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(CDCl3, 400 MHz) δ 8.31 (d, J = 8.2 Hz, 1H), 8.03 (d, J = 9.2 Hz, 1H),
7.89 (d, J = 16.0 Hz, 1H), 7.82 (d, J = 9.2 Hz, 1H), 7.78−7.74 (m, 2H),
7.56 (d, J = 8.3 Hz, 1H), 7.44 (d, J = 8.3 Hz, 1H), 7.38 (t, J = 7.8 Hz, 1H),
7.33 (dd, J = 7.8 Hz, 0.7 Hz, 1H), 7.15 (d, J = 16.0 Hz, 1H), 2.76 (s, 3H),
1.54 (s, 9H), 1.37 (s, 9H); 13C{1H} NMR (CDCl3, 100.6 MHz) δ 150.9,
146.3, 135.0, 133.8, 131.9, 131.8, 131.7, 131.5, 131.4, 130.1, 128.3, 126.6,
126.4, 125.8, 125.7, 123.8, 123.1, 122.3, 121.4, 37.9, 34.5, 31.3, 19.2;
HRMS (TOF MS CI+) calcd for C31H34 (M+) 406.2661, found
406.2654.
1,11-Di-tert-butyl-4-methyl[5]phenacene (16) and 1,13-Di-tert-
butyl-4-methyl[5]helicene (17). A solution of 0.128 g (0.31 mmol) of
ethene 15 and 0.096 g (0.37 mmol) of iodine in a mixture of 108 mL of
hexanes and 12 mL of 1-epoxybutane was irradiated for 2 h after which
time the reaction was judged complete by GC−MS analysis. The
reaction mixture was washed with three 75 mL portions of aq NaHSO3
followed by 75 mL of water. The organic phase was dried over Na2SO4,
and the hexanes were removed by rotary evaporation to give a pale
yellow solid that was chromatographed on a dry silica gel column (0.625
in. × 21 in.) using a mixture of 70% hexanes/30% CH2Cl2. The band
corresponding to Rf = 0.48 was isolated and the silica gel extracted with
diethyl ether in a Soxhlet. The ether was evaporated to give 0.126 g
(99%) of a pale yellow solid that was shown by NMR analysis to be a
mixture of 74% 16 and 26% 17. The solid was dissolved in hot EtOH and
allowed to cool slowly to room temperature whereupon a pale yellow
solid crystallized out. A second recrystallization from EtOH gave pure
phenacene 16: mp 203−204 °C; 1H NMR (CDCl3, 400 MHz) δ 8.80 (d,
J = 1.7 Hz, 1H), 8.69 (d, J = 9.2 Hz, 1H), 8.67 (s, 2H), 8.63 (d, J = 9.3 Hz,
1H), 8.07 (d, J = 9.2 Hz, 1H), 7.97 (d, J = 9.2 Hz, 1H), 7.94 (d, J = 8.4
Hz, 1H), 7.84 (d, J = 7.7 Hz, 1H), 7.73 (dd, J = 8.4 Hz, 1.8 Hz, 1H), 7.39
(dd, J = 7.7 Hz, 0.72 Hz, 1H), 2.74 (s, 3H), 1.61 (s, 9H), 1.54 (s, 9H);
13C{1H} NMR (CDCl3, 100.6 MHz) δ 149.5, 146.3, 131.9, 131.8, 131.6,
HRMS (TOF MS CI+) calcd for C30H33 (M + 1) 393.2582, found
393.2574.
1,11-Di-tert-butyl[5]phenacene (22) and 1,13-Di-tert-butyl[5]-
helicene (23). A solution of 0.177 g (0.45 mmol) of ethene 21 and
0.126 g (0.50 mmol) of iodine in a mixture of 162 mL of hexanes and 18
mL of 1-epoxybutane was irradiated for 3 h, after which time the reaction
was judged complete by GC−MS analysis. The reaction mixture was
extracted with four 75 mL portions of aq NaHSO3 followed by 75 mL of
water. The organic phase was then dried over Na2SO4 and, the hexanes
were removed by rotary evaporation to give a pale yellow solid that was
chromatographed on a dry silica gel column (0.625 in. × 21 in.) using a
mixture of 50% hexanes/50% CH2Cl2. The band corresponding to Rf =
0.57 was isolated, and the silica gel was extracted with diethyl ether in a
Soxhlet. The ether was removed to give 0.162 g (92%) of a pale yellow
solid shown by NMR analysis to be a mixture of 77% 16 and 23% 17.
