Aryl 1-chloroalkyl sulfoxides as acyl anion equivalents: A new synthesis of vinyl sulfides, ketones, and diketones from aryl 1-chloroalkyl sulfoxides and α,ω-dichloro-α,ω-disulfinylalkanes

Article abstract of DOI:10.1016/S0040-4020(00)01015-2

Treatment of aryl α-chloroalkyl sulfoxides, which were synthesized from aryl 1-chloroalkyl sulfoxides by alkylation with iodoalkanes, with trifluoroacetic anhydride and NaI in acetone at low temperature afforded vinyl sulfides in high yields. The vinyl sulfides were converted to ketones by hydrolysis with HClO₄ in refluxing 1,4-dioxane in good yields. In this procedure, the lithiated aryl 1-chloroalkyl sulfoxides acted as acyl anion equivalents. The procedure was extended to a synthesis of α,ω-diketones starting from α,ω-dichloro-α,ω-disulfinylalkanes. The procedure was found to work well when the length of the carbon chain of the α,ω-disulfinylalkanes is longer than four, and the yields of the diketones were found to be somewhat variable (60-80%).

Full text of DOI:10.1016/S0040-4020(00)01015-2

TETRAHEDRON
Pergamon
Tetrahedron 57 (2001) 493±500
Aryl 1-chloroalkyl sulfoxides as acyl anion equivalents: a new
synthesis of vinyl sul®des, ketones, and diketones from aryl
1-chloroalkyl sulfoxides and a,v-dichloro-a,v-disul®nylalkanes
*
Tsuyoshi Satoh, Daisaku Taguchi, Chihiro Suzuki and Satoshi Fujisawa
Department of Chemistry, Faculty of Science, Science University of Tokyo, Kagurazaka, Shinjuku-ku, Tokyo 162-8601, Japan
Received 10 October 2000; accepted 27 October 2000
AbstractÐTreatment of aryl a-chloroalkyl sulfoxides, which were synthesized from aryl 1-chloroalkyl sulfoxides by alkylation with
iodoalkanes, with tri¯uoroacetic anhydride and NaI in acetone at low temperature afforded vinyl sul®des in high yields. The vinyl sul®des
were converted to ketones by hydrolysis with HClO4 in re¯uxing 1,4-dioxane in good yields. In this procedure, the lithiated aryl 1-chloro-
alkyl sulfoxides acted as acyl anion equivalents. The procedure was extended to a synthesis of a,v-diketones starting from a,v-dichloro-a,v-
disul®nylalkanes. The procedure was found to work well when the length of the carbon chain of the a,v-disul®nylalkanes is longer than four,
and the yields of the diketones were found to be somewhat variable (60±80%). q 2001 Elsevier Science Ltd. All rights reserved.
Ketones are obviously one of the most important
compounds in organic chemistry. Among the methods for
synthesizing ketones, procedures by the use of umpoled
synthons1 are quite interesting and many useful reactions
have appeared. We have recently studied aryl 1-haloalkyl
sulfoxides 1 in developing new synthetic methods,2 and
some novel procedures for homologation of carbonyl
compounds were realized.3 In continuation of our studies,
we report herein a new method for synthesis of vinyl
sul®des 3 and ketones 4 from aryl 1-chloroalkyl sulfoxides
1 and alkyl halides through aryl a-chloroalkyl sulfoxides 2.
In this sequence, the carbanion of aryl 1-chloroalkyl sulf-
oxides acts as acyl anion equivalents 5. We also describe in
detail the extension of this method to synthesis of diketones
8 starting from a,v-dichloro-a,v-disul®nylalkane 6 via 7
(Scheme 1).
1. Results and discussion
1.1. Synthesis of vinyl sul®des and ketones from aryl
1-chloroalkyl sulfoxides
The synthesis of vinyl sul®des 11 and 12, and cyclohexyl
Scheme 1.
Keywords: aryl 1-chloroalkyl sulfoxides; acyl anion equivalents; vinyl sul®des; ketones; diketones.
* Corresponding author. Tel.: 181-3-3260-4271; fax: 181-3-3235-2214; e-mail: tsatoh@ch.kagu.sut.ac.jp
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)01015-2

494
T. Satoh et al. / Tetrahedron 57 (2001) 493±500
Scheme 2.
decyl ketone (13) is reported as a typical example of this
procedure (Scheme 2). Chloro(cyclohexyl)methyl p-tolyl
sulfoxide (9)2 was treated with LDA±HMPA in THF
followed by 1-iododecane to give 10 in high yield. Next,
we investigated reduction of the sulfoxide group of 10 to a
sul®de group. Olah's method4 by using MeSiCl3, however,
gave only a complex mixture. Reduction of the sulfoxide
group of 10 with TiCl35 did not proceed at all.
hydrolyses were studied and, ®nally, heating the vinyl
su®des with 10% aqueous HClO4 in 1,4-dioxane for 5 h
was found to be the conditions of choice (Scheme 2). The
conditions gave the desired ketone 13 in almost quantitative
yield.
