A facile method for the synthesis of thiocarbamates: Palladium-catalyzed reaction of disulfide, amine, and carbon monoxide

Article abstract of DOI:10.1021/jo048350h

(Equation Presented) A new method for the synthesis of thiocarbamates has been developed. When dialkyl or diaryl disulfides were allowed to react with secondary amines and carbon monoxide in the presence of a catalytic amount of a palladium complex, the thiocarbamates were obtained in moderate to good yields. In contrast to that of secondary amines, in the reaction of a primary amine, no formation of thiocarbamate was confirmed, but urea was formed in good yield.

Full text of DOI:10.1021/jo048350h

A Facile Method for the Synthesis of Thiocarbamates:
Palladium-Catalyzed Reaction of Disulfide, Amine, and Carbon
Monoxide
Yutaka Nishiyama,* Hiroaki Kawamatsu, and Noboru Sonoda*
Department of Applied Chemistry, Faculty of Engineering, Kansai University,
Suita, Osaka 564-8680, Japan
nishiya@ipcku.kansai-u.ac.jp
Received September 17, 2004
A new method for the synthesis of thiocarbamates has been developed. When dialkyl or diaryl
disulfides were allowed to react with secondary amines and carbon monoxide in the presence of a
catalytic amount of a palladium complex, the thiocarbamates were obtained in moderate to good
yields. In contrast to that of secondary amines, in the reaction of a primary amine, no formation of
thiocarbamate was confirmed, but urea was formed in good yield.
The development of the process to replace the use of
phosgene as a carbonylating reagent has received con-
siderable attention in recent years due to environmental
and industrial concerns. Carbon monoxide is one of the
promising agents for the replacement of phosgene; the
development of new methods for the carbonylation of
various organic compounds with carbon monoxide could
have a significant impact on organic and industrial
chemistries.1
A series of thiocarbamates is known as useful herbi-
cides, and many methods for the synthesis of thiocar-
bamates have already been reported.2 Among them, the
reaction of an amine with phosgene and a thiol or with
carbonyl sulfide followed by alkylation with alkyl halides
has been well-known as the general synthetic method.3,4
As another approach, the development of carbonylation
routes using carbon monoxide has attracted considerable
attention, and various synthetic routes of thiocarbamates
have been reported: (i) the reaction of a secondary amine,
carbon monoxide, sulfur, and alkyl halides,5 (ii) the
selenium-catalyzed four-component coupling of an amine,
sulfur, carbon monoxide, and alkyl halides,6 (iii) the
reaction of carbamoyllithium, which was prepared in situ
by the reaction of lithium amide with carbon monoxide,
with sulfur and alkyl halides or with disulfide,7 (iv)
nickel- and palladium-assisted or catalyzed coupling of
an amine, thiol, and carbon monoxide,8 and (v) pal-
ladium-catalyzed azathiolation of carbon monoxide using
sulfeneamide.9 However, there are several disadvantages
of these methods: (i) the requirement of high reaction
temperatures and highly pressurized carbon monoxide,
(ii) the need for expensive lithium amide, (iii) the use of
a thiol having a bad smell and unstable in air, (iv) low
turn-over number of catalyst, (v) low or moderate yields
of products, (vi) the use of unstable reagents, or (vii)
multistep procedures. Therefore, there is increased inter-
est in the development of convenient synthetic methods
for thiocarbamate formation by using carbon monoxide.
In this paper, we wish to report a facile method for the
(1) For recent reviews of carbonylation, see: (a) Dugal, M.; Koch,
D.; Naberfeld, G.; Six, C. In Applied Homogeneous Catalysis with
Organometallic Compounds, 2nd ed.; Wiley-VCH Verlag: Weinheim,
Germany, 2002; Vol. 3. (b) Negishi, E., Ed. In Handbook of Organo-
palladium Chemistry for Organic Synthesis; John Wiley & Sons: New
York, 2002; pp 2691-2704. (c) Skoda-Foldes, R.; Kollar, L. Corrent Org.
