Synthesis of aryl sulfones via L-proline-promoted CuI-catalyzed coupling reaction of aryl halides with sulfinic acid salts

Article abstract of DOI:10.1021/jo047758b

(Chemical Equation Presented) The CuI/L-proline sodium salt catalyzed coupling reaction of aryl halides with sulfinic acid salts readily occurs at 80-95°C in DMSO to give the corresponding aryl sulfones in good to excellent yields. This process is well-tolerated by a wide range of functional groups including hydroxyl, amino, acetanilide, ketone, ester, and nitrile. Using this method, 4-phenylsulfonyl- and 4-methanesulfonyl-substituted L-phenylalanine derivatives are prepared.

Full text of DOI:10.1021/jo047758b

Synthesis of Aryl Sulfones via L-Proline-Promoted CuI-Catalyzed
Coupling Reaction of Aryl Halides with Sulfinic Acid Salts
Wei Zhu† and Dawei Ma*,‡
Department of Chemistry, Fudan University, Shanghai 200433, China, and State Key Laboratory of
Bioorganic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy
of Sciences, 354 Fenglin Lu, Shanghai 200032, China
madw@mail.sioc.ac.cn
Received December 22, 2004
The CuI/L-proline sodium salt catalyzed coupling reaction of aryl halides with sulfinic acid salts
readily occurs at 80-95 °C in DMSO to give the corresponding aryl sulfones in good to excellent
yields. This process is well-tolerated by a wide range of functional groups including hydroxyl, amino,
acetanilide, ketone, ester, and nitrile. Using this method, 4-phenylsulfonyl- and 4-methanesulfonyl-
substituted L-phenylalanine derivatives are prepared.
Introduction
VLA-4,4 and the ATPase.5 The traditional procedures6,7
for assembling these compounds are mainly based on the
oxidation of the corresponding sulfides and the sulfony-
lation of suitable arenes. The drawbacks of limited
substrate sources or toleration problems for many func-
tional groups have stimulated considerable efforts to
explore alternative methods.8-11 Among emerging strate-
gies, direct coupling of aryl halides and sulfinic acid salts
(eq 1) showed some advantages because it worked at
The aryl sulfone moiety has been found in numerous
biologically interesting compounds. These compounds
include antifungal, antibacterial, or antitumor agents1
and inhibitors for several enzymes such as cyclooxyge-
nase-2 (COX-2),2 HIV-1 reverse transcriptase,3 intrgrin
† Fudan University, Shanghai, China.
‡ State Key Laboratory of Bioorganic and Natural Products Chem-
istry, Shanghai.
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10.1021/jo047758b CCC: $30.25 © 2005 American Chemical Society
Published on Web 03/03/2005
2696
J. Org. Chem. 2005, 70, 2696-2700

Synthesis of Aryl Sulfones
TABLE 1. Coupling Reaction of 4-iodoanisole with
CH3SO2Na under the Catalysis of Copper Salts and
Amino Acidsa
weakly basic conditions and was therefore suitable for
the preparation of aryl sulfones containing olefin, amine
and other acid- or oxidation-sensitive moieties.8-10 In
entry
catalytic system
yieldb (%)
1
2
3
CuI
25
73
62
1995, Suzuki and Abe first reported that this process
could be catalyzed by CuI in DMF at 110 °C.8 The
requirement of 1.5 equiv of CuI in this case had prompted
Baskin and Wang to develop a more efficient catalytic
procedure, which relied on the use of N,N′-dimethyleth-
ylenediamine as an additive.9 However, this procedure
was still limited to aryl iodides because low yields were
observed when aryl bromides were used. In addition, it
required less conveniently available catalyst ((CuOTf)2‚
PhH) and relatively higher reaction temperature (110
°C). Very recently, Cacchi and co-workers disclosed that
the combination of Pd2(dba)3/Xantphos was a powerful
catalytic system for this conversion which allowed syn-
thesis of diaryl sulfones from either aryl iodides or aryl
bromides.10 However, its practical application for larges-
cale preparation is problematic mainly because of the
high cost of the Pd catalyst and the phosphine ligand.
