Synthesis of Spiro Polycyclic Aromatic Hydrocarbons by Intramolecular Palladium-Catalyzed Arylation

Article abstract of DOI:10.1021/jo962059n

The palladium-catalyzed intramolecular arylation reaction has been applied to the synthesis of the spiro polycyclic aromatic hydrocarbons and planar polycyclic aromatic hydrocarbons by formation of a six-membered ring. The reaction proceeds more readily with aryl bromides substituted with electron-withdrawing groups by using palladium acetate in N,N-dimethylformamide as the solvent. For the less reactive p-methoxyaryl derivatives the use of LiI as an additive was shown to give the best results. The results obtained in the cyclization of nitro derivatives 21 and 23 suggest that the second step of the cyclization reaction is not an electrophilic substitution reaction.

Full text of DOI:10.1021/jo962059n

1286
J . Org. Chem. 1997, 62, 1286-1291
Syn th esis of Sp ir o P olycyclic Ar om a tic Hyd r oca r bon s by
In tr a m olecu la r P a lla d iu m -Ca ta lyzed Ar yla tion
J uan J . Gonza´lez, Nuria Garc´ıa, Berta Go´mez-Lor, and Antonio M. Echavarren*
Departamento de Quı´mica Orga´nica, Universidad Auto´noma de Madrid,
Cantoblanco, 28006 Madrid, Spain
Received November 4, 1996X
The palladium-catalyzed intramolecular arylation reaction has been applied to the synthesis of
the spiro polycyclic aromatic hydrocarbons and planar polycyclic aromatic hydrocarbons by formation
of a six-membered ring. The reaction proceeds more readily with aryl bromides substituted with
electron-withdrawing groups by using palladium acetate in N,N-dimethylformamide as the solvent.
For the less reactive p-methoxyaryl derivatives the use of LiI as an additive was shown to give the
best results. The results obtained in the cyclization of nitro derivatives 21 and 23 suggest that
the second step of the cyclization reaction is not an electrophilic substitution reaction.
Sch em e 1
In tr od u ction
The palladium-catalyzed intramolecular arylation re-
action offers one of the conceptually most simple solutions
for the synthesis of carbo- and heterocycles from the
corresponding halides (X ) Br, I) (Scheme 1).1,2 The
utility of this process has been recently extended by Rice
using aryl triflates as the substrates for the formation
of a five-membered ring in the synthesis of carbocycles
(X ) OTf).3,4 The reaction has usually been carried out
with Pd(OAc)2 or Pd(PPh3)2Cl2 as the catalyst in polar
solvents (DMF or DMA) at relatively high temperatures
(120-170 °C) in the presence of a base to trap HX.
However, despite the synthetic potential of this reaction,
very little is known about its mechanism. A simplified
mechanistic hypothesis for the arylation reaction is
outlined in Scheme 1 (ligands L on Pd are removed for
clarity). The initially formed arylpalladium(II) complex
[PdAr(L)nX] I (L ) phosphine or solvent molecule, n ) 1
or 2)5 may react with the aryl ring as an electrophile to
form II,1a,6,7 followed by a proton loss to form [PdArAr′-
(L)n] III. Finally, reductive elimination of III would give
rise to the biaryl product and the reactive Pd(0) species.
However, the fact that the reaction tolerates both strongly
electron-withdrawing and electron-releasing groups is
difficult to reconcile with this working mechanistic
hypothesis.1b,8
We wished to demonstrate the formation of six-
membered rings by using the palladium-catalyzed ary-
lation reaction as a prelude to the synthesis of more
complex polycyclic aromatic hydrocarbons related to the
X Abstract published in Advance ACS Abstracts, February 15, 1997.
(1) Synthesis of heterocycles by palladium-catalyzed arylation: (a)
Ames, D. E.; Bull, D. Tetrahedron 1982, 38, 383. (b) Ames, D. E.;
Opalko, A. Synthesis 1983, 234. (c) Ames, D. E.; Opalko, A. Tetrahe-
dron 1984, 40, 1919. (d) Kuroda, T.; Suzuki, F. Tetrahedron Lett. 1991,
32, 6915. (e) Kozikowski, A. P.; Ma, D. Tetrahedron Lett. 1991, 32,
3317.
(2) Application of the palladium-catalyzed arylation to the synthe-
sis of biaryls: (a) Bringmann, G.; Walter, R.; Weirich, R. Angew.
Chem., Int. Ed. Engl. 1990, 29, 977. (b) Stadlbauer, W.; Laschober,
R.; Kappe, T. Liebigs Ann. Chem. 1990, 531. (c) Deshpande, P. P.;
Martin, O. R. Tetrahedron Lett. 1990, 31, 6313. (d) Hosoya, T.;
Takashiro, E.; Matsumoto, T.; Suzuki, K. J . Am. Chem. Soc. 1994,
116, 1004. (e) Bringmann, G.; Keller, P. A.; Ro¨lfing, K. Synlett 1994,
423.
(3) Synthesis of carbocycles by palladium-catalyzed arylation: (a)
Rice, J . E.; Cai, Z.-W.; He, Z.-M.; LaVoie, E. J . J . Org. Chem. 1995,
60, 8101. (b) Rice, J . E.; Cai, Z.-W. J . Org. Chem. 1993, 58, 1415. (c)
Rice, J . E.; Cai, Z.-W. Tetrahedron Lett. 1992, 33, 1675.
(4) For the intermolecular palladium-catalyzed arylation, see: (a)
Akita, Y.; Inoue, A.; Yamamoto, K.; Ohta, A.; Kurihara, T.; Shimizu,
M. Heterocycles 1985, 23, 2327. (b) Aoyagi, Y.; Inoue, A.; Koizumi, I.;
Hashimoto, R.; Tokunaga, K.; Gohma, K.; Komatsu, J .; Sekine, K.;
Miyafuji, A.; Kunoh, J .; Honma, R.; Akita, Y.; Ohta, A. Heterocycles
1992, 33, 257. (c) Dyker, G. Angew. Chem., Int. Ed. Engl. 1992, 31,
1023. (d) Dyker, G. J . Org. Chem. 1993, 58, 6426. (e) Dyker, G. Chem.
Ber. 1994, 127, 739.
(5) Pd(0) may coordinate with the added halide to form reactive
anionic species: (a) Amatore, C.; Azzabi, M.; J utand, A. J . Am. Chem.
Soc. 1991, 113, 1670. (b) Amatore, C.; Azzabi, M.; J utand, A. J . Am.
Chem. Soc. 1991, 113, 8375. (c) Amatore, C.; J utand, A.; Suarez, A. J .
Am. Chem. Soc. 1993, 115, 9531. (d) Amatore, C.; Carre´, E.; J utand,
A.; M’Barki, M. A.; Meyer, G. Organometallics 1995, 14, 5605. (e)
Amatore, C.; Carre´, E.; J utand, A.; Tanaka, H.; Ren, Q.; Torii, S. Chem.
Eur. J . 1996, 2, 957.
(6) Farina, V. In Comprehensive Organometallic Chemistry II; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.; Pergamon: Oxford, 1995;
Vol. 12, Chapter 3.4, pp 228-229.
(7) (a) An electrophilic pathway has been shown to operate in
somewhat related palladation reactions: Canty, A. J . In Comprehensive
Organometallic Chemistry II; Abel, E. W., Stone, F. G. A., Wilkinson,
G., Eds.; Pergamon: Oxford, 1995; Vol. 9, Chapter 5 and references
cited therein. (b) The synthesis of palladacycles by intramolecular
palladation of an aryl ring has been demonstrated to proceed by
electrophilic substitution: Catellani, M.; Chiusoli, G. P. J . Organomet.
Chem. 1992, 425, 151.
(8) Additionally, products derived from a 1,5-hydrogen abstraction,
characteristic of radical intermediates, have also been observed in the
reaction of some aryl triflates.3b
S0022-3263(96)02059-2 CCC: $14.00 © 1997 American Chemical Society

Synthesis of Spiro Polycyclic Aromatic Hydrocarbons
J . Org. Chem., Vol. 62, No. 5, 1997 1287
Sch em e 2
thrylenes (benzo[b]fluoranthenes) proceeds in just two
steps from readily available materials and could be easily
applied for the preparation of substituted derivatives.12
It should be stressed that in all cases, and in contrast
with alternative procedures,12a-c a single regioisomer was
obtained in the cyclization.
