Unusual formation of a cyclyne dimer and an indenoindene derivative

Full text of DOI:10.1021/jo982111a

J . Org. Chem. 1999, 64, 2947-2949
2947
ethylidene rearrangement of alkynes.7 Indeno[2,1-a]-
indenes have been synthesized by the nucleophilic sub-
stitution of bromine from tetrabromodibenzo[a,e]cyclo-
octene by organolithium reagents.8 It has been reported
that substitution with bulky groups9 or benzofusion10,11
gives stability to the pentalene framework.
Un u su a l F or m a tion of a Cyclyn e Dim er
a n d a n In d en oin d en e Der iva tive
Manisha Chakraborty, Claire A. Tessier, and
Wiley J . Youngs*
Department of Chemistry, University of Akron,
Akron, Ohio 44325-3601
Received October 20, 1998
Stephens-Castro coupling1 and Sonogashira-Hagi-
hara coupling2 of o-ethynyliodoaryls have been used to
form cyclotriynes such as 2.3 The tetramer, 3, and
hexamer, 4, are typically low-yield side products in these
reactions. The formation of the dibenzocyclyne dimer 1
or substituted analogues by these types of coupling
reactions has not been reported for o-ethynyliodoben-
zenes4 or o-ethynyliodothiophenes.5
Here we present the unusual formation of the benzo-
cyclyne dimer (10) and the indeno[2,1-a]indene derivative
(11) under the conditions of the Sonogashira-Hagihara
reaction (Scheme 1). Desilylation of 3-iodo-5,6-dimethyl-
2-(2-(trimethylsilyl)ethynyl)hydroquinone (7)12 by potas-
sium fluoride in methanol gives 5,6-dimethyl-2-ethynyl-
3-iodohydroquinone (8) in 63% yield. The combination of
8 with tert-butyldimethylsilyl chloride13 and imidazole in
dry methylene chloride under argon at room temperature
for 2 days gives 5,6-dimethyl-2-ethynyl-3-iodo-1,4-bis-
[((1,1-dimethylethyl)dimethylsilyl)oxy]benzene (9) in 43%
yield. Palladium/copper-catalyzed coupling of 9 in 1:1
i-Pr2NH/toluene at 90 °C for 1 day gave dimer 10 in 10%
yield and 2,3,7,8-tetramethyl-1,4,6,9-tetra[((1,1-dimeth-
ylethyl)dimethylsilyl)oxy]-indeno[2, 1-a]indene (11) in
67% yield. The mass spectrum also revealed the presence
of traces of the trimer (12) and higher cyclics, e.g.,
tetramer, pentamer, and a series of linear oligomers. No
reaction was observed at room temperature when moni-
tored by TLC.
The steric hindrance between the bulky TBDMS
groups increases in going from 10 to 12. This steric
hindrance may be responsible for the preferential forma-
tion of 10 and 11.
Bromination followed by dehydrobromination is the
The high yield of the indenoindene derivative 11 may
be due to the thermal rearrangement of the dimer 10 to
the more stable indenoindene ring system. The yield of
11 in this case is much higher than the yield of com-
pound 6 from FVP of 5. This relatively high yield of 67%
is also noticeable when compared to the yields of 47%
for 2 and 8% for 3 isolated by Stephens-Castro cou-
pling3d and 36% for 2 from the Sonogashira-Hagihara
reaction.3c
only reported route to the formation of dibenzocyclyne
1.6
(5) (a) Solooki, D.; Kennedy, V. O.; Tessier, C. A.; Youngs, W. J .
Synlett 1990, 427. (b) Solooki, D.; Bradshaw, J . D.; Tessier, C. A.;
Youngs, W. J . Organometallics 1994, 13, 451.
(6) Wong, H. N. C.; Garratt, P. J .; Sondheimer, F. J . Am. Chem.
Soc. 1974, 96, 5604.
(7) Brown, R. F. C.; Eastwood, F. W.; Wong, N. R. Tetrahedron Lett.
1993, 34, 3607.
Flash vacuum pyrolysis of diphenylbutadiyne (5) gives
indeno[2,1-a]indene (6) in 19% yield by an ethyne-
(8) Hellwinkel, V. D.; Hasselbach, H.-J .; La¨mmerzahl, F. Angew.
Chem. 1984, 96, 713.
(9) Hafner, K.; Suss, H. U. Angew. Chem., Int. Ed., Engl. 1973, 12,
575.
