Effective Precursors for Sulfur Monoxide Formation

Article abstract of DOI:10.1021/jo9709864

When triphenylmethanesulfenyl chloride (12) (or its thio 13 or dithio homolog 14) are treated with hindered olefins 15 and 16, thiiranes 10 and 11 are produced in high isolated yields (ca. 94%). Treatment of 10 and 11 with m-chloroperoxybenzoic acid (m-CPBA) leads to the formation of thiirane 1-oxides 8 and 9 (99% isolated yields). The structures of 8-11 were established by ¹H and ¹³C NMR, mass spectrometry as well as by X-ray. Thermal decomposition of either 8 or 9 smoothly delivers sulfur monoxide to various 1,3-dienes giving cyclic sulfoxides in good yield. A variety of conditions were employed to optimize the yield of the trapped adducts.

Full text of DOI:10.1021/jo9709864

8366
J . Org. Chem. 1997, 62, 8366-8371
Effective P r ecu r sor s for Su lfu r Mon oxid e F or m a tion
Imad A. Abu-Yousef
Department of Chemistry, Al-alBayt University, P.O. Box 130040, Mafrag 25113, J ordan
David N. Harpp*
Department of Chemistry, McGill University, Montre´al, Que´bec, Canada H3A 2K6
Received J une 3, 1997X
When triphenylmethanesulfenyl chloride (12) (or its thio 13 or dithio homolog 14) are treated with
hindered olefins 15 and 16, thiiranes 10 and 11 are produced in high isolated yields (ca. 94%).
Treatment of 10 and 11 with m-chloroperoxybenzoic acid (m-CPBA) leads to the formation of thiirane
1
1-oxides 8 and 9 (99% isolated yields). The structures of 8-11 were established by H and 13C
NMR, mass spectrometry as well as by X-ray. Thermal decomposition of either 8 or 9 smoothly
delivers sulfur monoxide to various 1,3-dienes giving cyclic sulfoxides in good yield. A variety of
conditions were employed to optimize the yield of the trapped adducts.
In tr od u ction
product is Diels-Alder adduct 4 (eq 1) in yields generally
in the 20-40% range.
There is a considerable interest in finding simple
chemical methods to generate and examine the chemistry
of reactive diatomic molecules such as singlet diatomic
oxygen (1O2)1 and singlet diatomic sulfur (1S2)2 as well
as related species such as RPdS,3 RPdSe,4 RNdS,5
RNdO,6 and RNdSe.7 Relatively few studies have been
carried out on the chemistry of sulfur monoxide (SdO).8,9
Up to now, the main method to generate SdO has been
by the pyrolysis of ethylene episulfoxide (1) at ca. 100
°C.10,11 Other less-used methods of SdO production have
involved the thermal decomposition of sulfoxide 212 and
heterocycle 3.13
The work of Lemal focused primarily on the mecha-
nistic features of this trapping process,16,17 although he
found that isoprene (5) can be trapped to give 2,5-
dihydro-3-methylthiolene 1-oxide (6) in 72% isolated
yield.16 A recent, less direct route for the Diels-Alder
trapping of SdO has been carried out via complex 7.18
Recently, the detailed photochemistry of 1 has been
investigated for the first time.19
Diene and triene trapping experiments with SdO have
been carried out by a number of workers;14,15 the main
X Abstract published in Advance ACS Abstracts, October 1, 1997.
(1) Frimer, A. H. Singlet O2; CRC Press, Inc.: Boca Raton, FL, 1995.
(2) Tardif, S.; Williams, C. R.; Harpp, D. N. J . Am. Chem. Soc. 1995,
117, 9067. Harpp, D. N. Phosphorus, Sulfur Silicon 1997, 120/ 121,
41. Tardif, S. L.; Rys, A. Z.; Abrams, C. B.; Abu-Yousef, I. A.; Leste-
Lasserre, P. B. F.; Schultz, E. K. V.; Harpp, D. N. Tetrahedron 1997,
53, 12225. Steliou, K. Acc. Chem. Res. 1991, 24, 341.
(3) Bock, H.; Kremer, M.; Solouki, B.; Binnewies, M.; Meisel, M. J .
Chem. Soc., Chem. Commun. 1992, 9. Folkins, P. L.; Vincent, B. R.;
Harpp, D. N. Tetrahedron Lett. 1991, 32, 7009.
In order to further explore this chemistry, a more
convenient source of sulfur monoxide (SdO) was needed.
We recently reported our preliminary results which were
achieved by the thermal decomposition of adamantyli-
deneadamantanethiirane 1-oxide (8)9 and bicyclo[3.3.1]-
nonylidenebicyclo[3.3.1]nonanethiirane 1-oxide (9).20
(4) Bohle, D. S.; Rickard, C. E. F.; Roper W. R.; Schwerdtfeger, P.
Organometallics 1990, 9, 2068.
(5) Markovskii, L. N.; Solov’es, A. V.; Pen’kovskii, V. V.; Kolesnik,
N. P. Borodin, A. V.; Iksanova, S. V.; Shermolovich, Y. G. Zh. Org.
Khim. 1992, 28, 1388. Takahashi, M.; Okazaki, R.; Inamoto, N.;
Sugawara T.; Iwamura, H. J . Am. Chem. Soc. 1992, 114, 1830. Bryce
M. R; Heaton, J . N. Tetrahedron Lett. 1991, 32, 7459.
(6) Kirby, G. W.; Nazeer, M. J . Chem. Soc., Perkin Trans. 1 1993,
13, 1387. Gilchrist T.; Lemons, A. J . Chem. Soc., Perkin Trans. 1 1993,
13, 1391. Felber, H.; Kresze, G.; Schmidtchen, F. P.; Prewo R.; Vasella,
A. J ustus Liebigs Ann. Chem. 1993, 3, 261.
(13) Chow,Y. L.; Tam, J . N. S.; Blier, J . E. J . Chem. Soc., Chem.