Three other aryl a-chloroalkyl sulfoxides 2 were used for
studying the scope of the reaction described above, and the
results are summarized in Table 1. Entries 1 and 2 show that
the sulfoxides having a phenyl group as R also gave very
high yields of vinyl sul®des 16 and 17. Hydrolysis of the
phenyl-substituted vinyl sul®des was found to be much
slower than that of the vinyl sul®de having an alkyl group
as R. Especially, the vinyl sul®de 17 (entry 2) was very
stable under the hydrolysis conditions. In this case addition
of 3 equiv. of HgCl2 was found to be effective for the
hydrolysis; however, the reaction was still very slow and
the yield of the product, deoxybenzoin, was moderate. In a
trial to synthesize a ketone without isolation of the vinyl
sul®des, the experiment in entry 3 was conducted. The
produced mixture of the vinyl sul®des was not puri®ed,
and the crude extract was hydrolyzed with 10% HClO4 to
give 89% overall yield of 6-phenyl-2-hexanone (19).
Treatment of 10 with 6 equiv. of tri¯uoroacetic anhydride
(TFAA) in the presence of NaI (4 equiv.) in acetone at low
temperature6 gave a clean reaction mixture from which very
less polar products were obtained. Detailed inspection of the
mass spectra and 1H NMR of the product suggested that the
products were a mixture of unexpected vinyl sul®des 11 and
12 (89% yield; the ratio of 11:12ˆ3:7; E/Z of 12 was
assigned tentatively as 2:3 from the chemical shift of the
vinyl hydrogen).7
The presumed mechanism of this reaction is as follows
(Scheme 3). Reaction of a-chloroalkyl p-tolyl sulfoxide
10 with TFAA gave an acyloxysulfonium ion 14,8 which
is attacked by the iodide anion at the chlorine to give a
thionium ion 15. Elimination of the proton from 15 gives
the vinyl sul®des 11 and 12. Interestingly, the reaction of 10
with TFAA in the absence of NaI gave only a complex
mixture.
1.2. Synthesis of diketones from a,v-dichloro-a,v-
disul®nylalkanes
We next investigated the feasibility of the above-described
procedure for the synthesis of diketones starting from
a,v-dichloro-a,v-disul®nylalkanes 6.
Vinyl su®des are known to be hydrolyzed to ketones under
acidic conditions6b with a heavy metal such as mercuric
chloride.9 We investigated acid hydrolysis of the vinyl
sulides 11 and 12 without the toxic mercury. Several acidic
First, 1,10-di(phenylthio)decane (20) was synthesized from
Scheme 3.

T. Satoh et al. / Tetrahedron 57 (2001) 493±500
495
Table 1. Treatment of aryl a-chloroalkyl sulfoxides 2 with TFAA±NaI and the hydrolysis of the produced vinyl sul®des with aq. HClO4
Entry
2
Vinyl sul®de
(Yield/%)a
Conditions for
the hydrolysis
Ketone
Ar
Ph
R
R0
(Yield/%)a
1
Ph
Ph
CH3(CH2)8
Re¯ux 10 h
2
3
Ph
Ph
H
3 equiv. HgCl2
re¯ux 43 h
b
Tol
Ph(CH2)4
±
Re¯ux 5 h
Ph(CH2)4COCH3
19 (89)c
a Isolated yield after silica gel column chromatography.
b Not isolated.
c Two-step overall yield from the aryl a-chloroalkyl sulfoxide.
1,10-dibromodecane and 20 was chlorinated with N-chloro-
succinimide (NCS) followed by oxidization with 3-chloro-
peroxybenzoic acid (MCPBA) to give 1,10-dichloro-1,10-
di(phenylsul®nyl)decane (21) as a mixture of diastereo-
isomers in 98% overall yield. The chloro sulfoxide 21 was
found to be a stable compound. Alkylation of 21 was
conducted in the presence of HMPA as described above
with several iodoalkanes to give bis-alkylated sulfoxides
22a±d as a mixture of several diastereoisomers in 71±
86% yield (Scheme 4).
The bis-alkylated sulfoxide 22b (see Table 2) was treated
with TFAA (6 equiv.) and NaI (3 equiv.) in acetone at
2558C for 30 min. The reaction was quenched with aq.
Scheme 4.
Table 2. Synthesis of diketones 24 from dichlorodisulfoxides 22
22
Reaction time for step a
h
Reaction time for step b
24
R
h
Yield/%
22a
22b
22c
22d
H
CH3
(CH3)2CH
CH3(CH2)4
1.8
1.5
1.5
1.5
3
1.5
5
24a
24b
24c
24d
88
82
80
70
8.5

496
T. Satoh et al. / Tetrahedron 57 (2001) 493±500
Table 3. Synthesis of a,v-dichloro-a,v-disul®nylalkanes 26 having
various chain length
NaHCO3 and aq. Na2SO3 as above, and the product was
1
extracted. The H NMR spectrum of the crude product
showed that the product was a mixture of several isomeric
vinyl sul®des 23b. The crude products, without further
puri®cation, were hydrolyzed with 10% HClO4 in 1,4-diox-
ane at re¯ux for 1.5 h to give 3,12-tetradecadione (24b) in
82% yield as colorless crystals (Table 2, entry 2).
