfoxide (7b) with 2 or 3-trifluoroacetyl-1,3-thiazolidine-2-thione (8) to afford each corresponding product 5 or 9.
Eventually, we found a practically useful method for the synthesis of 5 and 9 by exploiting TiCl4 and sodium salt 12 or 13 of
1,3-thiazolidine-2-thiones. Interestingly, intramolecular non-bonded S···S interactions were recognized in the crystallographic
structures of 5 and 9. © 2000 Elsevier Science S.A. All rights reserved.
Keywords: Pummerer-type reaction; Sulfoxide; 4S-Isopropyl-1,3-thiazolidine-2-thione; 1,3-Thiazolidine-2-thione; Coupling reactions; Non-bonded
interactions; X-ray crystallographic analysis
1. Introduction
thiadiazolines as angiotensin II receptor antagonists [5].
Recently, we attempted an asymmetric Pummerer-type
reaction of trans-4-benzyloxythiane-1-oxide (1), adopt-
ing a preferential trans-diaxial conformer [6], with
3-trifluoroacetyl-4S-isopropyl-1,3-thiazolidine-2-thione
(2) in CH2Cl2 at room temperature, as shown in
Scheme 1. However, the desirable reaction to give 3 did
not occur, and the resultant reaction furnished 4S-
Intramolecular non-bonded S···X (X=O, S, N, etc.)
interactions have been investigated for characterization
of the molecular structures of a large number of
organosulfur compounds [1]. These intra- and inter-
molecular non-bonded interactions seem to be very
attractive from a viewpoint of the construction of a new
molecular recognition system in chemical reactions [2]
and medicinal biochemistry [3]. In the series of studies
on heterocycles such as thiazolidines, thiazoles, thiadia-
zoles, and their related compounds, we have developed
various asymmetric induction reactions employing C4-
chiral 1,3-thiazolidine-2-thiones [4] and clarified in-
tramolecular non-bonded 1,5-type S···O interactions in
2-acylamino-1,3,4-thiadiazoles and 2-acylimino-1,3,4-
* Corresponding author. Tel.: +81-88-633-7271; fax: +81-88-633-
9503.
E-mail address: ynagao@ph2.tokushima-u.ac.jp (Y. Nagao).
Scheme 1.
0022-328X/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(00)00460-5

Y. Nagao et al. / Journal of Organometallic Chemistry 611 (2000) 172–177
173
ment of 7a or 7b with 3-trifluoroacetyl-1,3-thiazolidine-
2-thione (8) in CH2Cl2 at room temperature gave
3-(1,3-thiazolin-2-yl)-1,3-thiazolidine-2-thione (9) (45%
or 35% yield), diphenyl sulfide (10a) (59% yield) or
thioanisole (10b) (40% yield), and a trace amount of
1,3-thiazolidine-2-thione (11), respectively, as shown in
Scheme 2. The structure of 9 was confirmed to be that
of the known compound [7], obtained from totally
different synthetic methods from the present procedure,
on the basis of the physical and spectroscopic data.
Subsequently, the same treatment of 7a or 7b with
3 - trifluoroacethyl - 4S - isopropyl - 1,3 - thiazolidine - 2-
thione (2) as described above afforded 4S-isopropyl-3-
(4S-isopropyl-1,3-thiazolin-2-yl)-1,3-thiazolidine-2-
thione (5) (45% or 35% yield) together with each corre-
sponding sulfide 10a ( 59% yield) or 10b (40% yield)
and 6.
Scheme 2.
Scheme 3.