Commun. 1970, 1604.
(14) Dodson, R. M.; Sauers, F. R. J . Chem. Soc., Chem. Commun.
1967, 1189.
(7) Bryce, M. R.; Chesney, A. J . Chem. Soc., Chem. Commun. 1995,
195.
(8) Abu-Yousef, I. A.; Harpp, D. N. Sulfur Rep. 1997, 20, 1. Further
references for hetero Diels-Alder reactions are found in the follow-
ing: Boger, D. L.; Weinreb, S. N. Hetero Diels-Alder Methodology in
Organic Synthesis; Academic Press: San Diego, 1987.
(15) Dodson, R. M.; Nelson, J . P. J . Chem. Soc., Chem. Commun.
1969, 1159.
(16) Chao, P.; Lemal, D. M. J . Am. Chem. Soc. 1973, 95, 920.
(17) Lemal, D. M.; Chao, P. J . Am. Chem. Soc. 1973, 95, 922.
(18) Heyke, O.; Neher A.; Lorenz, I.-P. Z. Anorg. Allg. Chem. 1992,
23, 608.
(9) Abu-Yousef, I. A.; Harpp, D. N. Tetrahedron Lett. 1995, 36, 201.
(10) Hartzell, G. E.; Paige, J . N. J . Am. Chem. Soc. 1966, 88, 2616.
Hartzell, G. E.; Paige, J . N. J . Org. Chem. 1967, 32, 459.
(11) Saito, S. Tetrahedron Lett. 1968, 4961.
(19) Wu, F.; Chen, X; Weiner, B. R. J . Am. Chem. Soc. 1996, 118,
8417.
(20) Abu-Yousef, I. A.; Harpp, D. N. New Sulfenyl Chloride Chem-
istry. Stable Precursors For Sulfur Monoxide Transfer; 25th Canadian
Chemical Conference, Guelph, Ontario, Canada, J une 1995.
(12) Dorer, F. H.; Salomon, K. E. J . Phys. Chem. 1980, 84, 3024.
S0022-3263(97)00986-9 CCC: $14.00 © 1997 American Chemical Society

Effective Precursors for Sulfur Monoxide Formation
J . Org. Chem., Vol. 62, No. 24, 1997 8367
Resu lts a n d Discu ssion
tetrahedral geometry of the sulfur atom shows the
chemical shifts for all of the carbon atoms in the ada-
mantyl skeleton moiety to be different. The electron
impact mass spectrum of thiirane 1-oxide 8 is straight-
forward, displaying both loss of O and SO from the parent
ion radical.
In simple episulfoxides, typical C-C bond lengths fall
in the range 1.37-1.60 Å and C-S bonds range from 1.37
to 1.92 Å.24 The C-C bond length in thiirane 1-oxide 8
is 1.505 Å, which suggests the presence of partial double
bond character, since a typical sp3-sp3 C-C bond length
is about 1.55 Å and a CdC bond length is 1.34 Å. The
bond lengths of S-O, C-S; bond angles of C-S-C,
C-C-S, and O-S-C in the three-membered ring moiety
of episulfoxide 8 and ethylene episulfoxide (1) were found
to be quite similar and are included in the Supporting
Information (Table 1).25
Thiirane 1-oxides 8 and 9 can be prepared from the
oxidation of the corresponding thiiranes 10 and 11 with
m-CPBA in high isolated yield (99%). Episulfides 10 and
11 (stable at rt for months) can be synthesized from the
reaction of triphenylmethanesulfenyl chloride 12 (or its
thio 13 or dithio homolog 14) with the corresponding
olefins in high isolated yield (98%).9
Thermal decomposition of episulfides 10 and 11 in
refluxing ethyl acetate for 15 h under a nitrogen atmo-
sphere affords the corresponding olefins 15 and 16,
respectively (98%), along with elemental sulfur (68%). In
addition, 10 and 11 were completely decomposed when
the mixture was refluxed for 2 h in toluene solution.
Thiirane 1-oxide 9 was prepared in the same way as
that of 8. Thiirane 11 was reacted with m-CPBA in
methylene chloride solution at -78 °C under a nitrogen
atmosphere to give thiirane 1-oxide 9 in high isolated
yield (98%). The structure of thiirane 1-oxide 9 was
established as for 8.
Tr a p p in g of Su lfu r Mon oxid e (SO)
In the literature there are only three reaction systems
reported which generate and trap sulfur monoxide in the
presence of 1,3-dienes; the yields are low. Moreover,
these methods have limitations. The major problem in
the case of Dodson,14,15 Lemal,16 Anastassiou,26 and
Heyke18 procedures is that ethylene episulfoxide (1) is
unstable at room temperature, has a disagreeable odor,
and causes skin burns.
When the above reactions were carried out in the
presence of 2,3-dimethyl-1,3-butadiene (17), the same
products were obtained (elemental sulfur and olefin). No
evidence was found for the trapping of diatomic sulfur
by diene 17. It would appear that the concatenation
mechanism of sulfur loss from episulfides was opera-
tive.21,22
Episulfide 10 was previously prepared by Nakayama
and co-workers23 from the treatment of elemental sulfur
with olefin 15, but the yield was low. The authors23
reported that episulfide 10 contained 10 peaks in the 13C
NMR spectra and the mp was 153-154 °C. In contrast,
we found that thiirane 10 showed only seven peaks in
13C NMR spectra. This can be explained by the fact,
revealed by X-ray analysis, that there is a plane of
symmetry passing through S, C1, C8, C9, and C10. This
symmetry makes C2 and C3, C4 and C5, and C6 and C7
equivalent. In addition, we found that episulfide 10 has
a lower melting point (142-143 °C) than previously
reported by Nakayama.23
In the case of the procedure of Chow13 the important
limitation is in the preparation of sulfoxide 3. The
authors could not isolate the corresponding episulfoxide
18 which they thought could have been resulted from the
thermolysis of sulfoxide 3. The yield of the trapped
adduct was low in each case.