Based on our previous investigations12 and inspired by
relative studies reported by other groups,13,14 we have
discovered that some amino acids could promote CuI-
catalyzed C-N, C-O, and C-C bond formation reac-
tions.15 As an extension of this research, we have explored
the coupling reaction of aryl halides with sulfinic acid
salts using Cu(I)/amino acid as a catalytic system. It was
found that this combination was superior to that reported
by Baskin and Wang9 in many aspects. Herein we
disclose our results
CuI/N-methylglycine/20 mol % NaOH
CuI/N,N-dimethylglycine hydrochloride
salt/40 mol % NaOH
4
5
6
7
8
9
CuI/L-proline/20 mol % NaOH
CuI/L-proline sodium salt
CuBr/L-proline sodium salt
CuCl/L-proline sodium salt
Cu(OAc)2/L-proline sodium salt
CuO/L-proline sodium salt
84
84
74
60
32
trace
a Reaction conditions: CuI (0.1 mmol), amino acid (0.2 mmol),
4-iodoanisole (1 mmol), CH3SO2Na (1.2 mmol), DMSO (2 mL), 80
°C, under Ar atmosphere, 24 h. b Isolated yield.
3). The best result was observed when L-proline sodium
salt gererated in situ was used as a promoter (entry 4).
No difference in yield was found when L-proline sodium
salt was directly used (entry 5). Next, several Cu(I) and
Cu(II) salts such as CuBr, CuCl, Cu(OAc)2, and CuO were
screened for this coupling reaction. It was found that CuI
gave the best result and Cu(I) salts generally showed
better reactivity than Cu(II) salts (compare entries 5-9).
In addition, several solvents such as DMSO, DMF,
dioxane, toluene, acetonitirle and ethanol were tested and
DMSO was found to be the best for this reaction.
Based on above results, we concluded that using CuI/
L-proline sodium salt as the catalytic system and DMSO
as the solvent are optimized combination for this coupling
reaction. Its scope was next explored with different aryl
halides, and the results are summarized in Table 2. We
were pleased to find that both electron-rich and electron-
deficient aryl iodides worked to provide the aryl methyl
sulfones in good to excellent yields (entries 1-7). It is
important to note that is that unprotected hydoxyl group
or amino group in aryl iodides did not hinder the reaction
and no O- or N-arylating product was detected in these
cases (entries 2 and 4). When reaction of 4-iodoacetanilide
and CH3SO2Na was carried out under Wang’s conditions,
poor yield of the product was obtained.9 However, in our
case this reaction gave 82% yield (entry 3), which might
be caused by the relatively low reaction temperature used
here.
Two heterocyclic aryl iodides were also compatible with
the present procedure (entries 8 and 9). For sterically
hindered aryl iodides, higher reaction temperature and
longer reaction time were necessary to ensure complete
conversion (compare entries 10 and 11, 12 and 13).
Since the coupling reaction of unactivated aryl bromid-
es with sulfinic acid salts was reportedly unsuccessful
under the previous conditions,8,9 we next checked these
substrates using our catalytic system. To our delight,
many aryl bromides worked well in our hands although
higher reaction temperature and longer reaction time
were required in comparison with aryl iodides. Interest-
ingly, electron-rich aryl bromides displayed higher reac-
tivity than those electron-deficient aryl bromides (com-
pare entries 15-17 and 18-19). A similar phenomenon
has been observed in CuI/L-proline sodium salt catalyzed
Results and discussions
As indicated in Table 1, we chose the coupling of
4-iodoanisole with sodium methanesulfinate as a model
for exploring the optimized reaction condition. It was
found that if CuI was used alone, the reaction in DMSO
at 80 °C for 24 h gave the coupling product in only 25%
yield (entry 1). When 20 mol % N-methylglycine sodium
salt generated in situ was added, the reaction yield
jumped to 73% (entry 2). Using N,N-dimethylglycine
sodium salt resulted in lower yield of the product (entry
(10) (a) Cacchi, S.; Fabrizi, G.; Goggiamani, A.; Parisi, L. M. Org.
