Hydrogenation and dehydrogenation of pentaphenylcyclopentadienes and pentaphenylcyclopentenes

Article abstract of DOI:10.1002/ejoc.201000821

Pentaaryl-substituted cyclopentadienes and cyclopentenes have been employed in catalytic hydrogenation and photochemical cyclodehydrogenation reactions, targeting strained bowl-shaped structures. Both types of reactions generally stop at the monohydrogena

Full text of DOI:10.1002/ejoc.201000821

FULL PAPER
DOI: 10.1002/ejoc.201000821
Hydrogenation and Dehydrogenation of Pentaphenylcyclopentadienes and
Pentaphenylcyclopentenes
Matthias Kanthak,[a] Enrico Muth,[a] and Gerald Dyker*[a]
Keywords: Carbocycles / Photochemistry / Dehydrogenation / Isomerization / Hydrogenation
Pentaaryl-substituted cyclopentadienes and cyclopentenes
have been employed in catalytic hydrogenation and photo-
chemical cyclodehydrogenation reactions, targeting strained
bowl-shaped structures. Both types of reactions generally
stop at the monohydrogenation and monocyclization stage,
respectively.
Introduction
During our ongoing studies on the synthesis and applica-
tions of pentaarylcyclopentadienes[5,6] we noticed that both
hydrogenation and dehydrogenation of pentaarylcyclopen-
tadienes 1 should lead to spherical structures with spatially
adjusted functional groups. The transformation to the
rather strained ultimate target structures (Scheme 1), the
circulene 3 and the all-cis-cyclopentane 2 with five aryl sub-
stituents resembling the fingers of a hand, should be diffi-
cult to achieve because of ring and steric strain. However,
the corresponding intermediates, monohydrogenated and
monocyclized products, deserve attention.
Non-planar polycyclic compounds with arenes confor-
mationally fixed in a bowl-shaped structure are favourite
objects in various fields of chemical research. Calixar-
enes[1,2] and resorcinarenes[1,3] in supramolecular chemistry
are prominent examples, as well as fullerene fragments[4] in
material science.
Herein we describe our attempts to hydrogenate pentaar-
ylcyclopentadienes at the central double bonds as well as to
oxidatively cyclize them at the aryl moieties and to finally
combine these two transformations.
Results and Discussion
Hydrogenation of Cyclopentadienes
We started our investigations with the hydrogenation of
cyclopentadienes 1a–c (Scheme 2). The pentamethyl- and
pentaester-substituted pentaarylcyclopentadienes 1b and 1c
were smoothly monohydrogenated with palladium on char-
coal at 3 bar within 2 days in 86 and 89% isolated yields,
respectively. In comparison, pentaphenylcyclopentadiene
(1a) reacted rather sluggishly under similar hydrogenation
conditions. Because of the poor solubility of 1a in methanol
and ethyl acetate a 1:1 mixture of chloroform and ethyl
acetate was chosen as the reaction medium. After 7 days at
a hydrogen pressure of 3 bar, with the addition of fresh cat-
alyst after 3 days, only 33% of 1a was converted into the
cyclopentene 4a. However, an exceptional yield of 60%
of 4a has been reported for the catalytic hydrogenation in
acetic acid.[7,8]
Scheme 1. Spherical target structures 2 and 3 from the reduction
and oxidation of cyclopentadiene 1.
[a] Faculty of Chemistry
Bochum,
& Biochemistry, Ruhr University
Universitätsstrasse 150, 44780 Bochum, Germany
E-mail: gerald.dyker@ruhr-uni-bochum.de
We also found that cyclopentene 4a could also be ob-
tained by the hydrogenation of pentaphenylcyclopenta-
dienol (5a), a reaction that was highly dependent on the
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Eur. J. Org. Chem. 2010, 6084–6091

Reactions of Pentaphenylcyclopentadienes and -cyclopentenes
the phenyl rings even when applying higher pressure. Also,
our attempts to reduce the double bond with diimide or by
hydroboration failed. Thus, all-cis cyclopentanes of type 2
remain a real challenge for synthesis.
Photo-Oxidation of Cyclopentadienes 1 and
Cyclopentadienol 5a
To achieve target structure 3 we tried several cyclodehy-
drogenation reactions, first, by photochemical oxidation of
the unsubstituted pentaphenylcyclopentadienol (5a) and
pentaphenylcyclopentadiene (1a). Surprisingly, standard re-
action conditions, which reliably convert stilbenes into
phenanthrenes,[11] did not lead to any clean reactions. Both
model substrates were virtually unreactive towards pro-
longed irradiation times (7 days). Also, varying the solvent
did not improve the result. On the other hand, the penta-
tolyl-substituted cyclopentadiene 1b, a derivative of 1a, was
converted into the bis-phenanthrene 8b in 25% isolated
Scheme 2. Catalytic hydrogenation of cyclopentadienes 1a–c. Rea-
gents and condtions: a) Pd/C, H2, 3 bar, 2 d, EtOAc (4b and 4c),
EtOAc/CHCl3 (4a), 7 d. The yield of 4a was estimated by 1H NMR
spectroscopy.
choice of solvent and catalyst (Scheme 3). Thus, the hydro-
genation of 5a in the presence of an excess of Raney nickel
mainly yielded the dehydroxylated[9] cyclopentene 4a,
whereas palladium on charcoal led to the regio- and stereo-
selective formation of the symmetrical cyclopentenol 6a as
the main product when a 7:1 mixture of ethyl acetate/meth-
anol was used as solvent. In addition, minor amounts of the
regular 1,2-hydrogenated cyclopentenol 7a, cyclopentene 4a
and pentaphenylcyclopentadiene (1a) were observed in the
crude reaction mixture, the latter clearly deriving from
water elimination from the quite acid-sensitive 7a. Chang-
ing to the acidic ethyl acetate/acetic acid combination as
solvent, again in a 7:1 ratio, a 1:1 mixture of the hydrogena-
yield in a non-photo-oxidative approach with AlCl3 and
[12]
CuCl2
(Scheme 4). Nevertheless, complete oxidation to
circulene 3 was not observed.
1
tion products 4a and 6a were obtained according to the H
NMR spectrum of the crude product.
Scheme 4. Cyclodehydrogenation of cyclopentadiene 1b to bis-
phenanthrene 8b. Reagents and conditions: a) AlCl3/CuCl2, CS2,
room temperature, 5 min.
Photo-Oxidation of Cyclopentenes
In contrast to the unreactive cyclopentadiene moiety, we
considered the cyclopentenes 4 to be more promising sub-
strates for photochemical phenanthrene formation. The cy-
clopentenes were thus employed in a photochemical cyclo-
dehydrogenation reaction. Typically, the all-cis-pentaphen-
ylcyclopentene (4a) was irradiated in oxygen-free toluene
with iodine as oxidant (Scheme 5).