It should be mentioned that trans-2,3-diphenylethene
sulfoxide has been shown to transfer sulfur monoxide to
ylides in low (11-19%) yield.27
In contrast, thiirane 1-oxides 8 and 9 are crystalline
and stable even if they are exposed to the atmospheric
moisture for several days. In addition, we found that
sulfur monoxide can be easily generated and trapped in
high, isolated yields to form substituted 2,5-dihydro-
thiophene 1-oxides through thermal decomposition of 8
and 9 in the presence of various 1,3-dienes.
Thiirane 1-oxide 8 was prepared by m-CPBA oxidation
of episulfide 10 in methylene chloride solution under a
nitrogen atmosphere at -78 °C. Recrystallization from
n-pentane gave a pure product of thiirane 1-oxide 8 in
an isolated yield of 99% (eq 2).
99%
The general procedure used for the reaction of 8 and 9
with 1,3-dienes is as follows: a solution of the diene and
The structure of thiirane 1-oxide 8 was established by
1H and 13C NMR, mass spectrometry, and X-ray analysis.
In contrast to thiirane 10, we found that thiirane 1-oxide
8 shows 10 carbon signals in 13C NMR spectra. The
(24) Patai S.; Rappoport Z.; Stirling C. The Chemistry of Sulphones
and Sulphoxides; J ohn Wiley and Sons: New York, 1988; pp 22, 385-
388.
(25) J ohnson, C. K. ORTEP, A Fortran Thermal Ellipsoid Plot
Program; Technical Report ORNL-5138, Oak Ridge, TN, 1976.
(26) Anastassiou, A. G.; Chao, B. Y. H. J . Chem. Soc., Chem.
Commun. 1971, 979.
(27) Bonini, B. F.; Maccagnani, Mazzanti, G.; Pedrini, P.; Piccinelli,
P. J . Chem. Soc., Perkin Trans. 1 1979, 1720.
(21) Chew, W.; Hynes, R. C.; Harpp, D. N. J . Org. Chem. 1993, 58,
4398.
(22) Williams, C. R.; MacDonald, J . G.; Harpp, D. N.; Steudel, R.;
Fo¨rster, S. Sulfur Lett. 1992, 13, 247.
(23) Nakayama, J .; Ilto Y.; Mizumura, A. Sulfur Lett. 1992, 14, 247.

8368 J . Org. Chem., Vol. 62, No. 24, 1997
Abu-Yousef and Harpp
Ta ble 1. Su m m a r y of Su lfu r Mon oxid e Tr a p p in g Exp er im en ts of 1,3-Dien es (5, 17, 20, 22) w ith Th iir a n e 1-Oxid e 8
sulfoxides (%)b
entry
no.
dienes (time (h))
Ra
solvent
temp (°C)
6
19
21
23
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
1:1
1:1
1:1
1:1
1:3
1:1
3:1
1:3
1:1
3:1
1:3
1:1
3:1
1:3
1:1
3:1
1:1
3:1
3:1
3:1
3:1
3:1
3:1
3:1
CHCl3
EtOAc
CH3CN
toluene
toluene
toluene
toluene
C6H5Cl
C6H5Cl
C6H5Cl
xylene
xylene
xylene
decane
decane
decane
decane
toluene
toluene
xylene
xylene
xylene
xylene
decane
61
77
81
all dienes (240)
all dienes (240)
all dienes (240)
all dienes (240)
NR
NR
NR
NR
80
110
110
110
132
132
132
138
138
138
135
135
135
174
110
110
110
138
138
138
110
5 (36)
5 (36)
5 (36)
-
5 (20)
5 (20)
-
17 (12)
20 (24)
22 (16)
22 (16)
22 (16)
-
22 (12)
22 (12)
-
62
58
69
-
30
35
-
73
74
80
30
30
33
32
34
37
33
34
36
12
70
76
69
35
10
0
65
64
70
-
25
27
-
46
40
65
-
23
27
-
17 (12)
17 (12)
17 (8)
17 (8)
17 (8)
17 (8)
17 (8)
17 (8)
17 (8)
17 (8)
17 (8)
17 (5)
17 (8)
17 (16)
17 (12)
17 (12)
17 (20)
17 (35)
17 (12)
20 (24)
20 (24)
-
20 (15)
20 (15)
-
5 (20)
5 (20)
-
20 (15)
22 (12)
22 (12)
-
33
40
-
26
29
-
22
28
-
20 (15)
-
-
-
-
-
-
-
5 (20)
5 (20)
-
-
22 (12)
22 (8)
-
37
12
-
-
-
30
15
-
-
20 (72)
70
-
-
-
-
-
-
-
-
-
-
-
5 (36)
-
22 (16)
-
64
-
-
48
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
67
-
-
a
b
Refers to the molar ratio of thiirane 1-oxide 8 to 1,3-dienes (5, 17, 20, 22). Isolated yields after flash chromatography.
