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LETTER
(5) (a) Otera, J. Pure Appl. Chem. 2006, 78, 731. (b) Orita, A.;
Otera, J. Chem. Rev. 2006, 106, 5387. For one-pot double
elimination protocols, see: (c) Orita, A.; Ye, F.; Babu, G.;
Ikemoto, T.; Otera, J. Can. J. Chem. 2005, 83, 716.
(d) Orita, A.; Nakano, T.; Yokoyama, T.; Babu, G.; Otera, J.
Chem. Lett. 2004, 33, 1298. (e) Orita, A.; Miyamoto, K.;
Nakashima, M.; Ye, F.; Otera, J. Adv. Synth. Catal. 2004,
346, 767. (f) Ye, F.; Orita, A.; Yaruva, J.; Hamada, T.;
Otera, J. Chem. Lett. 2004, 33, 528. (g) Ye, F.; Orita, A.;
Doumoto, A.; Otera, J. Tetrahedron 2003, 59, 5635.
(h) Orita, A.; Ye, F.; Doumoto, A.; Otera, J. Chem. Lett.
2003, 32, 104. (i) Orita, A.; An, D.-L.; Nakano, T.; Yaruva,
J.; Ma, N.; Otera, J. Chem. Eur. J. 2002, 8, 2005. (j) Orita,
A.; Hasegawa, D.; Nakano, T.; Otera, J. Chem. Eur. J. 2002,
8, 2000. (k) Orita, A.; Alonso, E.; Yaruva, J.; Otera, J.
Synlett 2000, 1333. (l) Orita, A.; Yoshioka, N.; Struwe, P.;
Braier, A.; Beckmann, A.; Otera, J. Chem. Eur. J. 1999, 5,
1355. For one-shot double elimination protocols, see:
(m) Shao, G.; Orita, A.; Nishijima, K.; Ishimaru, K.;
Takezaki, M.; Wakamatsu, K.; Gleiter, R.; Otera, J. Chem.
Asian J. 2007, 2, 489. (n) Orita, A.; Taniguchi, H.; Otera, J.
Chem. Asian J. 2006, 1, 430.
7.85, 7.88 (s, 1 H). 13C NMR (125 MHz, CDCl3): d = 94.1
(93.5), 122.7 (122.1), 128.7, 128.9, 129.1, 129.3, 128.1,
128.5, 128.6, 130.1, 130.4, 129.5, 129.7, 132.5, 132.9,
133.3, 133.6, 134.5, 132.1, 132.7, 133.4, 135.3, 136.4,
138.1, 139.0, 139.6, 137.1, 137.3, 137.6, 139.9, 141.6,
141.7.
1-(3-Bromophenyl)-2-[3-(4-methoxyphenyl-
ethynyl)phenyl]-1-(phenylsulfonyl)ethene (5a): A toluene
solution (14 mL) of 4a (1.20 g, 2.3 mmol), 4-methoxy-
phenylethyne (341 mg, 2.6 mmol), Pd(PPh3)4 (132 mg, 0.11
mmol), CuI (23.0 mg, 0.12 mmol) and diisopropylamine
(4.6 mL) was stirred at r.t. for 12 h. After filtration, the
filtrate was washed with aq NH4Cl, and the aqueous layer
was extracted with EtOAc. The combined organic layer was
washed with aq NaCl, dried over MgSO4 and evaporated.
The residue was subjected to column chromatography on
silica gel (10% EtOAc–hexane) to afford 5a (1.07 g, 88%).
Compound 5a: only one isomer was obtained. The geometry
E or Z isomer was not determined. 1H NMR (500 MHz,
CDCl3): d = 3.83 (s, 3 H), 6.87 (d, J = 8.9 Hz, 2 H), 6.90 (d,
J = 8.2 Hz, 1 H), 6.97 (d, J = 7.9 Hz, 1 H), 7.12 (t, J = 7.8
Hz, 1 H), 7.14–7.18 (m, 2 H), 7.29 (s, 1 H), 7.37–7.46 (m, 5
H), 7.49–7.53 (m, 1 H), 7.57 (t, J = 7.5 Hz, 1 H), 7.64 (d, J =
7.6 Hz, 2 H), 7.94 (s, 1 H). 13C NMR (125 MHz, CDCl3):
d = 55.3, 86.9, 90.4, 114.1, 114.9, 122.6, 124.4, 128.6, 128.7,
128.9, 129.0, 129.5, 130.3, 132.4, 132.6, 132.9, 133.1,
133.2, 133.4, 133.5, 133.9, 137.5, 138.3, 141.0, 159.9.
1-(3-Bromophenylethynyl)-3-(4-methoxyphenyl-
ethynyl)benzene (3a): To a toluene solution (22 mL) of 5a
(285 mg, 0.54 mmol) was added a THF solution of LiHMDS
(1.0 M, 2.2 mL, 2.2 mmol) at 0 °C, and the mixture was
stirred at r.t. for 2 h. After usual workup with EtOAc–aq
NH4Cl, the organic layer was evaporated, and the residue
was subjected to column chromatography on silica gel (2%
EtOAc–hexanes) to furnish 3a (161 mg, 77%). Compound
3a: 1H NMR (500 MHz, CDCl3): d = 3.84 (s, 3 H), 6.89 (d,
J = 8.9 Hz, 2 H), 7.23 (t, J = 7.9 Hz, 1 H), 7.33 (t, J = 7.8 Hz,
1 H), 7.43–7.50 (m, 6 H), 7.67–7.70 (m, 2 H). 13C NMR (125
MHz, CDCl3): d = 55.2, 87.1, 88.2, 89.9, 90.2, 114.0, 115.0,
122.1, 123.0, 124.0, 125.0, 128.4, 129.7, 130.1, 130.9,
131.4, 131.5, 133.1, 134.3, 134.4, 159.7.
(6) Typical Procedures
1-(3-Bromophenyl)-2-(3-iodophenyl)-1-(phenylsulfon-
yl)ethene (4a): To a THF solution (30 mL) of 3-bromo-
phenylmethyl phenyl sulfone (2.00 g, 6.4 mmol) was added
a THF solution of LiHMDS (1.0 M, 7.0 mL, 7.0 mmol) at
–78 °C, and the mixture was stirred for 0.5 h. A THF solution
(8 mL) of 3-iodobenzaldehyde (1.24 g, 5.3 mmol) was added
at –78 °C, and the mixture was stirred for 1 h. Diethyl
chlorophosphate (0.75 mL, 5.4 mmol) was added at –78 °C,
and the mixture was stirred at r.t. for 1 h. A THF solution of
LiHMDS (1.0 M, 5.4 mL, 5.4 mmol) was added at –78 °C,
and the mixture was stirred at r.t. overnight. After usual
workup with EtOAc–aq NH4Cl, the organic layer was
evaporated, and the residue was subjected to column
chromatography on silica gel (10% EtOAc–hexane) to
furnish 4a (2.24 g, 80%).Compound 4a: E/Z = 88:12 (the
geometry of E- or Z-isomers was not determined, several
signals overlapped in 13C NMR). 1H NMR (500 MHz,
CDCl3): d = 6.91 (t, J = 7.8 Hz, 1 H), 6.93–7.00, 7.03–7.12
(m, 2 H), 7.13–7.21, 7.32–7.37 (m, 2 H), 7.40–7.68 (m, 8 H),
Synlett 2008, No. 1, 55–60 © Thieme Stuttgart · New York