Lett. 2002, 4, 4719. (b) Cacchi, S.; Fabrizi, G.; Goggiamani, A.; Parisi,
L. M.; Bernini, R. J. Org. Chem. 2004, 69, 5608.
(11) Bandgar, B. P.; Bettigeri, S. V.; Phopase, J. Org. Lett. 2004, 6,
2105.
(12) (a) Ma, D.; Zhang, Y.; Yao, J.; Wu, S.; Tao, F. J. Am. Chem.
Soc. 1998, 120, 12459. (b) Ma, D.; Xia, C. Org. Lett. 2001, 3, 2583.
(13) Klapars, A.; Antilla, J.; Huang, X.; Buchwald, S. L. J. Am.
Chem. Soc. 2001, 123, 7727. (b) Wolter, M.; Klapars, A.; Buchwald, S.
L. Org. Lett. 2001, 3, 3803. (c) Gujadhur, R. K.; Bates, C. G.;
Venkataraman, D. Org. Lett. 2001, 3, 4315. (d) Buck, E.; Song, Z. J.;
Tschaen, D.; Dormer, P. G.; Volante, R. P.; Reider, P. J. Org. Lett. 2002,
4, 1623. (e) Antilla, J. C.; Klapars, A.; Buchwald, S. L. J. Am. Chem.
Soc. 2002, 124, 11684.
(14) For reviews, see: (a) Ley, S. V.; Thomas, A. W. Angew. Chem.,
Int. Ed. 2003, 42, 5400. (b) Kunz, K.; Scholz, U.; Ganzer, D. Synlett.
2003, 2428.
(15) (a) Ma, D.; Cai, Q.; Zhang, H. Org. Lett. 2003, 5, 2453. (b) Ma,
D.; Cai, Q. Org. Lett. 2003, 5, 3799. (c) Ma, D.; Cai, Q. SynLett. 2004,
1, 128. (d) Pan, X.; Cai, Q.; Ma, D. Org. Lett. 2004, 6, 1809. (e) Zhu,
W.; Ma, D. Chem. Commun. 2004, 888. (f) Ma, D.; Liu, F. Chem.
Commun. 2004, 1934. For related work, see: (f) Deng, W.; Wang, Y.;
Zou, W.; Liu, L.; Guo, Q. Tetrahedron Lett. 2004, 45, 2311. (g) Deng,
W.; Zou, Y.; Wang, Y. F.; Liu, F.; Guo, Q. X. Synlett 2004, 1254.
J. Org. Chem, Vol. 70, No. 7, 2005 2697

Zhu and Ma
TABLE 2. Coupling Reaction of Aryl Halides with
CH3SO2Na under the Catalysis of CuI/L-Proline Sodium
Salta
TABLE 3. Coupling Reaction of Aryl Halides with
PhSO2Na under the Catalysis of CuI/L-Proline Sodium
Salt
a Reaction conditions: CuI (0.1 mmol), L-proline sodium salt (0.2
mmol), aryl halide (1 mmol), PhSO2Na (1.2 mmol), DMSO (2 mL),
under Ar atmosphere. b Isolated yield. c Unreacted iodide was
recovered in 37% yields. d Unreacted bromide was recovered in
46% yields.
SCHEME 1
coupling of aryl halides with sodium azide.15e These re-
sults implied that the mechanism of these two coupling
reactions might slightly differ from that of CuI/amino
acid-catalyzed aryl amination and diaryl ether formation
reactions. More investigations are needed to address this
issue.