(1) (a) Stephens, R. D.; Castro, C. E. J . Org. Chem. 1963, 28, 3313.
(b) Castro, C. E.; Havlin, R.; Honward, V. K.; Malte, A.; Moje, S. J .
Am. Chem. Soc. 1969, 91, 6464.
(2) Sonogashira, K.; Tohda, Y.; Hagihara, N. Tetrahedron Lett. 1975,
4467.
(10) Blood, C. T.; Linstead, R. P. J . Chem. Soc. 1952, 2263.
(11) Anderson, M. R.; Brown, R. F. C.; Coulston, K. J .; Eastwood,
F. W.; Ward, A. Aust. J . Chem. 1990, 43, 1137.
(12) Nicolaou, K. C.; Liu, A.; Zeng, Z.; McComb, S. J . Am. Chem.
Soc. 1992, 114, 9279.
(13) (a) Kendall, P. M.; J ohnson, J . V.; Cook, C. E. J . Org. Chem.
1979, 44(9), 1421. (b) Corey, E. J .; Venkateswarlu, A. J . Am. Chem.
Soc. 1972, 94(17), 6190. (c) Green, T. W.; Wuts P. G. M. Protective
groups in organic synthesis; J ohn Wiley & Sons: New York, 1991; pp
77, 80. Hansen, D. W., J r.; Pilipauskas, D. J . Org. Chem. 1985, 50,
945.
(3) (a) Campbell, I. D.; Eglinton, G.; Henderson, W.; Raphael, R. A.
J . Chem. Soc., Chem. Commun. 1966, 87. (b) Staab, H. A.; Bader, R.
Chem. Ber. 1970, 103, 1157. (c) Huynh, C.; Linstrumelle, G. Tetrahe-
dron 1988, 44, 6337. (d) Solooki, D.; Ferrara, J . D.; Malaba, D.;
Bradshaw, J . D.; Tessier, C. A.; Youngs, W. J . Inorg. Synth. 1997, 31,
122.
(4) (a) Kinder, J . D.; Tessier, C. A.; Youngs, W. J . Synlett 1993, 149.
(b) Youngs, W. J .; Kinder, J . D.; Bradshaw, J . D.; Tessier, C. A.
Organometallics 1993, 12, 2406.
10.1021/jo982111a CCC: $18.00 © 1999 American Chemical Society
Published on Web 03/20/1999

2948 J . Org. Chem., Vol. 64, No. 8, 1999
Notes
Sch em e 1
Exp er im en ta l Section
Cyclizations of cyclic aryl alkynes have been previously
observed. Sondheimer14 and Staab15 synthesized hydro-
carbon 15 in attempts to synthesize 13. They proposed
14 to be the diradical intermediate in the transformation
of 13 to 15. Myers16 showed that 1,6-didehydro[10]-
Ma ter ia ls. Compounds 3-iodo-5,6-dimethyl-2-(2-(trimethyl-
18
silyl)ethynyl)hydroquinone (7)12 and Pd(PhCN)2Cl2 were pre-
pared according to literature procedures. Potassium fluoride,
tert-butyldimethylsilyl chloride, calcium hydride, copper iodide,
potassium hydroxide, and imidazole (Aldrich); diisopropylamine
and triphenylphosphine (J anssen Chimica); methanol, hexane,
toluene, carbon tetrachloride, methylene chloride, acetonitrile,
and sodium sulfate (Fisher); and deuterated chloroform (Cam-
bridge Isotope Laboratory) were used as received. Toluene was
distilled from sodium and benzophenone under nitrogen. Amines
and methylene chloride were distilled from KOH and calcium
hydride, respectively. All reactions were monitored by thin-layer
chromatography carried out on E. Merck silica gel plates (60F-
254) using UV light. Flash column chromatography19 was carried
out using silica gel (Baker: 40 µm).
5,6-Dim eth yl-2-eth yn yl-3-iod oh yd r oqu in on e (8). A solu-
tion of 7 (1.359 g, 3.77 mmol), KF (263 mg, 4.53 mmol), MeOH
(45 mL), and H2O (5 mL) was stirred at room temperature for 3
h in air. The reaction mixture was quenched with H2O (20 mL),
extracted with CH2Cl2 (3 × 30 mL), washed with H2O (3 × 15
mL), dried over MgSO4, and concentrated under vacuum. Flash
column chromatography of the solid crude with 7% ethyl acetate
in petroleum ether gave the title compound as a white solid with
annulene undergoes a facile rearrangement to a biradical
1,5-didehydronaphthalene. Compounds 2 and 3 undergo
a lithium-induced cyclization to fulvalene and diindeno-
chrysene derivatives, respectively, by a radical mecha-
nism.17
It is reasonable to propose that indeno[2,1-a]indene
derivative 11 is formed from cyclization of dimer 10
through the formation of a biradical 16 similar to 14.