Dibenzylated fluorene 5 gave spiro derivative 14 in
68% yield under the standard conditions (130 °C, 24 h)
(Scheme 2). The reaction of dimethoxy derivative 6
under these conditions failed to give spiro 15. Instead,
reduced fluorene 16 was isolated as the only product in
35% yield.13 The use of LiI as the additive (DMF, 135
°C, 5 d) allowed for the formation of 15, albeit in only
30% yield. However, no cyclization was observed in the
presence of LiBr or LiCl as the additives. Reaction of
unsymmetrically substituted 7 under these conditions
gave 17 as the only product (62% yield). On the other
hand, the cyclization of 8 furnished 18 (53% yield) under
the standard conditions at 95 °C. Interestingly, by
performing the reaction at 70 °C for 48 h in the presence
of only 0.5 equiv of BnMe3NBr, dihydrobenz[e]aceph-
enanthrylene 19 was obtained as the only product
(isolated in 47% yield). Under these conditions, methoxy
nitro derivative 9 yielded 20 (67% yield). The selective
cyclization of the p-nitroaryl bromides of 8 and 9 is
consistent with the more facile oxidative addition of aryl
halides substituted with electron-withdrawing groups.1a,14
Additionally, the faster cyclization of substrates bearing
a p-nitro substituent suggests that the oxidative addition
is the rate-determining step of the palladium-catalyzed
arylation.
corannulenes.9 Although the synthesis of six-membered
heterocycles has been reported,1,2 only a few carbocycles
of this size have been prepared by using this reaction.2e
We also wished to test the mechanistic proposal of
Scheme 1 by determining the effect of substituents on
the aromatic nucleus on the reaction. Herein, we report
the successful application of the palladium-catalyzed
arylation for the construction of spiro polycyclic hydro-
carbons related to the helicenes, the synthesis of some
planar polycyclic aromatic hydrocarbons, as well as some
observations that may be of some relevance to the
mechanism of this reaction.
Resu lts a n d Discu ssion
Alternatively, the selective cyclization of p-nitroaryl
substrates may be due to the higher electrophilicity of
the derived palladium(II) complexes I toward the second
aryl ring (Scheme 1). In order to determine if the second
step of the reaction is an electrophilic substitution
process, we prepared two substrates bearing a nitro group
ortho to the position attacked by the palladium(II). Thus,
benzylation of 2-nitrofluorene afforded 21 (75% yield),
which was cyclized at 70 °C in DMF under the standard
conditions but with only 0.5 equiv of BnMe3NBr to give
22 in 53% yield (eq 1). On the other hand, reaction of
Alkylation of the lithium anion of fluorene with an
o-bromobenzyl bromide gave derivatives 1-4 (Scheme 2).
Further reaction of the anions of 1-3 with a second equiv
of the appropriate o-bromobenzyl bromide gave dibenzy-
lated derivatives 5-9 in 51-71% yield. The cyclization
of 1 with Pd(OAc)2 (5 mol %), K2CO3 (8 equiv), and Bu4-
NBr (3 equiv) (standard conditions)10 in DMF (130 °C,
48 h) proceeded with concomitant dehydrogenation to
afford benz[e]acephenanthrylene (10) in 52% yield.11 The
cyclization of methoxy derivative 2 was very sluggish
under these conditions. However, replacing Bu4NBr with
LiI (2.5 equiv) led to 11 in 50% yield (130 °C, 4 d). In
contrast, the cyclization of p-nitroaryl derivative 3 pro-
ceeded readily at 70 °C under the standard conditions
in DMF to give 12 in 57% yield after 48 h. Similarly,
fluoro derivative 13 was obtained in 65% yield from 4.
This straightforward synthesis of benz[e]acephenan-
(12) Benz[e]acephenanthrylenes are an important class of en-
vironmental carcinogens. For recent syntheses, see: (a) Cho, B. P.;
Zhou, L. Tetrahedron Lett. 1996, 37, 1535. (b) Cho, B. P. Tetrahedron
Lett. 1995, 36, 2403. (c) Tanga, M. J .; Bupp, J . E. J . Org. Chem. 1993,
58, 4173. (d) Cho, B. P.; Kim, M.; Harvey, R. G. J . Org. Chem. 1993,
58, 5788. (e) Cho, B. P.; Harvey, R. G. J . Org. Chem. 1987, 52,
5668. (f) Amin, S.; Huie, K.; Hussain, N.; Balanikas, G.; Carmella,
S. G.; Hecht, S. J . Org. Chem. 1986, 51, 1206. (g) Amin, S.; Huie,
K.; Hussain, N.; Balanikas, G.; Hecht, S. S. J . Org. Chem. 1985, 50,
1948.
(13) For the formation of reduced products under palladium-
catalyzed conditions, see: Saa´, J . M.; Dopico, M.; Martorell, G.; Garc´ıa-
Raso, A. J . Org. Chem. 1990, 55, 991 and references cited therein.
(14) Stille, J . K. In The Chemistry of the Metal-Carbon Bond;
Hartley, F. R., Patai, S., Eds.; Wiley: Chichester, 1985; Vol. 2, Chap-
ter 9.
(9) Rabideau, P. W.; Sygula, A. Acc. Chem. Res. 1996, 29, 235.
(10) Standard conditions refer to the use of Pd(OAc)2 (5-12 mol%),
K2CO3 (2-8 equiv), and Bu4NBr or BnMe3NBr (2-3 equiv).
(11) Either no cyclization of 2 or very low yields were observed in
the presence of PPh3 or AsPh3. Reaction with Pd(CH3CN)2Cl2 as the
catalyst gave 10 in 30% yield. The use of DBU, 1,8-bis(dimethylamino)-
naphthalene, and N-methylimidazole as the base and/or ligand for Pd
gave only recovered starting material.

1288 J . Org. Chem., Vol. 62, No. 5, 1997
Gonza´lez et al.
(1)
(3)
the potassium anion of 9-methyl-2-nitrofluorene15 with
o-bromobenzyl bromide afforded 23, which reacted under
similar conditions at 100 °C to give a 2:1 mixture of 24
and 25 in 62% yield (eq 2). The observed ratio probably
In contrast with the successful cyclizations of the above
substrates, acenaphthene derivative 28, prepared by
Wittig olefination of acenaphthenequinone20 followed by
catalytic hydrogenation, led only to traces of cyclized
product 30 (Scheme 3). The crude reaction mixtures
showed that 28 suffered dehydrogenation and reductive
elimination of the bromide as the major decomposition
pathways. Interestingly, the reaction of its methyl enol
ether 29 with Pd(OAc)2 proceeded with concomitant
demethylation and oxidation to give known 4H-cyclopen-
ta[def]chrysen-4-one (30).21 The oxidation observed in
this process is reminiscent of that observed in the
oxidation of silyl enol ethers by Pd(OAc)2 to give enones.22
This work demonstrates that the palladium-catalyzed
intramolecular reaction can be applied for the formation
of six-membered ring carbocycles. The reaction proceeds
more readily with aryl bromides substituted with electron-
withdrawing groups. For the less reactive p-methoxyaryl
derivatives the use of LiI as an additive was shown to
give the best results. The rate enhancement observed
in the presence of LiI is a likely manifestation of the
known iodide catalysis effect on the oxidative addition
step. The ready construction of spiro derivatives 14-
18, 22, and 27 should allow for the synthesis of chiral
trans-chelating ligands based on these chiral hexacyclic
scaffolds. Progress on the application of this reaction for
the synthesis of more complex substrates is underway.