25
26
Other results for the transformation of bissulfoxides 22a,
22c, and 22d to the diketones 24a, 24c, and 24d are
summarized in Table 2. As shown in the table, 2,11-do-
decanedione (24a) was also obtained in high overall yield
(entry 1). However, in the cases of the bissulfoxides having
a branched alkyl group (entry 3) or a longer alkyl chain
(entry 4), the hydrolysis was found to require somewhat
longer reaction time than the other two examples. Similar
yields were obtained in these cases (entries 3 and 4).
n
Yield/%
25a
25b
25c
25d
25e
25f
10
6
4
3
2
26a
26b
26c
26d
26e
26f
98
81
85
94
77
76
1
We next investigated the limitation of this procedure on the
length of the methylene of the a,v-dichloro-a,v-disul®nyl-
alkanes 6. First, a,v-dichloro-a,v-di(phenylsul®nyl)-
alkanes 26a±26f were synthesized from a,v-bis(phenyl-
thio)alkanes 25a±25f in good to quantitative yields in a
similar procedure as described for the synthesis of 21. The
yields are summarized in Table 3. These products 26 are a
mixture of diastereoisomers and stable oily compounds.
Table 4. Alkylation of a,v-dichloro-a,v-disul®nylalkanes 26 with iodo-
methane and iodohexane
Entry
26
RCH2l
R
Reaction time
h
27
The alkylation of the bissulfoxides 26 with LDA in THF in
the presence of HMPA was carried out with two iodo-
alkanes, iodomethane and iodohexane, and quite interesting
results were obtained (Table 4). As shown in Table 4, the
alkylation of the bissulfoxide having a longer methylene
chain 26a (nˆ10; Table 4, entries 1 and 2) than the bissulf-
oxide described previously 21 (nˆ8) gave similar yields of
the alkylated products. The bissulfoxides having a shorter
methylene chain down to nˆ4 also gave good to excellent
yields of the alkylated products (entries 3±6). However, the
bissulfoxides having a much shorter methylene chain (nˆ2
and 1; entries 9±12) did not give the desired product but
only a complex mixture. The bissulfoxide having a three-
carbon methylene chain 26d (entries 7 and 8) gave methyl-
ated products; however, the yields were very poor. The
reason for these results is not clear; however, one reason
for the dif®culty of the alkylation must be the steric
n
Yield/%a
1
2
3
4
5
6
7
8
10
10
6
6
4
4
3
3
2
Hb
1.5
1.5
1.5
1
1.5
0.5
3
27a
70
98
53
67
86
92
13
9
b
b
b
c
CH3(CH2)4
Hb
CH3(CH2)4
Hb
CH3(CH2)4
Hc
CH3(CH2)4
H
27b
27c
27d
27e
27f
27g
27h
3
d
9
2.5
2.5
2.5
2
±
±
±
d
10
11
12
2
1
1
CH3(CH2)4
H
CH3(CH2)4
d
d
±
a Isolated yield after silica gel column chromatography.
b 4 equiv. of RCH2I were used.
c 5 equiv. of RCH2I were used.
d A complex mixture.
Table 5. Synthesis of diketones 28 from dichlorodisul®nylalkanes 27 via the vinyl sul®des
Entry
27
R
Reaction time for step a
h
Reaction time for step b
h
28
n
Yield/%a
1
2
3
4
5
6
27a
27b
27c
27d
27e
27f
H
10
10
6
6
4
2.5
1
1.5
1
2.5
0.7
8.5
4
9
4
6.5
4
28a
28b
28c
28d
28e
28f
69
73
78
60
66
69
CH3(CH2)4
H
CH3(CH2)4
H
CH3(CH2)4
4
a Isolated yield after silica gel column chromatography.

T. Satoh et al. / Tetrahedron 57 (2001) 493±500
497
hindrance of the carbon bearing the chlorine and the sul®nyl
group of 26d, 26e, and 26f.
cm21; 1H NMR d 1.45 (3H, s), 1.5±2.7 (8H, m), 2.42 (3H,
s), 7.1±7.7 (9H, m).
Finally, we investigated the conversion of the alkylated
products 27a±f to diketones 28. The results are summarized
in Table 5. The results indicate that all the alkylated bissulf-
oxides 27 gave moderate to good yields of diketones 28a±f.
2.1.2. Treatment of 10 with TFAA and NaI in acetone.
TFAA (0.34 ml, 2.4 mmol) was added dropwise with stir-
ring to a suspension of the sulfoxide 10 (164 mg, 0.4 mmol)
and NaI (1.6 mmol) in 4 ml of dry acetone at 2558C. The
reaction mixture turned from yellow to black±green in
color. The reaction mixture was stirred at 2558C for 1 h.
To the reaction mixture were added sat. aq. NaHCO3 (4 ml)
and sat. aq. Na2SO3 (4 ml). The whole was extracted with
ether±benzene. The product was puri®ed by silica gel
column chromatography to give 128 mg (89%) of a mixture
of the vinyl sul®de 11 and 12 as colorless oil. IR (neat) 1491,
In conclusion, we have found that the reaction of aryl
a-chloroalkyl sulfoxides with TFAA±NaI in acetone gave
vinyl sul®des in good to high yields. By acidic hydrolysis of
these vinyl sul®des we were able to synthesize ketones in
good yields. This method was found to be applicable to
synthesis of a,v-diketones starting from a,v-dichloro-
a,v-disul®nylalkanes.
1
1448, 804 cm21; H NMR d 0.88 (3H, CH3), 2.29, 2.31
(CH3), 5.51 (vinyl-H, t, Jˆ7.3 Hz), 5.92 (vinyl-H, t,
Jˆ6.9 Hz). MS m/z (%) 358 (M1, 100), 267 (13), 245
(27). Calcd for C24H38S: M, 358.2693. Found: m/z 358.2699.
