922
M. Arisawa et al. / Tetrahedron Letters 52 (2011) 920–922
Table 2
1-alkylthio-1-alkynes proceeded with 1,3-butadiynes, 1-decyne,
and (t-butylthio)ethyne. The carbothiolation reaction of 1-alkyl-
thio-1-alkynes has not yet been identified. The C–C bond formation
occurred at the less hindered carbon atom of alkynes (Fig. 2) with
the cis-stereochemistry.
In a two-necked flask equipped with a reflux condenser were
placed tetrakis(triphenylphosphine)hydriderhodium (5 mol %,
17.3 mg), dimethylphenylphosphine (15 mol %, 6.4 lL), 1-butyl-
thio-2-(triisopropylsilyl)ethyne 2 (0.30 mmol, 81.2 mg) and 1,4-
bis(4-methoxyphenyl)-1,3-butadiyne 1 (0.30 mmol, 78.7 mg) in
1,3-dimethyl-2-imidazolidinone (0.75 mL) under an argon atmo-
sphere, and the solution was heated at 135 °C for 6 h. Then, the sol-
vent was removed under reduce pressure, and the residue was
purified by flash column chromatography on silica gel giving (Z)-
3 (105.3 mg, 66%).
Rhodium-catalyzed carbothiolation reaction of 1-organothio-1-alkynes and 8
R2
St-Bu
R1S
R2
RhH(PPh3)4 (10 mol%)
dppb (30 mol%)
R1S
R1S
+
+
DMI, 75 °C., 6 h
t-BuS
t-BuS
t-BuS
H
(E)-10
(Z)-9
8
Entry
R1
R2
Yield (%)
(E)-10
(Z)-9
1
2
3
4
5
n-C4H9
n-C6H13
Ph
i-Pr3Si
i-Pr3Si
i-Pr3Si
50
42
39
34
17
16
15
Trace
14
4
n-C6H13
n-C6H13
2,4,6-Me3C6H2
1-Adamantyl
Acknowledgments
This work was supported by a Grant-in-Aid for Scientific
Research (No. 21229001), the GCOE program, and the WPI Initia-
tive from JSPS. M.A. expresses her thanks to the Grant-in-Aid for
Scientific Research (No. 22689001) and to the Asahi Glass
Foundation.
Ar
Ar
n-C8H17
H
t-BuS
H
Figure 2. The C–C bond formation sites in the carbothiolation reaction.
Supplementary data
Me2PhP (15 mol %) in DMI at 135 °C for 6 h, the (E)-adduct was
obtained in 75% yield without forming the (Z)-isomer (Scheme
3). In addition, no isomerization of (Z)-6 to (E)-6 was observed un-
der the rhodium-catalyzed conditions.
Supplementary data associated with this article can be found, in
1-(t-Butylthio)acetylene 8 was a good substrate for the carbo-
thiolation reaction. The reaction of 2 and 8 gave (Z)-4-(butyl-
thio)-4-(t-butylthio)-1-triisopropylsilyl-3-buten-1-yne (Z)-9a in
50% yield, which was accompanied by (E)-4-(butylthio)-1,4-bis(t-
butylthio)-3-buten-1-yne (E)-10a in 16% yield (Scheme 4). The
structure of (E)-10a was determined by NOE and HMBC experi-
ments. The minor product (E)-10a was formed by the butylthio
transfer from 2 to 8 giving 1-(t-butylthio)-2-butylthioacetylene
11, which underwent the carbothiolation reaction with 8. The
mechanism was confirmed by an independent reaction of 11 and
References and notes
1. A review. Kuniyasu, H.; Kambe, N. J. Synth. Org. Chem. Jpn. 2009, 67, 701.
2. Choi, N.; Kabe, Y.; Ando, W. Tetrahedron Lett. 1991, 32, 4573.
3. Hua, R.; Takeda, H.; Onozawa, S.; Abe, Y.; Tanaka, M. J. Am. Chem. Soc. 2001, 123,
2899.
4. Toyofuku, M.; Fujiwara, S.; Shin-ike, T.; Kuniyasu, H.; Kambe, N. J. Am. Chem.
Soc. 2005, 127, 9706.
5. Kamiya, I.; Kawakami, J.; Yano, S.; Nomoto, A.; Ogawa, A. Organometallics 2006,
25, 3562.
6. Minami, Y.; Kuniyasu, H.; Miyafuji, K.; Kambe, N. Chem. Commun. 2009, 3080.
7. Sugoh, K.; Kuniyasu, H.; Sugae, T.; Ohtaka, A.; Takai, Y.; Tanaka, A.; Machino, C.;
Kambe, N.; Kurosawa, H. J. Am. Chem. Soc. 2001, 123, 5108. and references cited
therein.
8. Hua, R.; Takeda, H.; Onozawa, S.; Abe, Y.; Tanaka, M. Org. Lett. 2007, 9, 263.
9. Nakamura, I.; Sato, T.; Yamamoto, Y. Angew. Chem., Int. Ed. 2006, 45, 4473;
Nakamura, I.; Sato, T.; Terada, M.; Yamamoto, Y. Org. Lett. 2008, 10, 2649.
10. Arisawa, M.; Fujimoto, K.; Morinaka, S.; Yamaguchi, M. J. Am. Chem. Soc. 2005,
127, 12226.
11. Arisawa, M.; Kubota, T.; Yamaguchi, M. Tetrahedron Lett. 2008, 49, 1975.
12. Arisawa, M.; Toriyama, F.; Yamaguchi, M. Chem. Pharm. Bull. 2010, 58, 1349.
13. Crystal Data Monoclinic Pa, Cell Dimensions: a = 18.943(7), b = 11.891(5),
c = 24.688(10) Å, b = 96.535(2)°, Z = 8, T = 173 K, Crystallographic data
excluding structure factors have been deposited with the Cambridge
Crystallographic Data Centre as supplementary publication number CCDC
795726. A copy of the data can be obtained free of charge from CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK or e-mail: deposit@ccdc.cam.ac.uk.
8
giving (E)-10a (Scheme 5). Similarly to that of 1-decyne
5(Scheme 2), the C–C bond formation of 8 occurred at the terminal
carbon by cis-addition. The high reactivity of 8 compared with
1-decyne 5 may be partly due to the interaction of the sulfur atom
with rhodium.
Several 1-alkylthio- and 1-phenylthio-1-alkynes were reacted
with 8, and the carbothiolated products (Z)-9 were obtained as
well as butylthio transfer products (E)-10 (Table 2). Not only triiso-
propylsilylacetylene but also 2,4,6-trimethylphenylacetylene and
(1-adamantyl)acetylene underwent the carbothiolation reaction
with 8.
In summary, in the presence of a rhodium complex and an
appropriate phosphine ligand, the carbothiolation reaction of