Synthesis of 7,10-bis(2-halophenyl)tribenzo [c,f,k]fluoranthene as a potential buckybowl precursor

Full text of DOI:10.1021/jo0003798

J . Org. Chem. 2000, 65, 5063-5065
5063
Syn th esis of
7,10-Bis(2-h a lop h en yl)tr iben zo[c,f,k]flu or -
a n th en e a s a P oten tia l Bu ck ybow l
P r ecu r sor
Zbigniew Marcinow and Peter W. Rabideau*
Department of Chemistry and Ames Laboratory, Iowa State
University, Ames, Iowa 50011
rabideau@iastate.edu
Received March 15, 2000
In tr od u ction
We and others have been involved in the synthesis of
polynuclear aromatic hydrocarbons having carbon frame-
works that can be identified on the buckminsterfullerene
surface (geodesic polyarenes or “buckybowls”).1,2 The
largest of these fullerene fragments known to date is a
C36H12 hydrocarbonsconstituting 60% of C60sby flash
vacuum pyrolysis (FVP) of 1,7,13-trichloro-decacyclene.2
While the pyrolysis route has produced some interesting
buckybowls, it is clear that a limit will be reached where
the pyrolysis precursor will no longer be sufficiently
volatile to go through the hot zone. This has led to efforts
to develop new methods for the conversion of these
systems to buckybowls without the need for pyrolysis.
Recent examples include the syntheses of dibenzocoran-
nulene and benzo[ghi]fluoranthenes by Scott and Reisch,3
and by Wang and Shevlin,4 respectively, based on pal-
ladium-catalyzed intramolecular coupling.
produced the phenyl(bromonaphthyl)ethylene (6a ) in 84%
yield. Pd-catalyzed coupling with trimethylsilylacetylene7
followed by photocyclization gave the 6-substituted benz-
[c]phenanthrene (7a ) in 95% yield. Exposure to concen-
trated HCl in glacial acetic acid at 80 °C yielded 6-(1-
chlorovinyl)benz[c]phenanthrene (7b) in 82% yield. Finally
FVP at 920 °C furnished the key intermediate 4 (70%)
(Scheme 1).
Benzeneseleninic anhydride (BSA) oxidation of the
ethylene bridge of 4 by a procedure we developed earlier8
proceeded in good yield (80%) to give diketone 8.
Knoevenagel condensation between the diketone and 9
(X ) Br or Cl) afforded almost quantitatively cyclopen-
tadienone 10 which was subjected without purification
to Diels-Alder reaction with benzyne formed in situ from
anthranilic acid and isoamyl nitrite to give 1 (X ) Br or
Cl) in good yield (80%).
In conclusion, we have provided a potentially useful
route to larger fullerene fragments. While we have yet
to discover a FVP procedure to convert 1 to the C40H10
buckybowl, some of the newer non-pyrolytic routes may
ultimately be successful with 1 or with other related
precursors that might be prepared by the methods
described above.
Resu lts a n d Discu ssion
Herein we report the preparation of 7,10-bis(2-halophe-
nyl)tribenzo[b,e,k]fluoranthene (1) as a potential precur-
sor for pentabenzocorannulene (2), itself a potential
precursor for C40H10 buckybowl 3; the carbon framework
of the latter would constitute two-thirds of the buckmin-
sterfullerene structure. Our synthesis of 1 involved benz-
[a]acephenanthrylene (4) as a key intermediate. Earlier
approaches to the synthesis of this system involved
syntheses with quite a number of steps and low yields,5a
and the newer preparation by Magnus and co-workers
represented a considerable improvement.5b Herein we
describe our own route that involves fewer steps than
the latter procedure, albeit with a flash vacuum pyrolysis.
