6946 J. Am. Chem. Soc., Vol. 122, No. 29, 2000
Kelly et al.
1H), 8.22 (dd, J ) 8.0, 2.0 Hz, 1H), 7.57 (d, J ) 8.0 Hz, 1H), 7.44
(apparent d, J ) 7.6 Hz, 3H), 7.35 (d, J ) 8.0 Hz, 1H), 7.21 (bs, 1H),
7.17 (dd, J ) 8.0, 2.0 Hz, 1H), 7.13 (apparent d, J ) 7.6 Hz, 2H),
7.03 (apparent t, J ) 7.2, 6.8 Hz, 2H), 6.95 (apparent t, J ) 7.6, Hz,
2H), 5.41 (s, 1H), 2.82 (s, 3H), 2.05 (s, 3H); 13C NMR (CDCl3, 126
MHz) δ 193.0, 168.8, 146.4, 146.3, 146.0, 142.6, 139.5, 136.6, 135.0,
134.7, 134.3, 134.0, 132.0, 125.3, 124.6, 124.0, 123.7, 123.5, 116.9,
116.4, 59.5, 54.3, 23.9, 19.0. HRMS (CI) calcd for C30H23NO2
429.1729, found 429.1740.
7-Methoxy-2-naphthyl Trifluoromethanesulfonate (38). To a cold
(0 °C) solution of 7-methoxy-2-naphthol (5.0 g; 0.029 mol) in anhydrous
CH2Cl2 (50 mL) were added neat anhydrous pyridine (14 mL; 0.17
mol) and trifluoromethanesulfonic anhydride (5.3 mL; 0.032 mol). The
resulting reaction mixture was stirred in the cold bath for an additional
0.5 h and then at room temperature overnight. The reaction was
quenched with water (25 mL) and extracted with EtOAc (5 × 50 mL).
The organic extracts were combined, washed sequentially with water,
10% HCl (aqueous) and water, dried over anhydrous sodium sulfate,
and concentrated to afford 8.5 g (97%) of the title compound as a yellow
oil, which was used without further purification: 1H NMR (CDCl3,
400 MHz) δ 7.82 (d, J ) 12.0 Hz, 1H), 7.76 (d, J ) 12.4 Hz, 1H),
7.64 (d, J ) 2.8 Hz, 1H), 7.25-7.21 (m, 2H), 7.14 (d, J ) 3.6 Hz,
1H) 3.93 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ 159.5, 148.4, 135.6,
130.9, 130.0, 128.5, 119.5 (q, J ) 1280 Hz), 120.9, 118.6, 117.6, 106.4,
56.0.
7-Methoxy-2-methylnaphthalene (39). A cold (-78 °C) suspension
of CuCN (dried under house and then high vacuum in a P2O5-equipped
round-bottomed flask immersed in an oil bath at >100 °C; 5.0 g; 0.056
mol) in anhydrous THF (40 mL) was treated with a solution of 1.4 M
methyllithium in ether (76 mL; 0.11 mol) and the resulting homoge-
neous solution was allowed to warm to -20 °C. The reaction mixture
was kept at -20 °C for 10 min, recooled to -78 °C, and a solution of
38 (5.0 g; 0.016 mol) in anhydrous THF (80 mL) was introduced
dropwise via a syringe over 30 min. Subsequently, the reaction was
allowed to warm to -25 °C, placed in a freezer (-25 °C) for 2 days,
and carefully quenched at that temperature by the dropwise (CAU-
TION: foaming) addition of 80 mL of saturated NH4Cl (aq). The
mixture was then extracted with ethyl acetate (3 × 50 mL) and the
combined organic extracts were washed with water, dried over
anhydrous sodium sulfate, and evaporated to furnish a dark yellow solid.
The solid was chromatographed on a silica gel column (30 cm × 4
cm), eluting with 5% EtOAc/hexanes, to afford 2.1 g (75%) of the
title compound as a colorless crystalline solid: mp 87-88 °C (lit.67
mp 87.5-88.5 °C); 1H NMR (CDCl3, 400 MHz) δ 7.68 (apparent t, J
) 9.2 Hz 2H), 7.52 (s, 1H), 7.16 (dd, J ) 8.0, 1.6 Hz, 1H), 7.09-7.06
(m, 2H), 3.91 (s, 3H), 2.49 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ
157.9, 136.2, 135.0, 129.3, 127.6, 127.3, 126.1, 126.0, 117.9, 105.5,
55.4, 21.9. HRMS (CI) calcd for C12H12O 173.0966, found 173.0962.