8 or 9 in an appropriate solvent was refluxed for a certain
time under a nitrogen atmosphere (eq 3). The reaction
was followed by thin layer chromatography using 15-
25% ethyl acetate in hexane as eluent. The first fraction
can be isolated in near quantitative yield by the same
eluent and was identified (98%) as the corresponding
olefin (15 from 8; 16 from 9). By eluting with methanol,
the second fraction was identified as the corresponding
2,5-dihydrothiophene 1-oxides as oily, pure product in the
case of dienes 5, 17, 22, and a solid product in the case
of diene 20; the yields are generally high (70-80% yield)
compared to other SO sources.12-18 The identity of
sulfoxides 6, 19, 21, and 23 was confirmed by 1H and 13C
NMR as well as by mass spectrometry.
yields. Ratios of thiirane 1-oxides 8 and 9 to diene were
varied from 1:3 to 3:1 with relatively little change in
yields (Tables 1 and 2). Interestingly, the choice of
solvent temperature is critical; no decomposition either
of 8 or of 9 took place over 10 days in refluxing
chloroform, ethyl acetate, or acetonitrile (T ) 61, 77, 81
°C, respectively).
The best conditions for the release of sulfur monoxide
and its subsequent trapping (ca. 82% isolated yield)
appear to be in refluxing toluene (110 °C) for 12 h in the
case of 2,3-dimethyl-1,3-butadiene (17) with thiirane
1-oxide 8 (Table 1, entry 7) and 8 h in the case of thiirane
1-oxide 9 (Table 2, entry 7, Supporting Information). At
110 °C in xylene and decane, trapped yields of adduct
19 were ca. 68% (Table 1, entries 20, 24). In refluxing
xylene (138 °C), the yield diminished to 35% (Table 1,
entry 21). When a pure sample of 19 was heated in
refluxing xylene for 20 h, only 10% remained. This
confirms the retrochelotropic decomposition; diene adduct
19 decomposed completely in 35 h in refluxing xylene
(138 °C) (Table 1, entry 23).
It is noteworthy to mention that Lemal17 found when
ethylene episulfoxide (1) reacted with each of the three
2,4-hexadiene isomers that mixtures of cis,cis-, cis,trans-,
and trans,trans-2,5-dihydro-2,5-dimethylthiophene 1-ox-
ides (24, 25, and 26, respectively) were formed. While
there was significant stereoselectivity, Lemal concluded
that because of the formation of multiple sulfoxide
isomers in each reaction, the thermal decomposition of
episulfoxide 1 proceeds via a biradical intermediate in
the triplet state. This view is also supported by Bald-
win28 and Glass.29
A variety of solvents, temperatures, times, and con-
centrations were employed to optimize the yields of the
trapped adducts. A summary of the results are shown
in Table 1 (episulfoxide 8) and Table 2 (episulfoxide 9);
the yields with 9 are similar to those with episulfoxide 8
and are included in the Supporting Information.
The assignments of relevant 13C NMR chemical shifts
relative to tetramethylsilane of 2,5-dihydrothiophene
1-oxide adducts are reported in the Supporting Informa-
tion. As mentioned earlier, ethylene episulfoxide (1) has
been shown to decompose at a temperature of 110 °C to
give ethylene and sulfur monoxide;10 the latter was
trapped by dienes in yields of ca. 40%. In contrast, we
found that thiirane 1-oxides 8 and 9 delivers sulfur
monoxide to 1,3-dienes smoothly to give the correspond-
ing 2,5-dihydrothiophene 1-oxide adducts in high, isolated
(28) Baldwin, J . E.; Holfe G.; Choi S. C. J . Am. Chem. Soc. 1971,
93, 2810.
(29) Glass, R. S.; J ung, W. Sulfur Lett. 1995, 36, 201. For further
mechanistic comments on this decomposition, see Kondo, K.; Mastsu-
moto, M.; Negishi, A. Tetrahedron Lett. 1971, 2131. Aalbersbert, M.
G. L.; Volhard, K. P. C. J . Am. Chem. Soc. 1977, 99, 2792.
(30) Shartz, N. N.; Blumberg, J . H. J . Org. Chem. 1976, 29, 1496.
(31) Still, W. C.; Khan M.; Mitra, A. J . Org. Chem. 1978, 43, 2923.

Effective Precursors for Sulfur Monoxide Formation
J . Org. Chem., Vol. 62, No. 24, 1997 8369
of m-CPBA (0.172 g, 1.0 mmol) in 20 mL of dry methylene
chloride was added dropwise to a stirred solution of adaman-
tylideneadamantanethiirane (10) (0.30 g, 1.0 mmol) in 30 mL
of dry methylene chloride under a nitrogen atmosphere at -78
°C . The mixture was stirred for 2 h. The solution was diluted
with 5% NaOH solution and extracted three times with 20 mL
portions of diethyl ether. The combined ethereal extracts were
dried with MgSO4, filtered, and evaporated to give the crude
adamantylideneadamantanethiirane 1-oxide (8). Recrystalli-
zation from n-pentane gave 0.313 g, 99%, of the corresponding
thiirane 1-oxide 8: mp 129-130 °C; 1H-NMR (CDCl3) δ 1.53-
2.38 (m) ppm; 13C-NMR (CDCl3) δ 27.0, 27.4, 27.6, 30.0, 36.2,
37.1, 37.2, 37.6, 37.6, and 72.9 ppm; MS (m/z, rel int, assign-
ment) 316 (18, M•+), 300 (10, M•+ - O), 268 (100, M•+ - SO);
HRMS m/z obsd 316.1864 (calcd for C20H28OS 316.1861). Anal.
Calcd for C20H28OS: C, 75.90; H, 8.92; S, 10.13. Found: C,
75.87; H, 9.44; S, 10.05.