Surprisingly, 4a produced the epimerized asymmetrical
phenanthrene 10a in 71% isolated yield (Table 1). This radi-
cal-driven epimerization clearly transfers one phenyl group
Scheme 3. Catalytic hydrogenation of cyclopentadienol 5a to cyclo-
pentene 4a and cyclopentenols 6a and 7a, respectively. Reagents
and conditions: a) Raney nickel, H2, 3 bar, 2 d, EtOAc/MeOH 5:1;
b) Pd/C, H2, 3 bar, 2 d, EtOAc/MeOH 7:1.
Most importantly, all hydrogenation reactions of the cy- to a less sterically demanding trans position, as shown in
clopentadiene moiety were accompanied by partial re- Scheme 5. Monitoring the process by 1H NMR spec-
duction of the phenyl rings.[10] Thus, the phenyl rings are troscopy suggested that the epimerization is faster than the
much more susceptible to hydrogenation than the isolated cyclization to the dihydrophenanthrene. Thus, the iso-
but sterically shielded double bond of the cyclopentene. merized cyclopentene 9a was observed as an intermediate to
Thus, a complete hydrogenation of the cyclopentadiene to the final product 10a and was isolated from an incomplete
the all-cis-cyclopentane will be unfeasible without affecting reaction for characterization.
Eur. J. Org. Chem. 2010, 6084–6091
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M. Kanthak, E. Muth, G. Dyker
FULL PAPER
Table 1. Photochemical conversion of cyclopentene 4a.
Solvent
Ar
Oxidant[a]
t [h]
1a[b]
11a[b]
9a[b]
10a[b]
PhCH3
PhCH3
PhCH3
MeOH
PhCH3
PhCH3
+
+
+
+
–
iodine
iodine
–
iodine
iodine, air
air
15
33
4.5
16
40
38
14
–
–
–
–
–
17
–
(77)
43 (23)
Traces
43 (33)
(71)
–
–
–
–
–
83
–
–
–
(33)[c]
–
23[d]
[a] Iodine was used in excess (2 equiv.). [b] The ratio of the major components was determined by 1H NMR analysis of the crude reaction
mixture. Isolated yields are given in parentheses. [c] Isolated as its oxidation product (diepoxide). [d] The ratio of 1a was not always well
reproducible.
the expected symmetrical phenanthrene 11c in oxygen-free
toluene with iodine as oxidant (Scheme 6). This result sug-
gests that the ester functionality in 4c somehow suppresses
the epimerization mechanism that proceeded under iden-
tical conditions with 4a.
Scheme 5. Formation of the epimeric phenanthrenes 10a and 11a
from cyclopentene 4a. Reagents and conditions: a) hν, I2, Ar, tolu-
ene, 33 h; b) hν, air, toluene, 33 h. The radical-driven formation of
9a preceeds the photocyclization–oxidation to 10a.
Scheme 6. Photochemical oxidation of cyclopentene 4c to phen-
anthrene 11c. Reagents and conditions: a) hν, I2, N2, toluene, 24 h.
Unexpectedly, changing from oxygen-free toluene to oxy-
gen-free methanol as solvent, the irradiation of 4a produced
the all-cis-phenanthrene 11a and pentaphenylcyclopentadi-
ene (1a), an oxidation product of 4a, in a preparatively poor
A combination of oxygen and iodine as oxidants, re-
ported to be advantageous[13] for shorter reaction times and
cleaner reactions, unfortunately in the case of 4a gave a
complex reaction mixture that included minor amounts of
phenanthrene derivatives, as concluded by the diagnostic
ratio (1:5 in favour of the cyclopentadiene 1a). In addition,
the poor solubility of the starting material in methanol ren-
1
downfield signals in the H NMR spectrum. Only an oxi-
dered any optimization unnecessary.
dation product of pentaphenylcyclopentadiene was isolated,
the NMR spectra of which were in accord with the struc-
Hence we attempted to change the oxidant to gain access
to the symmetrical phenanthrene 11a in preparatively valu-
able amounts. We considered air to be more suited than
iodine to overcoming the problem of radical-induced epi-
ture of the diepoxide, a known photoinduced rearrange-
ment product of the endoperoxide of 1a.[14]
merization of the starting all-cis-pentaphenylcyclopentene
(4a). Indeed, the irradiation of 4a in air-saturated toluene
in the absence of iodine afforded the desired phenanthrene
Photo-Oxidation of Cyclopentenol 6a
11a in 77% isolated yield (Scheme 5). Attempts to hydroge-
Consequently, we were interested in the behaviour of
nate 11a, targeting a monocyclized derivative of 2, did not cyclopentenol 6a under oxidative photocyclization condi-
lead to any conversion at the 9,10-double bond of the phen- tions (Table 2). The product distribution turned out to be
anthrene unit.
strongly influenced by the choice of solvent and oxidant.
In sharp contrast to the unsubstituted system 4a, the es- Surprisingly, irradiation of homoallylic alcohol 6a in oxy-
ter-functionalized pentaphenylcyclopentene 4c furnished gen-free toluene as solvent and iodine as oxidant did not
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Reactions of Pentaphenylcyclopentadienes and -cyclopentenes
Table 2. Photochemical conversion of cyclopentenol 6a.
Solvent
Ar
Oxidant[a]
t [h]
Additive
1a[b]
5a[b]
12[b]
13[b]
PhCH3
PhCH3
PhCH3
MeOH[c]
MeOH
MeOH
PhCH3
+
+
+
+
–
–
–
iodine
iodine
iodine
iodine
iodine
iodine
air
15
12
15
19
16
10
40
–
25
50
100
50
–
–
–
75
50
–
–
–
–
–
–
–
–
50
–
–
–
–
–
K2CO3
NEt3
–
–
K2CO3
20[d]
(41)
(55)
–
–
–
[a] Iodine was used in excess (2 equiv.). [b] The ratio of the major components was determined by 1H NMR analysis of the crude reaction
mixture. Isolated yields are given in parentheses. [c] In one (not reproducible) experiment 5a was observed instead of 1a. [d] 80%
unconverted starting material.
give any cyclization products, but yielded the simple oxi- to be virtually unreactive towards photocyclization. There-
dation products cyclopentadienol 5a and cyclopentadiene fore we assume that phenanthrene 13 is an intermediate of
1a, respectively.
