Photoinduced reactions of para-quinones with bicyclopropylidene leading to diverse polycyclic compounds with spirocyclopropanes

Article abstract of DOI:10.1021/jo4008767

Photoinduced reactions of bicyclopropylidene (BCP) with para-quinones (p-quinones) including benzoquinones, naphthoquinones, and anthraquinones were found to proceed via different cycloaddition pathways and lead to diverse polycyclic products bearing spiropropyl moiety. Photocycloaddition of BCP with benzoquinones gave spirooxetanes as the primary products, which upon irradiation were able to rearrange into the spiro[4.5]deca-6,9-diene-2,8-diones as secondary photoproducts. Chemoselectivity of the photocycloaddition of BCP with naphthoquinones relies largely on the substitution groups linked to the C=C in between the two carbonyl groups to give different types of products. Photoreaction of BCP with 9,10-anthraquinone gave not only the spirooxetane product, but also a novel spiro[indan-1,1′-phthalan]-3′-one product whose formation might be initiated by a transannular attack of the C4 cyclopropyl radical to the para-carbonyl group. Mechanisms involved in the formation of diverse primary or secondary products in the photoreactions of BCP with p-quinones were proposed. Some of the photoreactions also hold potentials as useful synthetic protocols for important spiropolycyclic compounds such as sesquiterpenes.

Full text of DOI:10.1021/jo4008767

Article
pubs.acs.org/joc
Photoinduced Reactions of para-Quinones with Bicyclopropylidene
Leading to Diverse Polycyclic Compounds with Spirocyclopropanes
Wei Wang,† Wen-Jie Zhang,† Lei Wang,† Ching Kheng Quah,‡ Hoong-Kun Fun,‡,§ Jian-Hua Xu,*,†
and Yan Zhang*,†
†State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University,
Nanjing 210093, China
‡X-ray Crystallography Unit, School of Physics, Universiti Sains Malaysia, 11800 USM Penang, Malaysia
§Department of Pharmaceutical Chemistry, College of Pharmacy, King Saud University, Riyadh 11451, Saudi Arabia
S
* Supporting Information
ABSTRACT: Photoinduced reactions of bicyclopropylidene (BCP) with para-quinones (p-quinones) including benzoquinones,
naphthoquinones, and anthraquinones were found to proceed via different cycloaddition pathways and lead to diverse polycyclic
products bearing spiropropyl moiety. Photocycloaddition of BCP with benzoquinones gave spirooxetanes as the primary
products, which upon irradiation were able to rearrange into the spiro[4.5]deca-6,9-diene-2,8-diones as secondary
photoproducts. Chemoselectivity of the photocycloaddition of BCP with naphthoquinones relies largely on the substitution
groups linked to the CC in between the two carbonyl groups to give different types of products. Photoreaction of BCP with
9,10-anthraquinone gave not only the spirooxetane product, but also a novel spiro[indan-1,1′-phthalan]-3′-one product whose
formation might be initiated by a transannular attack of the C4 cyclopropyl radical to the para-carbonyl group. Mechanisms
involved in the formation of diverse primary or secondary products in the photoreactions of BCP with p-quinones were
proposed. Some of the photoreactions also hold potentials as useful synthetic protocols for important spiropolycyclic compounds
such as sesquiterpenes.