2. Experimental
2.1. General
2.1.3. 1-Phenyl-1-phenylthio-1-undecene (16). Colorless
oil (E/Z-mixture); IR (neat) 1477, 1439, 739 cm21 1H
;
NMR d 0.88 (3H, t, Jˆ6.9 Hz), 1.1±1.6 (14H, m), 2.13
(q, Jˆ 7.3 Hz), 2.53 (q, Jˆ7.3 Hz), 6.14 (t, Jˆ7.2 Hz),
6.43 (t, Jˆ7.2Hz), 7.0±7.6 (10H, m). MS m/z (%) 338
(M1, 28), 225 (26), 218 (29), 105 (100). Calcd for
C23H30S: M, 338.2065. Found: m/z 338.2046.
Melting points were measured with a Yanagimoto micro
melting point apparatus and are uncorrected. 1H NMR spec-
tra were measured in a CDCl3 solution with JEOL JNM-LA
400 and 500 spectrometer. Electron-impact mass spectra
(MS) were obtained at 70 eV by direct insertion. Silica gel
60 (MERCK) containing 0.5% ¯uorescence reagent 254 and
a quartz column were used for column chromatography and
the products having UV absorption were detected by UV
irradiation. In experiments requiring a dry solvent, THF was
distilled from benzophenone ketyl; HMPA and diisopropyl-
amine were distilled from CaH2. Acetone was dried over
CaSO4 and distilled.
2.1.4. 1,2-Diphenyl-1-phenylthioethene (17). Colorless
solid; IR (KBr) 1579, 1477, 1439, 739, 692 cm21 1H
;
NMR d 6.79 (1H, s), 6.9±7.7 (15H, m). MS m/z (%) 288
(M1, 96), 210 (8), 179 (87), 178 (100). Calcd for C20H16S:
M, 288.0928. Found: m/z 288.0936.
2.1.5. Cyclohexyl decyl ketone (13). 10% Aqueous perch-
loric acid (1 ml) was added to a solution of the mixture of
the vinyl sul®des 11 and 12 (108 mg, 0.3 mmol) in 5 ml of
1,4-dioxane and the reaction mixture was heated under
re¯ux for 5 h. Sat. aq. NaHCO3 (2 ml) was added to the
reaction mixture and the whole was extracted with hexane.
The organic layer was washed once with sat. aq. NH4Cl and
dried over MgSO4. The product was puri®ed by silica gel
column chromatography to give 68 mg (96%) of the ketone
2.1.1. 1-Chloro-1-cyclohexyl-1-(p-tolylsul®nyl)undecane
(10). HMPA (0.73 ml, 4 mmol) was added to a solution of
LDA (3.5 mmol) in 10 ml of dry THF at 2608C. A solution
of 9 (768 mg, 2.8 mmol) in 2 ml of THF was added to the
above solution dropwise with stirring. After 10 min, 1-iodo-
decane (0.75 ml, 3.5 mmol) was added to the reaction
mixture. The solution was stirred and gradually allowed to
warm to 2258C for 2 h. The reaction was quenched with sat.
aq. NH4Cl and the whole was extracted with CHCl3. The
product was puri®ed by silica gel column chromatography
to give 1.11 g (95%) of 10 as a colorless oil. The sulfoxide
10 was a mixture of diastereoisomers and the structure was
determined by disappearance of the hydrogen on the carbon
bearing the sul®nyl group of 9. Selected data are reported.
13 as colorless oil. IR (neat) 1709 (CO), 1450, 1375 cm21
;
1H NMR d 0.88 (3H, t, Jˆ6.9 Hz), 1.2±1.9 (24H, m), 2.32
(1H, m), 2.41 (2H, t, Jˆ7.3 Hz). MS m/z (%) 252 (M1, 16),
169 (48), 126 (36), 111 (45), 83 (100). Calcd for C17H32O:
M, 252.2451. Found: m/z 252.2438.
2.1.6. 1-Phenyl-1-undecanone (18).11 Colorless oil; IR
1
(neat) 1687 (CO), 1448, 690 cm21; H NMR d 0.88 (3H,
1
IR (neat) 1082, 1060 (SO) cm21; H NMR d 0.88 (3H, t,
t, Jˆ6.9 Hz), 1.26 (14H, m), 1.73 (2H, m), 2.59 (2H, t, Jˆ
Jˆ6.3 Hz), 1.0±2.4 (29H, m), 2.44 (3H, s), 7.32 (2H, d,
7.6 Hz), 7.2±8.0 (5H, m).
Jˆ8.2 Hz), 7.65 (2H, d, Jˆ8.2 Hz).
2.1.7. 6-Phenyl-2-hexanone (19).12 Colorless oil; IR (neat)
1716 (CO), 1454, 1360, 700 cm21; 1H NMR d 1.62 (4H, m),
2.11 (3H, s), 2.44, 2.61 (each 2H, m), 7.1±7.5 (5H, m). MS
m/z (%) 176 (M1, 73), 158 (12), 129 (26), 118 (87), 91
(100).