As shown in Table 3, the coupling reaction between
aryl halides and sodium benzenesulfinate was explored
in order to extend the present method to the synthesis
of diaryl sulfones. For most of the aryl iodides tested, good
yields were obtained when the reaction was carried out
at 90 °C (entries 1-5). However, poor conversion was
seen when 4′-iodoacetophenone was used (entry 6), which
was consistent with the observation for reaction of 4′-
bromoacetophenone with sodium methanesulfinate. In
addition, aryl bromides also gave poor conversion as
a Reaction conditions: CuI (0.1 mmol), L-proline sodium salt (0.2
mmol), aryl halide (1 mmol), CH3SO2Na (1.2 mmol), DMSO (2 mL),
under Ar atmosphere. b Isolated yield. c Unreacted iodides or
bromides were recovered in 20-30% yields.
2698 J. Org. Chem., Vol. 70, No. 7, 2005

Synthesis of Aryl Sulfones
1-(4-(Methanesulfonyl)phenyl)ethanone 2f: pale yellow
solid; mp 125-127 °C; 1H NMR (400 MHz, CDCl3) δ 2.68 (s, 3
H), 3.09 (s, 3 H), 8.05 (d, J ) 8.2 Hz, 2 H), 8.13 (d, J ) 8.2 Hz,
2H); EI-MS (m/z) 198 (M+), 183, 167, 152, 139, 121, 104, 91,
76, 63, 43.
evidenced by that the reaction of 4-bromoanisole provided
the coupling product in only 46% yield (entry 7).
To further demonstrate the applicability of the present
procedure, iodide 4 derived from L-phenylalanine was
checked. It was found that reaction of 4 with sodium
methanesulfinate or sodium benzenesulfinate gave the
cross-coupling product 5 or 6 in good yields (Scheme 1).
These two products might serve as useful building blocks
for the synthesis of peptide mimics.
1-(Trifluoromethyl)-3-(methanesulfonyl)benzene 2g:
1
white solid; mp 58-60 °C; H NMR (400 MHz, CDCl3) δ 3.11
(s, 3H), 7.76 (t, J ) 8.0 Hz, 1H), 7.93 (d, J ) 8.4 Hz, 1H), 8.16
(d, J ) 8.0 Hz, 1H); 8.23 (s, 1H); EI-MS (m/z) 224 (M+), 209,
205, 193, 177, 162, 145, 125, 114, 95, 75, 63, 50, 39.
In conclusion, we have reported here a more effective
Cu(I) catalytic system, which allowed for coupling reac-
tion of aryl halides with sulfinic acid salts at relatively
low temperatures and was suitable for more substrates
especially to aryl bromides. A wide range of functional
groups such as hydroxyl, amino, acetanilide, ketone,
ester, and nitrile groups were compatible with the
present reaction conditions, which would permit to as-
semble aryl sulfones with great diversity. Further ap-
plications to the synthesis of biologically important
molecules and mechanism studies are in progress.
Methyl 4-(methanesulfonyl)benzoate 2h: white solid;
1
mp 118-120 °C; H NMR (400 MHz, CDCl3) δ 3.09 (s, 3 H),
3.98 (s, 3H), 8.03 (d, J ) 7.4 Hz, 2H), 8.22 (d, J ) 7.4 Hz, 2H);
EI-MS (m/z) 214 (M+), 199, 183, 166, 152, 135, 121, 104, 91,
77, 57, 43.
2-(Methanesulfonyl)thiophene 2i: white solid; mp 45-
47 °C; 1H NMR (400 MHz, CDCl3) δ 3.19 (s, 3H), 7.61 (m, 1H),
7.73 (m, 2H); EI-MS (m/z) 162 (M+), 147, 131, 115, 99, 83, 71,
57, 45, 39.
3-Methanesulfonylpyridine 2j: white solid; mp 52-54 °C;
1H NMR (400 MHz, CDCl3) δ 3.13 (s, 3H), 7.54 (m, 1H), 8.24
(m, 1H), 8.90 (m, 1H), 9.18 (d, J ) 2.3 Hz, 1H); EI-MS (m/z)
157 (M+), 142, 126, 110, 95, 82, 78, 66, 51.