2-(Bromomethyl)-7-methoxynaphthalene (40). 7-Methoxy-2-me-
thylnaphthalene (39, 500 mg; 2.9 mmol), 2,2′-azobisisobutyronitrile
(AIBN, 9 mg; 2 mol %) and CCl4 (120 mL) were introduced into a
250 mL two-neck, round-bottomed flask, which was fitted with a reflux
condenser and an N2 inlet. The mixture was heated at reflux, and
N-bromosuccinimide (NBS, 517 mg; 2.9 mmol) was added in ∼10 mg
portions over a 5 h period and the resulting reaction mixture was
refluxed for an additional 2 h. The reaction was allowed to cool to
room temperature, filtered and the yellow filtrate was concentrated to
provide a yellow solid. The solid was recrystallized from hexanes to
afford 640 mg (88%) of the title compound as a colorless crystalline
solid: mp 107-108 °C (lit.68 mp 108 °C); 1H NMR (CDCl3, 400 MHz)
δ 7.69-7.71 (m, 3H), 7.35 (dd, J ) 8.4, 1.6 Hz, 1H), 7.15 (dd, J )
8.8, 2.4 Hz, 1H), 7.10 (d, J ) 2.7 Hz, 1H), 4.64 (s, 2H), 3.91 (s, 3H);
13C NMR (CDCl3, 100 MHz) δ 158.3, 135.8, 134.6, 129.4, 128.7, 128.6,
127.0, 124.7, 119.6, 106.1, 55.5, 34.4.
suspension was allowed to cool to room temperature, and the solid
was filtered off and washed with hexanes to provide 890 mg (97%) of
the title compound as a colorless powder: mp 274-276 °C; 1H NMR
(CDCl3, 400 MHz) δ 7.80-7.72 (m, 8H), 7.65-7.56 (m, 9H), 7.42 (d,
J ) 11.2 Hz, 1H), 7.09-7.05 (m, 1H) 6.89 (d, J ) 3.2 Hz, 1H), 6.87-
6.83 (m, 1H), 5.42 (s, 1H), 5.38 (s, 1H), 3.84 (s, 3H); 13C NMR (CDCl3,
100 MHz) δ 157.8, 134.9, 134.8, 134.24, 134.15 130.1, 130.0, 129.9,
128.84, 128.80, 128.0, 127.93, 127.89, 127.86, 125.92, 125.88, 124.8
124.7, 119.4, 118.0, 117.1, 105.6, 55.3, 31.0, 30.5. Anal. Calcd for
C30H26BrOP: C, 70.18; H, 5.10. Found: C, 69.83; H, 5.06.
2-(Acetylamino)-9,10-dihydro-9-[4-methyl-3-[2-(7-methoxy-2-
naphthalenyl)ethenyl]phenyl]-9,10[1′,2′]-benzenoanthracene (42). A
cold (-78 °C) suspension of phosphonium salt 41 (3.4 g; 6.7 mmol)
in anhydrous THF (200 mL) was treated with a 1.0 M solution of
lithium bis(trimethylsilyl)amide (LHMDS) in THF (6.7 mL; 6.7 mmol).