(2)
reflects the steric influence of the nitro group. These
results are not easily reconciled with a cyclization
proceeding by a rate-determining electrophilic attack of
an arylpalladium(II) complex I onto the aryl ring to form
an arenium cation.16 The somewhat related alkylation
of aryl substrates by a cationic benzylpalladium complex
has been demonstrated to proceed in a low-coordinating
solvent such as CDCl3 by an electrophilic substitution
pathway.17 However, a different reaction course was
observed in a coordinating solvent.17 Although further
mechanistic work is clearly necessary to clarify this point,
the result with 23 suggests that the second step of the
intramolecular arylation reaction (see Scheme 1) is not
an electrophilic substitution reaction. An attractive
mechanistic alternative, suggested by the required pres-
ence of carbonate as the base, is the formation of
intermediate III from I (X ) carbonate) by an intramo-
lecular aromatic C-H activation.18,19
Exp er im en ta l Section
Solvents were purified and dried using standard procedures.
“Usual workup” means extraction with the stated solvent,
washing with 10% aqueous HCl, drying (Na2SO4 or MgSO4),
filtration, and evaporation. Chromatography purifications
were carried out using flash grade silica gel. All reactions were
carried out under an Ar atmosphere.
The following compounds were prepared according to the
published procedures: 1-bromo-2-(bromomethyl)-4-methoxy-
benzene,23 1-bromo-2-(bromomethyl)-4-nitrobenzene,24 9-meth-
yl-2-nitrofluorene,15 and 1-bromo-2-(bromomethyl)-4-fluoroben-
zene.25
Gen er a l P r oced u r es for th e Syn th esis of 1-8, 21, a n d
23: Meth od A. Fluorene was deprotonated with BuLi (1
equiv) in THF (-78 °C, 3 h) followed by addition of a solution
of the corresponding o-bromobenzyl bromide (0.8 equiv) in
THF. Usual workup and chromatographic purification (EtOAc-
hexane mixtures) led to pure compounds. Meth od B. Depro-
tonation of 1 with a suspension of NaH (60%) (1 equiv) in DMF
(2 mL) at 23 °C was followed by addition of a solution of the
The intramolecular arylation reaction was also applied
for the cyclization of 26 readily prepared by alkylation
of anthrone. The palladium-catalyzed cyclization of 26
proceeded under the standard conditions (140 °C, 36 h)
to give 27 in 80% yield (eq 3).
(15) Klemm, L. M.; Huber, E.; Klopfenstein, C. E. J . Org. Chem.
1964, 29, 1960.
(16) The palladium-catalyzed synthesis of dibenzofurans from 2-bro-
mophenyl ethers has been shown to take place in the presence of a
para or meta nitro group.1b
(17) Gretz, E.; Sen, A. J . Am. Chem. Soc. 1986, 108, 6038.
(18) This reaction may proceed by coordination of the second arene
(20) Rice, J . E.; Czech, A.; Hussain, N.; LaVoie, E. J . J . Org. Chem.
1988, 53, 1775.
(21) (a) Lee-Ruff, E.; Kruk, H.; Katz, M. J . Org. Chem. 1984, 49,
553. (b) Harvey, R. G.; Abu-shqara, E.; Yang, C. J . Org. Chem. 1992,
57, 6313.
(22) Ito, Y.; Hirao, T.; Saegusa, T. J . Org. Chem. 1978, 43, 1011.
(23) Breslow, R.; Garratt, S.; Kaplan, L.; LaFollette, D. J . Am. Chem.
Soc. 1968, 90, 4051.
(24) Lisitsyn, V. N.; Lugovskaya, E. K. Zh. Org. Khim. 1974, 10,
92.
(25) Carson, J . R.; Almond, H. R.; Brannan, M. D.; Carmosin, R. J .;
Flaim, S. F.; Gill, A.; Gleason, M. M.; Keely, S. L.; Ludovici, D. W.;
Pitis, P. M.; Rebarchak, M. C.; Villani, F. J . J . Med. Chem. 1988, 31,
630.
to Pd(II) in
a
η2 fashion: (a) Li, C.-S.; J ou, D.-C.; Cheng, C.-H.
Organometallics 1993, 12, 3945. (b) Li, C.-S.; Cheng, C.-H.; Liao, F.-
L.; Wang, S.-L. J . Chem. Soc., Chem. Commun. 1991, 710. (c) Ossor,
H.; Pfeffer, M.; J astrzebski, J . T. B. H.; Stam, C. H. Inorg. Chem. 1987,
26, 1169.
(19) Reaction of Ag2CO3 with (diphosphine)platinum dichloride
complexes led to (diphosphine)platinum carbonate complexes: (a)
Andrews, M. A.; Gould, G. L.; Voss, E. J . Inorg. Chem. 1996, 35, 5740.
(b) Andrews, M. A.; Gould, G. L.; Klooster, W. T.; Koening, K. S.; Voss,
E. J . Inorg. Chem. 1996, 35, 5478 and references cited therein. (c) For
the formation of bis(triphenylphosphino)carbonatopalladium: Nyman,
C. J .; Wymore, C. E.; Wilkinson, G. J . Chem. Soc. A 1968, 561.

Synthesis of Spiro Polycyclic Aromatic Hydrocarbons
J . Org. Chem., Vol. 62, No. 5, 1997 1289
the usual workup (Et2O), the residue was chromatographed
Sch em e 3
(10:1 hexane-CH2Cl2) to give 12 as a yellow solid (70 mg,
1
57%): mp 192-194 °C; H NMR (CDCl3, 200 MHz) δ 8.90 (d,
J ) 2.2 Hz, 1H), 8.74 (d, J ) 9.2 Hz, 1H), 8.46 (d, J ) 8.1 Hz,
1H), 8.44 (d, J ) 9.2 Hz, 1H), 8.29 (s, 1H), 8.10-7.90 (m, 3H),
7.83 (dd, J ) 8.1, 7.0 Hz, 1H), 7.52-7.42 (m, 2H); 13C NMR
(CDCl3, 75 MHz, 50 °C; DEPT) δ 146.05 (1C, s, Ar), 140.53
(1C, s, Ar), 137.64 (1C, s, Ar), 137.41 (1C, s, Ar), 137.24 (1C,
s, Ar), 134.32 (1C, s, Ar), 133.44 (1C, s, Ar), 133.37 (1C, s, Ar),
129.04 (1C, d, ArH), 128.96 (1C, d, ArH), 127.88 (1C, d, ArH),
126.47 (1C, s, Ar), 125.37 (1C, d, ArH), 124.05 (1C, d, ArH),
122.25 (1C, d, ArH), 122.10 (1C, d, ArH), 121.47 (1C, d, ArH),
121.08 (1C, d, ArH), 120.78 (1C, d, ArH), 120.38 (1C, d, ArH);
EI-MS m/ z 297 (M+, 100). Anal. Calcd for C20H11
-
NO2‚0.5H2O: C, 78.42; H, 3.95; N, 4.57. Found: C, 78.42; H,
3.71; N, 4.57. (The presence of water was confirmed by 1H
NMR.)
10-F lu or oben z[e]a cep h en a n th r ylen e (13). A suspension
of 4 (240 mg, 0.68 mmol), K2CO3 (281 mg, 2 mmol), BnMe3-
NBr (81 mg, 0.35 mmol), and Pd(OAc)2 (16 mg, 0.07 mmol) in
DMF (5 mL) was stirred at 120 °C for 48 h. After the usual
workup (Et2O), the residue was chromatographed (100:1
hexane-EtOAc) to give 13 as a white solid (120 mg, 65%): mp
corresponding o-bromobenzyl bromide (1 equiv) in DMF. (See
the Supporting Information for details and characterization
data).