1-Methyl-2-(methanesulfonyl)benzene 2k: white solid;
mp 54-56 °C; 1H NMR (400 MHz, CDCl3) δ 2.72 (s, 3H), 3.09
(s, 3H), 7.35 (m, 1H), 7.38 (m, 1H), 7.52 (m, 1H), 8.03 (m, 1H);
EI-MS (m/z) 170 (M+), 155, 107, 91, 77, 65, 51, 39.
1-(Methanesulfonyl)naphthalene 2m: yellow solid; mp
99-101 °C; 1H NMR (400 MHz, CDCl3) δ 3.22 (s, 3H), 7.61
(m, 1H), 7.63 (m, 1H), 7.73 (m, 1H), 7.99 (d, J ) 8.2 Hz, 1H),
8.13 (d, J ) 8.2 Hz, 1H), 8.35 (m, 1H), 8.73 (m, 1H); EI-MS
(m/z) 206 (M+), 191, 183, 175, 143, 127, 115, 101, 91, 77, 63,
51, 39.
4-Methanesulfonyl-1-phenylbenzene 2n: yellow solid;
mp 139-141 °C; 1H NMR (400 MHz, CDCl3) δ 3.10 (s, 3H),
7.45 (m, 3H), 7.61 (d, J ) 7.8 Hz, 2H), 7.77 (d, J ) 8.2 Hz,
2H), 8.01 (d, J ) 8.2 Hz, 2H); EI-MS (m/z) 232 (M+), 217, 201,
185, 169, 152, 141, 127, 115, 76.
Experimental
General Procedure for Coupling Reaction of 4-Io-
doanisole with CH3SO2Na (Table 1). A mixture of 4-io-
doanisole (1 mmol), sodium methanesulfunate (1.2 mmol),
copper salt (0.1 mmol), amino acid (0.2 mmol), and base (0.2
mmol) (or 0.2 mmol of proline sodium salt) in 2 mL of DMSO
in a sealed tube was heated at 80 °C under argon for 24 h.
The cooled mixture was partitioned between ethyl acetate and
water. The organic layer was separated, and the aqueous layer
was extracted with ethyl acetate twice. The combined organic
layers were washed with brine, dried over MgSO4, and
concentrated in vacuo. The residual oil was loaded on a silica
gel column and eluted with petroleum ether to afford the
product.
General Procedure for CuI-Catalyzed Coupling of
Aryl Halides and Sodium Methanesulfunate. A mixture
of aryl halide (1 mmol), sodium methanesulfunate (1.2 mmol),
copper iodide (0.1 mmol), L-proline sodium salt (0.2 mmol), and
2 mL of DMSO in a sealed tube was heated to 80 or 95 °C (for
aryl bromides) under argon. The cooled mixture was parti-
tioned between ethyl acetate and water. The organic layer was
separated, and the aqueous layer was extracted with ethyl
acetate twice. The combined organic layers were washed with
brine, dried over MgSO4, and concentrated in vacuo. The
residual oil was loaded on a silica gel column and eluted with
4:1 petroleum ether/ethyl acetate to afford the product.
1-Methoxy-4-(methanesulfonyl)benzene 2a: white solid;
mp 118-120 °C; 1H NMR (300 MHz, CDCl3) δ 3.05 (s, 3H),
3.90 (s, 3H), 7.04 (dd, J ) 7.5, 2.1 Hz, 2H), 7.88 (dd, J ) 7.5,
2.1 Hz, 2H); EI-MS (m/z) 186 (M+), 171, 155, 139, 123, 107,
92, 77, 63.
