Total Synergistic effect between triflic acid and bismuth(IIIr antimony(III) chlorides in catalysis of the Methanesulfonylation of Arenes

Article abstract of DOI:10.1002/ejoc.200400369

A total synergistic effect between bismuth(III) or antimony(III) chlorides and triflic acid has been observed in the Friedel-Crafts methanesulfonylation of arenes and has resulted in the development of the first efficient catalytic systems usable for the methanesulfonylation of both activated and deactivated arenes. A proposed mechanism to explain the observed effects is also discussed. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.

Full text of DOI:10.1002/ejoc.200400369

FULL PAPER
Total Synergistic Effect between Triflic Acid and Bismuth(III) or Antimony(III
Chlorides in Catalysis of the Methanesulfonylation of Arenes
)
[a]
[b]
[c]
[a]
´ `
´
`
Magali Peyronneau, Marie-Therese Boisdon, Nicolas Roques, Stephane Mazieres,*
and Christophe Le Roux*[a]
Keywords: Alkylsulfonylation / Catalysis / FriedelϪCrafts reaction / Triflic acid
A total synergistic effect between bismuth(III) or antimony(III
)
and deactivated arenes. A proposed mechanism to explain
the observed effects is also discussed.
chlorides and triflic acid has been observed in the
Friedel−Crafts methanesulfonylation of arenes and has re-
sulted in the development of the first efficient catalytic sys-
tems usable for the methanesulfonylation of both activated
( Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2004)
Introduction
fluorobenzene (9), benzene (10), chlorobenzene (11), o-di-
chlorobenzene (12), 1,3-difluorobenzene (13), o-fluorotolu-
ene (14), m-fluorotoluene (15) and p-fluorotoluene (16) (for
purposes of clarity these results are not shown in the table).
When system A or system B was used, however, an exother-
mic reaction occurred and a mixture of methyltolylsulfones
(17) was obtained in almost quantitative yields, ac-
companied by the release of hydrogen chloride (Table 1, En-
tries 2, 3). From testing of different ratios of 1, 2 and 3 in
the two systems it appeared that 10% mol is an optimum
amount for each component of these systems. The yields of
the sulfones (17؊29) obtained from various arenes (4؊16)
and methanesulfonyl chloride[7] are summarized in Table 1.
From these results one can conclude that system A is
able to catalyse the methanesulfonylation of various arenes
efficiently. In the case of m-xylene (7), the yield of the sul-
fone is lowered by the formation of tarry products, as pre-
viously reported.[9] Moreover, our results obtained for the
Trifluoromethanesulfonic acid (1) is a well known and
efficient superacid catalyst for FriedelϪCrafts reactions of
arenes.[1] Its catalytic activity can be enhanced by com-
plexation with metallic halides[1] or triflates.[2] In addition,
we recently reported that the catalytic activity of 1, which
is a poor catalyst for FriedelϪCrafts arylsulfonylation,[3]
could be improved by doping with BiCl3 (2).[4] Although
numerous catalysts for FriedelϪCrafts arylsulfonylation of
arenes have been reported,[5] few catalytic methods for the
preparation of alkyl sulfones are available.[5f,5h,6] Here we
report that extreme synergy between 1 and 2 (system A) or
between 1 and SbCl3 (3) (system B) has resulted in the first
efficient catalytic system for the methanesulfonylation of
arenes with the commercially available methanesulfonyl
chloride.
Results and Discussion
methanesulfonylation of p-xylene (8) with system
A
(Table 1, Entry 10) are similar to those recently reported by
Olah et al. with MsOH and Nafion-H, while system B pro-
ved to be less efficient (Table 1, Entry 11).[10] In analogy
with our previous work, we propose the mechanism shown
in Scheme 1, which is supported by the following obser-
vations: Step (a) concerns the reaction between 1 and 2 (sys-
Bismuth() chloride (2)[5f] is not an efficient catalyst for
the arylsulfonylation of arenes and, just as 1[3] and 3, pro-
ved to be inactive for the methanesulfonylation of toluene
(4) (Table 1, Entry 1) and a variety of other arenes such as
mesitylene (5), o-xylene (6), m-xylene (7), p-xylene (8),
tem A), which gives rise to the mixed bismuth chlorotriflates
[a]
´ ´
´
Laboratoire Heterochimie Fondamentale et Appliquee
[5f,11]
BiCln(OTf)3Ϫn
.