Chem. 2002, 6, 1097. (d) Bates, R. W. In Comprehensive Organometallic
Chemistry; Abel, E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon
Press: Oxford, UK, 1995; Vol. 12, pp 349-386. (e) Colquhoun, H. M.;
Thompson, D. J.; Twigg, M. V. In Carbonylation: Direct Synthesis of
Carbonyl Compounds; Plenum Press: New York, 1991.
(2) (a) Usugi, Y.; Ueji, M.; Koshioka, M. Pesticide data Book, 3rd
ed.; Soft Science Publ.: Tokyo, Japan, 1997. (b) Sanders, H. J. Chem.
Eng. News 1981, 59, 20. (c) Sugiyama, H. J. Synth. Org. Chem. Jpn.
1980, 38, 555.
(3) (a) Chin-Hsion, W. Synthesis 1981, 622. (b) Tilles, H. J. Am.
Chem. Soc. 1959, 81, 714.
(4) S-Alkyl thiocarbamates were prepared by the reaction of trichlo-
roacetyl chloride with amine and thiol. See: Wynne, J. H.; Jensen, S.
D.; Snow, A. W. J. Org. Chem. 2003, 68, 3733.
(5) (a) Mizuno, T.; Takahashi, J.; Ogawa. A. Tetrehedron 2003, 59,
1327. (b) Mizuno, T.; Iwai, T.; Ito, T. Tetrehedron 2004, 60, 2869. (c)
Grisley, D. W., Jr.; Stephens, J. A. J. Org. Chem. 1961, 26, 3568.
(6) (a) Mizuno, T.; Nishiguchi, I.; Sonoda, N. Tetrahedron 1994, 50,
5669. (b) Sonoda, N.; Mizuno, T.; Murakami, S.; Kondo, K.; Ogawa,
A.; Ryu, I.; Kambe, N. Angew. Chem., Int. Ed. Engl. 1989, 28, 452.
(7) (a) Mizuno, T.; Nishiguchi, I.; Okushi, T.; Hirashima, T. Tetra-
hedron Lett. 1991, 32, 6867. (b) Mizuno, T.; Kawanishi, A.; Nishiguchi,
I.; Hirashima, T. Chem. Express 1991, 6, 997. (c) Mizuno, T.; Nish-
iguchi, I.; Hirashima, T. Tetrahedron 1993, 49, 2403.
(8) (a) Jacob, J.; Reynolds, K. A.; Jones, W. D.; Goldleski, S. A.;
Valente, R. R. Organometallics 2001, 20, 1028. (b) Jones, W. D.;
Reynolds, K. A.; Sperry, C. K.; Lachicotte, R. J.; Godleski, S.; Valento,
R. R. Organometallics 2000, 19, 1661.
(9) Kuniyasu, H.; Hiraike, H.; Morita, M.; Tanaka, A.; Sugoh, K.;
Kurosawa, H. J. Org. Chem. 1999, 64, 7305.
10.1021/jo048350h CCC: $30.25 © 2005 American Chemical Society
Published on Web 02/26/2005
J. Org. Chem. 2005, 70, 2551-2554
2551

Nishiyama et al.
synthesis of S-aryl- and S-alkyl thiocarbamates by the
palladium-catalyzed reaction of a disulfide, amine, and
carbon monoxide (Scheme 1).
with a longer reaction time (15 h) giving 3a in 76% yield
(Scheme 2).