Toluene probably serves as the hydrogen atom donor for
the terminating radical recombination process.
1
a violet tint: yield 912 mg (84%); H NMR (CDCl3) δ 2.17 (s, 3
H), 2.26 (s, 3 H), 3.74 (s, 1 H), 5.03 (s, 1 H), 5.60 (s, 1 H); 13C
NMR (CDCl3) δ 12.53, 14.10, 81.24, 86.75, 94.60, 110.68, 125.03,
127.18, 147.26, 150.83; IR (CCl4) ν 3306 (vw, CH bound to
alkyne), 3511 (vw, OH) cm-1; FDMS found for C10H9O2I 288
(M+).
5,6-Dim eth yl-2-eth yn yl-3-iod o-1,4-bis[((1,1-d im eth yleth -
yl)d im eth ylsilyl)oxy]ben zen e (9). To a mixture of 8 (991 mg,
(14) (a) Grohmann, K.; Sondheimer, F. Tetrahedron Lett. 1967, 3121.
(b) Sondheimer, F. Proc. Robert A. Welch Found. Conf. Chem. Res.
1968, 12, 3121. (c) Mitchell, R. H.; Sondheimer, F. Tetrahedron 1970,
26, 2141.
(15) (a) Staab, H. A.; Nissen, A.; Ipaktschi, J . Angew. Chem., Int.
Ed. Engl. 1968, 7, 226. (b) Staab, H. A.; Ipaktschi, J .; Nissen, A. Chem.
Ber. 1971, 104, 1182.
(16) Myers, A. G.; Finney, N. S. J . Am. Chem. Soc. 1992, 114, 10986.
(17) (a) Youngs, W. J .; Djebli, A.; Tessier, C. A. Organometallics
1991, 10, 2089. (b) Malaba, D.; Djebli, A.; Chen, L.; Zarate, E. A.;
Tessier, C. A.; Youngs, W. J . Organometallics 1991, 12, 1266. (c)
Bradshaw, J . D.; Solooki, D.; Tessier, C. A.; Youngs, W. J . J . Am. Chem.
Soc. 1994, 116, 3177.
(18) Hartley, F. R. Organomet. Chem. Rev. A 1970, 6, 119.
(19) Still, W. C.; Kahn, M.; Mitra, A. J . Org. Chem. 1978, 43, 2923.

Notes
J . Org. Chem., Vol. 64, No. 8, 1999 2949
3.44 mmol), TBDMSCl (1.244 g, 8.25 mmol), and imidazole (562
mg, 8.25 mmol) in a Schlenk flask was added CH2Cl2 (60 mL).
The heterogeneous mixture was stirred at room temperature for
2 d under argon, opened to air, diluted with CH2Cl2 (180 mL),
washed with water (3 × 120 mL), and dried over Na2SO4. Flash
column chromatography of the solid crude with hexane gave the
sh), 270 (4.93, sh), 282 (5.15), 372 (4.26, br), 382 (4.41), 402 (4.63)
nm; HRMS (EI) calcd for C44H72Si4O4 776.4508, found 776.4519.
Anal. Calcd for C44H72Si4O4: C, 67.98; H, 9.33. Found: C, 67.03;
H, 9.37.
1
Characterization of 11: mp 269 °C; H NMR DEPT (CDCl3)
δ 0.142 (s, 12 H), 0.147 (s, 12 H), 1.04 (s, 18 H), 1.07 (s, 18 H),
1.96 (s, 12 H), 6.34 (s, 2 H indene hydrogens); 13C NMR DEPT
(CDCl3) δ -3.52 (2 Si(CH3)2), -2.72 (2 Si(CH3)2), 14.52 (CH3 on
benzene rings), 14.70 (CH3 on benzene rings), 18.50 (2 q-C of
tert-butyl), 18.60 (2 q-C of tert-butyl), 26.13 (2 (CH3)3), 26.33 (2
(CH3)3), 123.27, 124.64, 129.53, 130.45, 138.57, 143.25, 144.68,
145.79; IR (CCl4) 1264 (s); UV-vis (hexane) λmax (log ꢀ) 218
(4.60), 276 (4.81), 286 (4.79, sh), 430 (4.02), 456 (4.35, br), 486
(4.43) nm; HRMS (EI) calcd for C44H74Si4O4 778.4644, found
778.4677. Anal. Calcd: C, 67.86; H, 9.50. Found: C, 65.94; H,
9.51.