Step (b) involves the ligand exchange
´
(UMR-CNRS 5069), Universite Paul-Sabatier,
between the mixed bismuth() chlorotriflate[13] and
methanesulfonyl chloride, resulting in the regeneration of 2
and production of the mixed trifluoromethanesulfonic
methanesulfonic anhydride (MeSO2OTf) (30).[14] In step (c),
30 reacts with the arene to generate 1 and the methylsul-
fone. A similar mechanism is involved in the case of system
118 route de Narbonne, 31062 Toulouse Cedex 04, France
Fax: (internat.) ϩ33-5-61558204
E-mail: leroux@chimie.ups-tlse.fr
[b]
[c]
´
´
Institut Moleculaire de Chimie (FR-CNRS 1744), Universite
Paul-Sabatier,
118 route de Narbonne, 31062 Toulouse Cedex 04, France
Rhodia Organique Fine, Centre de Recherche de Lyon,
`
85 avenue des Freres-Perret, 69192 Saint-Fons Cedex, France
4636
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/ejoc.200400369
Eur. J. Org. Chem. 2004, 4636Ϫ4640

Enhanced Catalysis of the Methanesulfonylation of Arenes by Metal Halides
FULL PAPER
B, the mixed antimony chlorotriflate compound being
SbCl2OTf.[12] Interestingly, with system B almost no reac-
tion takes place in the case of 5 (Entry 5), while this system
proved to be efficient with fluorobenzene (9) (Entry 13).
Mesitylene (5) is a strong π donor arene capable of generat-
ing Menschutkin complexes, which are most probably in-
volved in deactivation of the catalyst.[15] When 10% mol of
pure SbCl2OTf[12] was used in the methanesulfonylation of
5, a 9% yield of methyl 2Ј,4Ј,6Ј-trimethylphenyl sulfone (18)
was isolated (same conditions than for Entry 5), indicating
that the deactivation of the system B arises from the inhi-
bition of the reaction between 1 and 3 through its com-
plexation with 5 (step a). In the case of 9, the difference
between the two systems stems from the solubility of 3 in
aromatics (a consequence of the respective ionic and coval-
ent natures of 2 and 3).[16] System B was therefore used for
the methanesulfonylation of various fluoroarenes (Table 1,
Entries 21Ϫ23).
Table 1. Catalytic methanesulfonylation of arenes
Entry
ArH[a]
Cat.
Temp. °C,[b]
(time, days)
Product[c]
(yield, %)[d]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
4
4
1 or 2 or 3
120 (1.5)
120 (1.5)
120 (1.5)
120 (0.7)
120 (0.7)
120 (3)
120 (3)
120 (1)
120 (1)
120 (3)
120 (3)
105 (3)
105 (3)
105 (6)
105 (6)
125 (7)
105 (7)
130 (7)
130 (7)
110 (7)
120 (4)
120 (7)
120 (7)
17 (0)
A[e]
B[f]
A
B
17 (92)
17 (92)
18 (80)
18 (8)
4
5
5
6
A
B
A
B
A
B
A
B
A
B
A
B
19 (87)
19 (18)
20 (31)
20 (12)
21 (91)
21 (45)
22 (0)
22 (97)
23 (94)
23 (91)
24 (78)
24 (73)
25 (19)
25 (13)
26 (93)
27 (87)
28 (71)
29 (89)
6
7
7
8
8
It may be noted that the reaction times for both systems
are quite long, and since the amount of the alkyl sulfone
increases during the course of the reaction, one might hy-
pothesize that this compound could interact strongly with
2 or 3 or the mixed chlorotriflate intermediate species, re-
sulting in a progressive deactivation of the catalytic system.
Indeed, when the methanesulfonylation of 4 (same con-
ditions as for Entries 2 and 3) was conducted in the pres-
ence of 0.6 equivalent of the sulfone 18, the yield of 17
dropped to 15% in both cases. An infrared study conducted
in toluene ([c]ϭ 86 m) revealed that 18 (νSO2asym. ϭ 1318
cmϪ1, νSO2sym. ϭ 1151 cmϪ1) is strongly complexed by 2
and 3, resulting in a shift of both symmetrical and unsym-
metrical absorption bands of SO2 to lower frequencies (for
the mixture 18ϩ2: νSO2asym.ϭ 1295 cmϪ1, νSO2sym.ϭ 1132
9
9
10
10
11
11
12
12
13
14
15
16
A
B
B
B
B
B
[a]
ArH/MeSO2Cl/cat. ϭ 3:1/0.1 mol %, arenes are: toluene (4),
mesitylene (5), o-xylene (6), m-xylene (7), p-xylene (8), fluoroben-
zene (9), benzene (10), chlorobenzene (11), o-dichlorobenzene (12),
m-difluorobenzene (13), o-fluorotoluene (14), m-fluorotoluene (15),
[b]
[c]
and p-fluorotoluene (16).
Temperature of the oil bath. Prod-
ucts are: mixture of methyl methylphenyl sulfones 17, methyl 2,4,6- cmϪ1; for the mixture 18ϩ3: νSO2asym. ϭ 1301 cmϪ1, νSO
sym.
ϭ 1142 cmϪ1). In addition, the respective amounts of
trimethylphenyl sulfone (18), mixture of dimethylphenyl methyl sul-
2
fones 19Ϫ21, mixture of fluorophenyl methyl sulfones 22, methyl
free and complexed sulfone were estimated by deconvol-
phenyl sulfone (23), mixture of chlorophenyl methyl sulfones 24,
ution calculations.[17]
mixture of dichlorophenyl methyl sulfones 25, mixture of difluoro-
phenyl methyl sulfones 26, mixture of fluoromethylphenyl methyl
[d]
sulfones 27Ϫ29.