The structure of the new chiral heterocyclic com-
pound 5 was determined by X-ray crystallographic
analysis (vide infra). Because 3-trifluoroacetyl-1,3-thia-
zolidine-2-thiones (2 and 8) were remarkably unstable,
an alternative synthetic method for 5 and 9 was investi-
gated by using a Lewis acid as follows. Diphenyl sulf-
oxide (7a) was tentatively treated with sodium salt 12
[8] or 13 of 1,3-thiazolidine-2-thiones in the presence of
TiCl4 in CH2Cl2 at room temperature, as shown in
Scheme 3. The desired reaction proceeded smoothly to
give 5 in 46% yield or 9 in 53% yield and diphenyl
sulfide (10a) in 65% or 59% yield, respectively. This
practically useful reaction for the synthesis of 5 and 9
using TiCl4 and diphenyl sulfoxide (7a) can be ex-
plained by speculative reaction mechanisms, as shown
in Scheme 4. Namely, the reaction of 7a with TiCl4
presumably generates a sulfurane intermediate 14 [9],
followed by nucleophilic attack by 12 or 13 to furnish
sulfenyl chloride 15 and diphenylsulfide (10a). The re-
sultant labile 15 may immediately react with 12 or 13 in
two ways, ‘a’ and ‘b’, giving disulfide 16 and/or sulfide
17 releasing Cl− or Cl− and sulfur atom. Both unstable
intermediates 16 and 17 would become stable com-
pound 5 or 9 via intramolecular nucleophilic reaction
releasing sulfur atom or via S“N rearrangement reac-
tion [10], respectively. In the reaction (Scheme 2) with
3-trifluoroacetyl-1,3-thiazolidine-2-thiones (2 and 8),
the reaction mechanism probably involves the forma-
tion of a sulfurane intermediate 18, followed by nucle-
ophilic attack by the corresponding 1,3-thiazoli-
dine-2-thione anions to give 16 and/or 17, as shown in
Fig. 1.
Scheme 4.
isopropyl-3-(4S-isopropyl-1,3-thiazolin-2-yl)-1,3-thiazo-
lidine-2-thione (5) in 46% yield, 4-benzyloxythiane (4)
in 69% yield, and a trace amount of 4S-isopropyl-1,3-
thiazolidine-2-thione (6). The chiral bicyclic heterocycle
5 seemed to be a new chiral ligand molecule for some
soft-acidic Lewis acids. Thus, we wished to research
more practically useful reaction conditions in order to
obtain the chiral heterocycle 5.
2. Result and discussion
2.2. Characterization of the crystallographic structures
of 5 and 9
2.1. Synthesis of bicyclic heterocycles 5 and 9
First of all, we examined a Pummerer-type reaction
by using commercially available diphenyl sulfoxide (7a)
and methyl phenyl sulfoxide (7b) instead of 1. Treat-
In order to clarify the structure of 5, the crystalline
compound 5 was submitted to X-ray crystallographic

174
Y. Nagao et al. / Journal of Organometallic Chemistry 611 (2000) 172–177
Fig. 2. Computer-generated drawing derived from the X-ray coordi-
nates of compounds 5 and 9.
Fig. 1. Speculative reaction mechanism for the reaction of Scheme 2.
quently, X-ray crystallographic analysis of 9 was car-
ried out (Tables 1 and 2). Similar close contact [3.024(2)
Table 1
Summary of X-ray crystallographic analyses of compounds 5 and 9
,
or 3.028(2) A] between S2 and S3 or between S5 and S6
in both crystalline structures (A and B) of 9 was also
recognized. The S2–C3–N1–C4–S3 and S5–C9–N3–
C10–S6 moieties in the structures A and B are almost
flat from the viewpoint of the related torsion angles
listed in Table 2. In the molecules 5 and 9, the non-
bonded S···S atoms distances are considerably shorter
5
9
Formula
C12H20N2S3
288.48
Yellow prism
Monoclinic
P21
C6H8N2S3
204.32
Yellow prism
Monoclinic
P21/n
Formula weight
Crystal description
Crystal system
Space group
,
Lattice parameters
than the sum (3.60 A) of the van der Waals radii (S and
,
a (A)
11.858(2)
5.873(2)
12.516(2)
116.85(1)
777.6(3)
2
7.766(3)
12.742(5)
17.90(1)
98.79(4)
1749.9900
8
S). There have been several papers that have discussed
the non-bonded S···S interaction, e.g. in geometrically
constrained 1,5-dithiocane derivatives [11], 1-to-
sylimino-1,5-dithiacyclooctane [12], bis(phenylthio)-
dibenzothiophenes [13], thiathiophthenes (‘bond switch-
ing’) [1e,g] etc.[14]. The 1,5-type intramolecular non-
bonded S···S interaction in the bicyclic heterocycles 5
and 9 may be regarded as another new type of close
contact and compound 9 will be a useful chiral ligand
for soft Lewis acids.
