3292
F. P. Ballistreri et al. / Tetrahedron Letters 49 (2008) 3291–3293
MTO
high yields by an efficient, simple, environmentally friendly,
and mild protocol.
R-SH
+
3H
2
O
2
>
R-SO
3
H
2
+ 3H O
CH
3
CN, 20 °C
Scheme 1. Oxidation of aromatic and aliphatic thiols to sulfonic acids.
Acknowledgement
We thank M.I.U.R. and the University of Catania for
financial support.
Table 1
Oxidation of thiols with CH
a
3
ReO
3
2 2 3
/H O in CH CN at 20 °C
Entry
Substrate
Product
Isolated
References and notes
yields (%)
1
. Kalir, A.; Kalir, H.H. In Biological Activity of Sulphonic Acid
Derivatives; Patai, S., Rappoport, Z., Eds.; 1991; pp 767–787.
. (a) Hoyle, J. In The Chemistry of Sulphonic Acids, Esters and Their
Derivatives; Patai, S., Rappoport, Z., Eds.; 1991; pp 351–399; (b)
Capozzi, G.; Modena, G. In The Chemistry of the Thiol Group; Patai,
S., Ed.; 1974; pp 785–839; Evans, B. J.; Doi, J. T.; Musker, K. J. Org.
Chem. 1990, 55, 2337–2344; (c) unpublished work from this
laboratory.
1
2
3
4
5
6
7
8
9
C
6
H
5
SH
4-CH -C
4-OCH -C
4-NO -C
4-Cl-C
CH
C
6
H
5
SO
4-CH -C
4-OCH -C
4-NO -C
4-Cl-C
CH
2-Naph-SO
3
H
85
87
91
3
6
H
5
SH
SH
SH
3
6
H
5
SO
SO
SO
SO
SO
3
H
2
3
6
H
5
3
6
H
5
3
H
b
2
6
H
5
2
6
H
5
3
H
92
6
H
5
SH
SH
6
H
5
3
H
H
85
93
94
C
6
H
5
2
C
6
H
5
2
3
2-Naph-SH
CH
CH
3
H
b
3
(CH
(CH
2
)
)
10CH
16CH
2
SH
SH
CH
CH
C
3
(CH
(CH
2
)
)
10CH
16CH
2
SO
SO
3
H
H
90
c
3. Hajipour, A. R.; Mirjalili, Bi Bi F.; Zarei, A.; Khazdooz, L.; Ruoho,
3
2
2
3
2
2
3
91
d
A. E. Tetrahedron Lett. 2004, 45, 6607–6609.
. Smith, K.; Hou, D. J. Org. Chem. 1996, 61, 1530–1532.
. Shefer, N.; Carmeli, M.; Rozen, S. Tetrahedron Lett. 2007, 48, 8178–
10
C
6
H
5
SH
General reaction conditions: thiol (1.2 mmol), H
CN (10 mL), 20 °C (t = 1/4–2 h), conversion
6
H
5
SO
3
H
88
4
5
a
2
2
O (30%, 12 mmol),
MTO (0.12 mmol), CH
00%.
3
8
181 and references therein.
. (a) Wang, X.; Chang, S.; Chan, C. C. J. Phys. Chem. C 2007, 111,
156–2164; (b) Margoles, D.; Melero, J. A.; Christiansen, S. C.;
1
6
b
3 3
In CHCl /CH CN (20/80).
In THF.
Reaction conditions: thiol (1.2 mmol), H
2
c
Chmelka, B. F.; Stucky, G. D. Chem. Mater. 2000, 12, 2448–2459; (c)
Cano-Serraro, E.; Campos-Martin, J. M.; Fierro, J. L. G. Chem.
Commun. 2003, 246–247; (d) Cano-Serraro, E.; Blanco-Brieva, G.;
Campos-Martin, J. M.; Fierro, J. L. G. Langmuir 2003, 19, 7621–
d
2 2
O (30%, 12 mmol), MTO
(
0.012 mmol), CH
3
CN (10 mL), 20 °C (t = 1/2 h), conversion 100%.
7
627.
The data reported in Table 1 are the first examples of the
7. Colladon, M.; Scarso, A.; Sgarbossa, P.; Michelin, R. A.; Strukul, G.
direct transformations of thiols to sulfonic acids catalyzed
by MTO. It is interesting to note that the reaction works as
well with short reaction times and in good yields employing
J. Am. Chem. Soc. 2007, 129, 7680–7689 and references therein.
. Lahti, D. W.; Espenson, J. H. Inorg. Chem. 2000, 39, 2164–2167 and
references therein.