12, obtained then by elimination of water under the acidic
Changing to methanol as solvent led to the formation of conditions provided by the simultaneously formed HI. In-
phenanthrene 12. The reaction in oxygen-free methanol in deed, air as oxidant in the absence as well as in the presence
the presence of iodine yielded an approximately 1:1 mixture of iodine provides less acidic conditions, thus enabling the
of phenanthrene 12[15] and pentaphenylcyclopentadiene isolation of the acid-sensitive phenanthrene derivative 13
(1a), which were separated by trapping the non-cyclized by- (Scheme 7).
product 1a as the Diels–Alder adduct with dimethyl acet-
ylenedicarboxylate[16] (Scheme 7). However, the best result
Conclusions
with a 55% isolated yield of annulated phenanthrene 13 was
obtained by using a toluene/air combination. Although 12
is formally a photocyclization–oxidation product from
pentaphenylcyclopentadiene 1a, we have already proved 1a
We have investigated the reactivity of pentaarylated
cyclopentadienes and cyclopentenes in hydrogenation and
dehydrogenation reactions. The product distribution of the
hydrogenation of the cyclopentadienes strongly depended
on the solvent and catalyst. We also confirmed the complete
hydrogenation of the cyclopentadiene moiety to bowl-
shaped all-cis-cyclopentanes to be unfeasible because the
phenyl groups are more susceptible to hydrogenation than
the sterically shielded cyclopentene moiety. The aryl-substi-
tuted cyclopentadienes did not show clean photo-oxidation
to phenanthrenes. Instead we succeeded through a non-
photochemical oxidation reaction to synthesize a bis-phen-
anthrene as a double cyclization product. In contrast, the
arylated cyclopentenes exhibited a significant reactivity in
the cyclodehydrogenation reactions to phenanthrenes by
standard photochemical pathways, the product distribution
being highly dependent on the choice of solvent and oxi-
dant.
Experimental Section
Scheme 7. Formation of phenanthrenes 12 and 13 from cyclopent-
enol 6a in the presence and absence of oxygen, respectively. The
transformation d is necessary for the separation of 12 and 1a. Rea-
gents and conditions. a) hv, MeOH, I2, Ar, 22 h; b) hv, toluene, O2.
68 h; c) hv, MeOH, I2, Ar, 6a; d) dimethyl acetylenedicarboxylate,
toluene, 110 °C, 16 h.
General: Melting points were determined with Reichert Thermovar
and Büchi (Dr. Tottoli) instruments. Infrared spectroscopy was per-
formed with a Perkin–Elmer 983 and a Bruker Equinox 55 spec-
trometer. UV/Vis spectra were recorded with Perkin–Elmer
Lambda 40 and Varian Cary 1 spectrophotometers. 1H and 13C
Eur. J. Org. Chem. 2010, 6084–6091
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M. Kanthak, E. Muth, G. Dyker
FULL PAPER
NMR spectra were recorded with the Bruker DPX 200, DRX 400
and DRX 600 spectrometers. Spectra were calibrated with the re-
sidual solvent peak or with TMS as the internal standard. Mass
spectrometry was performed with Varian MAT 311A ITD and
all-cis-1,2,3,4,5-Pentakis(4-methylphenyl)cyclopentene (4b): A solu-
tion of cyclopentadiene 1b (258 mg, 0.50 mmol) in EtOAc (100 mL)
was hydrogenated with Pd/C (50 mg, 10% Pd) under a hydrogen
pressure of 3 bar for 2 d. The catalyst was filtered off and the fil-
MATCH5 (70 eV) spectrometers. For analytical TLC, precoated trate was evaporated. The residue was submitted to flash column
plastic sheets “POLYGRAM SIL G/UV254” from Macherey–Nagel
were used. Elemental analyses were determined with a Euro Ele-
mental Analyzer 3000. The irradiations were conducted with a mer-
chromatography (silica, PE, Rf = 0.06; 0.00). The fraction with Rf
= 0.06 afforded cyclopentene 4b (223 mg, 86%) as colourless crys-
tals with m.p. 212 °C. IR (KBr): ν = 3020 (m), 2920 (m), 2879 (w),
˜
cury high-pressure lamp (Philips HPK 125 W). For experiments 1611 (m), 1509 (s), 1449 (w), 1188 (w), 1182 (w), 1020 (w), 820 (s),
1
performed under oxygen exclusion, either argon or nitrogen was
bubbled through the reaction solution vigorously for 30 min before
the irradiation was started. A constant but slow flow of inert gas
was sustained throughout the reaction. The procedure was identical
when air was used as the oxidant. Pressurized air from the standard
laboratory supply was used for this purpose. Solvents for irradia-
tion were distilled prior to use. THF was dried with sodium/benzo-
phenone and freshly distilled prior to use.
790 (m), 736 (m) cm–1. H NMR (600 MHz, CDCl3): δ = 2.15 (s,
3 H, CH3), 2.19 (s, 6 H, CH3), 2.23 (s, 6 H, CH3), 4.45 (t, J =
9.2 Hz, 1 H, 4-H), 4.58 (d, J = 9.1 Hz, 2 H, 3-H, 5-H), 5.95 (d, J
= 8.0 Hz, 2 H, Ph-o-H), 6.58 (d, J = 8.0 Hz, 2 H, Ph-m-H), 6.81
(d, J = 8.0 Hz, 4 H, Ph-m-H), 6.88 (d, J = 8.0 Hz, 4 H, Ph-o-H),
6.92 (d, J = 8.0 Hz, 4 H, Ph-o-H), 7.16 (d, J = 8.0 Hz, 4 H, Ph-m-
H) ppm. 13C NMR (150 MHz, CDCl3): δ = 21.1 (CH3), 21.2 (CH3),
21.3 (CH3), 54.5 (C-4), 60.7 (C-3, C-5), 127.2, 128.1, 128.9, 129.2,
130.6, 131.8 (all CH Ph), 135.0, 135.3, 135.6, 136.5 (all C Ph), 138.1
(C-1, C-2), 141.1 (C Ph) ppm. UV/Vis (MeCN): λmax (logε) = 209
(3.99), 264 (3.23) nm. MS (FAB): m/z (%) = 518 (100) [M]+. C40H38
(518.73): calcd. C 92.62, H 7.38; found C 92.23, H 6.96.
Chemicals were used as received. Pentaphenylcyclopentadienes 1b
and 1c were synthesized by the palladium-catalyzed arylation of
cyclopentadiene.[6]
Pentaphenylcyclopentadiene (1a): Tetracyclone (1.40 g, 3.64 mmol)
was dissolved in dry THF (50 mL) and phenyllithium (3.0 mL, 2 
in cyclohexane/Et2O, 6.0 mmol) was added at once at room tem-
perature. The mixture was stirred for 15 min and LiAlH4 was added
within 10 min. The mixture was then stirred for 30 min and hy-
drolyzed with satd. aq. NH4Cl (40 mL). The layers were separated
and the organic layer was extracted with CH2Cl2 (2ϫ20 mL). The
extracts were dried with Na2SO4 and the solvents evaporated. The
residue was treated in an ultrasonic bath with MeOH (5 mL) until
a precipitate formed. Pentaphenylcyclopentadiene (1a) was ob-
tained by filtration as an off-white solid (1.27 g, 78%) with m.p.