Isolated yield in ArSO2Me; for the determi-
[e]
nation of isomer ratios see Exp. Sect.
Cat. A ϭ BiCl3/TfOH.
Conclusion
[f] Cat. B ϭ SbCl3/TfOH.
In conclusion, total synergistic effects between triflic acid
and bismuth() chloride or antimony() chloride in the
catalytic FriedelϪCrafts methanesulfonylation of arenes
have been observed, these metal chlorides acting as shuttles
for triflate ligands. The screening of other catalytic systems
is currently underway.
Experimental Section
General Remarks: All experiments were carried out under argon
by use of standard Schlenk techniques. Arenes were purified by
conventional methods, and methanesulfonyl chloride was used as
received. Triflic acid was distilled twice over pure sulfuric acid,
stored under argon and added to the reaction mixture by syringe.
Commercially available bismuth() and antimony() chlorides
were dried by the following procedure: i) heating at reflux over
thionyl chloride for 1 h, ii) evaporation of thionyl chloride under
Scheme 1
Eur. J. Org. Chem. 2004, 4636Ϫ4640
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 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4637

`
M. Peyronneau, M.-T. Boisdon, N. Roques, S. Mazieres, C. Le Roux
FULL PAPER
reduced pressure (0.05 mm of Hg) at room temp., and iii) removal GC: 2 peaks, tR ϭ 4.94 (20b), 5.16 (20a) min (ratio 1:2 ϭ 81:19).
of the traces of thionyl chloride under reduced pressure (0.05 mm
MS (EI): m/z (%) of 20a ϭ 184 (72) [Mϩ·], 169 (35), 121 (45), 105
of Hg) at 80 °C [for bismuth() chloride] or 50 °C [for anti-
(100), 104 (11), 103 (31), 91 (24), 79 (42), 78 (29), 77 (59), 65 (15),
mony() chloride]. GC experiments were carried out with a 63 (18), 51 (21), 39 (23). MS (EI): m/z (%) of 20b: 184 (100) [Mϩ·],
HewlettϪPackard 6890 chromatograph fitted with a 30 ϫ 0.32 ϫ
0.25 column (methyl silicone doped with 5% phenyl silicone). GC-
169 (13), 121 (73), 105 (87), 104 (34), 103 (54), 91 (29), 79 (44), 78
(66), 77 (71), 65 (23), 63 (23), 51 (29), 39 (32). 1H NMR of the
MS experiments were performed with a HewlettϪPackard MS mixture of 20a, 20b and 20c (400 MHz, CDCl3): δ ϭ 2.35 (s,
5989 apparatus (EI 70 eV) fitted with a HewlettϪPackard 6890
chromatograph. 1H NMR spectra were recorded with a Bruker AM
400 spectrometer. Chemical shifts are reported in ppm downfield
from tetramethylsilane with the solvent resonance as the internal
C2ϪMe, 20a), 2.36 (s, C3,5ϪMe, 20c), 2.63 (s, C4ϪMe, 20a), 2.67
(s, C2,6ϪMe, 20b), 2.99 (s, SO2Me, 20c), 3.01 (s, SO2Me, 20a), 3.03
(s, SO2Me, 20b), 6.95Ϫ7.15 (m, C3,5H, 20a and C3,5H, 20b), 7.21
(m, C4H, 20c), 7.29 (t, J ϭ 7.7 Hz, C4H, 20b), 7.50 (s, C2,6H, 20c),
1
standard (deuteriochloroform: δ ϭ 7.26 ppm). 13C NMR spectra 7.86 (d, J ϭ 7.9 Hz, C6H, 20a); ratio 20a/20b/20c estimated by H
were recorded with a Bruker AM 400 spectrometer with complete
proton decoupling. Chemical shifts are reported in ppm downfield
from tetramethylsilane with the solvent resonance as the internal
standard (deuteriochloroform: δ ϭ 77.0 ppm). 19F NMR spectra
were recorded on Bruker AC 200 or ARX 400 spectrometers.
Chemical shifts are reported in ppm with trifluoroacetic acid as the
internal standard. Resonances were assigned by standard 2D NMR
correlation experiments (COSY, HMBC, HMQC). All known com-
pounds (18, 23) had characteristics identical to those previously re-
ported.[6c,18,19]
NMR ϭ 75:21:4. 13C NMR (100 MHz, CDCl3): δ ϭ 20.3 (C2Me,
20a), 21.4 (C3,5Me, 20c), 21.5 (C4Me, 20a), 23.1 (C2,6Me, 20b), 44.0
(CϪSO2Me, 20a), 44.4 (CϪSO2Me, 20b), 44.6 (CϪSO2Me, 20c),
125.0 (C2,6H, 20c), 127.5 (C5H, 20a), 129.5 (C6H, 20a), 131.7
(C3,5H, 20b), 132.9 (C4H, 20b), 133.6 (C3H, 20a), 135.5 (C4H, 20c),
136.0 (CϪSO2Me, 20a), 137.5 (C2Me of 20a and CϪSO2Me of
20b), 139.7 (C2,6Me, 20b), 144.7 (C4Me, 20a).