that the CC bond in BCP is 1.304 Å, significantly shorter
INTRODUCTION
■
than normal CC bonds.7 The relatively high HOMO energy
and low ionization potential8 enable BCP to be highly reactive
in additions across its CC bond toward a wide range of
electrophilic cycloaddends. As a result of the systematic
investigation of de Meijere and his co-workers6 as well as
other research groups9 on thermal reactions of BCP under
different conditions, BCP has emerged as a highly versatile
synthetic building block. The photoinduced reactions of BCP
with α-diketones including N-acetylisatin and isoquinoline-
triones have also been investigated by us, and unusual products
have been obtained via the photoinitiated sequential reactions
or acid-mediated transformations of the photocycloadducts.10
Photoinduced cycloaddition reactions along with subsequent
cascade reactions provide an efficient way to construct organic
framework with diversified structures that are difficult to obtain
by conventional thermal reactions.1 Polycycles with cyclopropyl
ring have been found to be frameworks in many natural
products,2 and the special reactivity of the highly strained
cyclopropane-containing compounds have been extensively
exploited in natural product synthesis.3 The cycloadditions of
methylenecyclopropanes with a variety of cyclophiles have
drawn much recent research interest and proved to be a
powerful tool in constructing various polycyclic systems.4
However, the potential of methylenecyclopropane type strained
alkenes in photoreactions has rarely been explored.5
Bicyclopropylidene (BCP) is an unconventional alkene with
high angular strain by incorporating two cyclopropane rings.6
Theoretical studies and X-ray crystal analysis have indicated
Received: April 27, 2013
© XXXX American Chemical Society
A
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Photocycloaddition of p-quinones such as benzoquinones
and naphthoquinones with alkenes was able to happen via nπ*
or ππ* excited state to give the oxetane or cyclobutane type
products.11,12 The substitution groups on the quinones have
shown significant influence on the photoreaction pathway
partition. For example, photoinduced reactions of halogenated
1,4-benzoquinones with olefins or 1,1-diarylethenes have been
reported to give unusual products with distributions highly
dependent on the steric nature of quinones and olefins.13
However, photoreactions of p-quinones with strained alkenes
still remain to be explored. Here we report the photoinduced
reactions of the highly strained alkene BCP with various p-
quinones including benzoquinones and naphthoquinones
bearing various substituents.
Buchi reaction.17 Product 1b is a spirocyclopropanated
̈
spiro[4.5]decadienedione. Control experiments show that 1b
is a secondary product derived from 1a under irradiation.
Therefore, independent irradiation of 1a under the same
photolysis conditions resulted in smooth and clean conversion
of 1a to 1b. Also, in the photoreactions of 1 with BCP, 1b can
be made the sole product in 98% yield simply by lengthening
the irradiation time to 24 h (Table 2). The proposed
mechanism for transformation of 1a to 1b is shown in Scheme
1. Homolytic scission of the C−O bond in the highly strained
oxetane ring in 1a followed by cyclopropane ring-opening leads
to the 1,5-diradical I. Subsequent radical pair recombination
after intersystem crossing in I furnishes the product.
Photoreactions of 2,6-dimethylbenzoquinone (2) and 2,6-
dichlorpbenzoquinone (5) with BCP, respectively, similarly
gave the spirooxetane (2a and 5a) and the spiro[4.5]-
decadienedione (2b and 5b) together when the irradiation
was stopped after a complete conversion of the quinone was
reached as indicated by TLC monitoring, while lengthy
irradiation resulted in the conversion of the spirooxetane to
spiro[4.5]decadienedione and gave 2b and 5b as the only
product in high yield (Table 2). These photocycloadditions are
regioselective, taking place at the 4-carbonyl group because 1-
carbonyl was blocked by two chlorine atoms or the two methyl
groups. The structures of 2a and 5a were confirmed by 1H−1H
NOESY measurements, which showed the steric proximity of
the cyclopropane protons with the dienone protons. The
structure of 5a was further unambiguously established by an X-
ray crystallographic analysis (Figure S1, Supporting Informa-
tion). Meanwhile, irradiation of 2-chlorobenzoquinone (4) with
BCP for 25 h afforded 4b in 68% yield. The regioselectivity in
RESULTS AND DISCUSSION
■
It was reported that product distribution of photoreactions
between p-quinones and olefins was mainly dependent on the
nature of the excited state of quinones (nπ* or ππ* triplet
state).11 Meanwhile, the involvement of photoinduced electron
transfer (PET) process and steric effect to the cycloaddition
also play important roles and may cause a reaction site
reversal.12a,b,14 To examine the possibility of PET process
involvement in the photoreactions between p-quinones and
BCP, free energy change for electron transfer (ΔGET) between
the triplet quinone and BCP has been evaluated using the
Weller equation15 (Table 1). The results showed that the PET
process with BCP to all the quinones investigated was
endergonic and it was unlikely to be involved in the
photoreactions.