250 °C (ref.[17] 248–250 °C). 1H NMR (200 MHz, CDCl3): δ = 5.09
(s, 1 H), 6.94–7.25 (m, 25 H) ppm.
all-cis-1,2,3,4,5-Pentakis(4-ethoxycarbonylphenyl)cyclopentene (4c):
A solution of cyclopentadiene 1c (403 mg, 0.50 mmol) in EtOAc
(100 mL) was hydrogenated with Pd/C (50 mg, 10% Pd) under a
hydrogen pressure of 3 bar for 2d. The catalyst was filtered off and
the filtrate was evaporated. The residue was submitted to flash col-
umn chromatography (silica, PE/MTBE, 2:1, Rf = 0.12; 0.00). The
fraction with Rf = 0.12 afforded cyclopentene 5c (360 mg, 89%) as
colourless crystals with m.p. 247 °C. IR (KBr): ν = 2982 (m), 2936
˜
(w), 1719 (s), 1608 (m), 1407 (m), 1367 (m), 1276 (s), 1180 (m), 1106
1
(s), 1021 (m), 859 (w), 775 (w), 715 (w) cm–1. H NMR (400 MHz,
CDCl3): δ = 1.32–1.37 (m, 15 H, CH3), 4.27–4.35 (m, 10 H, OCH2),
4.75 (“t”, J = 9.0 Hz, 1 H, 4-H), 4.87 (d, J = 9.0 Hz, 2 H, 3-H, 5-
H), 6.15 (d, J = 8.3 Hz, 2 H, Ph-H), 7.06 (d, J = 8.2 Hz, 4 H, Ph-
H), 7.29 (d, J = 8.3 Hz, 4 H, Ph-H), 7.46 (d, J = 8.4 Hz, 2 H, Ph-
H), 7.75 (d, J = 8.2 Hz, 4 H, Ph-H), 7.82 (d, J = 8.4 Hz, 4 H, Ph-
H) ppm. 13C NMR (100 MHz, CDCl3): δ = 14.4 (CH3), 54.5 (C-
4), 60.8 (C-3, C-5), 61.0 (OCH2), 61.1 (OCH2), 128.3 (CH Ph),
128.9 (C Ph), 129.2 (CH Ph), 129.3 (CH Ph), 129.5 (C Ph), 129.8
(CH Ph), 129.8 (C Ph), 130.3 (CH Ph), 131.5 (CH Ph), 141.2 (C
Ph), 142.2 (C Ph), 142.7 (C Ph), 144.9 (C Ph), 166.2 (CO), 166.4
(CO), 166.6 (CO) ppm. UV/Vis (MeCN): λmax (logε) = 204 (4.30),
244 (4.24), 368 (3.23) nm. MS (EI, 70 eV): m/z (%) = 808 (34) [M]+,
763 (100) [M – OCH2CH3]+. C50H48O10 (808.91): calcd. C 74.24,
H 5.98; found C 74.29, H 5.56.
all-cis-1,2,3,4,5-Pentaphenylcyclopentene (4a): Ni–Al alloy (1.5 g)
was suspended in H2O (15 mL) and sodium hydroxide pellets
(2.3 g) were added portionwise to keep the mixture boiling. The
mixture was left to stand for 10 min and was then placed in a water
bath (70 °C) and kept there for 30 min. The water was decanted
and the Raney nickel was washed twice each with water, ethanol
and ethyl acetate. Alcohol 5a (500 mg, 1.08 mmol) and the freshly
prepared Raney nickel were suspended in ethyl acetate/methanol
(5:1, 100 mL) and the mixture was hydrogenated under a hydrogen
pressure of 3 bar for 2 d. The nickel catalyst was filtered off and
the filtrate was evaporated. The residue was repeatedly crystallized
from dichloromethane/methanol to give cyclopentene 4a as colour-
less crystals (340 mg, 68%) with m.p. 213 °C (ref.[7] 217 °C). The
substance is known in the literature[7] but has not been completely
Pentaphenylcyclopentadienol (5a): Tetracyclone (1.37 g, 3.57 mmol)
was dissolved in dry THF (70 mL) and phenyllithium (3.0 mL, 2 
in cyclohexane/Et2O, 6.0 mmol) was added at once at room tem-
perature. The mixture was stirred for 15 min and hydrolyzed with
water. The mixture was extracted with MTBE (2ϫ20 mL) and the
organic extracts were dried with Na2SO4 and the solvents evapo-
rated. The residue was treated in the ultrasonic bath with methanol/
petroleum ether (1:1, 5 mL) until a precipitate formed. Cyclopen-
tadienol 5a was obtained by filtration as a colourless solid (1.26 g,
76%) with m.p. 174–175 °C (ref.[18] 175–176 °C). 1H NMR
(200 MHz, CDCl3): δ = 2.25 (s, 1 H, OH), 6.96–7.07 (m, 14 H),
7.09–7.17 (m, 6 H), 7.20–7.31 (m, 3 H), 7.57 (dd, J = 8.2, 1.4 Hz,
2 H) ppm.
characterized. IR (KBr): ν = 3102 (w), 3082 (w), 3054 (m), 3028
˜
(m), 2915 (w), 2881 (w), 2861 (w), 1597 (m), 1573 (w), 1491 (s),
1451 (s), 1442 (s), 1345 (w), 1304 (w), 1284 (w), 1266 (w), 1228 (w),
1203 (w), 1176 (m), 1153 (w), 1114 (w), 1074 (m), 1029 (m), 1001
(w), 989 (w), 968 (w), 912 (m), 873 (w), 844 (w), 812 (w), 784 (s),
761 (vs), 724 (s), 706 (vs), 695 (vs) cm–1. 1H NMR (400 MHz,
CDCl3): δ = 4.61 (“t”, J = 9.3 Hz, 1 H, 4-H), 4.75 (d, J = 9.2 Hz,
2 H, 3-H, 5-H), 6.06 (dd, J = 8.1, 1.0 Hz, 2 H, Ph-o-H), 6.78 (t, J
= 7.7 Hz, 2 H, Ph-m-H), 6.93–6.97 (tt, J = 7.4, 1.1 Hz, 1 H, Ph-p-
H), 7.04 (“s”, 10 H, Ph-H), 7.13–7.16 (m, 6 H, Ph-H), 7.29–7.33
(m, 4 H, Ph-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 55.1 (C-
4), 61.2 (C-3, C-5), 126.1, 126.4, 126.7, 127.3, 127.7, 128.4, 129.6,
130.9 (all CH Ph), 132.1 (o-CH Ph), 138.1, 138.6, 141.1, 142.0 (all
s) ppm. UV/Vis (MeCN): λmax (logε) = 230 (4.19), 260 (3.98) nm.