1
white solid 9 in 43% yield (763.2 mg): mp 94-95 °C; H NMR
(CDCl3) δ 0.22 (s, 6 H), 0.28 (s, 6 H), 1.04 (s, 9 H), 1.06 (s, 9 H),
2.07 (s, 3 H), 2.16 (s, 3 H, CH3), 3.44 (s, H); 13C NMR (CDCl3) δ
-2.65, -1.50, 14.86, 16.56, 18.77, 19.02, 26.29, 26.59, 84.40,
85.18, 94.78, 119.42, 129.49, 130.49, 148.74, 150.36; IR (CCl4)
2107 (vw, CtC), 3311 (m, CtH) cm-1; UV-vis (hexane) λmax
(log ꢀ) 216 (4.68), 252 (4.06, br), 266 (3.90, br sh), 316 (3.33, br)
nm; HRMS (EI) calcd for C22H37Si2O2I 516.1377, found 516.1370.
Anal. Calcd for C22H37Si2O2I: C, 51.16; H, 7.17. Found: C, 52.41;
H, 7.56.
Syn th esis of Dim er (10) a n d 2,3,7,8-Tetr a m eth yl-1,4,6,9-
tetr a [((1,1-d im eth yleth yl)d im eth ylsilyl)oxy]in d en o[2,1-a ]-
in d en e (11) by P d -Cu -Ca ta lyzed Self-Cou p lin g of 9. To a
mixture of 9 (300 mg, 0.58 mmol), Pd(PhCN)2Cl2 (0.011 g, 0.02
mmol), PPh3 (0.018 g, 0.06 mmol), and CuI (0.018 g, 0.09 mmol)
under argon was added toluene (10 mL) followed by i-Pr2NH
(10 mL). The reaction mixture (0.02 M with respect to 9) was
gradually heated. White insolubles formed after heating at 90
°C for 2-3 h. The color of the reaction mixture darkened from
straw yellow to orange yellow after heating at 90 °C for 1 d.
After 1 day, TLC showed two new spots and indicated no change
when the reaction was heated at 110 °C for an additional 2 h.
Volatiles were removed under vacuum, and hexane (50 mL) was
added to the residue. The white insoluble solid was filtered from
the orange solution and washed thoroughly with hexane (3 ×
20 mL), and the combined orange filtrate was concentrated
under vacuum to an orange solid. Flash column chromatography
of the orange solid eluting with 4% CH2Cl2 in hexane gave the
yellow solid dimer (10) in 10% (22.7 mg) yield and the orange
solid indenoindene conjugated system (11) in 67% (152 mg) yield.
Ack n ow led gm en t. We thank the National Institute
of General Medicine, National Institutes of Health
(Grant No. 1R15GM54294-01) for financial support,
Huihan Meng and Peter L. Rinaldi for assistance in
obtaining DEPT and COSY NMR spectra, and the
Kresge Foundation and the donors to the Kresge Chal-
lenge Program at the University of Akron for funds used
to purchase the 750 MHz NMR spectrometer used in
this work. We thank Dr. Robert Lattimer of BFGoodrich
for providing FDMS data, the Nebraska Center for Mass
Spectrometry for HRMS data, Professor Gerald F. Koser
of The University of Akron for useful discussions, and
Professor K. C. Nicolaou of Scripps Research Institute
for providing unpublished procedures for the synthesis
of 7. W.J .Y. and C.A.T. thank Professor Franc¸ois
Diederich and Professor Peter Chen for the opportunity
to spend their sabbaticals at ETH Zurich and the Swiss
National Science Foundation for support.
1
Characterization of 10: mp 300 °C; H NMR (CDCl3) δ 0.23
(s, 24 H), 1.02 (s, 36 H), 1.94 (s, 12 H); 13C NMR (CDCl3) δ -3.00,
14.57, 18.56, 26.28, 109.70, 121.93, 131.44, 145.95; IR (CCl4)
1258 (s) cm-1; UV-vis (hexane) λmax (log ꢀ) 214 (4.98), 242 (4.52,
J O982111A