9-[(2-Br om o-5-m eth oxyp h en yl)m eth yl]-9-[(2-br om o-5-
n itr op h en yl)m eth yl]flu or en e (9). Benzylation of 2 accord-
ing to method B gave 9 as a pale yellow solid (63%): mp
(CHCl3-Et2O) 168-170 °C; 1H NMR (CDCl3, 300 MHz) δ 7.61
(dd, J ) 8.7, 2.8 Hz, 1H), 7.58-7.51 (m, 4H), 7.42 (d, J ) 8.8
Hz, 1H), 7.35-7.27 (m, 4H), 7.23 (d, J ) 8.8 Hz, 1H), 7.14 (d,
J ) 2.7 Hz, 1H), 6.45 (dd, J ) 8.8, 3.1 Hz, 1H), 6.01 (d, J )
3.1 Hz, 1H), 3.79 (s, 2H), 3.68 (s, 2H), 3.29 (s, 3H); 13C NMR
(CDCl3, 50 MHz; DEPT) δ 157.73 (1C, s, Ar), 147.01 (2C, s,
Ar), 145.88 (1C, s, Ar), 140.74 (2C, s, Ar), 138.61 (1C, s, Ar),
137.19 (1C, s, Ar), 133.07 (1C, d, ArH), 132.90 (1C, d, ArH),
127.94 (2C, d, ArH), 126.98 (2C, d, ArH), 124.74 (1C, d, ArH),
124.68 (2C, d, ArH), 122.08 (1C, d, ArH), 119.93 (2C, d, ArH),
116.15 (1C, s, Ar), 115.30 (1C, d, ArH), 114.68 (1C, d, ArH),
56.18 (1C, s, Ar2C(CH2)2), 54.80 (1C, q, CH3O), 43.36 (2C, t,
ArCH2C) (one carbon signal overlaps); EI-MS m/ z 579, 577
(M+, 29, 16), 380, 378 (100), 252 (100). Anal. Calcd for
C28H21Br2NO3: C, 58.06; H, 3.65; N, 2.42. Found: C, 57.68;
H, 3.55; N, 2.56.
1
138-140 °C; H NMR (CDCl3, 300 MHz) δ 8.59 (dd, J ) 9.0,
5.5 Hz, 1H), 8.35 (d, J ) 8.0 Hz, 1H), 8.10 (s, 1 H), 8.03-7.90
(m, 3H), 7.74 (dd, J ) 8.2, 7.1 Hz, 1H), 7.65 (dd, J ) 9.8, 2.7
Hz, 1H), 7.46-7.38 (m, 3H); 13C NMR (CDCl3, 75 MHz; DEPT)
1
δ 161.28 [1C, d, J (13C-19F) ) 245.6 Hz, Ar], 140.72 (1C, Ar),
138.13 (1C, Ar), 136.98 (1C, Ar), 136.14 (1C, Ar), 135.34 [1C,
d, 3J (13C-19F) ) 8.7 Hz, Ar], 131.54 (1C, Ar), 128.43 (1C, ArH),
128.34 (1C, ArH), 127.45 (1C, ArH), 127.13 (1C, Ar), 127.07
(1C, Ar), 124.93 [1C, d, 3J (13C-19F) ) 8.8 Hz, ArH], 121.99
(1C, ArH), 121.32 (1C, ArH), 121.29 (1C, ArH), 120.32 [1C, d,
4J (13C-19F) ) 3.0 Hz, ArH], 119.22 (1C, ArH), 115.50 [1C, d,
2
2J (13C-19F) ) 23.6 Hz, ArH], 114.21 [1C, d, J (13C-19F) ) 20.8
Hz, ArH]; EI-MS m/ z 270 (M+, 100). Anal. Calcd for
C20H11F: C, 88.87; H, 4.10. Found: C, 88.72; H, 4.22.
1H ,16H -P h en a n t h r o[1,10,10-a ef]a cep h en a n t h r ylen e
(14). A suspension of 5 (300 mg, 0.60 mmol), K2CO3 (0.60 g,
4.3 mmol), Bu4NBr (360 mg, 1.1 mmol), and Pd(OAc)2 (17 mg,
6 mol %, 0.08 mmol) in DMF (10 mL) was stirred at 130 °C
for 24 h. After the usual workup (Et2O), the residue was
triturated with hexane and filtered to give 14 as a white solid
(140 mg, 68%): mp (hexane) 219-220 °C; 1H NMR (CDCl3,
300 MHz) δ 7.89 (dd, J ) 7.6, 1.1 Hz, 2H), 7.71 (dd, J ) 7.4,
1.0 Hz, 2H), 7.59 (dd, J ) 7.6, 1.0 Hz, 2H), 7.52 (t, J ) 7.4 Hz,
2H), 7.40 (br t, J ) 7.5 Hz, 2H), 7.29 (td, J ) 7.4, 1.1 Hz, 2H),
7.17 (br d, J ) 7.4 Hz, 2H), 3.21 (d, J ) 14.4 Hz, 2H), 2.41 (d,
J ) 14.4 Hz, 2H); 13C NMR (CDCl3, 75 MHz; DEPT) δ 147.97
(2C, s, Ar), 140.20 (2C, s, Ar), 137.08 (2C, s, Ar), 135.13 (2C,
s, Ar), 134.39 (2C, s, Ar), 130.09 (2C, d, ArH), 128.94 (2C, d,
ArH), 128.34 (2C, d, ArH), 127.54 (2C, d, ArH), 123.57 (2C, d,
ArH), 122.01 (2C, d, ArH), 119.39 (2C, d, ArH), 45.23 (1C, s,
Ar2C(CH2)2), 34.84 (2C, t, ArCH2C); EI-MS m/ z 342 (M+, 100).
Anal. Calcd for C27H18: C, 94.70; H, 5.30. Found: C, 95.03;
H, 5.00.
Ben z[e]a cep h en a n th r ylen e (10).3b A suspension of 1
(200 mg, 0.60 mmol), K2CO3 (662 mg, 4.80 mmol), Bu4NBr (560
mg, 1.8 mmol), and Pd(OAc)2 (7 mg, 5 mol %, 0.03 mmol) in
DMF (8 mL) was heated at 130 °C for 48 h. After the usual
workup (Et2O), the residue was chromatographed (hexane) to
give 10 as a white solid (80 mg, 52%):26 mp 162-164 °C (lit.
mp4b 168 °C); 1H NMR (CDCl3, 200 MHz) δ 8.67 (dd, J )
7.5, 2.2 Hz, 1H), 8.46 (d, J ) 8.1 Hz, 1H), 8.23 (s, 1H),
8.10-7.90 (m, 4H), 7.80-7.60 (m, 3H), 7.46-7.41 (m, 2H);
13C NMR (CDCl3, 50 MHz; DEPT) δ 140.63 (1C, s, Ar), 138.49
(1C, s, Ar), 136.91 (1C, s, Ar), 135.00 (1C, s, Ar), 133.96
(1C, s, Ar), 132.00 (1C, s, Ar), 130.65 (1C, s, Ar), 130.14 (1C,
d, ArH), 129.24 (1C, s, Ar), 128.10 (1C, d, ArH), 128.01 (1C, d,
ArH), 127.37 (1C, d, ArH), 126.94 (1C, d, ArH), 126.69 (1C, d,
ArH), 123.08 (1C, d, ArH), 121.87 (1C, d, ArH), 121.57 (1C, d,
ArH), 121.45 (1C, d, ArH), 121.31 (1C, d, ArH), 119.48 (1C, d,
ArH).
3,14-Dim eth oxy-1H,16H-ph en an th r o[1,10,10-a ef]aceph -
en a n th r ylen e (15). A suspension of 6 (200 mg, 0.35 mmol),
Pd(OAc)2 (8 mg, 10 mol %, 0.035 mmol), K2CO3 (100 mg, 0.7
mmol), and LiI (120 mg, 0.9 mmol) in DMF (5 mL) was stirred
at 135 °C for 5 d. After the usual workup (Et2O), the residue
was suspended in Et2O to give 15 as a yellow solid (42 mg,
10-Meth oxyben z[e]a cep h en a n th r ylen e (11).12f A sus-
pension of 2 (300 mg, 0.82 mmol), Pd(OAc)2 (19 mg, 10 mol %,
0.08 mmol), K2CO3 (227 mg, 1.6 mmol), and LiI (281 mg, 2.05
mmol) in DMF (5 mL) was stirred at 130 °C for 4 d. After the
usual workup (Et2O) the residue was suspended in hexane and
filtered to give 11 as a white solid (116 mg, 50%):27 mp 194-
1
30%): mp 238-240 °C; H NMR (CDCl3, 200 MHz) δ 7.78 (d,
J ) 8.7 Hz, 2H), 7.66-7.59 (m, 2H), 7.50-7.43 (m, 4H), 6.91
(dd, J ) 8.7, 3.0 Hz, 2H), 6.74 (d, J ) 3.0 Hz, 2H), 3.80 (s,
6H), 3.07 (d, J ) 14.5 Hz, 2H), 2.38 (d, J ) 14.5 Hz, 2H); 13C
NMR (CDCl3, 50 MHz; DEPT) δ 159.79 (2C, s, Ar), 147.13 (2C,
s, Ar), 140.17 (2C, s, Ar), 138.85 (2C, s, Ar), 134.27 (2C, s, Ar),
128.84 (2C, d, ArH), 127.99 (2C, s, Ar), 124.51 (2C, d, ArH),
121.35 (2C, d, ArH), 118.50 (2C, d, ArH), 116.13 (2C, d, ArH),
112.17 (2C, d, ArH), 55.38 (2C, q, CH3O), 45.26 (1C, s,
Ar2C(CH2)2), 35.24 (2C, t, ArCH2C); EI-MS m/ z 402 (M+, 100).