SCHEME 2
SCHEME 1
Results and Discussion
To determine the optimized reaction conditions, di-
phenyl disulfide (1a) was allowed to react with diethy-
lamine (2a) and carbon monoxide in the presence of a
catalytic amount of a transition metal complex under
various reaction conditions and the results are shown in
Table 1. When 1a was treated with 2a (15 equiv) in the
To determine the scope and limitation of the pal-
ladium-catalyzed synthesis of S-aryl-N,N-diethylthiocar-
bamates, various diaryl disulfides were reacted with
diethylamine and carbon monoxide in the presence of a
catalytic amount of Pd(PPh3)4 and the results are shown
in Table 2. In the case of di(3-methylphenyl), di(4-
methylphenyl), and di(4-methoxyphenyl) disulfide, the
reaction efficiently proceeded giving the corresponding
S-aryl-N,N-diethylthiocarbamates in 83%, 98%, and 78%
yields, respectively (entries 2-4). Similarly, the sterically
hindered diaryl disulfide, such as di(2-methylphenyl)
disulfide, was coupled with 2a and carbon monoxide to
form the S-(2-methylphenyl)-N,N-diethylcarbamate in
84% yield (entry 1). S-(4-Chlorophenyl)-N,N-diethylth-
iocarbamate was obtained in 70% yield for the reaction
of di(4-chlorophenyl) disulfide (entry 5). In the case of
the nitro-substituted diaryl disulfide, the product yield
was low due to the preparation of complex byproducts
(entry 6).
TABLE 1. The Reaction of Diphenyl Disulfide (1a),
Diethylamine (2a), and Carbon Monoxidea
2a/ temp/ CO/ time/ yield/
b
entry
catalyst
solvent
THF
THF
THF
THF
THF
THF
equiv °C atm
h
%
1
2
3
4
5
6
7
8
9
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
Pd(PPh3)4
5
10
15
15
15
15
70
70
70
70
50
70
70
70
70
70
70
70
70
70
70
70
70
70
70
70
50
50
50
50
50
25
50
50
50
50
50
50
50
50
50
50
50
50
50
50
5
5
5
3
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
43
55
85 (82)
53
35
35
81
84
63
83
68
62
9
1,4-dioxane 15
DMF
15
15
15
15
15
15
15
15
15
15
15
15
15
TABLE 2. Synthesis of Various S-Aryl Thiocarbamatesa
CH3CN
CHCl3
benzene
toluene
THF
10 Pd(PPh3)4
11 Pd(PPh3)4
12 Pd(PPh3)4
13 Pd(dba)2
14 Pd(OAc)2
15 PdCl2
16 PdCl2(PPh3)2
17 PdCl2(PhCN)2 THF
18 PdCl2(CH3CN)2 THF
entry
ArSSAr
yield/%b
THF
26
23
47
23
26
23
27
THF
THF
1
2
3
4
5
6
X ) 2-CH3
X ) 3-CH3
X ) 4-CH3
X ) 4-CH3O
X ) 4-Cl
84 (78) (3b)
83 (77) (3c)
98 (95) (3d)
78 (76) (3e)
70 (68) (3f)
25 (21) (3g)
19 RhCl(PPh3)3
20 Pt(PPh3)4
THF
THF
a Reaction conditions: 1a (1 mmol), solvent (2 mL), and catalyst
(5 mol %). b GC yield based on 1a. The number in the parentheses
shows the isolated yield.
X ) 4-NO2
a Reaction conditions: diaryl disulfide (1 mmol), diethylamine
(15 mmol), Pd(PPh3)4 (5 mol %), THF (2 mL), and CO (50 atm) at
70 °C for 5 h. b GC yield based on diaryl disulfide. The numbers
in parentheses show the isolated yield.
presence of Pd(PPh3)4 (5 mol %) under a pressure of
carbon monoxide (50 atm) at 70 °C for 5 h, S-phenyl-
N,N-diethyl carbamate (3a) was obtained in 85% yield
along with the formation of benzenethiol (75%) (entry 3).
