K. Okuma, K. Kojima, K. Oyama, K. Kubo, K. Shioji
FULL PAPER
which were chromatographed over silica gel by elution from hex-
ane/dichloromethane (2:1) to afford 2,2-bis(4-methoxyphenyl)-1-
(5 mL) was added in one portion to a solution of 3e (80 mg,
0.2 mmol) in THF (5 mL) at room temp. The resulting solution
trimethylsilylethylene (5c) (64 mg, 0.20 mmol) and 5b (40 mg, was refluxed for 6 h, and the solvents evaporated to give pale-yel-
0.087 mmol). 5c: Colorless oil. (ref.[23] colorless oil). 1H NMR
(CDCl3): δ ϭ Ϫ0.11 (s, 9 H, Me3Si), 3.79 (s, 3 H, OMe), 3.84 (s, 3
low oily crystals, which were chromatographed over silica gel by
elution with hexane and hexane/dichloromethane (1:1) to afford
H, OMe), 6.12 (s, 1 H, CHϭ), 6.79 (d, 2 H, Ar), 6.87 (d, 2 H, Ar), 4,5-dimethyl-2,2-diphenyl-3,6-dihydro-2H-selenopyran (8) (40 mg,
7.10 (d, 2 H, Ar), 7.20 (d, 2 H, Ar) ppm. 13C NMR (CDCl3): δ ϭ
0.00 (Me3Si), 55.10 (OMe), 55.14 (OMe), 113.00 (Ar), 113.13(Ar),
127.03 (CHϭ), 128.35(Ar), 130.67(Ar), 135.15(Ar), 136.25 (Ar),
156.09(Ar), 158.81(Ar), 159.11 (Ar) ppm. Reaction of 1b (128 mg,
0.47 mmol) with 2b (0.4 mL, 10% in hexane) was also carried out
at room temperature, yielding 2,2-bis(4-methylphenyl)-1-trimethyl-
silylethylene (5f) (12 mg, 0.043 mmol) and 5e (56 mg, 0.144 mmol).
5e: Orange oil. 1H NMR (CDCl3): δ ϭ Ϫ0.19 (s, 9 H, Me3Si), 2.25
(s, 3 H, Me), 2.31 (s, 3 H, Me), 6.13 (s, 1 H, CHϭ), 6.99 (d, 2 H,
Ar), 7.01 (d, 2 H, Ar), 7.07 (d, 2 H, Ar), 7.10 (d, 2 H, Ar) ppm.
HRMS: found 280.1655, calcd for C19H24Si [Mϩ]; 280.1647.
0.124 mmol). 8: Pale-yellow oil (ref.[26] pale-yellow oil).
Reaction of Benzophenone Hydrazone (4a) with Diselenium Dibro-
mide: A solution of diselenium dibromide (640 mg, 2.0 mmol) in
dichloromethane (10 mL) was added to a solution of 4a (196 mg,
1.0 mmol) and triethylamine (410 mg, 4.0 mmol) in dichlorometh-
ane (10 mL) at room temperature. The reaction mixture was stirred
for 3 h, then poured into water, filtered and extracted with di-
chloromethane (3 ϫ 5 mL). The combined extract was dried with
magnesium sulfate and the solvents evaporated to afford a brown
oil, which was chromatographed over silica gel by elution with hex-
ane/dichloromethane (1:1) to afford 5h (123 mg, 0.37 mmol) and
9a (2 mg, 0.01 mmol).
Reaction of 1a with 4,4Ј-Ditolyldiazomethane (2d): A solution of 2d
(110 mg, 0.50 mmol) in THF (5 mL) was added via a syringe to a
solution of 1a (152 mg, 0.50 mmol) in THF (5 mL) at Ϫ78 °C. The
reaction mixture was stirred for 1 h, then warmed to room temp.
and elemental selenium was precipitated. The resulting solution
was filtered and the solvents evaporated to give a pale-orange oil.
This was chromatographed over silica gel by elution with hexane/
dichloromethane (2:1) to afford 1,1-bis(4-methoxyphenyl)-2,2-
bis(4-methylphenyl)ethylene (5i) (156 mg, 0.36 mmol), 5b (5 mg,
0.01 mmol) and 5e (19 mg, 0.05 mmol) in 72, 5 and 20% yields,
The reaction of 4,4Ј-dimethylbenzophenone hydrazone (4b)
(224 mg, 1.0 mmol) with diselenium dibromide (640 mg, 2.0 mmol)
in the presence of triethylamine (410 mg, 4.02 mmol) was carried
out in a similar manner. Olefin 5e (85 mg, 0.22 mmol) and 9b
(72 mg, 0.17 mmol) were obtained.
Reaction of Benzophenone Hydrazone (4a) with Diselenium Dibro-
mide in Refluxing Benzene: A solution of diselenium dibromide
(640 mg, 2.0 mmol) in benzene (10 mL) was added to a refluxing
solution of 4a (196 mg, 1.0 mmol) and triethylamine (410 mg,
4.0 mmol) in benzene (10 mL). After refluxing for 3 h, the reaction
mixture was poured into water, filtered and extracted with dichloro-
methane (3 ϫ 5 mL). The combined extract was dried with mag-
nesium sulfate and the solvents evaporated to afford a brown oil
which was chromatographed over silica gel by elution with hexane/
dichloromethane (1:1) to afford 5h (143 mg, 0.43 mmol).