Wittig type condensation between 3-bromo-2-naph-
thaldehyde6 and benzyltriphenylphosphonium bromide
Exp er im en ta l Section
Meth od s a n d Ma ter ia ls. 1H (250.13 MHz) and 13C (62.90
MHz) NMR spectra were recorded in CDC13; mass spectra were
obtained by GC-MS. The flash vacuum pyrolysis apparatus was
purchased from Kontes Glass, Inc., and the following procedure
was employed. The sample is dissolved in CH2C12 and trans-
ferred to a small glass boat filled with glass wool. The solvent
is evaporated and the boat is placed in the inlet chamber
wrapped with a heating mantle that allows sublimation of the
substrate under vacuum with a small flow of nitrogen. The
pyrolysate condenses on the sidearm of the quartz tube exiting
the chamber which is cooled with dry ice and acetone. Benzene-
seleninic anhydride, bis(triphenylphosphine) palladium dichlo-
ride, and (trimethylsilyl)acetylene were purchased from Aldrich
(1) (a) Rabideau, P. W.; Sygula, A. Acc. Chem. Res. 1996, 29, 235-
242. (b) Scott, L. T. Pure App. Chem. 1996, 68, 291-300. (c) Mehta,
G.; Rao, H. S. P. Tetrahedron 1998, 54, 13325-13370.
(2) (a) Scott, L. T.; Bronstein, H. E.; Preda, D. V.; Ansems, R.B. M.;
Brachter, M. S.; Hagen, S. Pure App. Chem. 1999, 71, 209-219. (b)
Ansems, R. B. M.; Scott, L. T. J . Am. Chem. Soc. 2000, 122, 2719.
(3) (a) Scott, L. T,; Reisch, H. A. Abstract No. 515. 219th National
ACS Meeting, San Francisco, 2000. (b) Mehta, G.; Sarma, P. V. V. S.
Chem. Commun. 2000, 19.
(4) Wang, L.; Shevlin, P. B. Tetrahedron Lett. 2000, 41, 285.
(5) (a) Harvey, R. G. Polycyclic Aromatic Hydrocarbons; Wiley-
VCH: New York, 1996; p 417. (b) Magnus, P.; Moris, J . C.; Lynd, V.
Synthesis 1997, 506.
(7) Sakamato, T.; Shiraiwa, M.; Kondo, Y,; Yamanaka, H. Synthesis
1983, 312.
(6) Smith, J . G.; Dibble, P. W.; Sandborn, R.E. J . Org. Chem. 1986,
51, 3762
(8) Clayton, M. D.; Marcinow, Z.; Rabideau, P. W. Tetrahedron Lett.
1998, 39, 9127.
10.1021/jo0003798 CCC: $19.00 © 2000 American Chemical Society
Published on Web 07/20/2000

5064 J . Org. Chem., Vol. 65, No. 16, 2000
Notes
Sch em e 1
Chemical Co., Inc. 3-Bromo-2-naphthaldehyde (5),6 1,3-bis(2-
halophenyl)propanone (9),9 and 3-bromo-2-styrylnaphthalene
(6a )10 were synthesized by published procedures.
128.47, 128.30, 128.25, 128.01, 127.85, 127.76, 127.11, 126.49,
126.51, 126.41, 124.03, 118.45. MS (m/e, rel intensity); 288 (M+,
25), 253 (100), 126 (44); HRMS calcd for C20H13C1 288.0706,
found 288.0711.
Ben z[a ]a cep h en a n th r ylen e (4). Flash vacuum pyrolysis of
200 mg of 7b at 920 °C under vacuum with a slow nitrogen bleed
(∼1 mmHg) over a period of 2 h produced 140 mg of pyrolysate
which was recrystallized from hexane to give 4 as yellow needles
(122 mg, 70%): identical 1H NMR, 13C NMR, and mp with
previously described material.5
3-Tr im eth ylsilyleth yn yl-2-styr yln a p h th a len e (6b). 3-bro-
mo-2-styrylnaphthalene (6a ) (8.8 g, 28.7 mmol, cis/trans mix-
ture), bis(triphenylphosphine)palladium dichloride (0.76 g, 1.06
mmol), copper(I)iodide (0.38 g, 1.98 mmol), and (trimethylsilyl)-
acetylene (2.94. g, 30 mmol) in 250 mL of triethylamine were
refluxed under argon. The solution turned black immediately.