Other aryl a-chloroalkyl sulfoxides in Table 1 were synthe-
sized in a similar way as described above in almost quanti-
tative yields. Selected data are reported. 1-Chloro-1-phenyl-
1-(phenylsul®nyl)undecane (entry 1): Diastereoisomeric
mixture; colorless solid; IR (KBr) 1090, 1059 (SO) cm21
;
1H NMR d 0.87 (3H, t, Jˆ6.9 Hz), 1.1±1.8 (16H, m), 2.4±
2.9 (2H, m), 6.9±7.4 (10H, m). 1-Chloro-1,2-diphenyl-1-
(phenylsul®nyl)ethane (entry 2): See lit.10. 2-Chloro-6-
phenyl-2-(p-tolylsul®nyl)hexane (entry 3): Diastereoiso-
meric mixture; colorless solid: IR (KBr) 1080, 1051 (SO)
2.1.8. 1,10-Di(phenylthio)decane (20). Benzenethiol (3.5 ml,
32 mmol) was added to a solution of sodium ethoxide
(32 mmol) in 90 ml of ethanol. To this solution was added
dropwise a solution of 1,10-dibromodecane (4.50 g, 15 mmol)

498
T. Satoh et al. / Tetrahedron 57 (2001) 493±500
in ethanol and the reaction mixture was stirred at room
temperature for 45 min. The ethanol was evaporated and to
the residue was added water. The whole was extracted with a
mixture of ether±benzene. The organic layer was washed
successively with 5% NaOH and sat. aq. NH4Cl. The solution
was dried over MgSO4 and the solvent was evaporated to give
a crystalline residue, which was recrystallized from AcOEt±
hexane to give 20 (5.35 g, 91%) as colorless crystals; mp 87±
888C. IR (KBr) 1580, 1479, 1438, 732 cm21; 1H NMR d 1.2±
1.5 (12H, m), 1.63 (4H, m), 2.91 (4H, t, Jˆ7.3 Hz), 7.1±7.4
(10H, m). MS m/z (%) 358 (M1, 100), 249 (12), 123 (34), 110
(42). Calcd for C22H30S2: M, 358.1787. Found: m/z 358.1786.
Anal Calcd: C, 73.68; H, 8.43; S, 17.88. Found: C, 73.48; H,
8.48; S, 18.17.
4,13-di-(phenylsul®nyl)hexadecane (22c). Colorless oil; IR
1
(neat) 1444, 1082, 1052, 749 cm21; H NMR d 1.0±2.1
(34H, m),7.5±7.8 (10H). MS m/z (%) 572 (M1, trace),
143 (100), 126 (78). 7,16-Dichloro-7,16-di(phenylsul®nyl)-
docosane (22d). Colorless oil; IR (neat) 1444, 1082, 1052,
1
749 cm21; H NMR d 0.8±0.9 (6H, m), 1.2±1.7 (30H, m),
1.9±2.2 (6H, m), 7.5±7.8 (10H, m). MS m/z (%) 626 (M1,
trace), 531 (87), 125 (26).
2.1.12. 3,12-Tetradecanedione (24b). TFAA (0.17 ml,
1.2 mmol) was added dropwise with stirring to a suspension
of the sulfoxide 22b (51.6 mg, 0.1 mmol) and NaI (0.09 g,
0.6 mmol) in 3 ml of dry acetone at 2558C. The reaction
mixture turned from yellow to black±green in color. The
reaction mixture was stirred at 2558C for 1.5 h. To the
reaction mixture were added sat. aq. NaHCO3 and sat. aq.
Na2SO3. The whole was extracted with ether±benzene. The
organic layer was washed with sat. aq. NH4Cl and dried over
MgSO4. The solvent was evaporated to give a residue,
which was used in the next reaction without further puri®-
cation. 10% aqueous perchloric acid (1 ml) was added to a
solution of the mixture of the product (vinyl sul®des 23) in
5 ml of 1,4-dioxane and the reaction mixture was heated
under re¯ux for 1.5 h. Sat. aq. NaHCO3 was added to the
reaction mixture and the whole was extracted with ether±
benzene. The solution was dried over MgSO4 and the
solvent was evaporated. The product was puri®ed by silica
gel column chromatography to give 19.2 mg (82%) of the
ketone 24b as colorless crystals. Mp 71.5±728C (AcOEt±
2.1.9. 1,10-Dichloro-1,10-di(phenylsul®nyl)decane (21).
N-Chlorosuccinimide (puri®ed by recrystallization from
benzene; 0.59 g, 4.4 mmol) was added to a solution of 20
(0.72 g, 2 mmol) in carbon tetrachloride (40 ml). The
suspension was stirred at room temperature for 2.5 h. The
precipitates were ®ltered off and the solvent of the ®ltrate
was evaporated. The residue was dissolved with CH2Cl2
(70 ml) and the solution was cooled to 2608C. To the solu-
tion was added MCPBA (0.77 g, 4.4 mmol) portionwise
with stirring and the reaction mixture was stirred at
2608C for 2 h. The solution was washed twice with 5%
NaOH followed by sat. aq. NH4Cl. The solution was dried
over MgSO4 and the solvent was evaporated. The product
was puri®ed by silica gel column chromatography to give
900 mg (98%) of 21 (diastereoisomeric mixture) as color-
1
hexane). IR (KBr) 1710, 1701 (CO), 1376, 1116 cm21; H
1
less oil. IR (neat) 1444, 1086, 1052 (SO), 751 cm21; H
NMR d 1.05 (6H, t, Jˆ7.2 Hz), 1.28 (8H, m), 1.56 (4H, m),
2.37±2.44 (8H, m). MS m/z (%) 226 (M1, 3), 197 (17), 57
(100). Calcd for C14H26O2: M,226.1931. Found: m/z
226.1931. Anal Calcd: C, 74.29; H, 11.58. Found: C,
74.56; H, 11.63.