,
b (A)
,
c (A)
i (°)
Volume (A )
Z
3
,
Density (calculated)
1.232
1.551
(g cm−3
)
Residual R, Rw
Goodness-of-fit
p-factor
0.058, 0.074
1.48
0.0820
0.057, 0.073
1.83
0.0610
analysis (Tables 1 and 2). The computer-generated
drawing of the crystal structure of 5 proved to be the
desired desulfurilative bicyclic product, as shown in
Fig. 2. In the represented crystalline structure of 5,
3. Experimental
3.1. General methods
,
significant close contact [3.039(3) A] between S2 and S3
atoms and planarity of the S2–C3–N1–C7–S3 moiety
were recognized (see torsion angles in Table 2.). Subse-
All melting points were determined on a Yanagimoto
microapparatus and are uncorrected. The infrared (IR)
Table 2
,
Selected atom distances (A), bond angles (°), and torsion angles (°) in the structures 5 and 9 (A and B)
5
9 (A)
9 (B)
S2–S3
3.039(3)
3.60 a
S2–S3
3.024(2)
3.60 a
S5–S6
3.028(2)
3.60 a
C3–N1
N1–C7
C3–S2
1.364(7)
1.409(8)
1.648(7)
C3–N1
N1–C4
C3–S2
1.362(4)
1.405(5)
1.645(5)
C9–N3
N3–C10
C9–S5
1.369(5)
1.411(5)
1.639(5)
S3–C7–N1
C7–N1–C3
N1–C3–S2
C7–S3–C9
122.2(5)
S3–C4–N1
C4–N1–C3
N1–C3–S2
C4–S3–C5
122.6(3)
S6–C10–N3
C10–N3–C9
N3–C9–S5
122.9(3)
127.3(5)
128.5(5)
87.8(4)
126.7(4)
129.2(3)
88.9(2)
126.1(4)
129.2(4)
87.7(2)
C10–S6–C11
S3–C7–N1–C3
S2–C3–N1–C7
5.6(10)
−13.0(10)
S3–C4–N1–C3
S2–C3–N1–C4
4.5(6)
−3.9(6)
S6–C10–N3–C9
S5–C9–N3–C10
6.9(6)
1.1(6)
a Sum of van der Waals radii (S and S).

Y. Nagao et al. / Journal of Organometallic Chemistry 611 (2000) 172–177
175
spectra were recorded on a Perkin–Elmer 1720 IR
Fourier transform spectrometer. 1H-NMR (200 and 300
MHz) and 13C-NMR spectra were recorded on a
JEOL-FX200 or JEOL-AL300 spectrometer. Chemical
shifts are given in l values (ppm) using tetramethylsi-
lane as an internal standard. Electron impact (EI) mass
spectra [MS and high resolution (HR)] were obtained
on a JEOL-SX-102A instrument. Elementary combus-
tion analyses were performed by Yanagimoto CHN
corder and are within 0.4% of theoretical values. Opti-
cal rotations were recorded on a JASCO DIP-370 po-
larimeter. All reactions were monitored by thin-layer
chromatography employing 0.25 mm E. Merck silica
gel plates (60F-254). Preparative thin-layer chromatog-
raphy was performed on 0.5 mm E. Merck silica gel
plates (60F-254). Column chromatography was carried
out on E. Merck silica gel (60-9385, 230-400 mesh) or
Katayama silica gel (60-K070, 70-230 mesh). Usual
workup means washing with a water solution saturated
with NaCl, drying the organic portion over MgSO4,
filtration, and evaporation in vacuo.
crystals. Recrystallization of the mixture from hexane
and AcOEt gave the trans product 1 (2.1 g, 40%) as
colorless needles; m.p. 42°C. IR (neat) 2926, 1757,
1
1455, 1349, 1029, 913, 741, 701 cm−1. H-NMR (200
MHz, CDCl3) l 1.93 (dd, 2H, J=10.4, 4.5 Hz), 2.44–
2.54 (m, 2H), 2.74 (bd, 2H, J=13.4 Hz), 2.92 (td, 2H,
J=13.4, 3.5 Hz), 3.75 (m, 1H), 4.54 (s, 2H), 7.29–7.39
(m, 5H). HREI-MS calc. for C12H16O2S MW 224.0871,
found m/z 224.0879 (M+). Anal. Calc. for C12H16O2S:
C, 64.25; H, 7.19. Found: C, 63.93; H, 7.11%.