1
4b was also proved by a H−1H NOESY measurement. In
a
Table 1. Free Energy Change for Electron Transfer (ΔGET)
contrast, duroquinone (3) could not take part in photo-
reactions with BCP under the same conditions, probably
because of the ππ* nature of its excited triplet state18 and the
steric hindrance of the two methyl groups, which impedes the
[2 + 2] reaction leading to cyclobutane product.12d,19
between p-Quinones and BCP
red
E
b
1/2 c
d
entry
quinone
benzoquinone (1)
ET
(V)
ΔGET
1
2
3
4
5
6
7
8
5016a
e
−0.5116b
−0.3416b
−0.1816b
−0.7612b
−0.8112b
−0.5912b
−0.4912b
−0.9412c
17
13
9
chlorobenzoquinone (4)
50
It is noteworthy that the high-yielding formation of 1b−5b
provides a direct and convenient pathway for the construction
of the spiro[4,5]decane core structure commonly found in a
large variety of sesquiterpene natural products, such as in
acorane, spirovetivane, spirolaurane, spiroaxane and the vitrine
family of sesquiterpenes,20 and the spiro[4.5]deca-6,9-diene-
2,8-dione structures in 1b−5b are themselves important
synthetic intermediates for the synthesis of several spiro[4,5]-
decane sesquiterpenes.21
e
2,6-dichlorobenzoquinone (5)
naphthoquinone (6)
50
5816c
e
15
16
11
8
2-methyl-1,4-naphthoquinone (7)
2-chloro-1,4-naphthoquinone (8)
58
e
58
e
2,3-dichloro-1,4-naphthoquinone (9) 58
9,10-anthraquinone (15)
6112c
16
a
b
Estimated by the Weller equation. Triplet state energy in kcal/mol.
Half-wave reduction potential of the quinone (SCE, MeCN). In
kcal/mol. Presumed to have the same ET value as BQ and NQ,
c
d
e
Photoreaction of Naphthoquinones 6−13 with BCP.
For naphthoquinone, nπ* and ππ* triplet states are close in
energy and are both accessible to take part in reactions with
olefins.12d,22 In accord with this, irradiation of 1,4-naphthoqui-
none (6) with BCP in benzene with light of λ > 400 nm for 24
h led to a complete conversion of 6 to afford the cyclobutane
product 6a (for crystal structure, see: Figure S2, Supporting
Information) and the benzannulated spiro[4.5]deca-6,9-diene-
2,8-dione 6b derived from the primary spirooxetane product
(Table 3). At the same time, 2-methylnaphthoquinone (7)
afforded the cyclobutane 7a as main product, reflecting an
increased involvement of the ππ* excited state.23 The
regioselectivity in 7b was also determined by an 1H−1H
NOESY measurement.
respecively.
Photoreaction of Benzoquinones 1−5 with BCP.
Photoinduced reactions of 1,4-benzoquinone (1) with olefins
are often supposed to take place from the lowest nπ* triplet
excited state via a preoxetane diradical intermediate.12c,16a
Meanwhile, singlet exciplex and singlet diradical mechanism has
also been suggested in some cases.5 Reaction of 1 with BCP
proceeded smoothly in anhydrous benzene under irradiation
with light of wavelengths longer than 400 nm (500 W medium-
pressure mercury lamp was used with 20% aqueous sodium
nitrite as filter solution to cut off light of wavelength shorter
than 400 nm). After irradiation for 7 h, complete conversion of
1 was achieved and two products 1a and 1b were obtained. As
shown in Table 2, the major product, 1a, is a spirooxetane with
two spiro-fused cyclopropane rings, formed in the Paterno−
Irradiation of 2-chloronaphthoquinone (8) and 2,3-dichlor-
onaphthoquinone (9) with BCP in benzene, respectively, gave
the cyclobutanes 8a and 9a respectively in high yield without
B
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Table 2. Summary of the Photoreaction Products of Benzoquinones with BCP
a
a
entry
quinone
irrad. time (h)
products, yields (%)
irrad. time (h)
products, yields (%)
1
2
3
4
5
1
2
3
4
5
7
10
48
−
1a (53), 1b (42)
2a (53), 2b (36)
no reaction
24
24
−
1b (98)
2b (95)
−
−
25
4b (68)
24
5a (57), 5b (32)
48
5b (83)
a
Isolated yield.
Scheme 1. Proposed Mechanism for Transformation of 1a to
1b
Table 4. Summary on the Photoreaction Products of
Chloronaphthoquinones with BCP
a
entry
naphthoquinone
irrad. time (h)
products, yields (%)
Table 3. Summary on the Photoreaction Products of
Naphthoquinones with BCP
1
2
8
9
24
24
8a (87)
9a (80)
a
Isolated yeld.
opening in refluxing xylene for similar 1,2-dihydrocyclobuta-
[b]naphthalene-3,8-diones formed in photocycloadditions of 8
with simple alkenes followed by elimination of hydrogen
chloride. We believe that the electrocyclic ring-opening in 8b is
sterically hindered by the two spiro-fused cyclopropane rings.