2,5-Dimethylphenyl Methyl Sulfone (21): GC: tR ϭ 5.04 min. MS
(EI): m/z (%) ϭ 184 (94) [Mϩ·], 135 (61), 169 (23), 121 (61), 105
(100), 104 (42), 103 (43), 79 (49), 78 (44), 77 (62), 51 (22), 39 (20).
1H NMR (400 MHz, CDCl3): δ ϭ 2.34 (s, 3 H, C5Me), 2.62 (s, 3
H, C2Me), 3.02 (s, 3 H, SO2Me), 7.18 (d, J ϭ 7.7 Hz, 1 H, C3H),
Methyl 2-Methylphenyl Sulfone (17a), Methyl 3-Methylphenyl Sul-
fone (17b) and Methyl 4-Methylphenyl Sulfone (17c):[6c,18] GC: 3
peaks, tR ϭ 4.55, 4.63 and 4.75 min (17a/17b/17c ϭ 50:16:34). MS
(EI): m/z (%) of 17a ϭ 170 (50) [Mϩ·], 155 (15), 107 (36), 91 (100),
65 (52), 39 (34). MS (EI): m/z (%) of 17b ϭ 170 (43) [Mϩ·], 155
(18), 107 (33), 91 (100), 65 (66), 39 (51). MS (EI): m/z (%) of 17c ϭ
170 (32) [Mϩ·], 155 (31), 107 (33), 91 (100), 65 (57), 39 (45). 1H
NMR (400 MHz, [D6]DMSO): δ ϭ 2.40 (s, ArMe, 17c), 2.41 (s,
ArMe, 17b), 2.65 (s, ArMe, 17a), 3.18 (s, SO2Me, 17c), 3.20 (s,
SO2Me, 17b), 3.21 (s, SO2Me, 17a), 7.28Ϫ7.36 (m, 4 H, H1,5, 17a
and H3,5, 17c), 7.40Ϫ7.42 (m, 2 H, H4,5, 17b), 7.47 (td, J ϭ 1.4,
7.5 Hz, 1 H, H3, 17a), 7.67Ϫ7.71 (m, 2 H, H2,6, 17b), 7.75Ϫ7.80
(m, 2 H, H2,6, 17c), 7.97Ϫ8.00 (dd, J ϭ 1.4, 7.9 Hz, 1 H, H6, 17a)
ppm. 13C NMR (50 MHz, CDCl3): δ ϭ 20.2 (C2ϪMe,17a), 21.3
(C3ϪMe, 17b), 21.6 (C4ϪMe, 17c), 43.7 (CϪSO2Me, 17a), 44.5
(CϪSO2Me, 17b), 44.6 (CϪSO2Me, 17c), 124.4 (C2H, 17b), 126.7
(C5H, 17a), 127.3 (C2,6H, 17c), 127.6 (C6H, 17b), 129.1 (C6H, 17a),
129.3 (C4or 5H, 17b), 130.0 (C3,5H, 17c), 132.8 (C3H, 17a), 133.8
(C4H, 17a), 134.5 (C4 or 5H, 17b), 137.5 and 137.7 (C2 of 17a and
C3 of 17b), 138.7 (C1, 17c), 139.7 (C1, 17a), 140.4 (C1, 17b), 144.7
(C4, 17c) ppm.
7.28 (dd, J ϭ 7.7, 1.5 Hz, 1 H, C4H), 7.80 (m, 1 H, C6H) ppm. 13
C
NMR (100 MHz, CDCl3): δ ϭ 20.0 (C2ϪMe), 21.0 (C5ϪMe), 43.8
(CϪSO2Me), 129.7 (C6H), 132.8 (C3H), 134.4 (C2Me), 134.5
(C4H), 136.9 (C5Me), 138.4 (CϪSO2Me) ppm.
4-Fluorophenyl Methyl Sulfone (22a) and 2-Fluorophenyl Methyl
Sulfone (22b): GC: 2 peaks, tR ϭ 3.75 (22a) and 3.92 (2) min (ratio
22a/b ϭ 76:24). MS (EI): m/z (%) of 22a: 174 (24) [Mϩ·], 159 (32),
112 (21), 111 (25), 95 (100), 83 (23), 75 (64), 50 (20), 39 (28). MS
(EI): m/z (%) of 22b: 174 (38) [Mϩ·], 159 (35), 112 (57), 111 (25),
95 (100), 83 (27), 75 (72), 74 (19), 69 (21), 63 (20), 50 (23). 1H NMR
(250 MHz, CDCl3): δ ϭ 3.05 (s, SO2Me, 22a), 3.21 (s, SO2Me, 22b),
7.17Ϫ7.40 (m, C3,5H of 22a and C3,4,5H of 22b), 7.65 (m, C6H,
22b), 7.95 (m, C2,6H, 22a) ppm. 13C NMR (63 MHz, CDCl3): δ ϭ
44.4 (d, J ϭ 2.8 Hz, CϪSO2Me, 22b), 45.1 (s, CϪSO2Me, 22a),
117.2 (d, J ϭ 22.9 Hz, C3,5, 22a), 117.8 (d, J ϭ 21.3 Hz, C3, 22b),
125.5 (d, J ϭ 3.7 Hz, C5, 22b), 128.8 (d, J ϭ 14.8 Hz, C1, 22b),
130.1 (s, C6, 22b), 130.9 (d, J ϭ 9.7 Hz, C2,6, 22a), 136.9 (d, J ϭ
8.5 Hz, C4, 22b), 137.3 (d, J ϭ 3.0 Hz, C1, 22a), 160.0 (d, J ϭ
255 Hz, C2, 22b), 166.2 (d, J ϭ 255 Hz, C4, 22a) ppm. 19F NMR
(376 MHz, CDCl3): δ ϭ Ϫ34.1 (22b), Ϫ27.9 (22a) ppm.