3.2.3. Reaction of trans-4-benzyloxythiane-1-oxide (1)
with compound 2
To a solution of 4S-isopropyl-1,3-thiazolidine-2-
thione (6) (105 mg, 0.65 mmol) in CH2Cl2 (2 ml) was
added trifluoroacetic anhydride (900 ml, 6.30 mmol) at
−10 to −15°C under Ar atmosphere. After being
stirred at −10 to −15°C for 2 h, the reaction mixture
was evaporated in vacuo to give a yellow crude product
1
2. H-NMR (300 MHz, CDCl3) l 1.03 (d, 3H, J=6.8
Hz), 1.08 (d, 3H, J=6.8 Hz), 2.32–2.43 (m, 1H), 3.26
(dd, 1H, J=2.4, 11.6 Hz), 3.36 (dd, 1H, J=7.0, 11.6
Hz), 4.72–4.77 (m, 1H). HREI-MS calc. for
C8H10ONS2F3 MW 257.0156, found m/z 257.0138
(M+). The crude 2 was dissolved in CH2Cl2 (4 ml) and
then a solution of compound 1 (50 mg, 0.22 mmol) in
CH2Cl2 (2 ml) was added at −10°C. After being stirred
at room temperature for 20 h, the reaction mixture was
treated with water and then extracted with CH2Cl2. The
extract was submitted to the usual workup to give a
yellow oily residue, which was chromatographed on a
silica gel column with CH2Cl2–hexane (2:1) to afford
4S-isopropyl-3-(4S-isopropyl-1,3-thiazolin-2-yl)-1,3-
thiazolidine-2-thione (5) (23 mg, 46%), 4-benzyloxythi-
ane (4) (32 mg, 69%), and a trace amount of 4S-isopro-
pyl-1,3-thiazolidine-2-thione (6). Compound 5: yellow
prisms; mp 98–100°C (hexane). IR (KBr) 2960, 1589,
3.2. Synthesis and reaction of
trans-4-benzyloxythiane-1-oxide (1)
3.2.1. Synthesis of 4-benzyloxythiane (4)
To a solution of tetrahydrothiopyran-4-ol (500 mg,
4.23 mmol) in THF (10 ml) was added 60% NaH (338
mg, 8.45 mmol) under Ar atmosphere at 0°C. The
mixture was stirred at room temperature for 1 h and
then at 40°C for 2 h. After addition of benzyl bromide
(0.6 ml, 5.08 mmol) under ice-cooling, the mixture was
stirred at 40°C for 4.5 h and then treated with 5% HCl.
The acidic reaction mixture was extracted with AcOEt.
The extract was submitted to the usual workup to give
an oily residue, which was purified by silica gel column
chromatography with hexane–AcOEt (20:1) to afford
the pure product 4 (700 mg, 80% yield) as a colorless
1
1390, 1 266, 1034 cm−1. H-NMR (200 MHz, CDCl3)
l 0.94–1.06 (m, 12H), 1.79–1.89 (m, 1H), 2.57–2.66
(m, 1H), 2.92 (t, 1H, J=11.0 Hz), 3.09 (d, 1H, J=11.0
Hz), 3.26 (dd, 1H, J=8.0, 10.5 Hz), 3.60 (dd, 1H,
J=8.8, 11.2 Hz), 3.81–3.94 (m, 1H), 5.20–5.27 (m,
1H). 13C-NMR (100 MHz, CDCl3) l 198.7 (CꢀS), 155.8
(CꢀN). [h]1D3 +108.0 (c 1.25, CHCl3). HREI-MS calc.
for C12H20N2S3 MW 288.0789, found m/z 288.0800
(M+). Anal. Calc. for C12H20N2S3: C, 49.96 ; H, 6.99;
N, 9.71. Found: C, 49.98; H, 6.95; N, 9.55%.
oil. IR (neat) 3030, 2934, 1390, 1266, 1034 cm−1
.
1H-NMR (200 MHz, CDCl3) l 1.78–1.95 (m, 2H),
2.07–2.21 (m, 2H), 2.44–2.57 (m, 2H), 2.79–2.91 (m,
2H), 3.38–3.49 (m, 1H), 4.54 (s, 2H), 7.33 (s, 5H).
HREI-MS calc. for C12H16OS MW 208.0922, found
m/z 208.0912 (M+). Anal. Calc. for C12H16OS: C,
69.19; H, 7.74. Found: C, 69.39; H, 7.67%.