Meanwhile, 8b behaves as an electron-deficient olefin and
serves as a dienophile in Diels−Alder reaction with isoprene
and 1,3-cyclohexadiene, giving 8c and 8d (for crystal structure,
see: Figure S3, Supporting Information), respectively (Scheme
2).
a
entry
naphthoquinone
irrad. time (h)
products, yields (%)
1
2
6
7
24
24
6a (36), 6b (58)
7a (88), 7b (8)
a
Isolated yield.
Introduction of an electron-donating alkoxy group at C2
atom in naphthoquinone raises the energy of the nπ* excited
state,27 and the 2-alkoxy naphthoquines show reactivity of
typical ππ* excited state to give cyclobutane as primary product
exclusively.12d,19,22a Indeed, photoreaction of 2-phenoxynaph-
thoquinone (10) with BCP proceeds quickly and gives the
cyclobutane 10a in 87% yield upon the completion of the
reaction after 3 h irradiation (Table 5). Similarly, facile
photoreactions of 2-methoxynaphthoquinone (11), 2-ethox-
ynaphthoquinone (12) and 2-isopropoxynaphthoquinone (13)
with BCP afforded the corresponding cyclobutane 11a, 12a and
13a in high yield, respectively, if the irradiation was stopped
shortly after the starting quinone was completely consumed.
However, lengthy irradiation resulted in secondary intra-
molecular hydrogen abstraction reaction in the primary product
and resulted in the formation of the cyclobutane-oxetane
the formation of any spirooxetane product (Table 4). This is in
accord with the previous finding that 824 and 912a,b,25 afford
cyclobutane product with common olefins in photocycloaddi-
tions without single electron transfer (SET) process involve-
ment.
The cyclobutane product 8a can be converted to the
cyclobutene 8b26 via elimination of hydrogen chloride by
treatment with a base. The optimized reaction condition for
this is treating 8a in acetonitrile with potassium carbonate. In
this case, 8b is obtained in nearly quantitative yield. An attempt
to induce thermal cyclobutene ring-opening in 8b to give the
quinodimethane intermediate II (Scheme 2) by refluxing in
xylene and trapping it with such dienophiles as maleimide,
maleic anhydride, diethyl maleate and diethyl fumarate failed.
This is in sharp contrast with the facile cyclobutene ring-
C
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Scheme 2. Thermal Transformation of Compound 8a and 8b
Table 5. Summary on the Photoreaction Products of Alkoxy Naphthoquinones with BCP
a
a
entry
naphthoquinone
irrad. time (h)
products, yields (%)
irrad. time (h)
products, yields (%)
1
2
3
4
10
11
12
13
3
3
3
4
10a (87)
11a (87)
12a (85)
13a (88)
−
−
24
24
48
11b (85)
12b (88)
13a (6), 13b (54), 6a (25)
a
Isolated yield.
Scheme 3. Proposed Mechanism for Transformation of Compound 13a to 13b and 6a
products 11b, 12b and 13b (for crystal structure, see: Figure
S4, Supporting Information).12d,22a Therefore, either the
cyclobutane or the cyclobutane-oxetane can be made the
main or even the sole product in high yield simply by
monitoring the reaction course.
In the reaction of 13 with BCP, an additional product 6a was
also formed in significant amount. Possible mechanism for the
formation of 13b and 6a is shown in Scheme 3. In the 1,4-
diradical III formed by intramolecular hydrogen abstraction in
excited 13a, radical pair recombination furnishes 13b, while
hemolysis of the C2−O bond leads to the elimination of an
acetone to give 6a. The two germinal methyl groups at the
alkoxycarbinyl radical center in III cause serious steric
hindrance toward the radical pair recombination leading to
13b, enabling the C2−O bond homolysis to compete
effectively with the former process, resulting in the simulta-
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neous formation of 13b and 6a. In the intramolecular hydrogen
abstraction reactions in 11a and 12a, on the contrary, radical
pair recombination in the diradical intermediates IVa and IVb
(Scheme 3) meets no significant steric hindrance.