3,4-Dimethylphenyl Methyl Sulfone (19a) and 2,3-Dimethylphenyl
Methyl Sulfone (19b): GC: 2 peaks, tR ϭ 5.33, 5.45 min (ratio
51:49); For the peak at 5.33 min. MS (EI): m/z (%) ϭ 184 (81)
[Mϩ·], 169 (17), 121 (54), 105 (100), 104 (24), 103 (40), 91 (22), 79
(47), 78 (46), 77 (64), 65 (14), 51 (19), 39 (19); For the peak at
5.45 min. MS (EI): m/z (%) ϭ 184 (59) [Mϩ·], 169 (43), 121 (41),
105 (100), 103 (25), 91 (15), 79 (49), 78 (18), 77 (53), 65 (11), 63
(21), 51 (20), 39 (21). 1H NMR of the mixture of 19a and 19b
(400 MHz, CDCl3): δ ϭ 2.27 and 2.28 (2s, C3,4ϪMe, of 19a and
C3ϪMe, of 19b), 2.55 (s, C4ϪMe, 19b), 2.95 and 3.02 (2s, SO2Me
of 19a and 19b), 7.19 (m, C5H, 19b), 7.22 (d, J ϭ 7.7 Hz, C5H,
19a), 7.35 (dd, J ϭ 0.4, 7.5 Hz, C4H, 19b), 7.57 (dd, J ϭ 1.8, 8.0 Hz,
C6H, 19a), 7.61 (m, C2H, 19a), 7.84 (m, C6H, 19b) ppm. 13C NMR
(100 MHz, CDCl3): δ ϭ 16.3, 19.9, 20.2, 20.6 (CϪMe of 19a and
19b), 44.1, 44.8 (CϪSO2Me of 19a and 19b), 124.9, 126.2, 127.1,
128.2, 130.6, 135.4 (CH phenyl of 19a and 19b), 136.0, 138.0, 138.3,
139.2, 139.8, 143.5 (CϪMe and CϪSO2Me of 19a and 19b) ppm.
2-Chlorophenyl Methyl Sulfone (24a) and 4-Chlorophenyl Methyl
Sulfone (24b):[6c,19] GC: 2 peaks, tR ϭ 4.76 (24b) and 4.85 (24a)
min (ratio 24a/24b ϭ 74:26). MS (EI): m/z (%) of 24a ϭ 192 (22)
[Mϩ·], 190 (57) [Mϩ·], 177 (14), 175 (36), 130 (20), 129 (18), 128
(65), 127 (40), 113 (34), 111 (100), 99 (25), 76 (14), 75 (74), 74 (25),
73 (11), 51 (17), 50 (46). MS (EI): m/z (%) of 24b ϭ 192 (17) [Mϩ·],
190 (45) [Mϩ·], 177 (16), 175 (44), 128 (35), 127 (34), 113 (34), 111
(100), 99 (17), 75 (60). 1H NMR of the mixture of 24a and 24b
(400 MHz, CDCl3): δ ϭ 3.01 (s, SO2Me, 24b), 3.23 (s, SO2Me, 24a),
7.42Ϫ7.47 (ddd, J ϭ 7.8, 6.5, 2.2 Hz, C5H, 24a), 7.49Ϫ7.60 (m,
C3,4H of 24a and C3,5H of 24b), 7.83Ϫ7.87 (m, C2,6H, 24b), 8.11
(ddd, J ϭ 7.8, 1.3, 0.6 Hz, C6H, 24a) ppm. 13C NMR (50 MHz,
CDCl3): δ ϭ 42.8 (CϪSO2Me, 24a), 44.5 (CϪSO2Me, 24b), 127.7
(CH phenyl of 24a), 129.0 and 129.7 (CH phenyl of 24b), 130.8
and 131.9 (CH phenyl of 24a), 132.4 (CϪCl or CϪSO2Me of 24a),
2,4-Dimethylphenyl Methyl Sulfone (20a), 2,6-Dimethylphenyl 134.9 (CH phenyl of 24a), 137.9 (CϪCl or CϪSO2Me of 24a),
Methyl Sulfone (20b) and 3,5-Dimethylphenyl Methyl Sulfone (20c): 139.0 and 140.3 (CϪCl or CϪSO2Me of 24b) ppm.