Exp er im en ta l Section
P r ep a r a tion of Ad a m a n tylid en ea d a m a n ta n e (15). Ad-
amantylideneadamantane was prepared by the procedure of
McMurry.32 Potassium metal (3.84 g, 49 mmol) was added to
a stirred slurry of titanium trichloride (TiCl3) (4.30 g, 28 mmol)
in 150 mL of dry tetrahydrofuran (THF) under a nitrogen
atmosphere at room temperature. After 40 min of reflux, the
black mixture was cooled, a solution of adamantanone (1.05
g, 7.0 mmol) in 10 mL of THF was added, and the mixture
was further refluxed for 16 h. The mixture was cooled to room
temperature and filtered under an inert atmosphere. Removal
of the solvent under reduced pressure and chromatography of
the residue on silica gel with hexane afforded a solid product
which upon crystallization from n-hexane gave 0.75 g, 80%,
of adamantylideneadamantane (15): mp 184-186 °C (lit. mp
Th er m al Ch em istr y of Adam an tyliden eadam an tan eth i-
ir an e 1-Oxide (8). Adamantylideneadamantanethiirane 1-ox-
ide (8) (0.25 g, 0.791 mmol) was dissolved in 25 mL of toluene,
and the solution was refluxed for 2.5 h under a nitrogen
atmosphere. The reaction was followed by thin layer chro-
matography using 20% EtOAc in hexane as eluent. After the
solvent was evaporated under reduced pressure, the mixture
was adsorbed onto silica gel and chromatographed using the
same eluent (20% EtOAc in hexane) to give adamantylidene-
adamantane (15) in a yield of 97%.
1
183-185 °C32, 184-187 °C33); H-NMR (CDCl3) δ 1.58-1.98
(m, 24H) and 2.91 (br, 4H) ppm; 13C-NMR (CDCl3) δ 28.9, 32.2,
37.7, 40.0, and 133.5 ppm; MS (m/z, rel int, assignment) 268
(100, M•+).
Rea ction of Ad a m a n tylid en ea d a m a n ta n e (15) w ith
Tr ip h en ylm eth a n esu lfen yl Ch lor id e (12). A solution of
triphenylmethanesulfenyl chloride34 (12) (0.116 g, 0.373 mmol)
in 25 mL of dry methylene chloride was added dropwise to a
stirred solution of adamantylideneadamantane (15) (0.10 g,
0.373 mmol) in 20 mL of dry methylene chloride under a
nitrogen atmosphere at room temperature. The mixture was
stirred for 6 h. Removal of the solvent under reduced pressure
and chromatography of the residue on silica gel with 20%
chloroform in hexane afforded a solid product which upon
crystallization from n-hexane gave 0.101 g, 93%, of adaman-
tylideneadamantanethiirane (10): mp 142-143 °C (lit. mp
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 8 w ith 2,3-Dim eth yl-1,3-bu ta d ien e
(17). 2,3-Dimethyl-1,3-butadiene (17) (0.0513 g, 0.625 mmol)
was added to a mixture of adamantylideneadamantanethiirane
1-oxide (8) (0.593 g, 1.875 mmol) in 30 mL of dry toluene. The
solution was refluxed for 12 h under a nitrogen atmosphere.
The reaction was followed by thin layer chromatography using
15% EtOAc in hexane as eluent. After the solvent was
evaporated under reduced pressure, the first fraction was
isolated by column chromatography using the same eluent
(15% EtOAc in hexane) and was identified as adamantylide-
neadamantane (15) (99%). By eluting with methanol, the
second fraction was isolated (0.065 g, 80%) as an oily product
and identified as 2,5-dihydro-3,4-dimethylthiophene 1-oxide
(19): 1H-NMR (CDCl3) δ 3.83 (d, 2H), 3.48 (d, 2H), and 1.77
(s, 6H) ppm; 13C-NMR (CDCl3) δ 14.5, 64.3, and 126.1 ppm;
1
153-154 °C23, 131-132 °C35); H-NMR (CDCl3) δ 2.08-1.56
(m, 28H) ppm; 13C-NMR (CDCl3) δ 27.1, 27.7, 35.0, 37.8, 38.4,
38.6, and 71.7 ppm; MS (m/z, rel int, assignment): 268, 100%,
M
•+-S; 300, 14%, M•+. Chlorotriphenylmethane was isolated
in a yield of 58%. In addition, 15 reacted similarly with 13
and 14 to deliver thiirane 10 in excellent yield.
MS (m/z, rel int, assignment) 130 (100, M•+), 82 (30, M•+
-
SO), 67 (61, M•+ - SOCH3). The above reaction was repeated
in a variety of solvents, varying temperature, time, and
concentration using the above procedure. The same products
were isolated in each case but in varying yields as shown in
Table 1.
Th er m a l Ch em istr y of Th iir a n e 10 in th e P r esen ce of
2,3-Dim eth yl-1,3-bu ta d ien e (17). 2,3-Dimethyl-1,3-butadi-
ene (17) (0.073 g, 0.90 mmol) was added to a mixture of
adamantylideneadamantanethiirane (10) (0.18 g, 0.60 mmol)
in 15 mL of dry ethyl acetate. The solution was refluxed for
15 h under a nitrogen atmosphere. The reaction was followed
by thin layer chromatography using 15% CHCl3 in hexane as
eluent. After the solvent was evaporated under reduced
pressure, the products were separated by the same eluent (15%
CHCl3 in hexane), in which the first fraction was isolated and
identified as adamantylideneadamantane (15) (0.15 g, 91%):
mp 185-186 °C (lit. mp 183-185 °C32, 184-187 °C33); 1H-NMR
(CDCl3) δ 1.59-1.98 (m, 24H) and 2.91 (br, 4H) ppm; 13C-NMR
(CDCl3) δ 28.9, 32.2, 37.7, 39.9, and 133.5 ppm; MS (m/z, rel
int, assignment) 268 (100, M•+). The second fraction was
isolated and identified as elemental sulfur (55%). The reaction
was repeated in toluene using the above procedure. Adaman-
tylideneadamantanethiirane (10) was completely decomposed
when the solution was refluxed for 2 h in toluene solution (110
°C), giving adamantylideneadamantane (15) (98%) along with
elemental sulfur (68%).