1
respectively. 5i: M.p. 179Ϫ180 °C. H NMR (CDCl3): δ ϭ 2.25 (s,
3 H, Me), 3.73 (s, 3 H, OMe), 6.63 (d, 4 H, MeO Ar). 6.89 (s, 8 H,
Tol Ar), 6.92 (d, 4 H, MeO Ar) ppm. 13C NMR (CDCl3): δ ϭ
21.15 (Me), 55.05 (OMe), 112.70 (Ar), 128.33 (Ar), 130.95 (Ar),
132.50, 135.52, 136.77, 139.09, 141.45, 157.85 ppm. C30H28O2
(420.5): calcd. C 85.68, H 6.71; found C 85.34, H 6.65. Reaction
of 1a (25 mg, 0.082 mmol) with 2c (16 mg, 0.080 mmol) was also
carried out, yielding 1,1-bis(4-methoxypheny)-2,2-diphenylethylene
(5g) (11 mg, 0.028 mmol) and 5h (9 mg, 0.027 mmol). 5g: M.p.
160Ϫ161 °C. (ref.[24] m.p. 154Ϫ155 °C). 1H NMR (CDCl3): δ ϭ
3.74 (s, 6 H, OMe), 6.63 (d, 4 H, MeO Ar), 6.95 (d, 4 H, MeO Ar),
6.98Ϫ7.02 (m, 4 H, Ph), 7.05Ϫ7.16 (m, 6 H, Ph) ppm. C28H24O2
(392.5): calcd. C 85.68, H 6.16; found C 85.82, H 6.17.
The reaction of 4,4Ј-dimethylbenzophenone hydrazone (4b)
(224 mg, 1.0 mmol) with diselenium dibromide (640 mg, 2.0 mmol)
in the presence of triethylamine (410 mg, 4.0 mmol) was carried out
in a similar manner. Olefin 5e (159 mg, 0.41 mmol) was obtained.
The reaction of 4,4Ј-dimethoxybenzophenone hydrazone (4c)
(256 mg, 1.0 mmol) with diselenium dibromide (640 mg, 2.0 mmol)
in the presence of triethylamine (410 mg, 4.02 mmol) was carried
out in a similar manner. Olefin 5b (149 mg, 0.33 mmol) was ob-
tained.
Reaction of 1a (70 mg, 0.23 mmol) with 2e (61 mg, 0.24 mmol) was
also carried out at Ϫ45 °C. Tetrakis(4-methoxyphenyl)ethylene (5b)
was obtained. (87 mg, 0.193 mmol), m.p. 180Ϫ181 °C.
Reaction of Di-tert-butylselenoketone (1d) with Diphenyldiazome-
thane (2c): A solution of 2c (0.204 g, 1.05 mmol) in THF (10 mL)
was added to a solution of 1d (0.205 g, 1.0 mmol) in THF (10 mL)
at 0 °C. After being stirred for 2 h, the solvent was evaporated to
give pale-yellow crystals, which were crystallized from dichloro-
methane/hexane to afford yellow crystals of 1,3,4-selenadiazoline
(3e) (0.287 g, 0.72 mmol), m.p. 112Ϫ115 °C. (ref.[3b] m.p.
112Ϫ118 °C)
The reaction of 4,4Ј-dichlorobenzophenone hydrazone (4c)
(265 mg, 1.0 mmol) with diselenium dibromide (640 mg, 2.0 mmol)
in the presence of triethylamine (410 mg, 4.02 mmol) was carried
out in a similar manner. Tetrakis(4-chlorophenyl)ethylene (5k)
(236 mg, 0.42 mmol) was obtained. 5k: colorless crystals, m.p.
216Ϫ217 °C (ref.[14] m.p. 216Ϫ217 °C).
Reaction of Diselenium Dibromide with 4a and 4c: A solution of
Thermolysis of 3e: A solution of 3e (0.20 g, 0.5 mmol) in benzene
(10 mL) was refluxed for 13 h. Elemental selenium was precipitated
and filtered off, and the solvents were evaporated to give pale-blue
oily crystals, which were chromatographed over silica gel by elution
from hexane, hexane/dichloromethane (2:1), and dichloromethane
to afford 5h (0.010 g, 0.030 mmol), 1,1-di-tert-butyl-2,2-diphenyl-
ethylene (5j) (26 mg, 0.08 mmol), 1c (0.041 g, 0.020 mmol), and
benzophenone (7a) (50 mg, 0.275 mmol). 5j: Colorless crystals,
m.p. 138Ϫ140 °C (ref.[25] m.p. 140.5Ϫ141 °C).
diselenium dibromide (1.28 mg, 4.0 mmol) in dichloromethane
(20 mL) was added dropwise to
a solution of 4a (200 mg,
1.02 mmol), 4c (256 mg, 1.0 mmol), and triethylamine (404 mg,
4.0 mmol) in dichloromethane (15 mL) at room temperature. The
reaction mixture was stirred for 5 h, then washed with water (3 ϫ
10 mL ), dried with magnesium sulfate, filtered and the solvents
evaporated to give pale-brown oily crystals, which were chromato-
graphed over silica gel by elution with hexane and dichloromethane
to afford
a mixture of 5b (72 mg, 0.16 mmol), 5g (86 mg,
Reaction of 1,3,4-Selenadiazoline 3e with 2,3-Dimethyl-1,3-buta-
0.22 mmol) and 5h (53 mg, 0.16 mmol). The mixture was separated
diene: 2,3-Dimethyl-1,3-butadiene (82 mg, 1.0 mmol) in THF
by gel HPLC.
824
2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2004, 820Ϫ825