3.2.2. Synthesis of trans-4-benzyloxythiane-1-oxide (1)
To a solution of compound 4 in CH2Cl2 (50 ml) was
added m-chloroperbenzoic acid (8.7 g, 50.4 mmol) at
−78°C under N2 atmosphere. After being stirred at
−78°C for 3 h, the reaction mixture was filtered
through a celite bed. The filtrate was submitted to the
usual workup to obtain an oily residue. Purification o f
the residue was done by silica gel column chromatogra-
phy with CHCl3–MeOH (50:1) to give a mixture of
trans- and cis-4-benzyloxythiane-1-oxide as colorless
3.3. Reaction of diphenyl sulfoxide (7a) or methyl
phenyl sulfoxide (7b) with 3-trifluoroacetyl-1,3-
thiazolidine-2-thiones (2 and 8)
3.3.1. Reaction of diphenyl sulfoxide (7a) with
compound 2
To a solution of 4S-isopropyl-1,3-thiazolidine-2-
thione (6) (564 mg, 14.2 mmol) in CH2Cl2 (2 ml) was
added trifluoroacetic anhydride (2 ml, 14.2 mmol) at

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Y. Nagao et al. / Journal of Organometallic Chemistry 611 (2000) 172–177
−10 to −15°C under Ar atmosphere. After being
stirred at −10 to −15°C for 2 h, the reaction mixture
was evaporated in vacuo to give a yellow crude product
2. To a solution of crude 2 in CH2Cl2 (9 ml) was added
a solution of diphenyl sulfoxide (7a) (354 mg, 1.75
mmol) at −10°C, and the mixture was stirred at room
temperature for 26 h. After addition of water, the
reaction mixture was extracted with CH2Cl2 and then
the extract was submitted to the usual workup. The
resultant yellow oily residue was chromatographed on
silica gel plates with CH2Cl2–MeOH (50:1) to afford
4S-isopropyl-3-(4S-isopropyl-1,3-thiazolin-2-yl)-1,3-
thiazolidine-2-thione (5) (157 mg, 45%), diphenyl
sulfide (10a) (35 mg, 59%), and a trace amount of 6.
mmol) in CH2Cl2, gave compound 9 (32 mg, 35%),
methyl sulfide (10b) (69 mg, 40%), and a trace amount
of 11, respectively.
3.3.5. Reaction of diphenyl sulfoxide (7a) with TiCl4 in
the presence of sodium salt 12 of 4S-isopropyl-
1,3-thiazolidine-2-thione
To a solution of diphenyl sulfoxide (7a) (681 mg,
3.37 mmol) in CH2Cl2 (25 ml) was added TiCl4 (450 ml,
4.10 mmol) at 0°C under Ar atmosphere, and the
mixture was stirred at 0°C for 30 min. After addition of
the sodium salt 12 (1.40 mg, 7.64 mmol) obtained by
treatment of 4S-isopropyl-1,3-thiazolidine-2-thione (6)
with 60% NaH in THF, the mixture was stirred at
room temperature for 7 h and then treated with water.
The aqueous solution was extracted with CH2Cl2, and
the extract was submitted to the usual workup to give a
yellow oily residue. The residue was chromatographed
on a silica gel column with hexane–AcOEt (3:1) to
afford 4S-isopropyl-3-(4S-isopropyl-1,3-thiazolin-2-yl)-
1,3-thiazolidine-2-thione (5) (501 mg, 46%), diphenyl
sulfide (10a) (389 mg, 65%), and a trace amount of 6.
3.3.2. Reaction of methyl phenyl sulfoxide (7b) with
compound 2
Similar treatment of 7b (70 mg, 0.50 mmol) with
crude 2, obtained from the reaction of 6 (70 mg, 0.50
mmol) with trifluoroacetic anhydride (381 ml, 2.70
mmol) in CH2Cl2, gave compound 5 (102 mg, 35%),
methyl phenyl sulfide (10b) (51 mg, 40%), and a trace
amount of 6.