MS (EI, 70 eV): m/z (%) = 448 (100) [M]+, 370 (79), 357 (73).
C35H28 (448.60): calcd. C 93.71, H 6.29; found C 93.66, H 6.28.
(1r*,2R*,5S*)-1,2,3,4,5-Pentaphenylcyclopent-3-enol (6a): A solu-
tion of pentaphenylcyclopentadienol (5a; 440 mg, 0.95 mmol) in
ethyl acetate/methanol (7:1, 100 mL) was hydrogenated with Pd/C
(50 mg, 10% Pd) under a hydrogen pressure of 3 bar for 2 d. The
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Eur. J. Org. Chem. 2010, 6084–6091

Reactions of Pentaphenylcyclopentadienes and -cyclopentenes
catalyst was filtered off and the filtrate was evaporated. The residue
was submitted to flash column chromatography [silica, toluene, Rf
= 0.90 (4a, hydrogenated derivatives, 1a), 0.33, 0.19]. The fraction
with Rf = 0.33 contained allylic alcohol 7a (30 mg, 7%) as a colour-
and evaporation the residue was dissolved in toluene (5 mL) in a
screw-capped flask and dimethyl acetylenedicarboxylate (0.02 mL,
0.16 mmol) was added. The mixture was heated at 110 °C for 12 h.
Toluene was evaporated and the residue was submitted to flash
column chromatography (silica, pentane). The fraction with Rf =
less solid that easily decomposed to pentaphenylcyclopentadiene
1
(1a). H NMR (CDCl3, 200 MHz): δ = 2.24 (s, 1 H, OH), 4.48 (d, 0.22 (pentane, 7 runs) yielded phenanthrene 10a (100 mg, 33%).
J = 9.9 Hz, 1 H, 4-H/5-H), 5.08 (d, J = 9.8 Hz, 1 H, 4-H/5-H), 5.99 The fraction with Rf = 0.26 (PE/EtOAc, 20:1) afforded isomerized
(d, J = 7.2 Hz, 2 H), 6.76 (t, J = 7.5 Hz, 2 H), 6.87–7.02 (m, 6 H), cyclopentene 9a (68 mg, 23%) as a colourless solid. Recrystalli-
7.11–7.17 (m, 6 H), 7.19–7.28 (m, 5 H), 7.34–7.41 (m, 4 H) ppm. zation from CH2Cl2/MeOH gave colourless crystals with m.p. 176–
MS (EI, 70 eV): m/z (%) = 464 (1) [M]+, 446 (100) [M – H2O]+. 177 °C. IR (KBr): ν = 3078 (w), 3057 (w), 3021 (m), 2998 (w), 2896
˜
The fraction with Rf = 0.19 afforded the cyclopentenol 6a (257 mg,
(m), 2881 (w), 2854 (w), 1600 (m), 1576 (w), 1560 (w), 1541 (w),
1490 (m), 1444 (m), 1385 (w), 1335 (w), 1310 (w), 1223 (w), 1193
(w), 1158 (w), 1111 (w), 1070 (m), 1028 (m), 1002 (w), 983 (w), 960
58%) as a colourless solid with m.p. 191 °C. IR (KBr): ν = 3568
˜
(w), 3082 (w), 3060 (m), 3025 (m), 2923 (w), 2899 (w), 2866 (w),
1597 (m), 1493 (m), 1443 (m), 1381 (w), 1381 (w), 1332 (w), 1280
(w), 907 (w), 874 (w), 857 (w), 806 (w), 790 (m), 777 (m), 764 (s),
(w), 1261 (w), 1214 (w), 1180 (m), 1156 (w), 1090 (w), 1076 (w), 726 (m), 692 (s), 659 (m) cm–1. H NMR (CDCl3, 400 MHz): δ =
1
1066 (w), 1042 (m), 1027 (m), 1003 (w), 988 (m), 967 (w), 913 (w),
4.09 (“t”, J = 9.1 Hz, 1 H, 4-H), 4.76 (dd, J = 8.5, 1.6 Hz, 1 H, 3-
879 (w), 848 (w), 817 (w), 784 (m), 771 (m), 761 (s), 753 (m), 722 H/5-H), 4.91 (dd, J = 9.7, 1.6 Hz,1 H, 3-H/5-H), 6.87–6.94 (m, 4
1
(s), 711 (s), 698 (vs), 616 (w), 590 (w), 572 (m), 543 (m) cm–1. H
NMR (CDCl3, 400 MHz): δ = 2.97 (s, 1 H, OH), 4.62 (s, 2 H, 2-
H, 5-H), 6.40 (dd, J = 8.3, 0.9 Hz, 2 H, Ph-o-H), 6.75 (“t”, J =
7.8 Hz, 2 H, Ph-m-H), 6.90 (tt, J = 7.3, 1.1 Hz, 1 H, Ph-p-H), 7.03
H, Ph-H), 7.00–7.15 (m, 19 H, Ph-H), 7.21–7.24 (m, 2 H, Ph-
H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 59.07 (C-3/C-5), 60.72
(C-3/C-5), 60.93 (C-4), 126.18, 126.31, 126.36, 126.84, 127.02,
127.69, 128.00, 128.10, 128.15, 128.28, 128.83, 129.10, 129.27,
(s, 10 H, Ph-H), 7.12–7.15 (m, 6 H, Ph-H), 7.29–7.33 (m, 4 H, Ph- 129.35, 129.40 (all CH Ph), 137.12 (C Ph), 137.24 (C Ph), 139.72,
H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 77.23 (C-2, C-5), 86.47
(C-1), 125.90 (m-CH Ph), 126.16 (p-CH Ph), 126.77, 127.44, 127.76,
139.74, 141.21, 142.55, 142.84 (all s) ppm. UV/Vis (MeCN): λmax
(logε) = 225 (4.34), 259 (4.16), 265 (4.17) nm. MS (EI, 70 eV): m/z
128.33, 128.36, 129.50, 130.83 (all CH Ph), 137.62, 139.24, 139.37 (%) = 448 (100) [M]+, 370 (90) [M – Ph – 1]+, 357 (60). C35H28
(all C Ph), 140.51 (C-3, C-4) ppm. UV/Vis (MeCN): λmax (logε) = (448.60): calcd. C 93.71, H 6.29; found C 93.64, H 6.30.
213 (4.42), 263 (sh, 3.56) nm. MS (FAB): m/z (%) = 487 (6) [M +
Na]+, 464 (16) [M]+, 447 (69) [M – OH]+, 269 (100). C35H28O
(464.60): calcd. C 90.48, H 6.07; found C 90.39, H 5.85.