The yield of 3a was decreased when the reaction was
carried out with shorter reaction times, lower reaction
temperatures, and lower carbon monoxide pressures
(entries 3-6). The yield of 3a was also affected by the
amount of 2a (entries 1-3). Although 1a was coupled
with 2a and carbon monoxide, even using 1,4-dioxane,
DMF, CH3CN, CHCl3, benzene, and toluene instead of
THF as the solvent, the best yield was observed in the
THF solvent (entries 3 and 7-12). The other zerovalent
palladium catalyst, Pd(dba)2, divalent palladium com-
plexes, Pd(OAc)2, PdCl2, PdCl2(PPh3)2, PdCl2(PhCN)2, and
PdCl2(CH3CN)2, and other metal complexes containing
rhodium and platinum also functioned as a catalysts;
however, the yield of 3a distinctly decreased (entries 3
and 13-20). In this reaction, it is possible to still further
reduce the amount of the palladium complex (1 mol %)
The synthesis of S-alkyl thiocarbamates by the treat-
ment of dialkyl disulfide with diethylamine and carbon
monoxide in the presence of a catalytic amount of Pd-
(PPh3)4 was next examined. These results, summarized
in Table 3, showed that the reaction is amenable to the
synthesis of various S-alkyl-N,N-diethylcarbamates. When
dibutyl disulfide was allowed to react with 2a and carbon
monoxide under similar reaction conditions to that of the
diaryl disulfide, the yield of S-butyl-N,N-diethylcarbam-
ate was low (14%); however, the yield of the thiocarbam-
ate was improved by elevating the reaction temperature
and extending the reaction time (48 h) (entry 1). Simi-
larly, the di(sec-butyl), di(tert-butyl), di(cyclohexyl), and
di(benzyl) sulfides were coupled with 2a and carbon
monoxide to yield the corresponding thiocarbamates in
82-100% yields (entries 2-5).
2552 J. Org. Chem., Vol. 70, No. 7, 2005

Synthesis of Thiocarbamates
TABLE 3. Synthesis of Various S-Alkyl
SCHEME 3
SCHEME 4
Thiocarbamatesa
entry
RSSR
yield/%b
1
2
3
4
5
R ) n-C4H9
R ) s-C4H9
R ) t-C4H9
R ) c-C6H11
R ) C6H5CH2
78 (72) (3h)
89 (83) (3i)
100 (94) (3j)
100 (92) (3k)
82 (78) (3l)
a Reaction conditions: dialkyl disulfide (1 mmol), diethylamine
(15 mmol), Pd(PPh3)4(5 mol %), THF (2 mL), and CO (50 atm) at
120 °C for 48 h. b GC yield based on dialkyl disulfide. The numbers
in parentheses show the isolated yield.
TABLE 4. Synthesis of Various Thiocarbamatesa
entry
R1
R2
yield/%b
1
2
3
4
5
6
7
8
C2H5
C2H5
C2H5
i-C3H7
CH3
85 (3a)
72 (3m)
trace (3n)
trace (3o)
74 (3p)
56 (3q)
62 (3r)
i-C3H7
i-C3H7
C6H5
-(CH2)2O(CH2)2-
-(CH2)4-
-(CH2)5-
SCHEME 5
C4H9
H
0 (3s)
a Reaction conditions: PhSSPh (1 mmol), amine (15 mmol),
Pd(PPh3)4 (5 mol %), THF (2 mL), and CO (50 atm) at 70 °C for 5
h. b GC yield based on amine.
Next, diphenyl disulfide was allowed to react with
various amines in the presence of a catalytic amount of
Pd(PPh3)4 under pressurized carbon monoxide in order
to determine the application of the synthetic method of
thiocarbamates by the reaction of diphenyl disulfide with
various amines and carbon monoxide (Table 4). In the
reaction, the increase in the steric hindrance of the alkyl
group of secondary amines led to a decrease in the
thiocarbamate yield. Diethylamine and ethyl isoprop-
ylamine gave the corresponding S-phenyl-N,N-dialkyl-
carbamates in 85% and 72% yields (entries 1 and 2).