Anal. Calcd for C29H22O2: C, 86.54; H, 5.51. Found: C, 86.38;
H, 5.55.
1
196 °C (lit.12f mp 198-199 °C); H NMR (CDCl3, 200 MHz) δ
8.55 (d, J ) 8.9 Hz, 1H), 8.37 (d, J ) 8.9 Hz, 1H), 8.17 (s, 1H),
8.01-7.89 (m, 3H), 7.74 (dd, J ) 8.1, 7.1 Hz, 1H), 7.46-7.36
(m, 4H), 4.00 (s, 3H).
10-Nitr oben z[e]a cep h en a n th r ylen e (12). A suspension
of 3 (160 mg, 0.42 mmol), Pd(OAc)2 (13 mg, 11 mol %, 0.06
mmol), K2CO3 (440 mg, 3.2 mmol), and Bu4NBr (270 mg, 0.84
mmol) in DMF (10 mL) was stirred at 70 °C for 48 h. After
(26) Alternatively, palladium-catalyzed reaction of 9-(2-bromoben-
zylidene)fluorene afforded 10 in 44% yield.
9,9-Bis[(3-m eth oxyp h en yl)m eth yl]flu or en e (16). A so-
lution of 6 (30 mg, 0.05 mmol), Pd(OAc)2 (2.4 mg, 10 mol %,
(27) Alternatively, palladium-catalyzed reaction of 9-(2-bromo-5-
methoxybencyliden)fluorene12f gave 11 in 32% yield.

1290 J . Org. Chem., Vol. 62, No. 5, 1997
Gonza´lez et al.
0.01 mmol), K2CO3 (56 mg, 0.4 mmol), and Bu4NBr (25 mg,
0.08 mmol) in DMF (5 mL) was stirred at 120 °C for 36 h.
After the usual workup (Et2O), the residue was suspended in
EtOAc and filtered to give 16 as a white solid (7 mg, 35%):
2.2 Hz, 1H), 8.21 (dd, J ) 8.6, 2.2 Hz, 1H), 7.94 (d, J ) 8.6 Hz,
1H), 7.63-7.26 (m, 7H), 7.19-7.14 (m, 1H), 6.87-6.78 (m, 2H),
6.35-6.30 (m, 1H), 3.65 (d, J ) 15.1 Hz, 1H), 3.30 (d, J ) 12.9
Hz, 1H), 3.05 (d, J ) 12.9 Hz, 1H), 3.02 (d, J ) 15.1 Hz, 1H);
13C NMR (CDCl3, 50 MHz; DEPT) δ 149.56 (1C, s, Ar), 147.50
(1C, s, Ar), 147.08 (1C, s, Ar), 140.97 (1C, s, Ar), 140.75 (1C,
s, Ar), 139.70 (1C, s, Ar), 137.70 (1C, s, Ar), 136.11 (1C, s, Ar),
132.26 (1C, d, ArH), 131.13 (1C, d, ArH), 130.58 (1C, s, Ar),
129.10 (1C, d, ArH), 127.89 (1C, d, ArH), 127.73 (1C, d, ArH),
127.10 (1C, d, ArH), 125.99 (1C, d, ArH), 124.88 (1C, d, ArH),
124.35 (1C, d, ArH), 123.93 (1C, d, ArH), 122.88 (1C, d, ArH),
121.56 (1C, d, ArH), 120.66 (2C, d, ArH), 49.84 (1C, s,
Ar2C(CH2)2), 41.35 (1C, t, ArCH2C), 37.19 (1C, t, ArCH2C) (one
carbon signal overlaps); EI-MS m/ z 467 (M+, 1), 252 (100).28
7b,8-Dih yd r o-8a -[(2-br om o-5-m eth oxyp h en yl)m eth yl]-
10-n itr oben z[e]a cep h en a n th r ylen e (20). A suspension of
9 (210 mg, 0.36 mmol), Pd(OAc)2 (6 mg, 7.5 mol %, 0.027
mmol), K2CO3 (397 mg, 2.88 mmol), and BnMe3NBr (41.4 mg,
0.18 mmol) in DMF (6 mL) was stirred at 70 °C for 24 h. After
the usual workup (Et2O), the residue was chromatographed
(3:1 hexane-CH2Cl2) to give 20 (120 mg, 67%) as a white
1
mp 122-125 °C; H NMR (CDCl3, 200 MHz) δ 7.45-7.40 (m,
4H), 7.31-7.16 (m, 4H), 6.83 (t, J ) 7.1 Hz, 2H), 6.50 (dd, J )
7.1, 2.4 Hz, 2H), 6.30 (d, J ) 7.1 Hz, 2H), 6.13 (d, J ) 2.4 Hz,
2H), 3.44 (s, 6H), 3.35 (s, 4H); 13C NMR (CDCl3, 50 MHz;
DEPT) δ 158.34 (2C, s, Ar), 148.19 (2C, s, Ar), 140.97 (2C, s,
Ar), 138.49 (2C, s, Ar), 127.88 (2C, d, ArH), 126.98 (2C, d, ArH),
126.19 (2C, d, ArH), 124.50 (2C, d, ArH), 122.81 (2C, d, ArH),
119.76 (2C, d, ArH), 114.91 (2C, d, ArH), 112.25 (2C, d, ArH),
56.58 (1C, s, Ar2C(CH2)2), 54.77 (2C, q, CH3O), 43.52 (2C, t,
ArCH2C); EI-MS m/ z 406 (M+, 29), 285 (100). Anal. Calcd
for C29H26O2: C, 85.68; H, 6.45. Found: C, 85.30; H, 6.64.