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 8 w ith 2,3-Dip h en yl-1,3-bu ta d ien e
(20). 2,3-Diphenyl-1,3-butadiene36 (20) (0.129 g, 0.625 mmol)
was added to a mixture of adamantylideneadamantanethiirane
1-oxide (8) (0.593 g, 1.875 mmol) in 30 mL of dry toluene. The
solution was refluxed for 24 h under a nitrogen atmosphere.
The reaction was followed by thin layer chromatography using
20% EtOAc in hexane as eluent. After the solvent was
evaporated under reduced pressure, the first fraction was
isolated by column chromatography using the same eluent
(20% EtOAc in hexane) and was identified as adamantylide-
neadamantane (15) (98%). By eluting with methanol, the
second fraction was isolated and identified as 2,5-dihydro-3,4-
diphenylthiophene 1-oxide (21). Recrystallization from n-
hexane gave 0.111 g, 70% of pure sulfoxide 21: mp 134-135
1
°C; H-NMR (CDCl3) δ 4.05 (d, 2H), 4.41 (d, 2H), and 7.13-
7.26 (m, 10H) ppm; 13C-NMR (CDCl3) δ 64.5, 127.9, 128.5,
128.6, 132.0, and 135.6 ppm; MS (m/z, rel int, assignment) 254
(5, M•+), 236 (100, M•+ - H2O), 205 (59, M•+ - SO), 191 (12,
M•+ - SOCH2). The above reaction was further investigated
by varying the reaction conditions in a variety of ways. The
Oxidation of Adam an tyliden eadam an tan eth iir an e (10)
by m -Ch lor op er oxyben zoic Acid (m -CP BA). A solution
(32) McMurry, J . E.; Fleming, M. P.; Kees, K. L.; Krepski, L. R. J .
Org. Chem. 1978, 43, 3255.
(33) Geluk, H. W. Synthesis 1970, 652.
(34) Williams, C. R.; Britten, J . F.; Harpp, D. N. J . Org. Chem. 1994,
59, 806.
(35) Tolstikov, G. A.; Lerman, B. M.; Umanskaya, L. I.; Struchkov,
Yu. T.; Espenbetov, A. A; Yanovsky, A. L. Tetrahedron Lett. 1980, 21,
4189.
(36) For the preparation of 2,3-diphenyl-1,3-butadiene (20), see:
Fulcher, B. C.; Hunter, M. L.; Welker, M. E. Synth. Commun. 1993,
23 (2), 217. Newman, M. S. J . Org. Chem. 1961, 26, 582. Alder, K.;
Haydn, J . J ustus Liebigs Ann. Chem. 1950, 570, 201.

8370 J . Org. Chem., Vol. 62, No. 24, 1997
Abu-Yousef and Harpp
same products were isolated in each case but in varying yields
as shown in Table 1.
mL of dry methylene chloride under a nitrogen atmosphere
at room temperature. The mixture was stirred for 5 h.
Removal of the solvent under reduced pressure and chroma-
tography of the residue on silica gel with 15% chloroform in
hexane afforded a solid product which upon crystallization
from n-hexane gave 0.116 g, 93%, of bicyclo[3.3.1]nonyli-
denebicyclo[3.3.1]nonanethiirane (11): mp 166-167 °C (lit.39
mp 166.5-167 °C); 1H-NMR (CDCl3) δ 1.52-2.03 (m, 28H)
ppm; 13C-NMR (CDCl3) δ 20.7, 21.3, 31.9, 33.6, 34.8, and 70.4
ppm; MS (m/z, rel int, assignment) 276 (18, M•+), 244 (100,
M•+ - S), 121 (19, M•+ - C9H14S). Chlorotriphenylmethane
was isolated in a yield of 55%. In addition, 16 reacted similarly
with 13 and 14 to deliver thiirane 11 in excellent yield.
Th er m a l Ch em istr y of Th iir a n e 11 in th e P r esen ce of
2,3-Dim eth yl-1,3-bu ta d ien e (17). 2,3-Dimethyl-1,3-butadi-
ene (17) (0.036 g, 0.435 mmol) was added to a mixture of
bicyclo[3.3.1]nonylidenebicyclo[3.3.1]nonanethiirane (11) (0.12
g, 0.435 mmol) in 20 mL of dry ethyl acetate. The solution
was refluxed for 8 h under a nitrogen atmosphere. The
reaction was followed by thin layer chromatography using 20%
CHCl3 in hexane as eluent. After the solvent was evaporated
under reduced pressure, the products were separated by
column chromatography using the same eluent (20% CHCl3
in hexane) in which the first fraction was isolated and
identified as bicyclo[3.3.1]nonylidenebicyclo[3.3.1] nonane (16)
(0.10 g, 95%): mp 144-146 °C (lit. mp 143-144 °C37, 144-
145 °C38); 1H-NMR (CDCl3) δ 1.40-2.11 (m, 24H) and 2.86 (br,
4H) ppm; 13C-NMR (CDCl3) δ 23.0, 32.5, 34.5, and 131.6 ppm.
The second fraction was isolated and identified as elemental
sulfur (50%). The reaction was repeated in toluene using the
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 8 w ith Isop r en e (5). Isoprene (5)
(0.014 g, 0.211 mmol) was added to a mixture of adamantyl-
ideneadamantanethiirane 1-oxide (8) (0.20 g, 0.633 mmol) in
25 mL of dry toluene. The solution was refluxed for 36 h under
a nitrogen atmosphere. The reaction was followed by thin
layer chromatography using 20% EtOAc in hexane as eluent.