1-Methyl-4-(methanesulfonyl)benzene 2b: white solid;
mp 85-87 °C; 1H NMR (400 MHz, CDCl3) δ 2.46 (s, 3H), 3.04
(s, 3H), 7.36 (d, J ) 8.2 Hz, 2H), 7.82 (d, J ) 8.2 Hz, 2H);
EI-MS (m/z) 170 (M+), 155, 139, 121, 107, 91, 77, 65, 51, 39.
4-(Methanesulfonyl)phenol 2c: white solid; mp 94-96 °C;
1H NMR (300 MHz, DMSO-d6) δ 3.09 (s, 3H), 6.93 (m, 2H),
7.71 (m, 2H), 10.6 (br s, 1H); EI-MS (m/z) 172 (M+), 157, 141,
109, 94, 79, 65, 43.
4-Methanesulfonylbenzonitrile 2o: white solid; mp 142-
144 °C; 1H NMR (400 MHz, CDCl3) δ 3.10 (s, 3H), 7.90 (m
2H), 8.09 (m, 2H); EI-MS (m/z) 181 (M+), 166, 150, 119, 102,
75.
tert-Butyl (S)-1-(Methoxycarbonyl)-2-(4-(methanesulfo-
nyl)phenyl)ethylcarbamate 5: yellow solid; mp 78-80 °C;
[R]23D ) +44.9 (c ) 1.1, CHCl3); 1H NMR (400 MHz, CDCl3) δ
1.41 (s, 9H), 3.05 (s, 3H), 3.05-3.20 (m, 2H), 3.74 (s, 3H), 4.62
(m, 1H), 5.09 (d, J ) 7.3 Hz, 1H), 7.35 (d, J ) 7.8 Hz, 2H),
7.87 (d, J ) 7.8 Hz, 2H); 13C NMR (100 MHz, CDCl3) δ 171.4,
154.6, 142.6, 138.7, 129.9, 127.0, 79.6, 53.7, 52.0, 43.0, 37.7,
27.8; ESI-MS (m/z) 380.2 (M + Na)+; ESI HRMS found m/z
380.1146 (M + Na)+, C16H23NO6SNa requires 380.1144;
General Procedure for CuI-Catalyzed Coupling of
Aryl Halides and Sodium Benzenesulfonate. A mixture
of aryl halide (1 mmol), sodium benzenesulfonate (1.2 mmol),
copper iodide (0.1 mmol), L-proline sodium salt (0.2 mmol), and
2 mL of DMSO in a sealed tube was heated at the temperature
indicated in Table 3 under argon. After 24 or 36 h (for aryl
bromides), the cooled mixture was partitioned between ethyl
acetate and water. The organic layer was separated, and the
aqueous layer was extracted with ethyl acetate twice. The
combined organic layers were washed with brine, dried over
MgSO4, and concentrated in vacuo. The residual oil was loaded
on a silica gel column and eluted with 4:1 petroleum ether/
ethyl acetate to afford the product.
N-(4-Methanesulfonylphenyl)acetamide 2d: yellow solid;
mp 185-187 °C; 1H NMR (400 MHz, CDCl3) δ 2.23 (s, 3H),
3.04 (s, 3H), 7.60 (s, 1H), 7.72 (d, J ) 8.2 Hz, 2H), 7.87 (d, J
) 8.2 Hz, 2H); EI-MS (m/z) 213 (M+), 198, 171, 156, 140, 108,
92, 81, 65.
1-(p-Tolylsulfonyl)benzene 3a: white solid; mp 125-127
°C; 1H NMR (400 MHz, CDCl3) δ 2.40 (s, 3H), 7.29 (d, J ) 8.3
Hz, 2H), 7.50 (m, 3H), 7.82 (d, J ) 8.2 Hz, 2H), 7.93 (m, 2H);
EI-MS (m/z) 232 (M+), 184, 165, 152, 139, 125, 107, 91, 77, 65,
51, 39.