This solid was dissolved in hot EtOH and allowed to cool slowly to room
temperature whereupon a pale yellow solid crystallized out. A second
recrystallization from EtOH gave pure phenacene 22: mp 184−185 °C;
1H NMR (CDCl3, 400 MHz) δ 8.81 (d, J = 1.3 Hz, 1H), 8.74−8.67 (m,
3H), 8.61 (d, J = 9.0 Hz, 1H), 7.98−7.93 (m, 3H), 7.87 (d, J = 9.0 Hz,
1H), 7.75−7.70 (m, 2H), 7.54 (t, J = 7.6 Hz, 1H), 1.66 (s, 9H), 1.54 (s,
9H); 13C{1H} NMR (CDCl3, 100.6 MHz) δ 149.2, 148.2, 133.0, 131.3,
130.4, 129.7, 129.4, 129.3, 128.5, 128.2, 127.9, 127.7, 127.6, 126.4, 125.9,
125.0, 124.8, 121.1, 120.9, 118.4, 116.9, 37.9, 35.1, 34.3, 31.3; HRMS
(TOF MS CI+) calcd for C30H30 (M+) 390.2348, found 390.2338.
The filtrate from the first crystallization was chromatographed on a
silica gel preparative thin layer plate with a 25% CH2Cl2/75% hexane
mixture. The band corresponding to Rf = 0.40 was isolated and the silica
gel extracted with diethyl ether in a Soxhlet. The ether was evaporated
and the resulting material recrystallized from methanol to give helicene
23 as a pale yellow solid: mp 163−164 °C; 1H NMR (CDCl3, 400 MHz)
δ 7.88−7.74 (m, 7H), 7.71 (d, J = 8.3 Hz, 1H), 7.57−7.56 (m, 2H), 7.48
(dd, J = 8.4 Hz, 1.9 Hz, 1H), 7.30 (d, J = 1.9 Hz, 1H), 1.05 (s, 9H), 0.26
(s, 9H); 13C{1H} NMR (CDCl3, 100.6 MHz) δ 149.2, 147.4, 133.1,
131.5, 131.4, 130.5, 130.0, 129.7, 128.5, 128.2, 127.4, 127.2, 126.7, 126.4,
125.9, 125.4, 125.3, 125.1, 125.0, 124.8, 124.7, 123.9, 38.8, 34.4, 32.5,
31.0; HRMS (TOF MS CI+) calcd for C30H30 (M+) 390.2348, found
390.2332.
131.0, 130.0, 129.9, 129.8, 129.1, 128.5, 128.4, 128.2, 127.7, 126.60,
126.55, 125.0, 123.5, 121.3, 120.8, 118.6, 117.0, 38.0, 35.4, 34.6, 31.6,
19.3; HRMS (TOF MS CI+) calcd for C31H32 (M+) 404.2504, found
404.2505.
The filtrate from the first crystallization was chromatographed on a
silica gel preparative thin layer plate with a 30% CH2Cl2/70% hexane
mixture. The band corresponding to Rf = 0.54 was isolated and the silica
gel extracted with diethyl ether in a Soxhlet. The ether was evaporated
and the resulting material recrystallized from EtOH to give helicene 17
1-Methyl-7-naphthaldehyde (39). The aldehyde was prepared as
described previously.6,7 The crude product was recrystallized from
hexanes to give 39 as a white crystalline solid (3.02 g, 80%): mp 54.5−
55.5 °C (lit.7 mp 55.5−56.5 °C).
1
as a pale yellow solid: mp 213.0−214.5 °C; H NMR (CDCl3, 400
MHz) δ 7.99 (d, J = 8.5 Hz, 1H), 7.88−7.83 (m, 2H), 7.81−7.78 (m,
3H), 7.75 (d, J = 8.5 Hz, 1H), 7.47 (dd, J = 8.4 Hz, 1.9 Hz, 1H), 7.44−
7.43 (m, 2H), 7.23 (d, J =1.9 Hz, 1H), 2.81 (s, 3H), 1.06 (s, 9H), 0.22 (s,
9H); 13C{1H} NMR (CDCl3, 100.6 MHz) δ 147.4, 147.1, 132.0, 131.5,
131.1, 130.5, 130.4, 130.1, 129.8, 128.4, 128.1, 127.3, 127.2, 126.7, 126.4,
125.7, 125.3, 124.9, 124.70, 124.65, 123.9, 123.2, 38.5, 34.4, 32.6, 31.0,
19.3; HRMS (TOF MS CI+) calcd for C31H32 (M+) 404.2504, found
404.2498.