After the solvent was evaporated under reduced pressure, the
first fraction was isolated by column chromatography using
the same eluent (20% EtOAc in hexane) and was identified as
adamantylideneadamantane (15) (97%). By eluting with
methanol, the second fraction was isolated (0.0168 g, 69%) as
an oily product and identified as 2,5-dihydro-3-methylthiolene
1-oxide (6): 1H-NMR (CDCl3) δ 5.58 (m, 1H), 3.69-3.90 (m,
2H), 3.34-3.58 (m, 2H), and 1.90 (s, 3H) ppm; 13C-NMR
(CDCl3) δ 16.7, 60.0, 62.9, 119.1, and 125.0 ppm; MS (m/z, rel
int, assignment) 116 (100, M•+), 68 (49, M•+ - SO), 67 (86,
M•+ - SOH), 53 (46, M•+ - SOCH3). The above reaction was
repeated in a variety of solvents, varying temperature, time
and concentration using the above procedure. The same
products were isolated in each case but in varying yields as
shown in Table 1.
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 8 w ith Myr cen e (22). Myrcene (22)
(0.069 g, 0.506 mmol) was added to a mixture of adamantyl-
ideneadamantanethiirane 1-oxide (8) (0.480 g, 1.519 mmol) in
20 mL of dry toluene. The solution was refluxed for 16 h under
a nitrogen atmosphere. The reaction was followed by thin
layer chromatography using 25% EtOAc in hexane as eluent.
After the solvent was evaporated under reduced pressure, the
first fraction was isolated by column chromatography using
the same eluent (25% EtOAc in hexane) and was identified as
adamantylideneadamantane (15) (98%). By eluting with
methanol, the second fraction was isolated (0.06 g, 65%) as
an oily product and identified as 3-(4′-methyl-3′-pentenyl)-2,5-
dihydrothiophene 1-oxide (23): 1H-NMR (CDCl3) δ 1.60 (s, 3H),
1.68 (s, 3H), 2.12-2.31 (m, 4H), 3.35-3.59 (m, 2H), 3.70-3.89
(m, 2H), 5.07 (m, H), and 5.60 (m, H) ppm; 13C-NMR (CDCl3)
δ 17.7, 25.6, 26.2, 31.3, 59.7, 61.6, 117.9, 123.9, 132.6, and
139.9 ppm; MS (m/z, rel int, assignment) 184 (39, M•+), 136
(27, M•+ - SO), 135 (55, M•+ - SOH), 116 (44, M•+ - C5H9),
69 (100, M•+ - C5H7SO). The above reaction was further
investigated by varying the reaction conditions in a variety of
ways. The same products were isolated in each case but in
varying yields as shown in Table 1.
above procedure.
Bicyclo[3.3.1]nonylidenebicyclo[3.3.1]-
nonanethiirane (11) was completely decomposed after the
solution was refluxed for 2.5 h in toluene (110 °C) under a
nitrogen atmosphere giving bicyclo[3.3.1]nonylidenebicyclo-
[3.3.1]nonane (16) in a yield of 98%. In addition, elemental
sulfur was isolated (58%).
Oxid a t ion of Bicyclo[3.3.1]n on ylid en eb icyclo[3.3.1]-
n on a n eth iir a n e (11) by m -Ch lor op er oxyben zoic Acid (m -
CP BA). A solution of m-CPBA (0.0624 g, 0.362 mmol) in 20
mL of dry methylene chloride was added dropwise to a stirred
solution of bicyclo[3.3.1]nonylidenebicyclo[3.3.1]nonanethiirane
(11) (0.10 g, 0.362 mmol) in 25 mL of dry methylene chloride
under a nitrogen atmosphere at -78 °C. The mixture was
stirred for 2.5 h. The solution was diluted with 5% NaOH
solution and extracted three times with 20 mL portions of
diethyl ether. The combined ethereal extracts were dried with
MgSO4, filtered, and evaporated to give the crude bicyclo-
[3.3.1]nonylidenebicyclo[3.3.1]nonanethiirane 1-oxide (9). Re-
crystallization from n-hexane gave 0.104 g, 98%, of the
P r ep a r a t ion
of
Bicyclo[3.3.1]n on ylid en eb icyclo-
[3.3.1]n on a n e (16). Potassium metal (5.76 g, 147 mmol) was
added to a stirred slurry of titanium trichloride (TiCl3) (6.45
g, 42 mmol) in 250 mL of dry tetrahydrofuran (THF) under a
nitrogen atmosphere at room temperature. After 1.5 h of
refluxing, the black mixture was cooled and a solution of
bicyclo[3.3.1]nonan-9-one (1.45 g, 10.50 mmol) in 15 mL of THF
was added. After the mixture was further refluxed for 24 h,
the mixture was cooled to room temperature and filtered under
an inert atmosphere. Removal of the solvent under reduced
pressure and chromatography of the residue on silica gel with
hexane afforded a solid product which upon crystallization
from n-hexane gave 2.17 g, 85%, of bicyclo[3.3.1]nonyli-
denebicyclo[3.3.1]nonane (16): mp 144-145 °C (lit. mp 143-
144 °C37, 144-145 °C38); 1H-NMR (CDCl3) δ 1.40-2.12 (m,
24H) and 2.85 (br, 4H) ppm; 13C-NMR (CDCl3) δ 23.0, 32.5,
34.5, and 131.6 ppm; MS (m/z, rel int, assignment) 244 (72,
1
corresponding thiirane 1-oxide 9: mp 150-151 °C; H-NMR
(CDCl3) δ 1.45-2.34 (m, 28H) ppm; 13C-NMR (CDCl3) δ 21.3,
27.5, 30.1, 30.3, 30.8, 31.3, 32.3, and 71.5 ppm; MS (m/z, rel
int, assignment) 292 (17, M•+), 276 (7, M•+ - O), 244 (100, M•+
- SO), 121 (81, M•+ - C9H14SO); HRMS m/z obsd 292.1859
(calcd for C18H28OS 292.1861).