8
9
. (a) Al-Ajlouni, A. M.; Espenson, J. H. J. Am. Chem. Soc. 1995, 117,
1
% of catalyst instead of 10% (entries 1 and 10).
9
243–9250; (b) Herrmann, W. A.; Fischer, R. W.; Marz, D. W.
Other metals than rhenium lead to the formation of the
Angew. Chem., Int. Ed. Engl. 1991, 30, 1638–1641; (c) Adam, W.;
Saha-Moller, C. R.; Weichold, O. J. Org. Chem. 2000, 65, 5001–5004;
2
corresponding disulfides. As a matter of fact, molybde-
num oxo diperoxo complex MoO(O ) HMPA oxidizes
(
d) Kuhn, F. E.; Scherbaum, A.; Hermann, W. A. J. Organomet.
2
2
Chem. 2004, 689, 4149–4164.
C H CH SH exclusively to the corresponding disulfide in
6
5
2
1
0. (a) Adam, W.; Hermann, W. A.; Lin, J.; Saha-Moller, R. C. Angew.
Chem. Int., Ed. Engl. 1994, 33, 2475–2477; (b) Bianchini, G.;
Crucianelli, M.; De Angelis, F.; Neri, V.; Saladino, R. Tetrahedron
Lett. 2005, 46, 2427–2432.
2
c
CH CN at 25 °C, according to the lower reactivity of
3
Mo(VI) diperoxo complex compared with that of the
corresponding rhenium diperoxo derivative.
1
1
1
1. (a) Zhu, Z.; Espenson, J. H. J. Org. Chem. 1995, 60, 1326–1332; (b)
Moreover, electron-donating or withdrawing groups on
the aromatic ring do not affect the efficiency of the reaction
entries 1–5).
Murray, R. W.; Iyanar, K.; Chen, J.; Wearing, J. T. J. Org. Chem.
1
996, 61, 8099–8102.
(
2. (a) Adam, W.; Mitchell, C. M.; Saha-Moller, C. R. J. Org. Chem.
1999, 64, 3699–3707; (b) Adam, W.; Mitchell, C. M.; Saha-Moller, C.
R. Eur. J. Org. Chem. 1999, 785–790.
3. (a) Lasalvia, M.; Musumeci, D.; Piccialli, V.; Sica, D. J. Chem. Res.
(S) 1998, 694–695; (b) Ballistreri, F. P.; Chillemi, R.; Sciuto, S.;
Tomaselli, G. A.; Toscano, R. M. Steroids 2006, 71, 565–577.
4. Adam, W.; Saha-Moller, C. R.; Weichold, O. J. Org. Chem. 2000, 65.
The two oxidation steps leading to sulfonic acids from
thiols can start from a proton-coupled electron transfer
leading to disulfides (a) or from an S-oxygen transfer step
2
b
(
b), respectively:
1
1
Å
RSH ! RS ! RSSR !!! RSO H
ðaÞ
ðbÞ
3
5
001–5004 and references therein.
5. The following general oxidation procedure was applied to all thiols
reported in Table 1. To a solution of 30% hydrogen peroxide
RSH ! ðRSOHÞ ! RSO
2
H ! RSO
3
H
(
3
12 mmol, 10 equiv) in CH CN (3 mL) at 20 °C was added a solution
We are not able at this stage to suggest a mechanism for
the oxidation reaction of thiols to sulfonic acids by H O /
MTO, even if the not detected intermediate disulfides in the
oxidation step might indicate the pathway (b) as more
probable.
of methyltrioxorhenium (Aldrich) (0.12 mmol, 0.1 equiv) in CH CN
(2 mL). This yellow mixture was stirred for 1 min. Then a solution of
3
2
2
thiol (1.2 mmol, 1 equiv) in CH
stirring was continued for a suitable reaction time. After completing
the reaction (monitored by TLC), a catalytic amount of MnO was
3
CN (5 mL) was added and the
2
16
added. The organic phase was concentrated under reduced pressure
to afford the crude product, which was purified by column
chromatography (chloroform and acetonitrile as eluents) over silicic
In conclusion, the oxidant system MTO/H O provides
2
2
a new entry for the synthesis of sulfonic acids from thiols in