(E)-1-(2-Bromophenyl)-2-(8′-methyl-2′-naphthyl)ethene (40). A
procedure similar to that employed for the preparation of 36 was
used. From 5.45 g (17.7 mmol) of diethyl 2-bromobenzylphosphonate8
and 3.02 g (17.7 mmol) of aldehyde 397 there was obtained, after
recrystallization of the crude product from EtOH, 4.04 g (71%) of 40 as
white needles: mp 115−116 °C; 1H NMR (C6D6, 400 MHz) δ 7.90 (br
s, 1H), 7.78 (d, J = 16.1 Hz, 1H), 7.72 (dd, J = 8.6 Hz, 1.7 Hz, 1H), 7.64
(d, J = 8.6 Hz, 1H), 7.54 (d, J = 8.2 Hz, 1H), 7.43 (dd, J = 8.1 Hz, 1.1 Hz,
1H), 7.41 (dd, J = 7.4 Hz, 1.6 Hz, 1H), 7.20 (t, J = 7.0 Hz, 1H), 7.12 (d, J
= 6.9 Hz, 1H), 7.04 (d, J = 16.2 Hz, 1H), 6.95 (td, J = 7.5 Hz, 0.6 Hz,
1H), 6.70 (td, J = 7.6 Hz, 1.6 Hz, 1H), 2.46 (s, 3H); 13C{1H} NMR
(CDCl3, 100.6 MHz) δ 137.2, 134.5, 134.4, 133.4, 133.1, 132.8, 132.0,
129.1, 128.8, 127.6, 127.2, 126.7, 126.2, 125.9, 124.2, 123.9, 123.0, 19.4;
HRMS (TOF MS CI+) calcd for C19H15Br (M+) 322.0357, found
322.0364.
9-Bromo-1-methylbenzo[c]phenanthrene (41). The general pro-
cedure was similar to that described for the preparation of 11. Ethene 40
(2.00 g, 6.2 mmol) and iodine (0.39 g, 1.5 mmol) were dissolved in a
mixture of hexanes (800 mL) and toluene (200 mL) and irradiated for
18 h. After the usual workup there was obtained a tan material that was
recrystallized from EtOH to give 41 (1.58 g, 79%) as an off-white solid:
mp 97−98 °C; 1H NMR (CDCl3, 400 MHz) δ 8.40 (dd, J = 8.8 Hz, 1.7
Hz, 1H), 7.99 (br d, J = 8.4 Hz, 1H), 7.97 (d, J = 8.8 Hz, 1H), 7.89−7.84
(m, 2H), 7.85 (dd, J = 7.5 Hz, 1.1 Hz, 1H), 7.76 (d, J = 8.4 Hz, 1H), 7.62
(t, J = 7.5 Hz, 1H), 7.54 (br d, J = 7.0 Hz, 1H), 7.39 (dd, J = 8.4 Hz, 7.6
Hz, 1H), 2.37 (s, 3H); 13C{1H} NMR (CDCl3, 100.6 MHz) δ 135.8,
134.3, 131.81, 131.77, 130.5, 129.87, 129.85, 129.51, 129.45, 128.5,
(E)-1-(4-tert-Butylphenyl)-2-(5′-tert-butyl-1′-phenanthryl)ethene
(21). A solution of 0.38 g (0.81 mmol) of 18 in 20 mL of dry diethyl
ether was cooled to 0 °C under an argon atmosphere after which n-BuLi
(0.103 g, 1.6 mmol) as a 2.5 M solution in hexane was added dropwise
over 15 min. The reaction mixture was stirred at 0 °C for 1 h during
which time it turned dark red. Water (8.0 mL) was then added dropwise
over 20 min. The reaction mixture was allowed to warm to room
temperature where it was maintained for 1 h. The mixture was diluted
with an additional 50 mL of diethyl ether and washed successively with
50 mL of 5% H3PO4, 50 mL of aq NaHCO3 and 50 mL of water. The
organic layer was dried over Na2SO4 and the solvent removed by rotary
evaporation. The resulting solid was recrystallized from a methanol/
hexanes mixture to give 0.24 g (76%) of 21 as a white crystalline solid:
mp 179−180 °C; 1H NMR (CDCl3, 400 MHz) δ 8.38 (bd, J = 8.2 Hz,
1H), 7.99 (d, J = 9.0 Hz, 1H), 7.88 (dd, J = 7.7 Hz, 1.2 Hz, 1H), 7.86 (d, J
=16.0 Hz, 1H), 7.75 (d, J = 7.2 Hz, 1H), 7.62−7.58 (m, 2H), 7.56−7.53
(m, 2H), 7.47 (t, J = 7.6 Hz, 1H), 7.44−7.38 (m, 3H), 7.13 (d, J = 16.0
Hz, 1H), 1.58 (s, 9H), 1.35 (s, 9H); 13C{1H} NMR (CDCl3, 100.6
MHz) δ 150.9, 135.0, 134.1, 133.3, 131.71, 131.69, 131.5, 128.7, 127.6,
126.4, 125.9, 125.7, 125.2, 123.9, 122.6, 121.8, 38.0, 34.7, 34.4, 31.3;
I
dx.doi.org/10.1021/jo501965y | J. Org. Chem. XXXX, XXX, XXX−XXX