However, for the more hindered diisopropylamine or
aromatic amine, no thiocarbamate formation was ob-
served even if the reaction was carried out under harsh
reaction conditions (entries 3 and 4). S-Phenyl pyrroli-
dine, S-phenyl piperidine, and S-phenyl morpholine
carbamate were synthesized in moderate yields by the
same method (entries 5-7). On the other hand, in the
case of the primary amines, the corresponding thiocar-
bamate was not obtained and the corresponding urea was
formed (entry 8). S-Phenyl-N-butylcarbamate was not
obtained, even if the reaction was stopped after 2 h. In
addition, when S-phenyl-N-butylcarbamate was treated
with butylamine and carbon monoxide at 70 °C for 1 h,
a 75% yield of dibutyl urea and an 82% yield of diphenyl
disulfide were formed (Scheme 3).10 Based on these
results, we suggested that thiocarbamate formed in situ
was very susceptible to nucleophilic substitution by
primary amines to produce urea.
Although we cannot clearly determine the catalytic
reaction pathway for the synthesis of thiocarbamates, the
catalytic cycles shown in Schemes 4 and 5 were suggested
for the reaction. The oxidative addition of a disulfide into
a low-valent palladium species generated in situ gave the
thiopalladium species (4) as the first step in the reaction.
Jones et al. have reported the palladium-catalyzed
synthesis of thiocarbamates by the reaction of a thiol with
an amine and carbon monoxide.8 On the basis of the
kinetic study and the isolation of intermediates, they
disclosed the reaction mechanism including the insertion
of CO into the Pd-N bond.11,12 From the information
provided, we proposed the reaction pathway including the
(11) Alper et al. have reported the Co-catalyzed carbonylation of
thiazolidines, in which insertion of CO into the Co-N bond has been
proposed. See: Khumtaveeporn, K.; Alper, H. J. Am. Chem. Soc. 1994,
116, 5662.
(12) There are some reports on the insertion of CO into the metal-
nitrogen bond. See: (a) Piotti, M. E.; Alper, H. J. Am. Chem. Soc. 1996,
118, 111. (b) Rahim, M.; Bushweller, C. H.; Ahmed, K. J. Organome-
tallics 1994, 13, 4952. (c) Calet, S.; Urso, F.; Alper, H. J. Am. Chem.
Soc. 1989, 111, 931. (d) Bryndza, H. E.; Fultz, W. C.; Tam, W.
Organometallics 1985, 4, 939.
(10) When the reaction was carried out in the absence of palladium
complex or under an atmosphere of nitrogen, the yields of urea were
decreased (37% in the absence of palladium complex; 65% under the
nitrogen atmosphere).
J. Org. Chem, Vol. 70, No. 7, 2005 2553

Nishiyama et al.
organic solvent was removed under reduced pressure. Purifi-
cation by column chromatography (hexane/AcOEt (6/1)) on
silica gel gave the corresponding S-alkyl N,N-diethylthiocar-
bamates. The product was characterized by comparison of its
spectra data with those of authentic samples (3h7c and 3l7c).
The structures of the product (3i, 3j, and 3k) were assigned
ligand exchange with an amine, insertion of CO into the
Pd-N bond, and subsequent reductive elimination
(Scheme 4). On the other hand, Kuniyasu and Kurosawa
et al. have shown the palladium complex catalyzed
azathiolation of carbon monoxide using sulfeneamide.9
For the reaction, they proposed that the insertion of CO
into the Pd-S bond of Pd(SPh)2(PPh3)3, which was
generated in situ by the reaction of the palladium
complex with a sulfeneamide, providing the short-lived
Pd[C(O)SPh](SPh)(PPh3)3, was a key step in the reaction.
From this information, an alternative reaction pathway
involving the insertion of carbon monoxide into the
palladium-sulfur bond of 4, ligand exchange with the
amine, and subsequent reductive elimination cannot be
ruled out (Scheme 5).
1
by their H and 13C NMR and IR spectra.