4-Methanesulfonylaniline 2e: yellow solid; mp 136-138
1
°C; H NMR (400 MHz, CDCl3) δ 3.00 (s, 3H), 4.22 (br, 2H),
6.71 (m 2H), 7.69 (m, 2H); EI-MS (m/z) 171 (M+), 156, 140,
4-(Benzenesulfonyl)phenol 3b: brown solid; mp 135-137
1
108, 92, 80, 65.
°C; H NMR (400 MHz, CDCl3) δ 5.28 (br s, 1H), 6.88 (d, J )
J. Org. Chem, Vol. 70, No. 7, 2005 2699

Zhu and Ma
8.0 Hz, 2H), 7.47 (m, 3H), 7.72 (d, J ) 8.0 Hz, 2H), 7.85 (d, J
) 8.0 Hz, 2H); EI-MS (m/z) 234 (M+), 191, 175, 161, 78, 63,
45.
N-(4-Benzenesulfonylphenyl)acetamide 3c: yellow solid;
mp 191-193 °C; 1H NMR (400 MHz, CDCl3) δ 2.17 (s, 3H),
7.35-7.60 (m, 3H), 7.65 (d, J ) 8.7 Hz, 2H), 7.83-7.91 (m,
5H); EI-MS (m/z) 275 (M+), 233, 169, 156, 140, 125, 108, 77,
43.
1-(4-Methoxyphenylsulfonyl)benzene 3d: yellow solid;
mp 88-90 °C; 1H NMR (300 MHz, CDCl3) δ 3.84 (s, 3H), 6.96
(m, 2H), 7.51 (m, 3H), 7.90 (m, 4H); EI-MS (m/z) 248 (M+),
184, 169, 155, 141, 123, 107, 92, 77, 51.
2-(Benzenesulfonyl)thiophene 3e: yellow solid; mp 119-
121 °C; 1H NMR (400 MHz, CDCl3) δ 7.08 (m, 1H), 7.52-7.70
(m, 5H), 7.99 (m, 2H); EI-MS (m/z) 224 (M+), 160, 131, 125,
115, 99, 83, 71, 51, 45, 39.
tert-Butyl (S)-1-(methoxycarbonyl)-2-(4-(benzenesulfo-
nyl)phenyl)ethylcarbamate 6: yellow solid; mp 82-84 °C;
[R]23D ) +33.6 (c ) 1.1, CHCl3); 1H NMR (400 MHz, CDCl3) δ
1.41 (s, 9H), 3.05-3.20 (m, 2H), 3.74 (s, 3H), 4.60 (m, 1H), 5.00
(d, J ) 7.3 Hz, 1H), 7.28 (d, J ) 8.2 Hz, 2H), 7.55 (m, 3H),
7.86 (d, J ) 7.8 Hz, 2H), 7.93 (d, J ) 7.8 Hz, 2H); 13C NMR
(100 MHz, CDCl3) δ 171.3, 154.5, 142.0, 141.1, 139.7, 132.7,
129.8, 128.8, 127.3, 127.1, 79.7, 53.6, 52.0, 37.8, 27.7; ESI-MS
(m/z) 442.2 (M + Na)+; ESI HRMS found m/z 442.1293 (M +
Na)+, C21H25NO6SNa requires 442.1300.
Acknowledgment. We are grateful to the Chinese
Academy of Sciences, National Natural Science Founda-
tion of China (Grant Nos. 20321202 and 20132030), and
Science and Technology Commission of Shanghai Mu-
nicipality (Grant Nos. 02JC14032 and 03XD14001) for
their financial support.
1-(4-(Benzenesulfonyl)phenyl)ethanone 3f: yellow solid;
mp 132-134 °C; 1H NMR (400 MHz, CDCl3) δ 2.62 (s, 3H),
7.51-7.60 (m, 3H), 7.95-8.05 (m, 6H); EI-MS (m/z) 260 (M+),
245, 217, 191, 167, 152, 141, 125, 104, 97, 77, 51, 43.
JO047758B
2700 J. Org. Chem., Vol. 70, No. 7, 2005