4638
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Org. Chem. 2004, 4636Ϫ4640

Enhanced Catalysis of the Methanesulfonylation of Arenes by Metal Halides
FULL PAPER
2,3-Dichlorophenyl Methyl Sulfone (25a) and 3,4-Dichlorophenyl
J ϭ 21.9 Hz, C5, 28a), 114.8 (d, J ϭ 23.9 Hz, C3, 28c), 117.4 (d,
Methyl Sulfone (25b): GC: 2 peaks, tR ϭ 5.79 (25b) and 5.94 (25a) J ϭ 20.9 Hz, C3, 28b), 119.3 (d, J ϭ 22.2 Hz, C3, 28a), 125.2 (d,
min. MS (EI): m/z (%) of 25a ϭ 226 (46) [Mϩ·], 224 (Mϩ., 64), J ϭ 14.8 Hz, C1, 28b), 125.3 (d, J ϭ 3.1 Hz, C5, 28b), 127.0 (d, J ϭ
211 (22), 209 (33), 165 (14), 164 (51), 163 (29), 162 (80), 161 (37),
12.6 Hz, C1, 28c), 128.8 (d, J ϭ 3 Hz, C5, 28c), 129.2 (s, C6, 28b),
147 (64), 145 (100), 111 (24), 109 (65), 75 (50), 74 (61), 63 (20), 50 132.0 (d, J ϭ 9.9 Hz, C6, 28a), 134.4 (d, J ϭ 10.4 Hz, C4, 28c),
(13). MS (EI): m/z (%) of 25b ϭ 226 (36) [Mϩ·], 224 (52) [Mϩ·], 134.7 (d, J ϭ 3 Hz, C1, 28a), 140.7 (s, C6, 28c), 141.0 (d, J ϭ
211 (34), 209 (50), 165 (10), 164 (23), 163 (31), 162 (37), 161 (45), 9.3 Hz, C2, 28a), 148.0 (d, J ϭ 8.4 Hz, C4, 28b), 159.1 (d, J ϭ
147 (65), 145 (100), 111 (20), 109 (58), 75 (41), 74 (47), 63 (14), 50
254 Hz, C2, 28b), 160.2 (d, J ϭ 253 Hz, C5, 28c), 165.1 (d, J ϭ
1
(11). H NMR of the mixture of 25a and 25b (400 MHz, CDCl3): 255 Hz, C5, 28a) ppm. 19F NMR (376 MHz, CDCl3): δ ϭ Ϫ29.5
δ ϭ 3.04 (s, SO2Me, 25b), 3.26 (s, SO2Me, 25a), 7.40 (t, J ϭ 8 Hz, (28a), Ϫ31.1 (28c) and Ϫ35.5 (28b) ppm.
C5H, 25a), 7.64 (d, J ϭ 8.4 Hz, C5H, 25b), 7.70Ϫ7.77 (m, J ϭ 8.4,
2-Fluoro-5-methylphenyl Methyl Sulfone (29a), 2-Methyl-5-fluoro-
phenyl Methyl Sulfone (29b): GC: tR ϭ 4.23 (not assigned), and
4.50 (not assigned) min in the respective proportions 48:52; For the
2 Hz, C4H of 25a and C6H of 25b), 8.0 (d, J ϭ 2 Hz, C2H, 25b),
8.07 (dd, J ϭ 8, 2 Hz, C6H, 25a) ppm; ratio 25a/25b estimated by
1H NMR ϭ 4:96. 13C NMR of 25b (50 MHz, CDCl3): δ ϭ 44.5
peak at 4.23 min. MS (EI): m/z (%) ϭ 188 (100) [Mϩ·], 173 (19),
(CϪSO2Me), 126.6, 129.6, 131.6 (C2,5,6H), 134.2, 138.9 and 140.2
125 (33), 125 (54), 109 (83), 108 (79), 107 (32), 83 (43); For the
(C1,3,4) ppm.