3-Meth oxy-1H,16H-ph en an th r o[1,10,10-a ef]aceph en an -
th r ylen e (17). A suspension of 7 (300 mg, 0.56 mmol), Pd-
(OAc)2 (14 mg, 10 mol %, 0.06 mmol), K2CO3 (250 mg, 1.8
mmol), and LiI (206 mg, 1.5 mmol) in DMF (10 mL) was stirred
at 130 °C for 4 d. After the usual workup (Et2O), the residue
was suspended in Et2O and filtered to give 17 as a white solid
1
1
(130 mg, 62%): mp 216-219 °C; H NMR (CDCl3, 300 MHz)
solid: mp (CHCl3-Et2O) 144-146 °C; H NMR (CDCl3, 200
δ 7.89 (dd, J ) 7.5, 1.1 Ηz, 1H), 7.80 (d, J ) 8.4 Hz, 1H), 7.70
(dd, J ) 7.4, 0.8 Hz, 1H), 7.68 (dd, J ) 6.6, 1.7 Hz, 1H), 7.59-
7.49 (m, 4H), 7.40 (br t, J ) 7.5 Hz, 1H), 7.27 (td, J ) 7.5, 1.1
Hz, 1H), 7.19 (br d, J ) 2.6 Hz, 1H), 6.92 (dd, J ) 8.4, 2.6 Hz,
1H), 6.74 (d, J ) 2.6 Hz, 1H), 3.85 (s, 3H), 3.13 (AB system,
part A, J ) 14.6 Hz, 1H), 3.08 (AB system, part A, J ) 14.6
Hz, 1H), 2.41 (AB system, part B, J ) 14.3 Hz, 1H), 2.40 (AB
system, part B, J ) 14.4 Hz, 1H); 13C NMR (CDCl3, 50 MHz;
DEPT) δ 159.74 (1C, s, Ar), 147.77 (1C, s, Ar), 147.19 (1C, s,
Ar), 140.22 (1C, s, Ar), 140.01 (1C, s, Ar), 138.80 (1C, s, Ar),
137.01 (1C, s, Ar), 135.06 (1C, s, Ar), 134.27 (1C, s, Ar), 130.10
(1C, d, ArH), 128,84 (2C, d, ArH), 128.26 (1C, d, ArH), 127.89
(1C, s, Ar), 127.41 (1C, d, ArH), 124.51 (1C, d, ArH), 123.46
(1C, d, ArH), 121.82 (1C, d, ArH), 121.35 (1C, d, ArH), 119.29
(1C, d, ArH), 118.50 (1C, d, ArH), 116.07 (1C, d, ArH), 112.01
(1C, d, ArH), 55.32 (1C, q, CH3O), 45.20 (1C, s, Ar2C(CH2)2),
35.13 (1C, t, ArCH2C), 34.81 (1C, t, ArCH2C) (one carbon signal
overlaps); EI-MS m/ z 372 (M+, 100).28
MHz) δ 8.30 (d, J ) 2.7 Hz, 1H), 8.19 (dd, J ) 8.6, 2.7 Hz,
1H), 7.93 (d, J ) 8.6 Hz, 1H), 7.63-7.28 (m, 7H), 7.00 (d, J )
8.6 Hz, 1H), 6.37 (dd, J ) 8.6, 3.2 Hz, 1H), 5.76 (d, J ) 3.2 Hz,
1H), 3.63 (AB system, part A, J ) 15.1 Hz, 1H), 3.40 (s, 3H),
3.32 (AB system, part A, J ) 12.9 Hz, 1H), 2.97 (AB system,
part B, J ) 15.1 Hz, 1H), 2.96 (AB system, part B, J ) 12.9
Hz, 1H); 13C NMR (CDCl3, 50 MHz; DEPT) δ 157.37 (1C, s,
Ar), 149.72 (1C, s, Ar), 147.24 (1C, s, Ar), 147.03 (1C, s, Ar),
141.12 (1C, s, Ar), 140.75 (1C, s, Ar), 139.75 (1C, s, Ar), 137.70
(1C, s, Ar), 136.80 (1C, s, Ar), 132.58 (1C, d, ArH), 130.74 (1C,
s, Ar), 129.15 (1C, d, ArH), 127.94 (1C, d, ArH), 127.15 (1C, d,
ArH), 124.83 (1C, d, ArH), 124.25 (1C, d, ArH), 123.93 (1C, d,
ArH), 122.88 (1C, d, ArH), 121.56 (1C, d, ArH), 120.77 (1C, d,
ArH), 120.61 (1C, d, ArH), 116.23 (1C, s, Ar), 115.39 (1C, d,
ArH), 114.97 (1C, d, ArH), 54.96 (1C, q, CH3O), 49.90 (1C, s,
Ar2C(CH2)2), 41.62 (1C, t, ArCH2C), 37.40 (1C, t, ArCH2C); EI-
MS m/ z 499, 497 (M+, 2), 252 (100). Anal. Calcd for C28H20
-
BrNO3: C, 67.48; H, 4.05; N, 2.81. Found: C, 67.48; H, 4.24;
N, 2.80.
3-Nit r o-1H ,16H -p h en a n t h r o[1,10,10-a ef]a cep h en a n -
th r ylen e (18). A suspension of 8 (320 mg, 0.58 mmol), K2-
CO3 (600 mg, 4.3 mmol), Bu4NBr (360 mg, 1.1 mmol), and
Pd(OAc)2 (17 mg, 12 mol %, 0.08 mmol) in DMF (10 mL) was
stirred at 95 °C for 48 h. After the usual workup (Et2O), the
residue was chromatographed (3:1 hexane-CH2Cl2) to give 18
as a white solid (120 mg, 53%): mp (CHCl3-Et2O) 221-225
°C; 1H NMR (CDCl3, 200 MHz) δ 8.23 (dd, J ) 8.1, 2.1 Hz,
1H), 7.99 (d, J ) 2.1 Hz, 1H), 7.94 (d, J ) 8.1 Hz, 1H), 7.85
(dd, J ) 7.5, 1.6 Hz, 1H), 7.75 (dd, J ) 7.0, 1.6 Hz, 1H), 7.68
(dd, J ) 7.0, 1.1 Hz, 1H), 7.60-7.48 (m, 4H), 7.39 (td, J ) 7.5,
1.6 Hz, 1H), 7.28 (td, J ) 7.5, 1.6 Hz, 1H), 7.12 (br d, J ) 7.5
Hz, 1H), 3.21 (d, J ) 14.5 Hz, 1H), 2.96 (d, J ) 14.5 Hz, 1H),
2.38 (d, J ) 14.5 Hz, 2H); 13C NMR (CDCl3, 50 MHz; DEPT)
δ 148.42 (1C, s, Ar), 147.40 (1C, s, Ar), 147.00 (1C, s, Ar),
141.48 (1C, s, Ar), 140.58 (1C, s, Ar), 139.56 (1C, s, Ar), 138.54
(1C, s, Ar), 136.06 (1C, s, Ar), 134.71 (1C, s, Ar), 134.37 (1C,
s, Ar), 132.11 (1C, s, Ar), 129.97 (1C, d, ArH), 129.29 (1C, d,
ArH), 129.21 (1C, d, ArH), 128.62 (1C, d, ArH), 127.77 (1C, d,
ArH), 124.72 (1C, d, ArH), 123.93 (1C, d, ArH), 123.60 (1C, d,
ArH), 123.09 (1C, d, ArH), 122.52 (1C, d, ArH), 122.35 (1C, d,
ArH), 121.11 (1C, d, ArH), 119.42 (1C, d, ArH), 44.73 (1C, s,
Ar2C(CH2)2), 34.86 (1C, t, ArCH2C), 34.69 (1C, t, ArCH2C); EI-
MS m/ z 387 (M+, 100). Anal. Calcd for C27H17NO2: C, 83.70;
H, 4.42; N, 3.62. Found: C, 83.25; H, 4.30; N, 3.56.28
6-Nit r o-1H ,16H -p h en a n t h r o[1,10,10-a ef]a cep h en a n -
th r ylen e (22). A suspension of 21 (400 mg, 0.73 mmol), K2-
CO3 (805 mg, 5.8 mmol), BnMe3NBr (84 mg, 0.37 mmol), and
Pd(OAc)2 (8 mg, 5.5 mol %, 0.04 mmol) in DMF (20 mL) was
heated at 70 °C for 32 h. After the usual workup (Et2O), the
residue was chromatographed (4:1 hexane-CH2Cl2) to give 22
as a yellow solid (150 mg, 53%): mp (CHCl3-Et2O) 231-232
°C; 1H NMR (CDCl3, 300 MHz) δ 7.87 (dd, J ) 7.6, 1.2 Hz,
1H), 7.79-7.73 (m, 3H), 7.65 (dd, J ) 7.7, 0.9 Hz, 1H), 7.63-
7.53 (m, 2H), 7.41 (br t, J ) 7.3 Hz, 1H), 7.37-7.34 (m, 2H),
7.30 (dd, J ) 7.4, 1.4 Hz, 1H), 7.22-7.20 (m, 1H), 7.08 (br d,
J ) 7.4 Hz, 1H), 3.08 (d, J ) 14.2 Hz, 1H), 2.82 (d, J ) 14.4
Hz, 1H), 2.40 (br d, J ) 14.4 Hz, 1H), 2.35 (br d, J ) 14.2 Hz,
1H); 13C NMR (CDCl3, 75 MHz; DEPT) δ 150.95 (1C, s, Ar),
148.83 (1C, s, Ar), 145.89 (1C, s, Ar), 143.06 (1C, s, Ar), 138.25
(1C, s, Ar), 138.09 (1C, s, Ar), 136.07 (1C, s, Ar), 134.41 (1C,
s, Ar), 134.29 (1C, s, Ar), 130.12 (1C, d, ArH), 129.97 (1C, d,
ArH), 129.93 (1C, s, Ar), 129.57 (1C, d, ArH), 129.32 (1C, d,
ArH), 128.63 (1C, d, ArH), 127.73 (1C, d, ArH),127.37 (1C, d,
ArH), 127.17 (1C, s, Ar), 126.61 (1C, d, ArH), 124.69 (1C, d,
ArH), 123.59 (1C, d, ArH), 123.07 (1C, d, ArH), 119.90 (1C, d,
ArH), 119.58 (1C, d, ArH), 46.63 (1C, s, Ar2C(CH2)2), 34.57 (1C,
t, ArCH2C), 33.91 (1C, t, ArCH2C); EI-MS m/ z 387 (M+, 100).28
7b ,8-Dih yd r o-8a -m e t h yl-6-n it r ob e n z[e]a ce p h e n a n -
th r ylen e (24) a n d 7b,8-Dih yd r o-8a -m eth yl-1-n itr oben z-
[e]a cep h en a n th r ylen e (25). A suspension of 23 (220 mg,
0.56 mmol), K2CO3 (230 mg, 1.7 mmol), BnMe3NBr (130 mg,
0.56 mmol), and Pd(OAc)2 (13 mg, 11 mol %, 0.06 mmol) in
DMF (8 mL) was stirred at 100 °C for 24 h. After the usual
workup (Et2O), the residue was chromatographed (3:1 hexane-
CH2Cl2) to give a 2:1 mixture of 24 and 25 (109 mg, 62%). After
recrystallization (CHCl3-Et2O), 24 was obtained as a yellow
7b,8-Dih ydr o-8a-[(2-br om oph en yl)m eth yl]-10-n itr oben z-
[e]a cep h en a n th r ylen e (19). A suspension of 8 (400 mg, 0.73
mmol), Pd(OAc)2 (12 mg, 7 mol %, 0.05 mmol), K2CO3 (806
mg, 5.8 mmol), and BnMe3NBr (84 mg, 0.37 mmol) in DMF
(15 mL) was stirred at 70 °C for 48 h. After the usual workup
(Et2O), the residue was chromatographed (5:1 hexane-CH2-
Cl2) to give 19 (140 mg, 41%) as a yellow solid: mp (CHCl3-
1
Et2O) 184-185 °C; H NMR (CDCl3, 200 MHz) δ 8.32 (d, J )
1
solid: mp (CHCl3-Et2O) 178-179 °C; H NMR (CDCl3, 200
(28) Copies of the 1H and 13C NMR spectra are provided as
Supporting Information.