Photoreaction of 1,4-Anthraquinone (14) and 9,10-
Anthraquinone (15) with BCP. 1,4-Anthraquinone (14) has
a ππ* T1 state in thermal equilibrium with a slightly higher nπ*
T2 state at room temperature.28 To our knowledge, there is
only one previous report on photocycloaddition reactions of 14
with olefins where cyclobutanes are exclusively formed.28 In our
work, photoreactions of 14 with BCP in benzene gave rise to
the cyclobutane 14a and the spirocyclopentanone 14b
concomitantly (Table 6), in line with the participation of the
15a in benzene, little consumption of the starting material was
observed, and no transformation to 15b even in a trace amount
could be detected. This indicates that 15a and 15b are both
primary products in the photoreactions of 15 with BCP. The
proposed mechanism for the formation of 15a and 15b is
shown in Scheme 4. Radical pair recombination following
intersystem crossing in the triplet 1,4-diradical V furnishes the
spirooxetane 15a. However, in diradical intermediate V, the
specific conformation for efficient intersystem crossing (ISC)30
and the ISC process from this conformation are both
significantly impeded by the unfavorable steric hindrance
between the bulky cyclopropyl at the radical center and the
benzene ring at either side of it. This enables an alternative
pathway to be operative via a transannular attack of the
cyclopropyl radical toward the C10 carbonyl, leading to the 1,6-
diradical VI, from which diradical VII is derived by homolytic
scission of the C−O bond α- to the alkoxycarbinyl center in VI.
Another transannular attack of the alkoxy radical in VII to the
C9 carbonyl inducing a α-cleavage at the latter, furnishing the
rearranged product 15b. The formation of the unusual product
15b represents an unprecedented reaction pathway in the
Table 6. Summary on the Photoreaction Products of
Anthraquinones with BCP
Paterno−Buchi reaction of anthraquinone. Since the driving
̈
force for this alternative pathway leading to 15b is the severe
steric hindrance to the radical pair recombination induced by
the interaction between the bulky substituents at the C4 radical
center in the 1,4-diradical and the neighboring benzene ring,
this pathway may also be operative in the Paterno−Buchi
̈
reaction of para-quinones in cases where the structures of the
quinone and the alkene are suitable to lead to serious steric
hindrance for the oxetane ring formation in the 1,4-diradical
intermediate, similar to that seen in the intermediate V.
a
Isolated yield.
Photoreaction of Naphtho[2,3-b]furan-4,9-diones
16−19 with BCP. Photoinduced reactions of the avicequinone
B (Naphtho[2,3-b]furan-4,9-dione) derivatives 16−19 with
BCP were also investigated. Quinones 16 and 17 with an ester
group at C3 atom showed a typical ππ* excited state reactivity
to give the cyclobutane products 16a and 17a (for crystal
structure, see: Figure S6, Supporting Information) in high
yields (Table 7). However, similar irradiation of 18 and 19 with
an acyl group at C3 atom resulted in the unexpected formation
of the spirocyclopropane and spirofuranone annulated 1H-
benz[f]inden-9-one products 18b and 19b (Table 7). The
structure of 19b was unequivocally established by X-ray
crystallographic analysis (Figure S7, Supporting Information).
thermally equilibrated ππ* and nπ* triplet states. At the same
time, photocycloadditions of 9,10-anthraquinone (15) having a
distinct ππ* T1 state29 have been widely investigated and found
to invariably give spirooxetane product exclusively. However,
we found that in photoreactions of 9,10-anthraquinone with
BCP in benzene, the spirooxetane 15a (55% yield) was formed
along with an unexpected spiro[indan-1,1′-phthalan]-3′-one
product 15b (41% yield) (Table 6). The structure of 15b was
established by X-ray crystallographic analysis (Figure S5,
Supporting Information).
Control experiments showed that 15a was photostable under
the reaction conditions, and upon prolonged irradiation of pure
Scheme 4. Proposed Mechanism for Formation of Compound 15a and 15b
E
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Alternatively, initial C−C bond homolysis in the cyclobutane
ring followed by C−O bond cleavage in the furan ring also
leads to the diradical VIII (pathway b). Attack of the
cyclopropyl radical to the C4′ atom in the benzene ring
furnishes IX. Ring-opening of one of the cyclopropyls in IX via
a cyclopropylcarbinyl to allylcarbinyl radical transformation
affords the diradical X, where a 5-exo-trig cyclization followed
by radical pair recombination gives the deeply rearranged
addition product 18b and 19b. At this time, we have no definite
explanation on why products 16a and 17a are stable while 18a
and 19a are so labile as to be too elusive to be isolated from the
reaction mixture, although it is speculated that the stronger
absorption in the long wavelength region used for the
photolysis and the heavier steric congestion of the acyl
substituted 18a and 19a than the ethoxycarbonyl substituted
16a and 17a may contribute to the stability difference.