(1R*,3R*)-1,2,3-Triphenyl-2,3-dihydro-1H-cyclopenta[l]phen-
anthrene (10a): A solution of cyclopentene 4a (135 mg, 0.30 mmol)
and iodine (78 mg, 0.6 mmol) in deoxygenated toluene (250 mL)
was irradiated for 33 h under argon. The solvent was evaporated
and the residue was dissolved in dichloromethane and washed with
aq. satd. Na2SO3 to remove iodine. The organic layer was dried
with Na2SO4 and dichloromethane was removed in vacuo. The resi-
due was subjected to flash column chromatography (silica, pentane,
7 runs; Rf = 0.22, 0.26, 0.32). The fraction with Rf = 0.22 gave
phenanthrene 10a (95 mg, 71%) as a colourless solid. Recrystalli-
zation from dichloromethane/petroleum ether afforded colourless
3,6,11,14-Tetramethyl-17-(4-methylphenyl)-17H-cyclopenta[1,2-
l:3,4-lЈ]diphenanthrene (8b): CuCl2 (269 mg, 2.00 mmol), AlCl3
(267 mg, 2.00 mmol) and cyclopentadiene 1b (516 mg, 1.00 mmol)
in CS2 (200 mL) were stirred for 5 min at room temperature. After
dilution with ethanol (200 mL) the resulting precipitate was filtered
off and washed with ethyl acetate (100 mL). The collected filtrates
were concentrated in vacuo and the residue was submitted to flash
column chromatography (silica, PE, Rf = 0.06; 0.00). The fraction
with Rf = 0.06 gave polycycle 8b (133 mg, 25%) as bright-yellow
crystals with m.p. 199–200 °C. IR (KBr): ν = 3101 (w), 3073 (w),
˜
3059 (w), 3023 (m), 3002 (w), 2982 (w), 2856 (w), 1599 (m), 1489
(m), 1450 (m), 1429 (w), 1393 (w), 1336 (w), 1312 (w), 1264 (w),
1238 (w), 1180 (w), 1167 (w), 1154 (w), 1109 (w), 1080 (w), 1066
(w), 1045 (w), 1030 (m), 1001 (w), 987 (w), 960 (w), 945 (w), 918
(w), 894 (w), 875 (w), 856 (w), 838 (w), 812 (m), 756 (s), 726 (s),
crystals with m.p. 246 °C. IR (KBr): ν = 3022 (w), 2920 (m), 2862
˜
(w), 1606 (w), 1512 (s), 1442 (w), 1407 (w), 1384 (w), 1182 (w),
1129 (w), 1106 (w), 1034 (w), 1021 (w), 819 (s), 771 (w), 738 (w),
1
723 (w), 699 (m), 692 (w) cm–1. H NMR (400 MHz, CDCl3): δ =
2.18 (s, 3 H, CH3), 2.56 (s, 6 H, CH3), 2.67 (s, 6 H, CH3), 5.75 (s,
1 H, 17-H), 6.93 (d, J = 8.0 Hz, 2 H, Ph-H), 7.15 (d, J = 8.0 Hz,
2 H, Ph-H), 7.29 (d, J = 8.1 Hz, 2 H, 2-H, 15-H), 7.45 (d, J =
8.3 Hz, 2 H, 7-H, 10-H), 7.96 (d, J = 8.1 Hz, 2 H, 1-H, 16-H), 8.47
(s, 2 H, 4-H, 13-H), 8.55 (s, 2 H, 5-H, 12-H), 8.62 (d, J = 8.2 Hz,
2 H, 8-H, 9-H) ppm. 13C NMR (100 MHz, CDCl3): δ = 21.2 (CH3),
22.15 (CH3), 22.2 (CH3), 54.8 (C-17), 123.1 (C-4, C-13), 123.5 (C-
5, C-12), 124.4 (C-1, C-16), 126.4 (C-8a, C-8d), 126.7 (C-7, C-10),
127.2 (C-16a, C-17b), 127.8 (C-8, C-9), 128.6 (C-2, C-15), 128.67
(CH Ph), 129.7 (CH Ph), 130.6 (C-4a, C-12b), 131.7 (C-4b, C-12a),
135.3 (C-6, C-11), 135.4 (C-3, C-14), 136.1 (C Ph), 136.1 (C-8b, C-
8c), 138.4 (C Ph), 144.4 (C-16b, C-17a) ppm. UV/Vis (MeCN): λmax
(log ε) = 214 (4.29), 218 (4.33), 254 (4.27), 340 (3.91) nm. MS
(FAB): m/z (%) = 512 (100) [M]+. C40H32 (512.68): calcd. C 93.71,
H 6.29; found C 93.33, H 6.15.
1
701 (s), 613 (w), 577 (w) cm–1. H NMR (CDCl3, 400 MHz): δ =
4.17 (“t”, J = 9.0 Hz, 1 H, 2-H), 5.27 (d, J = 9.4 Hz, 1 H, 1-H/3-
H), 5.30 (d, J = 8.6 Hz,1 H, 1-H/3-H), 6.65 (dd, J = 7.8, 1.3 Hz, 2
H, Ph-H), 6.88–6.91 (m, 2 H, Ph-H), 6.95–7.06 (m, 6 H, Ph-H),
7.09–7.12 (m, 2 H, Ph-H), 7.16–7.21 (m, 3 H, Ph-H), 7.37 (ddd, J
= 8.1, 7.0, 1.0 Hz, 1 H, 5-H/10-H), 7.47 (ddd, J = 8.0, 7.1, 1.0 Hz,
1 H, 5-H/10-H), 7.51 (dd, J = 8.0, 0.8 Hz, 1 H, 4-H/11-H), 7.58–
7.63 (m, 2 H, 6-H, 9-H), 7.70 (d, J = 8.0, 0.8 Hz, 1 H, 4-H/11-H),
8.77 (“t”, J = 7.7 Hz, 2 H, 7-H, 8-H) ppm. 13C NMR (CDCl3,
100 MHz): δ = 56.04 (C-1/C-3), 56.28 (C-1/C-3), 63.72 (C-2),
123.29 (C-7/C-8), 123.47 (C-7/C-8), 126.06 (C-4/C-11), 126.10 (C-
6/C-9), 126.32 (C-4/C-11), 126.36 (C-5/C-10), 126.42 (CH Ph),
126.44 (CH Ph), 126.48 (CH Ph), 126.58 (CH Ph), 126.97 (C-5/C-
10), 127.73 (CH Ph), 128.06 (CH Ph), 128.20 (CH Ph), 128.77 (CH
Ph), 129.09 (CH Ph), 129.44 (two overlapping signals, C-3b, C-
(3R*,5R*)-1,2,3,4,5-Pentaphenylcyclopentene (9a): A solution of 11a), 129.50 (CH Ph), 131.59 (C-7a/C-7b), 131.73 (C-7a/C-7b),
pentaphenylcyclopentene (4a) (300 mg, 0.65 mmol) and iodine 139.14 (C-3a, C-11b), 139.40 (C-3a, C-11b), 139.83 (C Ph), 140.69
(167 mg, 1.31 mmol) in deoxygenated toluene (250 mL) was irradi-
ated for 15 h under argon. The solution was concentrated and
washed with satd. aq. Na2SO3 (10 mL). After drying over Na2SO4
(C Ph), 144.82 (C Ph) ppm. UV/Vis (MeCN): λmax (logε) = 217
(4.51), 247 (4.52, br), 271 (4.23, sh), 279 (4.06), 290 (4.03), 302
(4.08), 352 (2.70) nm. MS (EI, 70 eV): m/z (%) = 446 (100) [M]+,
Eur. J. Org. Chem. 2010, 6084–6091
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
6089

M. Kanthak, E. Muth, G. Dyker
FULL PAPER
368 (43), 355 (41). C35H26 (446.58): calcd. C 94.13, H 5.87; found
C 93.72, H 5.67.