NMR d 1.2±1.8 (12H, m), 1.96 (2H, m), 2.23 (2H, m),
4,40 (1.5H, dd, Jˆ9.7, 2.7 Hz), 4.53 (0.5H, dd, Jˆ9.1,
4.0 Hz), 7.5±7.8 (10H, m). MS m/z (%) 458 (M1, trace),
442 (trace), 333 (17), 126 (100). Calcd for C22H28Cl2O2S2:
M, 458.0908. Found: m/z 458.0899.
2.1.13. 2,11-Dodecanedione (24a). Colorless crystals; mp
66±678C (H2O). IR (KBr) 1701 (CO), 1560, 1363 cm21; 1H
NMR d 1.28 (8H, m), 1.53±1.59 (4H, m), 2.13 (6H, s), 2.41
(4H, t, Jˆ7.3 Hz). MS m/z (%) 198 (M1, trace), 183 (trace),
141 (10), 123 (12), 43 (100). Calcd for C12H22O2: M,
198,1618. Found: m/z 198,1614. Anal Calcd: C, 72.68; H,
11.18. Found: C, 72.45; H, 10.92.
2.1.10. 3,12-Dichloro-3,12-di(phenylsul®nyl)tetradecane
(22b). To a solution of LDA (1.5 mmol) in 10 ml of THF
at 2788C was added dropwise with stirring a solution of 21
(230 mg, 0.5 mmol) in THF followed by HMPA (0.26 ml,
1.5 mmol). The reaction mixture was stirred for 10 min,
then iodoethane (0.16 ml, 2 mmol) was added and the solu-
tion was stirred and allowed to warm to 2508C for 3 h. The
reaction was quenched by sat. aq. NH4Cl and the whole was
extracted with ether±benzene. The solution was dried over
MgSO4 and the solvent was evaporated. The product was puri-
®ed by silica gel column chromatography to give 204 mg
(86%) of 22b (diastereoisomeric mixture) as light yellow oil.
IR (neat) 1444, 1082, 1049 (SO), 750 cm21; 1H NMR d 1.01
(6H, CH3), 1.1±1.9 (14H, m), 1.9±2.3 (6H, m), 7.4±7.8
(10H, m). MS m/z (%) 514 (M1, trace), 262 (6), 126 (100).
2.1.14. 2,15-Dimethyl-4,13-hexadecanedione (24c). Color-
less oil; IR (neat) 1702 (CO), 1466, 1411 cm21; 1H NMR d
0.90 (12H, d, Jˆ6.6 Hz), 1.27 (8H, m), 1.55 (4H, quint, Jˆ
7.1 Hz). 2.13 (2H, septet, Jˆ6.8 Hz), 2.27 (4H, d, Jˆ6.8 Hz)
2.36 (4H, t, Jˆ7.1 Hz). MS m/z (%) 282 (M1, 7), 225 (17),
183 (52), 85 (100). Calcd for C18H34O2: M, 282.2556. Found:
m/z 282.2553.
2.1.15. 7,16-Docosanedione (24d). Colorless crystals; mp
2.1.11. a,v-Dichloro-a,v-di(phenylsul®nyl)alkanes (22a,
22c, and 22d). These alkylated chloro sulfoxides were
synthesized from 21 in a similar way as described above.
These products are a mixture of several diastereoisomers,
and it was found dif®cult to obtain the data for high-resolu-
tion mass spectra. 2,11-Dichloro-2,11-di(phenylsul®nyl)do-
decane (22a). Colorless oil; IR (neat) 1444, 1082, 1052
86±878C (hexane). IR (KBr) 1700 (CO), 1654, 1543 cm21
;
1H NMR d 0.88 (6H, t, Jˆ6.6 Hz), 1.27 (20H, m), 1.5±1.6
(8H, m), 2.38 (8H, t, Jˆ6.9Hz). MS m/z (%) 338 (M1, 5),
253 (21), 211 (94), 113 (95), 43 (100). Calcd for C22H42O2:
M, 338.3177. Found: m/z 338.3182. Anal Calcd: C, 78.04;
H, 12.50. Found: C, 77.78; H, 12.21.
1
(SO), 749 cm21; H NMR d 1.2±1.8 (19H, m), 2.0±2.2
2.1.16. 1,12-Dichloro-1,12-di(phenylsul®nyl)dodecane
(26a). Colorless oil; IR (neat) 1444, 1087, 1052 (SO),
(3H, m), 7.5±7.6 (6H, m), 7.7±7.8 (4H, m). MS m/z (%)
488 (M1, trace), 126 (100). 4,13-Dichloro-2,15-dimethyl-
1
750 cm21; H NMR d 1.3±1.7 (16H, m), 1.9±2.0 (2H, m),

T. Satoh et al. / Tetrahedron 57 (2001) 493±500
499
2.2±2.3 (2H, m), 4.41 (1.5H, dd, Jˆ9.8, 2.8 Hz), 4.53 (0.5H,
dd, Jˆ9.1, 4.1 Hz), 7.5±7.8 (10H, m). MS m/z (%) 361
([M2PhSO]1, 8), 126 (100).
sul®nyl)octane (27e). Colorless oil. IR (neat) 1444, 1085,
1
1049 (SO), 750 cm21; H NMR d 1.4±2.2 (14H, m), 7.5±
7.8 (10H, m). MS m/z (%) 430 (M1, trace), 305 (11), 143
(100). 7,12-Dichloro-7,12-di(phenylsul®nyl)octadecane
(27f). Colorless oil. IR (neat) 1443, 1082, 1051 (SO),
2.1.17. 1,8-Dichloro-1,8-di(phenylsul®nyl)octane (26b).