Th er m al Ch em istr y of Bicyclo[3.3.1]n on yliden ebicyclo-
[3.3.1]n on a n et h iir a n e 1-Oxid e (9). A sample of bicyclo-
[3.3.1]nonylidenebicyclo[3.3.1]nonanethiirane 1-oxide (9) (0.20
g, 0.685 mmol) was dissolved in toluene, and the solution was
refluxed for 4 h under a nitrogen atmosphere. The reaction
was followed by thin layer chromatography using 30% EtOAc
in hexane as eluent. After the solvent was evaporated under
reduced pressure, the mixture was adsorbed onto silica gel and
chromatographed using the same eluent (30% EtOAc in
hexane) to give bicyclo[3.3.1]nonylidenebicyclo[3.3.1]nonane
(16) in a yield of 98%.
M
•+), 121 (100, M•+ - C9H14).
R ea ct ion of Bicyclo[3.3.1]n on ylid en eb icyclo[3.3.1]-
n on a n e (16) w ith Tr ip h en ylm eth a n esu lfen yl Ch lor id e
(12). A solution of triphenylmethanesulfenyl chloride34 (12)
(0.152 g, 0.492 mmol) in 30 mL of dry methylene chloride was
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 9 w ith 2,3-Dim eth yl-1,3-bu ta d ien e
added dropwise to
nonylidenebicyclo[3.3.1]nonane (16) (0.12 g, 0.492 mmol) in 25
a stirred solution of bicyclo[3.3.1]-
(39) Ando, W.; Sonobe, H; Akasaka, T. Tetrahedron Lett. 1987, 28,
6653.
(40) The author has deposited atomic coordinates for structures 8
and 9 with the Cambridge Crystallographic Data Centre. The
(37) Keul, H. Chem. Ber. 1975, 108, 1207.
(38) Brown, R. S.; Nagorski, R. W.; Bennet, A. J .; McClung, R. E.
D.; Arts, G. H. M.; Klobukowski, M.; McDonald, R.; Santarsiero, B. D.
J . Am. Chem. Soc. 1994, 116, 2448.
coordinates can be obtained, on request, from the Director, Cambridge
Crystallographic Data Centre, 12 Union Road, Cambridge, CB2 1EZ,
UK.

Effective Precursors for Sulfur Monoxide Formation
J . Org. Chem., Vol. 62, No. 24, 1997 8371
(17). By using thiirane 1-oxide 9, in a similar preparation, a
82% yield of 19 was obtained which had identical spectral
properties as when prepared using 1-oxide 8. 1H- and 13C-
NMR and MS were completely consistent as in the preparation
of 19 via 8. In addition, bicyclo[3.3.1]nonylidenebicyclo[3.3.1]-
nonane (16) was isolated in a yield of 98%. A variety of
solvents, temperatures, times, and concentrations were em-
ployed to optimize the yields of the trapped adducts (Table 2,
Supporting Information).
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 9 w ith 2,3-Dip h en yl-1,3-bu ta d ien e
(20). By using thiirane 1-oxide 9, in a similar preparation, a
73% yield of 21 was obtained which had identical spectral
properties as when prepared using 1-oxide 8. NMR and MS
data were consistent with structure of 21 which was prepared
via 8. Bicyclo[3.3.1]nonylidenebicyclo[3.3.1]nonane (16) was
isolated in a yield of 98%. The above reaction was further
investigated by varying the reaction conditions in a variety of
ways. The same products were isolated in each case but in
varying yields as shown in Table 2 (Supporting Information).
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 9 w ith Isop r en e (5). By using thiirane
1-oxide 9, in a similar preparation, a 72% yield of 6 was
obtained which had identical spectral properties as when
prepared using 1-oxide 8. Spectral data were consistent with
previous preparation of 6 via 8. In addition, bicyclo[3.3.1]-
nonylidenebicyclo[3.3.1]nonane (16) was isolated in a yield of
99%. A variety of solvents, temperatures, times and concen-
trations, were used to optimize the yields of the trapped
adducts (Table 2, Supporting Information).
Tr a p p in g of Su lfu r Mon oxid e fr om th e Decom p osition
of Th iir a n e 1-Oxid e 9 w ith Myr cen e (22). By using
thiirane 1-oxide 9, in a similar preparation, a 68% yield of 23
was obtained which had identical spectral properties as when
prepared using 1-oxide 8. 1H- and 13C-NMR and MS were
completely consistent as in the preparation of 23 via 8.
Bicyclo[3.3.1]nonylidenebicyclo[3.3.1]nonane (16) was isolated
in a yield of 98%. The above reaction was repeated in a variety
of solvents, varying temperature, time and concentration using
the above procedure. The same products were isolated in each
case but in varying yields as shown in Table 2 (Supporting
Information).
Ack n ow led gm en t. We thank the Natural Sciences
and Engineering Research Council of Canada and FCAR
(Que´bec) for financial support of this work.
Su p p or tin g In for m a tion Ava ila ble: 1H- and 13C-NMR
spectra of compounds 6, 8-11, 19, 21, and 23 and Table 2 a
summary of solvents, temperatures, times, and concentrations,
employed to optimize the yields of the trapped adducts
(episulfoxide 9) (12 pages). This material is contained in
libraries on microfiche, immediately follows this article in
microfilm version of the journal, and can be ordered from the
ACS; see any current masthead page for ordering information.
J O9709864