After stirring 20 h, the reaction mixture was quenched with
water and the product was extracted with CH2C12. The organic
layer was dried over MgS04, filtered and evaporated. The crude
material was flash chromatographed on silica gel to give an oily
mixture of cis and trans isomers of 6b (7.98 g, 86%) which was
used in the next photocyclization step; separation of the mixture
was not attempted.
Ben z[a ]a cep h en a n th r ylen e-4,5-d ion e (8). A solution of 4
(1.01 g, 4 mmol) and benzeneseleninic anhydride (1.65 g, 4.6
mmol) in 100 mL of chlorobenzene was heated for 5 h at 110
°C. The crude product was purified by flash column chromatog-
raphy on silica gel with a 1:1 mixture of hexane and CH2C12 to
give 0.91 g (80%) of a yellow solid: mp 279-280 °C (ethanol);
1H NMR (250 MHz, CDC13) δ 9.24 (d, J ) 8.5 Hz, 2H), 8.50 (s,
2H), 8.27 (d, J ) 8.0 Hz, 2H), 8.00-7.75 (m, 4H); 13C NMR (62.9
MHz, CDC13) δ 189.14, 139.10, 133.53, 133.23, 130.73, 127.72,
127.01, 126.81, 125.87, 125.09 (one quaternary carbon not
observed); MS (m/e, rel intensity) 282 (M+, 47), 254 (100), 226
(85); HRMS calcd for C20H10O2 282.0681, found 282.0688.
7,10-Bis(2-br om oph en yl)tr iben zo[b,e,k]flu or an th en e (la).
To a suspension of 510 mg (1.8l mmol) of 8 and 670 mg (1.82
mmol) of 1,3-bis(2-bromophenyl)propanone in 25 mL of methanol
was added a methanolic solution of sodium hydroxide (1.82 mmol
of NaOH in 20 mL of methanol). The suspension was allowed to
stir at 25 °C overnight, and then the dark brown precipitate was
separated, washed with methanol and dried to yield almost
quantitatively (1.10 g) cyclopentadienone 10 which was used in
the next step without further purification: mp 313-315 °C; 1H
NMR (250 MHz, CDC13) δ 9.22 (d, J ) 8.5 Hz, 2H), 8.08-7.33
(m,16H); 13C NMR (62.9 MHz, CDC13) δ 198.21, 134.99, 133.65,
133.59, 133.13, 133.01, 132.47, 131.98, 131.79, 131.28, 130.06,
128.99, 128.55, 127.49, 127.07, 126.92, 126.78, 126.56, 124.49.
Anal. Calcd for C35H18Br2O: C, 68.43; H, 2.95. Found: C, 68.61;
H, 2.87.
6-(Tr im eth ylsilyleth yn yl)ben zo[c]p h en a n th r en e (7a ). A
solution of 6b (650 mg, 2 mmol) and 20 mg of iodine in
cyclohexane (300 mL) was irradiated with a 450-W high pressure
quartz Hg-vapor lamp for 2 h. Evaporation of the solvent
provided a yellow oil which slowly solidified. The nearly pure
7a (614 mg, 95%) was recrystallized from hexane to give yellow
needles: mp 113-114 °C; 1H NMR (250 MHz, CDC13) δ 9.06
(m, 2H), 8.48 (d, J ) 8.8 Hz, 1H), 8.20 (s, 1H), 8.02-7.96 (m,
3H), 7.70-7.63 (m, 4H), 0.43 (s, 9H); 13C NMR (62.9 MHz,
CDC13) δ 133.71, 132.82, 132.66, 130.42, 130.38,130.24, 128.41,
128.51, 128.25, 128.20, 128.07, 127.82, 127.15, 126.45, 126.40,
126.34, 124.75, 119.59, 103.73, 99.45, 0.38; MS (m/e, rel inten-
sity) 324 (M+, 100), 309 (195), 226 (85); HRMS calcd for C23H20
Si 324.1334, found 324.1342.