3.3.6. Reaction of diphenyl sulfoxide (7a) with TiCl4 in
the presence of sodium salt 13 of 1,3-thiazolidine-
2-thione
3.3.3. Reaction of diphenyl sulfoxide (7a) with
3-trifluoroacetyl-1,3-thiazolidine-2-thione (2)
To a solution of 1,3-thiazolidine-2-thione (11) (81
mg, 0.66 mmol) in CH2Cl2 (2 ml) was added tri-
fluoroacetic anhydride (268 ml, 1.9 mmol) at −10 to
−15°C under Ar atmosphere. After being stirred at
−10 to −15°C for 2 h, the reaction mixture was
evaporated in vacuo to give a crude yellow product 8.
1H-NMR (300 MHz, CDCl3) l 3.48 (t, 3H, J=7.1 Hz),
4.56 (t, 3H, J=7.1 Hz). HREI-MS calc. for
C5H4ONS2F3 MW 214.9686, found m/z 214.9701 (M+).
The crude product 8 was dissolved in CH2Cl2 (4 ml)
and then a solution of diphenyl sulfoxide (7a) (67 mg,
0.33 mmol) in CH2Cl2 (2 ml) was added at −10°C.
After being stirred at room temperature for 18 h, the
reaction mixture was treated with water (10 ml) and
then extracted with CH2Cl2. The extract was submitted
to the usual workup to give a yellow oily residue, which
was chromatographed on silica gel plates with CH2Cl2–
MeOH (50:1) to afford 3-(1,3-thiazolidin-2-yl)-1,3-thia-
zolidine-2-thione (9) (23 mg, 45%), diphenyl sulfide
(10a) (35 mg, 59%), and a trace amount of 1,3-thiazo-
lidine-2-thione (11). All spectroscopic data of the syn-
thesized compound 9 (yellow prisms, m.p. 79–80°C
(CH2Cl2–hexane)) were identical with those of litera-
ture data [7].
Similar treatment of diphenyl sulfoxide (7a) (112 mg,
0.55 mmol) with TiCl4 (73 ml, 0.66 mmol) and 13 (170
mg, 1.2 mmol) in CH2Cl2 gave 3-(1,3-thiazolin-2-yl)-
1,3-thiazolidine-2-thione (9) (65 mg, 53%), diphenyl
sulfoxide (10a) (60 mg, 59%), and a trace amount of 11,
respectively.
3.4. X-ray crystallographic analysis of compound 5
The single crystals were obtained by recrystallization
from hexane. All measurements were made on a
Rigaku AFC7R diffractometer with filtered Cu–Ka
radiation and a rotating anode generator. The data
were corrected using the ꢀ–2q scan technique to a
maximum 2q value of 129.9°. A total of 1520 reflections
was collected. A correction for secondary extinction
was applied (coefficient 9.41120×10−7). The structure
was solved by direct methods [15] and expanded using
Fourier techniques [16]. The non-hydrogen atoms were
refined anisotropically. Hydrogen atoms were included
but not refined. The final cycle of full-matrix least-
squares refinement was based on 2013 observed reflec-
tions (I\3.00|(I)) and 200 variable parameters. The
maximum and minimum peaks on the final difference
−3
,
Fourier map corresponded to 0. 37 and −0.42 e A
,
3.3.4. Reaction of methyl phenyl sulfoxide (7b) with
compound 8
respectively. All calculations were performed using the
SAN crystallographic software package of Molecu-
TEX
Similar treatment of 7b (143 mg, 1.02 mmol) with
crude 8, obtained from the reaction of 11 (243 mg, 2.04
mmol) with trifluoroacetic anhydride (850 ml, 6.00
lar Structure Corporation (1985 and 1999). The crystal
data and the selected atom distances, bond angles, and
torsion angles are listed in Tables 1 and 2, respectively.

Y. Nagao et al. / Journal of Organometallic Chemistry 611 (2000) 172–177
177
Organic Sulfur Chemistry, Butterworths, London, 1975, pp.
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3.5. X-ray crystallographic analysis of compound 9
The single crystals were obtained by recrystallization
from hexane–CH2Cl2. All measurements were made on
a Rigaku RAXIS-IV imaging plate diffractometer with
graphite monochromated Mo–Ka radiation. The data
were corrected using an ꢀ–2q scan technique to a
maximum 2q value of 55.0°. A total of 2680 reflections
was collected. The data were corrected for Lorentz and
polarization effects. A correction for secondary extinc-
tion was applied (coefficient 9.41120×10−7). The
structure was solved by direct methods [15] and ex-
panded using Fourier techniques [16]. The non-hydro-
gen atoms were refined anisotropically. Hydrogen
atoms were included but not refined. The final cycle of
full-matrix least-squares refinement was based on 2013
observed reflections (I\3.00|(I)) and 200 variable
parameters. The maximum and minimum peak on the
final difference Fourier map corresponded to 0.37 and
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Nagao, J. Org. Chem. 63 (1983) 8145.