Table 7. Summary on the Photoreaction Products of
Naphtho[2,3-b]furan-4,9-diones with BCP
CONCLUSION
■
In summary, photoreactions of BCP with various substituted p-
quinones proceeded cleanly and resulted in distinct product
distribution from the photoreactions of p-quinones with
common alkenes. The special structural features of BCP have
shown profound influences on reaction modes and the
formation of special secondary products. The high steric
hindrance of the cyclopropyl radical in the Paterno−Buchi 1,4-
̈
diradical intermediate toward ring closure by radical pair
recombination may hamper the spirooxetane formation and
open new reaction channels. Along with the spirooxetanes and
cyclobutanes that resulted from common photocycloaddition
via nπ* and ππ* triplet of quinones, secondary products such as
the spiro[4.5]deca-6,9-diene-2,8-diones with the spiro[4.5]-
decane core that presents in many natural products were
obtained in the photoreactions of BCP with benzoquinones,
naphthoquinone and 1,4-anthraquinone. In the case of 9,10-
anthraquinone, an unprecedented reaction pathway was
a
Isolated yield.
observed via the Paterno−Buchi 1,4-diradical intermediate,
Although no primary products were isolated, we suggest that
18b and 19b are derived from secondary photoreactions of the
primary cyclobutane products (18a and 19a), and a possible
mechanism is proposed in Scheme 5. Homolytic scission of the
C−O bond in the furan ring and the ensuing cleavage of one of
the C−C bonds between two quarternary carbon atoms in the
cyclobutane ring lead to the diradical VIII (pathway a).
̈
enforcing a transannular attack of the C4 carbinyl radical to the
para-carbonyl group and leading to the formation of the novel
addition-rearrangement product 15b. In photocycloadditions of
the acyl substituted furanonaphthoquinones (18 and 19) with
BCP, steric congestion caused by the two spiro-fused
cyclopropyls in the primary cyclobutane product led to the
Scheme 5. Proposed Mechanism for the Formation of Compound 18b and 19b
F
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2b: 6,8-Dimethyldispiro[2.0.5.3]dodeca-5,8-diene-7,12-dione, white
powder, mp 114−115 °C; H NMR (400 MHz, CDCl3) δ 6.59 (s,
formation of deeply rearranged cycloadducts (18b and 19b).
The photoreactions of BCP with p-quinones therefore provided
facile approach to a range of novel polycyclic framework with
one or two spiro-fused cyclopropane rings via known or new
reaction pathways.
1
2H), 2.61 (t, J = 7.9 Hz, 2H), 2.21 (t, J = 7.9 Hz, 2H), 1.90 (s, 6H),
1.16−1.13 (m, 2H), 0.75−0.72 (m, 2H); 13C NMR (100 MHz,
CDCl3) δ 216.2, 186.7, 145.9, 134.7, 45.4, 36.2, 35.9, 32.5, 16.2, 15.8;
IR (ATR, neat) 2966, 2944, 2929, 1717, 1670, 1636, 1456, 1435, 1414,
1399, 1373, 1359, 1310, 1255, 1226, 1203, 1090, 1059, 1028, 982, 935,
921, 904, 845, 816, 774, 754, 661 cm−1; MS (ESI+) m/z 217 [M +
H]+; HRMS (ESI) m/z [M + Na]+ calcd for C14H16O2Na 239.1048,
found 239.1044.
EXPERIMENTAL SECTION
■
General Methods. Commercial reagents were used as supplied or
purified by standard techniques when necessary. Benzene was distilled
1
from Na and benzophenone. H NMR and 13C NMR spectra were
Photolysis of 3 with BCP in Anhydrous Benzene. A solution of
3 (328 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 48 h,
and TLC analysis showed no conversion of 3. Flash column
chromatography on 300−400 mesh silica gel with petroleum ether/
ethyl acetate as eluents only recovered 3.
Photolysis of 4 with BCP in Anhydrous Benzene. A solution of
4 (285 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 25 h to
reach a complete conversion of 4. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 4b (302 mg, 68%).