peak at 4.50 min. MS (EI): m/z (%) ϭ 188 (64) [Mϩ], 173 (36), 126
2,4-Difluorophenyl Methyl Sulfone (26): GC: tR ϭ 3.51 min. MS
(44), 125 (37), 109 (100), 107 (19), 97 (18), 63 (28), 57 (31). 1H
(EI): m/z (%) ϭ 192 (46) [Mϩ], 177 (56), 130 (44), 129 (100), 113 NMR (400 MHz, CDCl3): δ ϭ 2.36 (s, CϪMe, 29a), 2.63 (s,
1
(70), 101 (25), 63 (56). H NMR (250 MHz, CDCl3): δ ϭ 3.12 (s, CϪMe, 29b), 3.05 and 3.16 (s, SO2Me, 29a,or 29b), 7.09 (dd, J ϭ
3 H, SO2Me), 6.90Ϫ7.10 (m, 2 H, C3,5H), 7.80Ϫ7.95 (m, 1 H, C6H)
8.5, 9.7 Hz, C3H, 29a), 7.18 (td, J ϭ 2.8, 7.9 Hz, C4H, 29b), 7.29
ppm. 13C NMR (50 MHz, CDCl3): δ ϭ 43.9 (d, J ϭ 1.5 Hz, (dd, J ϭ 5.2, 8.5 Hz, C3H, 29b), 7.38 (m, C4H, 29a), 7.60Ϫ7.80 (m,
SO2Me), 105.8 (t, J ϭ 25.6 Hz, C3H), 112.3 (dd, J ϭ 22, 3.8 Hz, C6H of 29a and C6H of 29b) ppm. 13C NMR (50 MHz, CDCl3):
C5H), 125.0 (dd, J ϭ 15 and 4 Hz, C1), 131.8 (dd, J ϭ 10.5, 1.2 Hz,
δ ϭ 19.6 (s, CϪMe, 29b), 20.7 (s, CϪMe, 29a), 43.6 (s, CϪSO2Me,
C6H), 160.4 (dd, J ϭ 259, 11.7 Hz, C2 or 4ϪF), 166.5 (dd, J ϭ 257, 29a or 29b), and 44.0 (d, CϪSO2Me, 29a or 29b), 116.5, 116.7,
13 Hz, C2 or 4ϪF) ppm. 19F NMR (376 MHz, CDCl3): δ ϭ Ϫ29.4, 116.9 and 117.1 (C3H of 29a and C2H of 29b), 120.8 (d, J ϭ 21 Hz,
Ϫ23.4 ppm.
C4H, 29b), 128.0 (d, J ϭ 18.5 Hz, C1, 29a), 129.7 (C6, 29a), 133.3
(d, J ϭ 3.6 Hz, C2, 29b), 134.6 (d, J ϭ 7 Hz, C5H, 29b), 135.0 (d,
J ϭ 3.9 Hz, C5H, 29a), 136.6 (d, J ϭ 8 Hz, C4H, 29a), 140.2 (C1,
29b), 157.7 (d, J ϭ 252 Hz, C2, 29a), 160.8 (d, J ϭ 250 Hz, C5,
29b) ppm. 19F NMR (376 MHz, CDCl3): δ ϭ Ϫ35.0 and Ϫ36.3
(29a and 29b) ppm.
4-Fluoro-3-methylphenyl Methyl Sulfone (27a), 3-Fluoro-2-meth-
ylphenyl Methyl Sulfone (27b), 3-Fluoro-4-methylphenyl Methyl Sul-
fone (27c), 2-Fluoro-3-methylphenyl Methyl Sulfone (27d): GC: tR ϭ
4.24 (27c), 4.35 (27a), 4.39 (not assigned), and 4.56 (not assigned)
min in the respective proportions 6:66:16:12; For 27a: MS (EI): m/
z (%) of 27a ϭ 188 (50) [Mϩ], 173 (42), 125 (33), 109 (100), 83 (30).
1H NMR of the mixture (400 MHz, CDCl3): δ ϭ 2.30Ϫ2.33 (m,
CϪMe, 27a, 27b, 27d), 2.57 (d, J ϭ 2.5 Hz, CϪMe, 27c), 2.99 (s,
SO2Me, 27a, 27b or 27d), 3.00 (s, SO2Me, 27a, 27b or 27d), 3.05 (s,
SO2Me, 27c), 3.17 (s, SO2Me, 27a, 27b or 27d), 7.13 (t, 1 H, C5H,
27a), 7.17Ϫ7.20 (m, not assigned), 7.25Ϫ7.38 (m, not assigned),
7.42Ϫ7.47 (m, not assigned), 7.51Ϫ7.60 (m, not assigned),
7.70Ϫ7.74 (m, C6H, 27a), 7.74Ϫ7.78 (m, C2H, 27a), 7.79Ϫ7.85 (m,
not assigned) ppm. 13C NMR of 27a (50 MHz, CDCl3): δ ϭ 15.0
(d, J ϭ 3.5 Hz, CϪMe), 44.8 (CϪSO2Me), 116.3 (d, J ϭ 23.9 Hz,
C5), 127.0 (d, J ϭ 18.5 Hz, C3), 127.6 (d, J ϭ 9.8 Hz, C6), 131.3
(d, J ϭ 6.7 Hz, C2), 136.3 (d, J ϭ 3.5 Hz, C1), 164.5 (d, J ϭ 255 Hz,
C4) ppm. 19F NMR (376 MHz, CDCl3): δ ϭ Ϫ28.9 (27a), Ϫ33.6,
Ϫ34.3, Ϫ35.2 ppm.
Acknowledgments
Thanks are due to the Centre National de la Recherche Scientifique
and Rhodia Organique Fine for financial support. Professor Ram
Mohan is gratefully acknowledged for his kind contribution to the
preparation of the manuscript.