MHz) δ 8.38 (d, J ) 2.1 Hz, 1H), 8.31 (dd, J ) 8.5, 2.1 Hz,
1H), 7.89-7.85 (m, 1H), 7.86 (d, J ) 8.5 Hz, 1H), 7.70 (dd, J

Synthesis of Spiro Polycyclic Aromatic Hydrocarbons
J . Org. Chem., Vol. 62, No. 5, 1997 1291
) 7.5, 0.7 Hz, 1H), 7.67 (dd, J ) 6.8, 0.7 Hz, 1H), 7.49 (dd, J
) 7.5, 6.8 Hz, 1H), 7.44-7.29 (m, 3H), 3.31 (AB system, part
A, J ) 14.7 Hz, 1H), 2.92 (AB system, part B, J ) 14.7 Hz,
1H), 1.30 (s, 3H); 13C NMR (CDCl3, 75 MHz; DEPT) δ 154.23
(1C, s, Ar), 150.87 (1C, s, Ar), 147.07 (1C, s, Ar), 146.86 (1C,
s, Ar), 136.01 (2C, s, Ar), 133.03 (1C, s, Ar), 132.09 (1C, s, Ar),
130.20 (1C, d, ArH), 128.95 (1C, d, ArH), 128.57 (1C, d, ArH),
127.54 (1C, d, ArH), 123.63 (1C, d, ArH), 123.55 (1C, d, ArH),
123.12 (1C, d, ArH), 120.92 (1C, d, ArH), 120.31 (1C, d, ArH),
118.63 (1C, d, ArH), 46.15 (1C, s, Ar2(CH3)CCH2), 38.13 (1C,
t, ArCH2C), 23.54 (1C, q, CH3); EI-MS m/ z 313 (M+, 52), 252
(100). The filtrate from the recrystallization showed a 1:1
mixture of 24 and 25 that could not be separated by chroma-
tography. 25: 1H NMR (CDCl3, 200 MHz) (only distinctive
signals) δ 3.19 (AB system, part A, J ) 14.5 Hz, 1H), 2.87 (AB
system, part B, J ) 14.5 Hz, 1H), 1.13 (s, 3H). The EI-MS of
the mixture of 24 and 25 was identical with that of pure 24.28
10,10-Bis[(2-b r om op h e n yl)m e t h yl]-9(10H )-a n t h r a -
cen on e (26). A solution of 9(10H)-anthracenone (1.00 g, 5
mmol) and 1-bromo-2-(bromomethyl)benzene (3.75 g, 15 mmol)
in CH2Cl2 (20 mL) was treated with a solution of BnEt3NBr
(250 mg) in aqueous NaOH (30%, 15 mL). The mixture was
stirred for 2 h. After the usual workup (CH2Cl2), the residue
was chromatographed (10:1 hexane-EtOAc) to give 9-[(2-
br om op h en yl)m eth oxy]-10-[(2-br om op h en yl)m eth yl]a n -
th r a cen e as a yellow solid (0.60 g, 23%): mp 146-148 °C; 1H
NMR (CDCl3, 300 MHz) δ 8.44-8.38 (m, 2H), 8.09-8.01 (m,
3H), 7.68 (dd, J ) 7.9, 1.3 Hz, 1H), 7.67 (dd, J ) 8.0, 1.2 Hz,
1H), 7.53-7.43 (m, 5H), 7.30 (td, J ) 7.4, 1.7 Hz, 1H), 7.04
(td, J ) 7.4, 1.7 Hz, 1H), 6.93 (td, J ) 7.4, 1.4 Hz, 1H), 6.43
(dd, J ) 7.7, 1.6 Hz, 1H), 5.35 (s, 2H), 5.00 (s, 2H); 13C NMR
(CDCl3, 75 MHz; DEPT) δ 150.55 (1C, s, Ar), 139.86 (1C, s,
Ar), 137.05 (1C, s, Ar), 132.67 (1C, d, ArH), 132.43 (1C, d, ArH),
131.34 (2C, s, Ar), 129.73 (1C, d, ArH), 129.39 (1C, d, ArH),
129.03 (1C, d, ArH), 127.76 (1C, d, ArH), 127.66 (1C, d, ArH),
127.51 (1C, d, ArH), 127.14 (1C, s, Ar), 126.31 (2C, d, ArH),
125.18 (2C, d, ArH), 124.94 (2C, d, ArH), 124.73 (2C, s, Ar),
124.51 (1C, s, Ar), 122.90 (2C, d, ArH), 122.30 (1C, s, Ar), 76.51
(1C, t, ArCH2O), 34.05 (1C, t, ArCH2Ar); EI-MS m/ z 532, 530
(M+, 12, 7), 363 (100), 361 (99). Anal. Calcd for C28H20Br2O:
C, 63.18; H, 3.79. Found: C, 63.13; H, 3.79. Elution with 5:1
hexane-EtOAc afforded 26 as a white solid (1.00 g, 38%): mp
bromobenzyl)triphenylphosphonium bromide (4.2 g, 8.2 mmol)
in CH2Cl2 (80 mL) was treated with aqueous LiOH (5 M, 10
mL) at 23 °C for 2 h. After the usual workup (CH2Cl2), the
residue was chromatographed (4:1 hexane-EtOAc) to afford
a yellow solid whose 1H NMR spectrum showed several
multiplets at 8.25-7.25 ppm. This solid was dissolved in
EtOAc (100 mL) and stirred under hydrogen (1 atm) in the
presence of Pd/C 10% (500 mg) at 23 °C for 18 h. The mixture
was filtered through Celite, evaporated, and chromatographed
(6:1 hexane-EtOAc) to afford 28 as a white solid (1.51 g, 82%,
overall yield): mp (Et2O) 86-88 °C; 1H NMR (CDCl3, 200 MHz)
δ 8.09 (d, J ) 8.6 Hz, 1H), 8.00 (d, J ) 6.3 Hz, 1H), 7.81-7.61
(m, 3H), 7.50-7.42 (m, 1H), 7.33-7.13 (m, 3H), 6.86 (d, J )
7.0 Hz, 1H), 4.22 (dd, J ) 10.1, 5.5 Hz, 1H), 3.70 (dd, J ) 13.3,
5.5 Hz, 1H), 3.01 (dd, J ) 14.1, 10.2 Hz, 1H); 13C NMR (CDCl3,
50 MHz) δ 204.25, 141.76, 138.38, 138.26, 132.96, 131.83,
131.55, 130.65, 128.34, 128.11, 127.92, 127.15, 124.84, 123.99,
121.57, 121.45, 50.54, 37.45 (one carbon signal overlaps); EI-
MS m/ z 338, 336 (M+, 2), 257 (100). Anal. Calcd for C19H13
-
BrO: C, 67.67; H, 3.89. Found: C, 67.63; H, 3.65.