4b: 6-Chlorodispiro[2.0.5.3]dodeca-5,8-diene-7,12-dione, colorless
crystal, mp 92−94 °C; 1H NMR (400 MHz, CDCl3) δ 7.03 (d, J = 2.9
Hz, 1H), 6.87 (dd, J = 10.0, 2.9 Hz, 1H), 6.35 (d, J = 10.0 Hz, 1H),
2.65 (t, J = 7.9 Hz, 2H), 2.33 (t, J = 7.9 Hz, 2H), 1.26−1.19 (m, 2H),
0.86−0.79 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 214.4, 178.4,
150.8, 146.6, 132.7, 127.7, 48.7, 36.0, 35.7, 32.2, 16.0, 16.0; IR (ATR,
neat) 3050, 3002, 2975, 2923, 1722, 1660, 1592, 1414, 1354, 1314,
1230, 1138, 1088, 1053, 1033, 976, 899, 838, 824, 813, 760, 718, 672,
606 cm−1; MS (ESI+) m/z 223 [M + H]+, 245 [M + Na]+; HRMS
(ESI) m/z [M + Na]+ calcd for C12H11ClO2Na 245.0345, found
245.0339.
Photolysis of 5 with BCP in Anhydrous Benzene. A solution of
5 (354 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 5. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 5a (292 mg, 57%) and 5b (164 mg, 32%). Photolysis for 48 h
gave 5b (425 mg, 83%) only.
recorded on a 300 or 400 MHz spectrometer in CDCl3 using TMS as
an internal standard. Data are presented as follows: chemical shift,
multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m =
multiplet). J = coupling constant in hertz. NOESY spectra were
recorded on a 400 MHz spectrometer. IR spectra were with an FT-IR
spectrophotometer and are reported as cm−1. HRMS analyses were
carried out on an electrospray ionization apparatus using time-of-flight
mass spectrometry. Melting points are uncorrected.
General Procedures for the Preparative Photoreactions. The
light source for the photolysis was a medium-pressure mercury lamp
(500 W) in a cooling water jacket that was further surrounded by a
layer of filter solution (1 cm thick, 20% aqueous sodium nitrite) to cut
off light of wavelength shorter than 400 nm. The solution of para-
quinone and an excess amount of BCP in anhydrous benzene was
irradiated under continuous nitrogen purging. The reaction course was
monitored by TLC. At the end of the reaction, the solvent was
removed under reduced pressure, and the residue was separated by
flash chromatography on a silica gel column.
Photolysis of 1 with BCP in Anhydrous Benzene. A solution of
1 (216 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 7 h to
reach a complete conversion of 1. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 1a (199 mg, 53%) and 1b (158 mg, 42%). Photolysis for 24 h
gave 1b (368 mg, 98%) only.
1a: 13-Oxatrispiro[2.0.2.0.5.1]trideca-8,11-diene-10-one, white
1
powder, mp 76−78 °C; H NMR (300 MHz, CDCl3) δ 7.26 (d, J =
10.3 Hz, 2H), 6.17 (d, J = 10.3 Hz, 2H), 0.94−0.89 (m, 2H), 0.54−
0.43 (m, 6H); 13C NMR (75 MHz, CDCl3) δ 185.4, 147.1, 128.6,
79.2, 71.7, 31.3, 7.8, 5.7; IR (ATR, neat) 3068, 3044, 2996, 1661, 1625,
1599, 1402, 1377, 1296, 1245, 1223, 1170, 1151, 1080, 1054, 1023,
996, 957, 925, 853, 778, 715, 681 cm−1; MS (ESI+) m/z 189 [M +
H]+; HRMS (ESI) m/z [M + H]+ calcd for C12H13O2 189.0916, found
189.0906.
5a: 9,11-Dichloro-13-oxatrispiro[2.0.2.0.5.1]trideca-8,11-diene-10-
1
one, white powder, mp 92−94 °C; H NMR (300 MHz, CDCl3) δ
7.46 (s, 2H), 0.96−0.91 (m, 2H), 0.64−0.51 (m, 4H), 0.50−0.45 (m,
2H); 13C NMR (75 MHz, CDCl3) δ 172.6, 143.2, 131.6, 80.8, 72.2,
31.7, 7.8, 6.1; IR (ATR, neat) 3071, 3047, 1806, 1686, 1639, 1599,
1480, 1448, 1347, 1296, 1263, 1211, 1154, 1029, 1007, 941, 890, 855,
837, 771, 751, 737, 695, 656, 611 cm−1; MS (ESI+) m/z 257 [M +
H]+. Anal. Calcd for C12H10O2Cl2: C, 56.06; H, 3.92. Found: C, 56.07;
H, 3.99.
