SPECIAL TOPIC
Synthesis of Substituted Indenes and cis-Stilbenoid Hydrocarbons
2657
3,4,6-Trimethyl-2-phenyl-1H-indene (3d)6
90:10) gave the cross-coupling product. The Z configuration of alk-
1H NMR showed a 91:9 ratio. Analytic sample of 3,4,6-trimethyl-2-
phenyl-1H-indene (3d) was obtained by recrystallization of the
mixture of 3,4,6-trimethyl-2-phenyl-1H-indene (3d) and 2,4,6-tri-
methyl-3-phenyl-1H-indene (3d¢) in hexanes.
ene products was established by comparison with reported data.2,3
(Z)-3,4-Bis(pentamethylphenyl)hex-3-ene (4a)6,15a
1H NMR (600 MHz, CDCl3): d = 2.50 (q, J = 7.8 Hz, 4 H), 2.10 (s,
6 H), 2.02 (s, 12 H), 2.00 (s, 12 H), 1.06 (t, J = 7.8 Hz, 6 H).
1H NMR (600 MHz, CDCl3): d = 7.39 (m, 4 H), 7.27 (m, 1 H), 7.13
(s, 1 H), 6.88 (s, 1 H), 3.64 (s, 2 H), 2.62 (s, 3 H), 2.42 (s, 3 H), 2.36
(s, 3 H).
13C NMR (150 MHz, CDCl3): d = 139.5, 139.3, 132.0, 131.6, 131.1,
29.3, 19.6, 16.5, 16.4, 13.3.
13C NMR (150 MHz, CDCl3): d = 143.6, 142.1, 140.2, 138.0, 136.0,
134.3, 130.9, 130.2, 128.6, 128.2, 126.4, 122.2, 41.2, 21.1, 20.3,
15.6.
(Z)-3,5-Bis(pentamethylphenyl)oct-4-ene (4b)15a
1H NMR (600 MHz, CDCl3): d = 2.40 (m, 4 H), 2.11 (s, 6 H), 2.02
(s, 12 H), 2.00 (s, 12 H), 1.52 (m, 4 H), 0.93 (t, J = 7.2 Hz, 6 H).
The structure of 3,4,6-trimethyl-2-phenyl-1H-indene (3d) was es-
13C NMR (150 MHz, CDCl3): d = 139.6, 138.7, 131.9, 131.6, 131.1,
39.2, 22.2, 19.7, 16.6, 16.4, 15.0.
tablished by comparison with reported data.6
4-Methyl-2,3-diphenyl-1H-indene (3e)6
(Z)-3,4-Bis(2,4,6-trimethylphenyl)hex-3-ene (4c)6,15a
1H NMR (600 MHz, CDCl3): d = 7.41–7.37 (m, 4 H), 7.33 (m, 2 H),
7.19 (d, J = 7.8 Hz, 2 H), 7.15 (d, J = 7.8 Hz, 2 H), 7.13 (t, J = 7.8
Hz, 2 H), 6.99 (d, J = 7.8 Hz, 1 H), 3.90 (s, 2 H), 1.85 (s, 3 H).
1H NMR (600 MHz, CDCl3): d = 6.63 (s, 4 H), 2.47 (q, J = 7.8 Hz,
4 H), 2.15 (s, 6 H), 2.06 (s, 12 H), 1.02 (t, J = 7.8 Hz, 6 H).
13C NMR (150 MHz, CDCl3): d = 138.6, 138.5, 135.7, 134.9, 128.1,
28.2, 20.9, 20.8, 13.4.
13C NMR (150 MHz, CDCl3): d = 144.1, 142.7, 141.5, 141.2, 139.2,
136.6, 131.9, 129.7, 129.6, 128.6, 128.0, 128.0, 127.2, 126.6, 124.9,
121.3, 40.9, 20.0.
(Z)-4,5-Bis(2,4,6-trimethylphenyl)oct-4-ene (4d)
1H NMR (600 MHz, CDCl3): d = 6.62 (s, 4 H), 2.37 (m, 4 H), 2.15
(s, 6 H), 2.05 (s, 12 H), 1.45 (m, 4 H), 0.93 (t, J = 7.2 Hz, 6 H).
2,3-Diethyl-4-methyl-1H-indene (3f)6
1H NMR (300 MHz, CDCl3): d = 7.29 (m, 1 H), 7.06 (m, 2 H), 3.31
(s, 2 H), 2.73 (q, J = 7.5 Hz, 2 H), 2.65 (s, 3 H), 2.52 (q, J = 7.5 Hz,
2 H), 1.21 (t, J = 7.5 Hz, 6 H).
13C NMR (150 MHz, CDCl3): d = 138.7, 137.8, 135.6, 134.8, 128.1,
38.1, 22.4, 21.0, 20.8, 14.9.
13C NMR (150 MHz, CDCl3): d = 144.7, 144.3, 143.8, 139.8, 129.9,
(Z)-1-Phenyl-1,2-bis(2,4,6-trimethylphenyl)prop-1-ene (4e)6
1H NMR (600 MHz, CDCl3): d = 7.27 (m, 4 H), 7.16 (m, 1 H), 6.68
(s, 2 H), 6.59 (s, 2 H), 2.173 (s, 3 H), 2.165 (s, 3 H), 2.16 (br s, 6 H),
2.13 (s, 3 H), 2.04 (s, 6 H).
13C NMR (150 MHz, CDCl3): d = 142.5, 139.3, 138.3, 137.9, 136.4,
135.7, 135.5, 135.3, 135.1, 130.1, 128.3, 127.3, 125.8, 23.0, 21.7,
21.0, 20.83, 20.81.