After 10 min, the cold bath was removed, and the reaction mixture
was allowed to warm to room temperature. Subsequently, the reaction
was cooled to -78 °C, followed by the dropwise addition over 20 min
of a solution of aldehyde 32 (2.60 g; 6.05 mmol) in anhydrous THF
(40 mL). The resulting mixture was kept stirring at -78 °C for an
additional 2.5 h and then at room temperature overnight. The reaction
was quenched with water (∼50 mL) and extracted with ethyl acetate
(5 × 100 mL). The combined organic extracts were washed with brine
solution until (∼5 × 30 mL) the aqueous layer became neutral to pH
paper, dried over anhydrous sodium sulfate, filtered, and concentrated
to furnish a solid. The solid was chromatographed on silica gel (30 cm
× 4 cm), eluting with EtOAc : hexanes : CH2Cl2 (2:1:1), to afford 2.5
g (71%) of a 1:4 mixture of the Z and E isomers of the title compound
as a tan solid. The isomers can be separated by column chromatography
(silica gel, EtOAc : hexanes : CH2Cl2; 1:2:1) for analyses and
characterizations. Z-Stilbene 42: mp 128-130 °C; 1H NMR (CDCl3,
400 MHz) δ 7.90-7.86 (m, 2H), 7.64-7.53 (m, 4H), 7.29-7.23 (m,
4H), 7.09-7.01 (m, 4H), 6.92-6.74 (m, 6H), 6.62 (s, 1H), 6.35
(apparent t, J ) 7.2 Hz, 2H), 5.26 (s, 1H), 3.85 (s, 3H), 2.54 (s, 3H),
1.89 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ 168.2, 158.1, 147.6, 146.5,
143.2, 137.8, 135.6, 135.5, 134.9, 134.3, 133.7, 132.2, 131.3, 131.0,
130.7, 130.4, 129.3, 128.0, 127.7, 127.6, 125.1, 124.8, 124.6, 124.5,
123.9, 123.7, 123.4, 119.0, 117.2, 116.9, 106.1, 60.0, 55.5, 54.6, 24.4,
19.9. HRMS (EI) calcd for C42H33NO2 583.2511, found 583.2505.
E-Stilbene 42: mp 233-234 °C; 1H NMR (CDCl3, 400 MHz) δ 8.42
(d, J ) 2.4 Hz, 1H), 7.93 (dd, J ) 10.8, 2.4 Hz, 1H), 7.78-7.70 (m,
3H), 7.66-7.59 (m, 2H), 7.50 (d, J ) 8.0 Hz, 1H), 7.44-7.42 (m,
3H), 7.38 (d, J ) 8.0 Hz, 1H), 7.32 (m, 2H), 7.29-7.25 (m, 2H), 7.12-
7.09 (m, 2H), 7.05-6.96 (m, 5H), 5.41 (s, 1H), 3.92(s, 3H), 3.65 (s,
3H), 2.09 (s, 3H); 13C NMR (CDCl3, 100 MHz) δ 168.3, 158.0, 147.5,
146.7, 143.1, 136.5, 135.6, 134.90, 134.86, 134.6, 133.8, 130.8, 130.6,
129.2, 128.6, 128.4, 128.1, 126.6, 125.8, 125.3, 124.7, 123.9, 123.6,
121.5, 118.6, 117.5, 116.8, 106.1, 60.2, 55.3, 54.6, 24.3, 19.7. Anal.
Calcd for C42H33NO2: C, 86.42; H, 5.70; N, 2.40. Found: C, 86.04;
H, 5.75; N, 2.24.
Photocyclization of Stilbene 42 to 2-(Acetylamino)-9,10-dihydro-
9-(11-methoxy-4-methylbenzo[c]phenanthren-1-yl)-9,10[1′,2′]-ben-
zenoanthracene (43). General Considerations. The photoreactor,
similar to Ace Glass catalog no. 7840, was a cylindrical glass vessel
with a quartz immersion well, connected through a standard taper 60/
40 ground glass joint. The immersion well was a double-walled quartz
tube cooled by water containing an Hanovia 450-W medium-pressure
quartz Hg vapor lamp (Ace Glass, Inc. catalog no. 7825-34) and a Pyrex
filter. The molarity of the solutions with respect to the starting stilbene
was kept in the 10-3 M range. Propylene oxide was used69 to scavenge
1
HI. The photoirradiation was monitored by H NMR (aliquots were
taken via the angle joint and washed with 15% Na2S2O3 (aqueous);
the organic phase was dried over sodium sulfate, the solvent was
evaporated, and the residue was dissolved in CDCl3).
[(7-Methoxy-2-naphthyl)methyl]triphenylphosphonium Bromide
(41). To a solution of bromide 40 (450 mg; 1.79 mmol) in anhydrous
toluene (15 mL) was added triphenylphosphine (517 mg; 1.97 mmol)
and the reaction mixture was heated at reflux for 20 h. The resulting
Specific Procedure. To the photochemical vessel containing a
magnetically stirred solution of stilbene 42 (700 mg; 1.2 mmol) as a
mixture of E/Z isomers in benzene (850 mL) were added iodine (1.8
g; 7.2 mmol) and propylene oxide (29.4 mL; 0.42 mol). The resulting
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