F. Huang, R. A. Batey / Tetrahedron 63 (2007) 7667–7672
7671
Table 5. Copper catalyzed cross-coupling of alkenyboronic acids with
sodium sulfinate salts
dichloromethane (7.5 ml) and DMSO (0.5 ml). The mixture
was stirred for 72 h at 40 ꢀC. After cooling, the reaction mix-
ture was filtered through Celite and the filter cake was
washed with ethyl acetate. The filtrate was concentrated in
vacuo and purified by flash column chromatography (silica
gel) to give the sulfone products.
Cu(OAc)2·H2O (10 mol%)
O O
1,10-phen (20 mol%)
R2
B(OH)2
S
SO2Na
R1
R1
R2
CH2Cl2/DMSO (15:1),
O2, 4Å MS,40 °C, 72 h
3
Entry
Alkenylboronic
acid
Sulfinate
salt
Sulfone Yielda (%)
product
4.2.1. 1-Trifluoromethyl-4-(toluene-4-sulfonyl)benzene
(1e). White solid; mp¼112–113 ꢀC; Rf ¼0.48 (EtOAc/hex-
anes, 4:1); IR (Thin Film) (NaCl) 3153, 3023, 1594, 1404,
B(OH)2
1
2
3
PhSO2Na
3a
84
84
76
1
1323, 1155, 1106, 1072, 1060, 717, 660 cmꢁ1; H NMR
(300 MHz, CDCl3) d 8.06 (2H, d, J¼8.0 Hz), 7.86–7.83
(2H, m), 7.76 (2H, d, J¼8.5 Hz), 7.33 (2H, d, J¼8.0 Hz),
2.41 (3H, s); 13C NMR (300 MHz, CDCl3) d 145.8, 145.2,
137.8, 134.8 (q, J¼33.0 Hz), 130.4, 128.2, 128.1, 126.6 (q,
J¼4.0 Hz), 123.3 (q, J¼273.0 Hz), 21.8; MS (EI) m/e (rel in-
tensity) 91 (31), 107 (50), 139 (35), 300 (100); HRMS (EI)
m/e calcd (M+) 300.0432, found 300.0434.
B(OH)2
B(OH)2
TolSO2Na 3b
MeSO2Na 3c
B(OH)2
B(OH)2
B(OH)2
4
5
PhSO2Na
3d
52
68
47
TolSO2Na 3e
MeSO2Na 3f
4.2.2. 1-Trifluoromethyl-2-(toluene-4-sulfonyl)benzene
(1j). White solid; Rf ¼0.24 (EtOAc/hexanes, 4:1); 1H NMR
(300 MHz, CDCl3) d 8.43 (1H, d, J¼6.5 Hz), 7.85–7.71 (5H,
m), 7.30 (2H, d, J¼8.0 Hz), 2.41 (3H, s); 13C NMR
(300 MHz, CDCl3) d 144.6, 140.4, 138.4, 133.5, 132.7,
132.5, 129.8, 128.9 (q, J¼33.0 Hz), 128.6 (q, J¼6.5 Hz),
128.1, 122.7 (q, J¼274.5 Hz), 21.8.
6
a
Isolated yield.
symmetric copper-based cross-couplings to biaryls, and
oxidative coupling to phenols and biaryl ethers.
4. Experimental section
4.1. General
4.2.3. 1-Benzenesulfonyl-4-methoxybenzene (2f). White
solid; Rf ¼0.10 (EtOAc/hexanes, 4:1); 1H NMR (300 MHz,
CDCl3) d 7.90–7.85 (2H, m), 7.27–7.70 (2H, m), 3.89 (3H,
s), 3.04 (3H, s); 13C NMR (300 MHz, CDCl3) d 163.9,
132.4, 129.7, 114.7, 55.9, 45.0.
CH2Cl2 was distilled from CaH2 under nitrogen. All other
commercial reagents were used as received (Aldrich, Fischer
Scientific Ltd. or BDH). All glassware was flame-dried.
4.2.4. (E)-Methanesulfonyl-hex-1-ene (3f). Light yellow
liquid; 1H NMR (300 MHz, CDCl3) d 6.96 (1H, dt,
J¼15.0, 7.0 Hz), 6.37 (1H, dt, J¼15.5, 1.5 Hz), 2.93 (3H,
s), 2.32–2.25 (2H, m), 1.53–1.26 (4H, m), 0.93 (3H, t,
J¼7.5 Hz); 13C NMR (300 MHz, CDCl3) d 149.0, 129.5,
43.1, 31.3, 29.8, 22.3, 13.9.
1
Melting points are uncorrected. H and 13C NMR were re-
corded at 400 and 300 MHz, respectively, on a Varian Unity
400 spectrometer, Mercury 300 MHz spectrometer, and
Gemini 300 MHz spectrometer. Proton chemical shifts
were internally referenced to the residual proton resonance
in CDCl3 (d 7.26). Carbon chemical shifts were internally
referenced to the deuterated solvent signals in CDCl3 (d
77.23). FTIR spectra were recorded on a Perkin–Elmer
Spectrum 1000, with samples loaded as neat films on NaCl
plates. Low resolution mass spectra were recorded on
a Bell and Howell 21-490 spectrometer, and high resolution
spectra were recorded on an AEI MS3074 spectrometer.
Analytical thin layer chromatography (TLC) was performed
on pre-coated silica gel plates (Silicycle Inc.), visualized
with a UV254 lamp (Spectroline, Longlife Filter) and
stained with 20% phosphomolybdic acid in ethanol. Full
Acknowledgements
This work was supported by the Natural Science and Engi-
neering Research Council (NSERC) of Canada. We thank
Dr. A. B. Young for mass spectrometric analysis.
References and notes
1
spectral data are provided for new compound 1e and H
and 13C NMR are provided for the known compounds 1j,
2f, and 3f, which lack full characterization in the literature.
1. For reviews on Pd catalyzed Buchwald–Hartwig C–N and C–O
bond formation reactions, see: (a) Muci, A. R.; Buchwald, S. L.
Top. Curr. Chem. 2002, 219, 131–209; (b) Hartwig, J. F. Angew.
Chem., Int. Ed. 1998, 37, 2046–2067.
4.2. General procedure for the preparation of sulfones
1–3
2. For an excellent general review of the early literature, see:
Lindley, J. Tetrahedron 1984, 40, 1433–1456.
3. For more reviews on more recent developments in Cu catalyzed
C–C, C–N, and C–O bond formation reactions, see: (a)
Beletskaya, I. P.; Cheprakov, A. V. Coord. Chem. Rev. 2004,
248, 2337–2364; (b) Nelson, T. D.; Crouch, R. D. Org.
React. 2004, 63, 265–555; (c) Kunz, K.; Scholz, U.; Ganzer,
D. Synlett 2003, 2428–2439; (d) Hassan, J.; Sevignon, M.;
Gozzi, C.; Schulz, E.; Lemaire, M. Chem. Rev. 2002, 102,
To a mixture of the organoboronic acid (2.00 mmol), copper
acetate monohydrate (20.0 mg, 0.100 mmol), 1,10-phen-
˚
anthroline (36.0 mg, 0.200 mmol), powdered 4 A molecular
sieves (0.75 g), and sodium sulfinate salt (1.00 mmol) under
an atmosphere of oxygen (reaction vessels are attached to
an oxygen manifold at atmospheric pressure) were added