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Chem. Soc. 104 (1982) 2079. (b) Y. Nagao, T. Inoue, E. Fujita,
S. Terada, M. Shiro, J. Org. Chem. 48 (1983) 132. (c) Y. Nagao,
T. Inoue, E. Fujita, S. Terada, M. Shiro, Tetrahedron 40 (1984)
1215. (d) Y. Nagao, T. Kumagai, S. Tamai, T. Abe, T.
Kuramoto, S. Aoyagi, Y. Nagase, M. Ochiai, Y. Inoue, E.
Fujita, J. Am. Chem. Soc. 108 (1986) 4673. (e) Y. Nagao, W.-M.
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−0.42 e A−3, respectively. All calculations were per-
formed using the TE SAN crystallographic software
,
X
package of Molecular Structure Corporation (1985 and
1999). The crystal data and the selected atom distances,
bond angles, and torsion angles are listed in Tables 1
and 2, respectively.
[5] Y. Nagao, T. Hirata, S. Goto, S. Sano, A. Kakehi, K. Iizuka,
M. Shiro, J. Am. Chem. Soc. 120 (1998) 3104.
4. Supplementary material
[6] Y. Nagao, M. Goto, K. Kida, M. Shiro, Heterocycles 41 (1995)
419.
Complete details have been deposited at the Cam-
bridge Crystallographic Data Centre, CCDC no.
143786 for compound 5 and CCDC no. 143787 for
compound 9. Copies of this information can be ob-
tained free of charge from The Director, CCDC, 12
Union Road, Cambridge CB2 1EZ, UK (Fax: +44-
1223-336033; e-mail: deposit@ccdc.cam.ac.uk or www:
http://www.ccdc.cam.ac.uk).
[7] (a) A.D. Clark, P. Sykes, J. Chem. Soc. C (1971) 103. (b) E.
Fujita, Y. Nagao, K. Seno, S. Takao, T. Miyasaka, M. Kimura,
W.H. Watson, J. Chem. Soc. Perkin Trans I (1981) 914.
[8] Y. Nagao, Y. Hagiwara, Y. Hasegawa, M. Ochiai, T. Inoue, M.
Shiro, E. Fujita, Chem. Lett. (1988) 381.
[9] G.A. Olah, S.C. Narang, Tetrahedron 38 (1982) 2225.
[10] L.P.J. Burton, J.D. White, Tetrahedron Lett. (1980) 3147.
[11] R.S. Glass, L. Adamowicz, J.L. Broeker, J. Am. Chem. Soc. 113
(1991) 1065.
[12] F. Iwasaki, N. Furukawa, Acta Crystallogr. Sect. C 43 (1987) 80.
[13] M. Yasui, S. Murata, F. Iwasaki, N. Furukawa, Bull. Chem.
Soc. Jpn. 68 (1995) 744.
[14] (a) S.M. Johnson, C.A. Maier, I.C. Paul, J. Chem. Soc. B (1998)
1603. (b) M.M. Olmstead, K.A. Williams, W.K. Musker, J. Am.
Chem. Soc. 104 (1982) 5567. (c) J.T. Doi, R.M. Kessler, D.L. de
Leeuw, M.M. Olmstead, W.K. Musker, J. Org. Chem. 48 (1983)
3707. (d) V. Nenajdenko, N.E. Shevchenko, E.S. Balenkova,
Tetrahedron 54 (1970) 5353.
[15] A. Altomare, M.C. Burla, M. Camalli, M. Cascarano, C. Giaco-
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435 SIR92.
[16] P.T. Beurskens, G. Admiraal, G. Beurskens, W.O. Bosman, R.
de Gelder, R. Israel, J.M.M. Smits, The DIRDIF-94 Program
System, Technical Report of the Crystallography Laboratory,
University of Nijmegen, The Netherlands, 1994.
Acknowledgements
This work was partly supported by Grant-in-Aid for
Scientific Research on Priority Areas (No. 11120239)
from the Ministry of Education, Science, Sports, and
Culture, Japan.
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