-
6-(L-Ch lor ovin yl)ben zo[c]p h en a n th r en e (7b). To a solu-
tion of 800 mg (2.47 mmol) of 7a in 800 mL of glacial acetic acid
was added 2 mL of concentrated hydrochloric acid. The solution
was stirred at 80 °C for 3 h, then quenched with water and
extracted with CH2C12 (three times). The organic layer was
washed with aq. sodium bicarbonate and water. The crude
product was purified by column chromatography with hexane
to give 584 mg (82%) of a white solid: mp 59-61 °C (hexane);
1H NMR (250 MHz, CDC13) δ 9.08 (d, J ) 7.6 Hz, 2H), 8.19 (d,
J ) 8.8 Hz, 1H), 8.20 8.01(m, 3H), 7.94 (s, 1H), 7.71-7.65 (m,
4H), 5.92 (s, 1H), 5.69 (s, 1H); 13C NMR (62.9 MHz, CDC13) δ
139.36, 135.52, 133.55, 132.54, 130.74, 130.36, 129.04, 128.59,
Solutions of anthranilic acid (685 mg, 5 mmol) in DME (20
mL) and isopentyl nitrite (860 mg, 7.4 mmol) in DME (10 mL)
were added simultaneously from two dropping funnels to a
boiling solution of crude 10 (500 mg, 0.83 mmol) in 20 mL of
DME. The mixture was stirred at reflux for another 1 h, DME
was removed under reduced pressure, and the resulting mixture
was extracted with CH2C12, washed with water and dried. The
residue was recrystallized from ethanol to afford 430 mg (80%)
of la (X ) Br) as a pale yellow solid: mp ) 390-392 °C; 1H NMR
(250 MHz, CDC13) δ 9.21 (d, J ) 8.5 Hz, 2H), 8.01 (d, J ) 7.6
(9) Bennet, M. A.; Neumann, H. Aust. J . Chem. 1980, 33, 1251.
(10) (a) Martin, R. H.; Baes, M. Tetrahedron 1975, 31, 2135. (b)
Stammel, C.; Fro¨hlich, R.; Wolff, C.; Wenck, H.; de Meijere, A.; Mattay,
J . Eur. J . Org. Chem. 1999, 1709.

Notes
J . Org. Chem., Vol. 65, No. 16, 2000 5065
Hz, 2H), 7.74-7.49 (m, 16H), 6.94 (s, 2H); 13C NMR (62.9 MHz,
CDC13) δ 139.81, 135.32, 135.09, 134.45, 134.38, 133.75, 132.52,
132.42, 131.10, 130.76, 130.49, 130.17, 128.67, 127.06, 126.93,
126.60, 126.57, 125.93, 125.01, 124.44, 123.88; MALDI MS 662,
582, 502. Anal. Calcd for C40H22Br2: C, 72.53; H, 3.35. Found;
C, 72.58; H, 3.41.
135.03, 134.47, 132.71, 132.67, 132.47, 132.26, 131.08, 130.77,
130.62, 130.55, 130.05, 128.05, 127.99, 127.05, 126.93, 126.61,
126.51, 125.92, 123.80; MALDI MS 572, 535, 500. Anal. Calcd
for C40H22C12: C, 83.77; H, 3.87. Found: C, 83.83 H, 3.93
Ack n ow led gm en t. This work was supported by the
Ames Laboratory, which is operated for the U.S. De-
partment of Energy by Iowa State University under
Contract No. W-7405-Eng-82.
Following the same two-step procedure using 1,3-bis(2-chlo-
rophenyl)propanone, 1b (X ) C1) was obtained in 78% as a pale
1
yellow solid: mp ) 348-350 °C; H NMR (250 MHz, CDC13) δ
9.22 (d, J ) 8.4 Hz, 2H), 7.80 (d, J ) 8.3 Hz, 2H), 7.74-7.40 (m,
16H), 6.96 (s, 2H); 13C NMR (62.9 MHz, CDC13) δ 137.77, 135.29,
J O0003798