1-[(1-Br om op h en yl)m et h yl]-2-m et h oxya cen a p h t h yl-
en e (29). A solution of 28 (500 mg, 1.48 mmol), trimethyl
orthoformate (1.62 mL, 14.8 mmol), and p-toluenesulfonic acid
monohydrate (3 mg) in MeOH (30 mL) was stirred at 65 °C
for 2 h. After being cooled to room temperature, the reaction
mixture was made alkaline by addition of aqueous NaOH
(50%), and the solvent was evaporated. After the usual
workup (Et2O), the residue was chromatographed (9:1 hexane-
Et2O) to afford 29 as a bright red solid (410 mg, 79%): mp
1
(Et2O) 66-68 °C; H NMR (CDCl3, 200 MHz) δ 7.76 (d, J )
7.8 Hz, 2H), 7.65-7.48 (m, 3H), 7.41-7.33 (m, 1H), 7.28-7.23
(m, 2H), 7.19-7.01 (m, 2H), 4.17 (s, 2H), 4.15 (s, 3H); 13C NMR
(50 MHz, CDCl3) δ 157.22, 139.84, 138.32, 133.69, 132.39,
130.14, 127.83, 127.54, 127.32, 126.98, 125.29, 124.44, 122.02,
120.89, 117.28, 59.85, 30.29 (three carbon signals overlap); EI-
MS m/ z 352, 350 (M+, 59), 321, 319 (40), 337, 335 (10), 255
(100). Anal. Calcd for C20H15BrO: C, 68.39; H, 4.30. Found:
C, 68.71; H, 4.13.
4H-Cyclop en ta [d ef]ch r ysen -4-on e (30). A mixture of 29
(88 mg, 0.25 mmol), Pd(OAc)2 (67 mg, 0.3 mmol), K2CO3 (276
mg, 2 mmol), and BnMe3NBr (174 mg, 0.75 mmol) in DMF (3
mL) was stirred for 4 days at 160 °C. After the usual workup
(Et2O), the residue was chromatographed (6:1 hexane-EtOAc)
to afford 30 as a pale yellow solid with 1H NMR and MS data
in agreement with those reported (25 mg, 39%): mp (CH2Cl2)
180-181 °C (lit.21,29 mp 204-205 °C; 1H NMR (CDCl3, 200
MHz) δ 8.49 (d, J ) 8.6 Hz, 1H), 8.33 (d, J ) 9.4 Hz, 1H), 8.14
(s, 1H), 8.07-7.86 (m, 4H), 7.77-7.56 (m, 3H); 13C NMR (75
MHz, CDCl3) δ 192.73, 138.38, 134.34, 134.26, 134.13, 132.56,
132.46, 131.70, 130.74, 129.00, 128.74, 127.91, 126.76, 125.03,
125.02, 123.62, 123.16, 122.30, 121.74; EI-MS m/ z 254 (M+,
100).
1
189-190 °C; H NMR (CDCl3, 300 MHz) δ 8.26 (dd, J ) 7.7,
1.6 Hz, 2H), 7.60-7.35 (m, 8H), 6.87 (td, J ) 7.7, 1.7 Hz, 2H),
6.72 (td, J ) 7.6, 1.4 Hz, 2H), 6.07 (dd, J ) 7.8, 1.7 Hz, 2H),
3.85 (s, 4H); 13C NMR (CDCl3, 75 MHz; DEPT) δ 183.21 (1C,
s, CO), 145.27 (2C, s, Ar), 135.40 (2C, s, Ar), 133.37 (2C, d,
ArH), 132.62 (2C, s, Ar), 132.56 (2C, d, ArH), 131.21 (2C, d,
ArH), 127.87 (2C, d, ArH), 127.66 (2C, d, ArH), 127.35 (2C, d,
ArH), 126.70 (2C, d, ArH), 126.49 (2C, d, ArH), 126.33 (2C, s,
Ar), 48.10 (2C, t, ArCH2C), 47.27 (1C, s, Ar2C(CH2)2); EI-MS
m/ z 532, 530 (M+, 11, 6), 363 (100), 361 (100). Anal. Calcd
for C28H20Br2O: C, 63.18; H, 3.79. Found: C, 63.00; H, 3.89.
1H ,17H -Din a p h t h o[1,2,3-d e:3,2,1-fg]a n t h r a cen -9-on e
(27). A suspension of 26 (200 mg, 0.37 mmol), Pd(OAc)2 (10
mg, 3 mol %, 0.044 mmol), K2CO3 (420 mg, 3.0 mmol), and
Bu4NBr (400 mg, 1.24 mmol) in DMF (5 mL) was stirred at
140 °C for 36 h. After the usual workup (Et2O), the residue
was chromatographed (3:1 hexane-EtOAc) to give 27 as a
white solid (120 mg, 88%): mp > 300 °C; 1H NMR (CDCl3,
300 MHz) δ 8.38 (dd, J ) 7.8, 1.3 Hz, 2H), 8.05 (dd, J ) 7.8,
1.3 Hz, 2H), 7.92 (br d, J ) 7.8 Hz, 2H), 7.63 (t, J ) 7.8 Hz,
2H), 7.41 (br t, J ) 7.8 Hz, 2H), 7.22 (td, J ) 7.5, 1.3 Hz, 2H),
6.75 (br d, J ) 7.5 Hz, 2H), 2.95 (AB system, part A, J ) 15.4
Hz, 2H), 2.67 (AB system, part B, J ) 15.4 Hz, 2H); 13C NMR
(CDCl3, 75 MHz; DEPT) δ 183.17 (1C, s, CO), 143.74 (2C, s,
Ar), 135.33 (2C, s, Ar), 134.78 (2C, s, Ar), 134.44 (2C, s, Ar),
129.92 (2C, s, Ar), 129.45 (2C, d, ArH), 129.02 (2C, d, ArH),
128.38 (2C, d, ArH), 127.79 (2C, d, ArH), 127.60 (2C, d, ArH),
126.54 (2C, d, ArH), 123.07 (2C, d, ArH), 37.24 (2C, t, ArCH2C),
35.83 (1C, s, Ar2C(CH2)2); EI-MS m/ z 370 (M+, 100).28
Ack n ow led gm en t. We are grateful to the DGICYT
(Project PB94-0163) for support of this research. J . J .G.
and B.G.-L. acknowledge the receipt of a fellowship and
a contract, respectively, by the Ministerio de Educacio´n
y Ciencia.
Su p p or tin g In for m a tion Ava ila ble: Experimental pro-
cedures and characterization data for fluorenes 1-8, 21, and
23 and copies of the NMR spectra for 17-19, 22, 24, and 27
(17 pages). This material is contained in libraries on micro-
fiche, immediately follows this article in the microfilm version
of the journal, and can be ordered from the ACS; see any
current masthead page for ordering information.
J O962059N
(29) Recrystallized 30 showed consistently a mp of 180-181 °C,
approximately 24 °C lower than that reported in ref 21. However, the
1H NMR spectrum matches the reported data within experimental
error.21b
2-[(2-Br om op h en yl)m eth yl]a cen a p h th en -1-on e (28). A
mixture of acenaphthenequinone (1.0 g, 5.5 mmol) and (2-