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in the respective proportions 62:12:26; For the peak at 4.08 min.
MS (EI): m/z (%) of 28a ϭ 188 (58) [Mϩ·], 173 (42), 125 (35), 109
(100), 107 (19), 83 (36), 57 (10). MS (EI): m/z (%) of 28c ϭ 188
(94) [Mϩ·], 173 (34), 125 (100), 109 (84), 107 (35), 83 (46), 57 (24);
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NMR (400 MHz, CDCl3): δ ϭ 2.35 (s, CϪMe, 28b), 2.61 (s,
CϪMe, 28a and 28c), 3.00 (s, SO2Me, 28a), 3.10 (s, SO2Me, 28b),
3.16 (d, J ϭ 2 Hz, SO2Me, 28c), 6.93Ϫ7.08 (m, not assigned), 7.37
(td, J ϭ 8 and 5.5 Hz, C4H, 28c), 7.69 (t, J ϭ 7.7 Hz, C6H, 28b),
7.94 (dd, J ϭ 9.5, 5.5 Hz, C6H, 28a) ppm. 13C NMR (125 MHz,
CDCl3): δ ϭ 20.8 (s, CϪMe, 28a), 20.9 (s, CϪMe, 28c), 21.4 (s,
CϪMe, 28b), 43.6 (s, CϪSO2Me, 28a), 43.7 (d, J ϭ 2.8 Hz,
CϪSO2Me, 28b), 45.3 (d, J ϭ 5.9 Hz, CϪSO2Me, 28c), 113.5 (d,
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www.eurjoc.org
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4639

`
M. Peyronneau, M.-T. Boisdon, N. Roques, S. Mazieres, C. Le Roux
FULL PAPER
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[13]
[6] [6a]
The formation of transient mixed bismuth chlorotriflate com-
pounds BiCln(OTf)3Ϫn (with n ϭ 1 or 2) and their role as trifl-
ate transfer agents has been postulated for the arylsulfonylation
of arenes catalysed by bismuth() triflate.[5f,5j] Such Cl/OTf li-
gand exchange based on the halophilicity of bismuth has al-
ready been reported in cases of sulfonylation[5f,5j] and acylation
reactions.[11a] In addition, when the methanesulfonylation of 5
was carried out with the use of 10 mol % of BiCl(OTf)2, methyl
2Ј,4Ј,6Ј-trimethylphenyl sulfone (18) was isolated in 60% yield.
Finally, it has been demonstrated that the reaction between 1
and 2 with formation of BiCl(OTf)2 (same experimental pro-
cedure as ref.[14] is not inhibited in the presence of a molar
amount of 18.
The synthesis of 30 by use of a stoichiometric reaction between
an alkanesulfonyl bromide and silver triflate has been reported
by Effenberger et al.: K. Huthmacher, G. König, F. Effen-
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[7]
Typical procedure: Compound 2 (630 mg, 2 mmol), toluene (4,
5.53 g, 60 mmol), methanesulfonyl chloride (2.29 g, 20 mmol)
and 1 (0.3 g, 2 mmol) were placed successively in a 50 mL flask.
The flask was fitted with a condenser connected to an argon
line, immersed in an oil bath, and heated for 36 h at 110 °C.
After the system had cooled, dichloromethane (20 mL) and
aqueous HCl (6%, 20 mL) were added. The products were ex-
tracted with dichloromethane (2 ϫ 20 mL). The combined or-
ganic phases were dried with MgSO4 and concentrated. The
crude mixture was subjected to flash chromatography on silica
gel (eluent: CH2Cl2/pentane, 1:1) to give the tolylmethylsul-
fones (17, 3.13 g, 92% isolated yield). All products 17Ϫ29 were
identified by comparison with authentic samples prepared by
known procedures[6b,6c,8] and their isomer compositions were
determined by GC analysis.
[14]
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G. A. Olah, Friedel Crafts and Related Reactions (Ed.: G. A.
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[17]
The amounts of 18 in complexation with 2 or 3 were estimated
from stoichiometric mixtures of 2 or 3 and 18 in toluene (c ϭ
86 m) and were found to be 58 and 30%, respectively. For
solubility reasons the same experiment could not be run with
BiCl(OTf)2 or SbCl2OTf. In the case of FeCl3 the amount of
complexed sulfone is nearly quantitative, which explains the
need for stoichiometric amounts of FeCl3 for these reactions.[8a]
P. Camps, C. Iglesias, M. J. Rodriguez, M. D. Grancha, M. E.
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[9]
[10]
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[18]
[19]
[11] [11a]
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S. Repichet, C. Le Roux, J. Dubac, J. R. Desmurs, Eur. J.
[11b]
Org. Chem. 1998, 2743.
We have recently shown that use
of an excess of triflic acid results only in BiCl(OTf)2, the struc-
J. A. Hyatt, A. W. White, Synthesis 1984, 214.
ture of which has been determined by X-ray diffraction.[12]
Received May 24, 2004
4640
 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
Eur. J. Org. Chem. 2004, 4636Ϫ4640