S-sec-Butyl-N,N-diethylthiocarbamate (3i). 1H NMR
(CDCl3) δ 0.98 (t, J ) 7.2 Hz, 3H), 1.25 (m, 6H), 1.33 (d, J )
6.8 Hz, 3H), 1.56-1.71 (m, 4H), 3.38-3.51 (m, 3H). 13C NMR
(CDCl3) δ 11.6, 13.3, 21.3, 29.7, 29.9, 30.0, 41.6, 42.0, 167.1.
IR (neat) 666, 860, 1115, 1250, 1380, 1405, 1461, 1650, 2933,
2969 cm-1. Anal. Calcd for C9H19NOS: C, 57.10; H, 10.12; N,
7.40. Found: C, 56.83; H, 10.38; N, 7.45.
S-tert-Butyl-N,N-diethylthiocarbamate (3j). 1H NMR
(CDCl3) δ 1.15 (t, J ) 6.8 Hz, 6H), 1.51 (s, 9H), 3.48 (q, J )
6.8 Hz, 4H). 13C NMR (CDCl3) δ 13.5, 30.6, 47.2, 167.2. IR
(neat) 859, 1112, 1248, 1361, 1403, 1460, 1644, 1742, 2854,
2925 cm-1. Anal. Calcd for C9H19NOS: C, 57.10; H, 10.12; N,
7.40. Found: C, 57.26; H, 10.45; N, 7.26.
In summary, from the viewpoint of a simple operation,
mild reaction conditions, and good yields, the present
reaction provides a useful method for the synthesis of
thiocarbamates.
S-Cyclohexyl-N,N-diethylthiocarbamate (3k). 1H NMR
(CDCl3) δ 1.16 (t, J ) 6.4 Hz, 6H), 1.12-1.39 (m, 1H), 1.43 (q,
J ) 6.4 Hz, 4H), 1.57-1.61 (m, 1H), 1.69-1.77 (m, 2H), 1.98-
2.02 (m, 2H), 3.36-3.45 (m, 5H). 13C NMR (CDCl3) δ 13.4, 25.7,
26.2, 33.9, 42.1, 43.6, 166.9. IR (neat) 665, 755, 859, 1097, 1116,
Experimental Section
1221, 1248, 1380, 1405, 1449, 1650, 2853, 2932, 2974 cm-1
.
General Procedure for the Pd(PPh3)4-Catalyzed Reac-
tion of Diaryl Disulfide with Diethylamine and Carbon
Monoxide. In a 50 mL stainless steel autoclave were placed
diaryl disulfide (1.0 mmol), diethylamine (1.5 mL, 15.0 mmol),
Pd(PPh3)4 (58 mg, 0.05 mmol), and THF (2 mL). The autoclave
was then flushed several times with carbon monoxide and
finally charged with carbon monoxide at 50 atm at room
temperature. The reaction was carried out at 70 °C for 5 h
maintaining the pressure of carbon monoxide. After the
reaction was complete, di(isopropyl) ether (ca. 30 mL) was
added to the crude reaction mixture. The brown precipitate
was removed through Celite. The residual filtrate was con-
centrated in vacuo, and the residual mixture was purified by
column chromatography on silica gel using hexane/AcOEt
(6/1) as eluent giving the corresponding S-aryl N,N-diethyl-
thiocarbamates. The product was characterized by comparison
of its spectra data with those of authentic samples (3a,7c 3b,13
3c,14 3d9, 3f,9 and 3g15). The structure of product (3e) was
Anal. Calcd for C11H21NOS: C, 61.35; H, 9.83; N, 6.50.
Found: C, 61.74; H, 9.65; N, 6.71.