1
Colorless oil; IR (neat) 1444, 1087, 1052 (SO), 756 cm21
;
749 cm21; H NMR d 0.8±0.9 (6H, t, Jˆ7 Hz), 1.2±1.8
1H NMR d 1.2±1.7 (8H, m), 1.96 (2H, m), 2.23 (2H, m),
4.40 (1.5H, m), 4.5±4.6 (0.5H, m), 7.5±7.8 (10H, m). MS
m/z (%) 431 ([M1H]1, trace), 305 (21), 126 (100). Calcd
for C20H25Cl2O2S2: [M1H], 431.0687. Found: m/z
431.0662.
(22H, m), 1.9±2.2 (6H, m), 7.5±7.6 (6H, m), 7.7±7.8 (4H,
m). MS m/z (%) 318 (10), 283 (6), 126 (98), 78 (100). 2,6-
Dichloro-2,6-di(phenylsul®nyl)heptane (27g). Colorless oil.
1
IR (neat) 1444, 1091, 1051 (SO), 746 cm21; H NMR d
1.2±2.5 (12H, m), 7.5±7.9 (10H, m). MS m/z (%) 302 (7),
250 (16), 126 (84). 7,12-Dichloro-7,12-di(phenylsul®nyl)-
octadecane (27h). Colorless oil. IR (neat) 1443, 1083,
2.1.18. 1,6-Dichloro-1,6-di(phenylsul®nyl)hexane (26c).
1
Colorless oil; IR (neat) 1440, 1086, 1047 (SO), 745 cm21
;
1053 (SO), 749 cm21; H NMR d 0.8±0.9 (6H, m), 1.2±
1H NMR d 1.6±2.3 (8H, m), 4.39 (1.5H, m), 4.5±4.6 (0.5H,
m), 7.5±7.8 (10H, m). MS m/z (%) 403 ([M1H]1, trace),
277 (12), 126 (100), 78 (100). Calcd for C18H21Cl2O2S2:
[M1H], 403.0360. Found: m/z 403.0375.
2.5 (26H, m), 7.3±7.8 (10H, m). MS m/z (%) 290 (18), 126
(100).
2.1.23. 2,13-Tetradecanedione (28a). Colorless crystals;
mp 73±748C (hexane). IR (KBr) 1715, 1701 (CO), 1379,
1
2.1.19. 1,5-Dichloro-1,5-di(phenylsul®nyl)pentane (26d).
1165 cm21; H NMR d 1.27 (12H, m), 1.57 (4H, m), 2.13
Colorless oil; IR (neat) 1444, 1088, 1051 (SO), 752 cm21
;
(6H, s). 2.42 (4H, t, Jˆ7.5 Hz). MS m/z (%) 226 (M1, 3),
211 (2), 169 (12), 151 (10), 43 (100). Calcd for C14H26O2:
M, 226.1931. Found: m/z 226.1928. Anal Calcd: C, 74.29;
H, 11.58. Found: C, 73.97; H, 11.38.
1H NMR d 1.6±1.9 (2H, m), 2.0±2.2 (2H, m), 2.30 (2H, m),
4.3±4.4 (1.5H, m), 4.5±4.6 (0.5H, m), 7.5±7.8 (10H, m).
MS m/z (%) 388 (M1, trace), 263 (18), 126 (100). Calcd for
C17H18Cl2O2S2: M, 388.0125. Found: m/z 388.0132.
2.1.24. 7,18-Tetracosanedione (28b). Colorless crystals;
mp 89±908C (hexane). IR (KBr) 1705, 1699 (CO), 1458,
1381 cm21; 1H NMR d 0.88 (6H, m), 1.29 (24H, m), 1.52±
1.57 (8H, m), 2.38 (4H, t, Jˆ7.5 Hz), 2.39 (4H, t,
Jˆ7.5 Hz). MS m/z (%) 366 (M1, 29), 296 (27), 239
(100), 113 (88). Calcd for C24H46O2: M, 366.3496. Found:
m/z 366.3502. Anal Calcd: C, 78.61; H, 12.64. Found: C,
78.39; H, 12.62.
2.1.20. 1,4-Dichloro-1,4-di(phenylsul®nyl)butane (26e).
A mixture of colorless oil and crystals; IR (neat) 1443,
1
1086, 1045 (SO), 748 cm21; H NMR d 2.1±2.2 (1H, m),
2.3±2.5 (2H, m), 2.6±2.7 (1H, m), 4,4±4.7 (2H, m), 7.5±7.8
(10H, m). MS m/z (%) 374 (M1, 2), 249 (91), 125 (89), 109
(100). Calcd for C16H16Cl2O2S2: M, 373.9969. Found: m/z
373.9971.
2.1.21. 1,3-Dichloro-1,3-di(phenylsul®nyl)propane (26f).
2.1.25. 2,9-Decanedione (28c). Colorless crystals; mp 53±
548C (hexane). IR (KBr) 1715, 1702 (CO), 1375,
Colorless oil; IR (neat) 1444, 1087, 1045 (SO), 744 cm21
;
1H NMR d 2.3±2.4 (1H, ddd, Jˆ14.5, 11.5, 2.8 Hz), 2.7±
2.8 (1H, ddd, Jˆ13.9, 11.3, 2.8 Hz), 4.6±4.7 (1H, dd,
Jˆ11.3, 2.8 Hz), 4.8±4.9 (1H, dd, Jˆ11.3, 2.8 Hz), 7.5±
7.7 (10H, m). MS m/z (%) 360 (M1, trace), 235 (11), 125
(91), 109 (100). Calcd for C15H14Cl2O2S2: M, 359.9812.