129.5, 123.8, 121.5, 39.9, 21.6, 20.3, 20.1, 15.6, 14.9.
3,4-Dimethyl-2-phenyl-1H-indene (3g)6
1H NMR showed a 90:10 ratio. Analytic sample of 3,4-dimethyl-2-
phenyl-1H-indene (3g) was obtained by recrystallization of the
mixture of 3,4-dimethyl-2-phenyl-1H-indene (3g) and 2,4-dimeth-
yl-3-phenyl-1H-indene (3g¢) in hexanes. White solid; mp 75–77 °C.
1H NMR (600 MHz, CDCl3): d = 7.40 (m, 4 H), 7.30 (m, 2 H), 7.09
(t, J = 7.2 Hz, 1 H), 7.05 (d, J = 7.2 Hz, 1 H), 3.67 (s, 2 H), 2.66 (s,
3 H), 2.44 (s, 3 H).
13C NMR (150 MHz, CDCl3): d = 144.6, 143.3, 141.3, 137.9, 136.2,
131.3, 129.4, 128.6, 128.3, 126.6, 124.6, 121.4, 41.4, 20.4, 15.6.
(Z)-3,4-Bis(2,6-dimethylphenyl)hex-3-ene (4f)15a
1H NMR (600 MHz, CDCl3): d = 6.90 (d, J = 7.2 Hz, 2 H), 6.80 (d,
J = 7.2 Hz, 4 H), 2.52 (d, J = 7.2 Hz, 4 H), 2.11 (s, 12 H), 1.40 (t,
J = 7.2 Hz, 6 H).
13C NMR (150 MHz, CDCl3): d = 141.1, 138.7, 137.8, 136.9, 127.2,
125.8, 27.9, 21.0, 13.3.
The structure of 3,4-dimethyl-2-phenyl-1H-indene (3g) was estab-
lished by comparison with reported data.6
(Z)-1,2-Bis(2,6-dimethylphenyl)-1-phenylprop-1-ene (4g)6
1H NMR (600 MHz, CDCl3): d = 7.29 (m, 4 H), 7.19 (m, 1 H), 6.92
(t, J = 7.2 Hz, 1 H), 6.89 (t, J = 7.2 Hz, 1 H), 6.85 (d, J = 7.2 Hz, 2
H), 6.77 (d, J = 7.8 Hz, 2 H), 2.22 (s, 3 H), 2.20 (s, 6 H), 2.08 (s, 6
H).
13C NMR (150 MHz, CDCl3): d = 142.0, 140.9, 137.9, 136.6, 135.8,
135.3, 130.1, 127.4, 126.3, 126.1, 126.0, 22.8, 21.8, 21.1.
4,5,6,7-Tetramethyl-2,3-diphenyl-1H-indene (3h)6
1H NMR (600 MHz, CDCl3): d = 7.38 (t, J = 7.2 Hz, 2 H), 7.34 (t,
J = 7.2 Hz, 1 H), 7.29 (d, J = 7.2 Hz, 2 H), 7.16 (d, J = 7.8 Hz, 2 H),
7.13 (t, J = 7.8 Hz, 2 H), 7.09 (t, J = 7.8 Hz, 1 H), 3.79 (s, 2 H), 2.38
(s, 3 H), 2.30 (s, 3 H), 2.19 (s, 3 H), 1.80 (s, 3 H).
13C NMR (150 MHz, CDCl3): d = 142.16, 141.42, 140.5, 139.9,
139.1, 137.1, 134.6, 132.1, 129.7, 128.6, 128.2, 128.0, 127.9, 127.0,
126.3, 40.6, 16.4, 16.24, 16.21, 16.1.
(Z)-1,2-Bis(pentamethylphenyl)-1,2-diphenylethene (4h)6,15a
1H NMR (600 MHz, CDCl3): d = 7.05–7.03 (m, 6 H), 7.00–6.98 (m,
4 H), 2.11 (s, 18 H), 2.01 (s, 12 H).
13C NMR (150 MHz, CDCl3): d = 143.3, 141.5, 139.0, 132.8, 131.8,
131.7, 130.9, 127.2, 125.6, 20.0, 16.6, 16.4.
Dichlorobis(triphenylphosphine)palladium-Catalyzed Cross-
Coupling Reactions of (E)-1,2-Dibromoethenes with Hindered
Grignard Reagents; General Procedure
In a glove box with an N2 atmosphere, PdCl2(PPh3)2 (0.015 mmol),
(E)-1,2-dibromoethene (0.5 mmol), and THF (1 mL) were added to
a Schlenk flask. The mixture was stirred for 2 min and then the
Grignard reagent in THF soln (1.25 mmol) was added. The mixture
was stirred under reflux for 20 h. The reaction was quenched with
H2O and extracted with EtOAc (2 × 20 mL). The organic layer was
washed with brine, dried (Na2SO4), and concentrated under vacu-
um. The crude mixtures were analyzed by 1H NMR, from which the
ratio of cyclization product to cross-coupling product were deter-
mined. Flash chromatography (silica gel, hexane–EtOAc, 100:0 to
Acknowledgment
We gratefully thank the NIH (GM69704) and NSF(CHE079311)
for funding. Partial support from the Petroleum Research Fund, ad-
ministered by the American Chemical Society (44428-AC1) and
PSC-CUNY Research Award Programs, is also gratefully acknowl-
edged. We also thank Frontier Scientific, Inc. for its generous gifts
of Pd(OAc)2 and Pd(PPh3)4.
Synthesis 2008, No. 16, 2650–2658 © Thieme Stuttgart · New York