761 (100) [M – OCH2CH3]+. C50H46O10 (806.89): calcd. C 74.43,
H 5.75; found C 74.56, H 5.44.
1,2,3-Triphenyl-1H-cyclopenta[l]phenanthrene (12): A solution of
cyclopentenol 6a (215 mg, 0.46 mmol) and iodine (117 mg,
0.92 mmol) in deoxygenated methanol was irradiated for 22 h un-
der argon. MeOH was evaporated and the residue was dissolved in
CH2Cl2 and washed with aq. satd. Na2SO3 (1ϫ5 mL). The organic
layer was filtered through a short plug of silica (CH2Cl2, EtOAc)
and the filtrate was evaporated. Dimethyl acetylenedicarboxylate
(0.03 mL, 0.24 mmol) was added to a solution of a sample of the
crude product (90 mg) in toluene (3 mL) and the mixture was
stirred for 16 h at 110 °C. After evaporation of the solvent the resi-
due was subjected to flash column chromatography (silica, pentane,
4 runs, Rf = 0, 0.14, 0.24, 0.33, 0.47). The fraction with Rf = 0.14
afforded phenanthrene 12 (20 mg, 27 %) as an off-white solid.
Crystallization from CH2Cl2/PE afforded slightly yellow crystals
with m.p. 217–219 °C (ref.[15] 224–225 °C). The substance has been
described in the literature[15] but the reported NMR data do not
fit our observations. 1H NMR (CDCl3, 400 MHz): δ = 5.47 (s, 1
H), 7.02–7.11 (m, 6 H), 7.13–7.19 (m, 4 H), 7.26–7.31 (m, 2 H),
7.38–7.44 (m, 3 H), 7.50–7.66 (m, 5 H), 7.87 (d, J = 8.0 Hz, 1 H),
8.70 (d, J = 8.3 Hz, 1 H), 8.76 (d, J = 8.3 Hz, 1 H) ppm. 13C NMR
(CDCl3, 100 MHz): δ = 58.75, 123.46, 123.53, 124.66, 125.37,
125.72, 125.87, 126.12, 126.73, 126.85, 126.91, 127.71, 127.77,
128.45, 128.62, 128.69, 128.91, 129.17, 129.64, 129.80, 131.02,
131.62, 136.79, 138.59, 129.06, 139.66, 141.44, 142.97, 150.35 ppm.
all-cis-1,2,3-Triphenyl-2,3-dihydro-1H-cyclopenta[l]phenanthrene
(11a): A solution of cyclopentene 4a (95 mg, 0.2 mmol) in air-satu-
rated toluene (250 mL) was irradiated for 33 h. The solvent was
evaporated and the residue was dissolved directly in toluene in a
screw-capped flask and dimethyl acetylenedicarboxylate was
added. The mixture was heated to 110 °C for 16 h. After cooling
to room temperature the solution was submitted directly to a short
plug of silica and eluted with toluene. The fraction with Rf ≈ 1 gave
phenanthrene 11a (72 mg, 77%) as a colourless solid. Recrystalli-
zation from dichloromethane/petroleum ether gave colourless crys-
tals with m.p. 261–264 °C. IR (KBr): ν = 3102 (w), 3080 (w), 3058
˜
(m), 3024 (m), 3001 (w), 2929 (w), 2870 (w), 1620 (w), 1600 (m),
1492 (m), 1452 (m), 1432 (w), 1395 (w), 1338 (w), 1301 (w), 1262
(w), 1239 (w), 1224 (w), 1203 (w), 1174 (w), 1156 (w), 1077 (w),
1032 (m), 1000 (w), 985 (w), 966 (w), 951 (w), 915 (w), 873 (w),
845 (w), 814 (w), 793 (w), 778 (w), 759 (s), 739 (m), 725 (s), 700
(vs), 630 (w), 616 (w), 592 (w), 549 (w) cm–1. 1H NMR (CDCl3,
400 MHz): δ = 4.75 (t, J = 9.5 Hz, 1 H, 2-H), 5.29 (d, J = 9.5 Hz,
2 H, 1-H, 3-H), 6.10 (d, J = 7.3 Hz, 2 H, Ph-o-H), 6.77 (“d”, J =
7.1 Hz, 4 H, Ph-o-H), 6.83 (t, J = 7.7 Hz, 2 H, Ph-H), 6.95–7.05
(m, 7 H, Ph-H), 7.45 (ddd, J = 8.0, 7.0, 0.9 Hz, 2 H, 5-H, 10-H),
7.60–7.66 (m, 4 H, 4-H, 6-H, 9-H, 11-H), 8.81 (d, J = 8.3 Hz, 2 H,
7-H, 8-H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 56.25 (C-1, C-
3), 56.50 (C-2), 123.36 (C-7, C-8), 126.21 (CH Ph), 126.35 (C-4, C-
6, C-9, C-11, overlapping), 126.64 (CH Ph), 126.75 (CH Ph), 126.97
(C-5, C-10), 127.65 (CH Ph), 129.83 (C-3b, C-11a), 130.41 (o-CH
Ph), 131.44 (C-7a, C-7b), 132.29 (o-CH Ph), 138.13 (C Ph), 139.56
(C-3a, C-11b), 141.36 (C Ph) ppm. UV/Vis (MeCN): λmax (logε) =
209 (sh, 4.45), 247 (4.37), 255 (4.47), 278 (3.79), 288 (3.73), 300
(3.82) nm. MS (EI, 70 eV): m/z (%) = 446 (100) [M]+, 368 (35) [M –
Ph + 1]+, 355 (51). C35H26 (446.58): calcd. C 94.13, H 5.87; found
C 94.17, H 5.72.