Found: m/z 359.9820.
1163 cm21; H NMR d 1.30 (4H, m), 1.54±1.60 (4H, m),
1
2.13 (6H, s), 2.42 (4H, t, Jˆ7.3 Hz). MS m/z (%) 170 (M1,
trace), 152 (8), 113 (20). Calcd for C10H18O2: M, 170.1306.
Found: m/z 170.1310. Anal Calcd: C, 70.55; H, 10.66.
Found: C, 70.13; H, 10.34.
2.1.26. 7,14-Eicosanedione (28d). Colorless crystals; mp
83±848C (hexane). IR (KBr) 1698 (CO), 1420,
2.1.22. a,v-Dichloro-a,v-di(phenylsul®nyl)alkanes (27a±
27h). Similar to the sulfoxides 22, these sulfoxides are a
mixture of several diastereoisomers, and it was dif®cult to
obtain the data for mass spectrum. 2,13-Dichloro-2,13-
di(phenylsul®nyl)tetradecane (27a). Light yellow oil. IR
1
1382 cm21; H NMR d 0.88 (6H, t, Jˆ6.4 Hz), 1.27 (16H,
m), 1.53±1.58 (8H, m), 2.38 (8H, t, Jˆ7.3 Hz). MS m/z (%)
310 (M1, 18), 225 (30), 183 (100). Calcd for C20H38O2: M,
310.2869. Found: m/z 310.2856. Anal Calcd: C, 77.36; H,
12.34. Found: C, 77.09; H, 12.36.
1
(neat) 1444, 1085, 1051 (SO), 750 cm21; H NMR d 1.2±
1.8 (22H, m), 2.0±2.2 (4H, m), 7.5±7.6 (6H, m), 7.7±7.8
(4H, m). MS m/z (%) 126 (100). 7,18-Dichloro-7,18-
di(phenylsul®nyl)tetracosane (27b). Light yellow oil. IR
2.1.27. 2,7-Octanedione (28e). Colorless oil; IR (neat)
1
1717, 1700 (CO) cm21; H NMR d 1.56 (4H, m), 2.14
1
(neat) 1444, 1082, 1052 (SO), 749 cm21; H NMR d 0.8±
(6H, s), 2.45 (4H, t, Jˆ6.7 Hz). MS m/z (%) 142 (M1,
0.6), 124 (0.6), 84 (32), 43 (100). Calcd for C8H14O2: M,
142.0994. Found: m/z 142.0990.
1.7 (40H, m), 1.9±2.2 (6H, m), 7.5±7.8 (10H, m). MS m/z
(%) 402 (100), 126 (47). 2,9-Dichloro-2,9-di(phenylsul®-
nyl)decane (27c). Colorless oil. IR (neat) 1444, 1088,
1
1054 (SO), 747 cm21; H NMR d 1.2±1.8 (16H, m), 2.0±
2.1.28. 7,12-Octadecanedione (28f). Colorless crystals; mp
2.2 (2H, m), 7.5±7.6 (6H, m), 7.7±7.8 (4H, m). MS m/z (%)
126 (100), 78 (50). 7,14-Dichloro-7,14-di(phenylsul®nyl)ei-
cosane (27d). Colorless oil. IR (neat) 1444, 1088, 1054
75±768C (hexane). IR (KBr) 1700 (CO), 1684, 1466 cm21
;
1H NMR d 0.88 (6H, t, Jˆ6.8 Hz), 1.25±1.32 (12H, m),
1.51±1.58 (8H, m), 2.33±2.43 (8H, m). MS m/z (%) 282
(M1, 3), 264 (12), 212 (20), 176 (60), 113 (89), 34 (100).
Calcd for C18H34O2: M, 282.2565. Found: m/z 282.2557.
Anal Calcd: C, 76.60; H, 12.14. Found: C, 76.29; H, 11.84.
(SO), 747 cm21 1H NMR d 0.8±0.9 (6H, m), 1.2±1.7
;
(26H, m), 1.9±2.1 (6H, m), 7.5±7.8 (10H, m). MS m/z
(%) 346 (17), 126 (100). 2,7-Dichloro-2,7-di(phenyl-

500
T. Satoh et al. / Tetrahedron 57 (2001) 493±500
4. Olah, G. A.; Husain, A.; Singh, B. P.; Mehrotra, A. K. J. Org.
Acknowledgements
Chem. 1983, 48, 3667.
5. Arai, Y.; Yamamoto, M.; Koizumi, T. Bull. Chem. Soc. Jpn.
1988, 61, 467.
This work was supported by a Grant-in-Aid for Scienti®c
Research No. 11640545 from the Ministry of Education,
Science, Sports, and Culture, which is gratefully acknowl-
edged.
6. (a) Bravo, P.; Piovosi, E.; Resnati, G. J. Chem. Soc., Perkin
Trans. 1, 1989, 1201. (b) Imanishi, T.; Ohara, T.; Sugiyama,
K.; Ueda, Y.; Takemoto, Y.; Iwata, C. J. Chem. Soc., Chem.
Commun. 1992, 269.
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