General Procedure for the Pd(PPh3)4-Catalyzed Three-
Component Coupling of Diphenyl Disulfide with Sec-
ondary Amines and Carbon Monoxide. In a 50 mL
stainless steel autoclave, diphenyl disulfide (0.218 g, 1.0
mmol), amines (15.0 mmol), Pd(PPh3)4 (58 mg, 0.05 mmol), and
THF (2 mL) were placed under a nitrogen atmosphere. The
autoclave was then flushed several times with carbon mon-
oxide and finally charged with carbon monoxide at 50 atm at
room temperature. The reaction was carried out at 70 °C for
5 h maintaining the pressure of carbon monoxide. After the
reaction was complete, the resulting solution was dried over
MgSO4. The organic solvent was removed under reduced
pressure. Purification by column chromatography (hexane/
AcOEt (6/1)) on silica gel gave the corresponding S-phenyl
thiocarbamates. The product was characterized by comparison
of its spectral data with those of authentic samples (3p,16 3q,7c
and 3r7c). The structure of the product (3m) was assigned by
1
assigned by its H and 13C NMR and IR spectra.
S-4-Methoxyphenyl-N,N-diethylthiocarbamate (3e). 1H
NMR (CDCl3) δ 1.15-1.26 (m, 6H), 3.40 (q, J ) 7.1 Hz, 4H),
3.79 (s, 3H), 6.88-6.92 (m, 2H), 7.38-7.42 (m, 2H). 13C NMR
(CDCl3) δ 13.1, 13.6, 42.2, 55.1, 54.9, 114.3, 119.3, 137.1, 160.2,
166.1. IR (neat) 537, 661, 827, 854, 1018, 1030, 1095, 1115,
1173, 1218, 1246, 1290, 1404, 1461, 1495, 1593, 1661, 2935,
2974 cm-1. Anal. Calcd for C12H17NO2S: C, 60.02; H, 7.16; N,
5.85. Found: C, 60.37; H, 7.53; N, 5.62.
1
its H and 13C NMR and IR spectra.
S-Phenyl-N,N-ethylisopropylthiocarbamate (3m). 1H
NMR (CDCl3) δ 1.10-1.25 (m, 9H), 3.24-3.34 (m, 2H), 4.20-
4.45 (m, 1H), 7.36-7.41 (m, 3H), 7.44-7.53 (m, 2H). 13C NMR
(CDCl3) δ 15.9, 20.9, 35.5, 35.5, 49.0, 128.4, 128.7, 128.8, 131.9,
132.0, 135.6, 163.1. IR (neat) 689, 748, 810, 848, 1090, 1109,
1209, 1252, 1277, 1335, 1378, 1401, 1440, 1661, 2935, 2974
cm-1. Anal. Calcd for C12H17NOS: C, 64.53; H, 7.67; N, 6.27.
Found: C, 67.71; H, 7.65; N, 6.37.
General Procedure for the Pd(PPh3)4-Catalyzed Three-
Component Coupling of Dialkyl Disulfides with Dieth-
ylamine and Carbon Monoxide. In a 50 mL stainless steel
autoclave, dialkyl disulfide (1.0 mmol), diethylamine (1.5 mL,
15.0 mmol), Pd(PPh3)4 (58 mg, 0.05 mmol), and THF (2 mL)
were placed under a nitrogen atmosphere. The autoclave was
then flushed several times with carbon monoxide and finally
charged with carbon monoxide at 50 atm at room temperature.
The reaction was carried out at 120 °C for 48 h maintaining
the pressure of carbon monoxide. After the reaction was
complete, the resulting solution was dried over MgSO4. The
Acknowledgment. This research was supported by
a Grant-in-Aid for Science Research (No.15550096) and
the Research and Development Organization of Industry-
University Cooperation from the Ministry of Education,
Culture, Sports, Science and Technology of Japan.
Supporting Information Available: Characterization of
products. This material is available free of charge via the
Internet at http://pubs.acs.org.
JO048350H
(13) Beaulieu, F.; Snieckus, V. Synthesis 1992, 112.
(14) Minnemeyer, H. J.; Clarke, P. B.; Tieckelmann, H. J. Org.
Chem. 1966, 31, 406.
(16) Kim, Y.-H.; Chung, B.-C.; Chang, H.-S. Tetrahedron Lett. 1985,
26, 1079.
(15) Miyazaki, K. Tetrahedron Lett. 1968, 2793.
2554 J. Org. Chem., Vol. 70, No. 7, 2005