(1R*,2r*,3S*)-1,2,3-Triphenyl-2,3-dihydro-1H-cyclopenta[l]phen-
anthrene-2-ol (13):
A solution of cyclopentenol 6a (111 mg,
0.24 mmol) in air-saturated toluene was irradiated for 68 h. The
solvent was evaporated and the residue was subjected to flash col-
umn chromatography (silica, toluene, Rf = 0.06, 0.23, 0.34, 0.39,
0.55, 0.90). The fraction with Rf = 0.23 yielded phenanthrene 13
as a colourless solid (61 mg, 55%). Crystallization with dichloro-
methane/petroleum ether yielded colourless crystals with m.p. 277–
279 °C. IR (KBr): ν = 3545 (m), 3064 (w), 3024 (w), 2923 (w), 2877
˜
(w), 1494 (m), 1448 (m), 1433 (w), 1360 (w), 1333 (m), 1316 (m),
1261 (w), 1251 (w), 1225 (w), 1188 (w), 1169 (m), 1110 (w), 1086
(w), 1076 (w), 1032 (m), 1023 (m), 999 (m), 953 (w), 942 (w), 915
(w), 882 (w), 846 (w), 806 (w), 791 (w), 778 (m), 751 (s), 733 (m),
Diethyl all-cis-1,2,3-Tris(4-ethoxycarbonylphenyl)-2,3-dihydro-1H-
cyclopenta[l]phenanthrene-6,9-dicarboxylate (11c): A solution of cy-
clopentene 4c (404 mg, 0.50 mmol) and iodine (127 mg, 1.00 mmol)
in toluene (150 mL) was irradiated under nitrogen for 24 h. The
solvent was removed in vacuo and the residue was submitted to
flash column chromatography (silica, PE/MTBE 2:1, Rf = 0.12;
0.10). The fraction with Rf = 0.10 afforded polycycle 11c (210 mg,
1
722 (s), 704 (s), 658 (w), 634 (w), 616 (w), 595 (m) cm–1. H NMR
(CDCl3, 400 MHz): δ = 2.98 (s, 1 H, OH), 5.14 (s, 2 H, 1-H, 3-H),
6.40 (d, J = 7.6 Hz, 2 H, Ph-o-H), 6.85–6.76 (m, 6 H, Ph-H), 6.96–
7.09 (m, 7 H, Ph-H), 7.48 (ddd, J = 8.0, 7.0, 0.9 Hz, 2 H, 5-H, 10-
H), 7.59 (dd, J = 8.0, 0.9 Hz, 2 H, 4-H, 11-H), 7.68 (ddd, J = 8.3,
7.1, 1.2 Hz, 2 H, 6-H, 9-H), 8.84 (d, J = 8.3 Hz, 2 H, 7-H, 8-
H) ppm. 13C NMR (CDCl3, 100 MHz): δ = 68.05 (C-1, C-3), 88.57
(C-2), 123.44 (C-7, C-8), 125.87 (CH Ph), 126.28 (C-6, C-9), 126.62,
126.76, 126.84, 127.10, 127.84, 128.64, 130.00 (all CH Ph), 130.50
(C-3b, C-11a), 131.66 (C-7a, C-7b), 138.15 (C-3a, C-11b), 138.96
(C Ph), 139.91 (C Ph) ppm. UV/Vis (MeCN): λmax (logε) = 223
(4.48), 245 (4.49), 278 (4.09), 287 (4.09), 299 (4.15), 350 (2.66) nm.
MS (EI, 70 eV): m/z (%) = 462 (3) [M]+, 444 (100) [M – OH +
1]+, 368 (27), 355 (22). C35H26O (462.58): calcd. C 90.88, H 5.67;
found C 90.78, H 5.53.
52%) as colourless crystals with m.p. 258 °C. IR (KBr): ν = 2981
˜
(w), 2934 (w), 1715 (s), 1610 (m), 1464 (w), 1417 (w), 1367 (m),
1277 (s), 1180 (w), 1105 (s), 1021 (m), 865 (w), 772 (w), 715
1
(w) cm–1. H NMR (400 MHz, CDCl3): δ = 1.33 (t, J = 7.0 Hz, 6
H, CH3), 1.36 (t, J = 7.0 Hz, 3 H, CH3), 1.47 (t, J = 7.5 Hz, 6 H,
CH3), 4.30 (q, J = 7.5 Hz, 4 H, OCH2), 4.32 (q, J = 7.0 Hz, 2 H,
OCH2), 4.50 (q, J = 7.0 Hz, 4 H, OCH2), 4.92 (t, J = 9.5 Hz, 1 H,
2-H), 5.40 (d, J = 9.5 Hz, 2 H, 1-H, 3-H), 6.17 (d, J = 8.0 Hz, 2
H, Ph-o-H), 6.79 (d, J = 8.5 Hz, 4 H, Ph-o-H), 7.52 (d, J = 8.5 Hz,
2 H, 4-H, 11-H), 7.53 (d, J = 8.5 Hz, 2 H, Ph-m-H), 7.68 (d, J =
8.0 Hz, 4 H, Ph-m-H), 8.09 (dd, J = 8.5, 1.4 Hz, 2 H, 5-H, 10-H),
9.61 (d, J = 1.4 Hz, 2 H, 7-H, 8-H) ppm. 13C NMR (100 MHz,
CDCl3): δ = 14.4 (two overlapping signals, CH3), 14.6 (CH3), 55.9
(C-2), 56.1 (C-1, C-3), 61.1 (two overlapping signals, OCH2), 61.6
(OCH2), 126.0 (C-7, C-8), 126.6 (C-4, C-11), 127.7 (C-5, C-10),
128.3 (CH Ph), 129.0 (C-3a, C-11b), 129.1 (C Ph), 129.3 (C Ph),
129.4 (CH Ph), 130.0 (CH Ph), 131.4 (C-7a, C-7b), 131.9 (CH Ph),
132.1 (C-3b, C-11a), 141.1 (C-6, C-9), 141.9 (C Ph), 145.3 (C Ph),
166.4 (two overlapping signals, CO), 166.7 (CO) ppm. UV/Vis
(MeCN): λmax (logε) = 204 (4.21), 250 (4.25), 276 (3.85, sh), 314
(3.59), 328 (3.53) nm. MS (EI, 70 eV): m/z (%) = 806 (45) [M]+,
Supporting Information (see also the footnote on the first page of
1
this article): H and 13C NMR spectra of new compounds.
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© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2010, 6084–6091

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1
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Received: June 8, 2010
Published Online: September 10, 2010
Eur. J. Org. Chem. 2010, 6084–6091
© 2010 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
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