1b: Dispiro[2.0.5.3]dodeca-5,8-diene-7,12-dione, white powder, mp
80−81 °C; 1H NMR (400 MHz, CDCl3) δ 6.86−6.82 (m, 2H), 6.29−
6.25 (m, 2H), 2.64 (t, J = 7.9 Hz, 2H), 2.29 (t, J = 7.9 Hz, 2H), 1.21−
1.18 (m, 2H), 0.81−0.79 (m, 2H); 13C NMR (100 MHz, CDCl3) δ
215.2, 185.3, 150.9, 128.5, 46.0, 35.9, 35.7, 32.0, 15.7; IR (ATR, neat)
3071, 1806, 1707, 1639, 1598, 1480, 1444, 1347, 1308, 1295, 1262,
1208, 1198, 1090, 1087, 1023, 1008, 966, 941, 890, 856, 837, 774, 751,
737, 707, 695, 657 cm−1; MS (ESI+) m/z 189 [M + H]+; HRMS
(ESI) m/z [M + H]+ calcd for C12H13O2 189.0916, found 189.0909.
Photolysis of 2 with BCP in Anhydrous Benzene. A solution of
2 (272 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 10 h to
reach a complete conversion of 2. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 2a (229 mg, 53%) and 2b (156 mg, 36%). Photolysis for 24 h
gave 2b (410 mg, 95%) only.
2a: 9,11-Dimethyl-13-oxatrispiro[2.0.2.0.5.1]trideca-8,11-diene-10-
one, colorless crystal, mp 100−101 °C; 1H NMR (400 MHz,
CDCl3) δ 7.02 (s, 2H), 1.90 (s, 6H), 0.90−0.86 (m, 2H), 0.50−0.40
(m, 6H); 13C NMR (100 MHz, CDCl3) δ 186.9, 142.1, 135.5, 79.2,
71.0, 31.2, 15.8, 7.8, 5.8; IR (ATR, neat) 3068, 1806, 1639, 1598, 1483,
1447, 1347, 1314, 1292, 1256, 1211, 1196, 1096, 1078, 1008, 966, 941,
891, 856, 838, 774, 751, 737, 707, 695, 657 cm−1; MS (ESI+) m/z 217
[M + H]+. Anal. Calcd for C14H16O2: C, 77.75; H, 7.46. Found: C,
77.61; H, 7.42.
5b: 6,8-Dichlorodispiro[2.0.5.3]dodeca-5,8-diene-7,12-dione, white
1
powder, mp 134−136 °C; H NMR (300 MHz, CDCl3) δ 7.06 (s,
2H), 2.67 (t, J = 7.9 Hz, 2H), 2.38 (t, J = 7.9 Hz, 2H), 1.29−1.25 (m,
2H), 0.88−0.84 (m, 2H); 13C NMR (75 MHz, CDCl3) δ 213.5, 172.2,
146.9, 131.5, 49.5, 36.0, 35.5, 32.2, 16.1; IR (ATR, neat) 3041, 2941,
2914, 1724, 1667, 1595, 1453, 1417, 1353, 1315, 1287, 1253, 1088,
977, 887, 838, 771, 729, 705, 670 cm−1; MS (ESI+) m/z 257 [M +
H]+. Anal. Calcd for C12H10O2Cl2: C, 56.06; H, 3.92. Found: C, 56.13;
H, 4.01.
Photolysis of 6 with BCP in Anhydrous Benzene. A solution of
6 (316 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 6. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 6a (171 mg, 36%) and 6b (276 mg, 58%).
6a: 1′,2′,2′a,8′a-Tetrahydrodispiro[cyclopropane-1,1′-cyclobuta[b]-
naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white powder, mp
1
136−138 °C; H NMR (400 MHz, CDCl3) δ 8.16−8.12 (m, 2H),
7.81−7.77 (m, 2H), 3.75 (s, 2H), 0.70−0.65 (m, 2H), 0.50−0.40 (m,
4H), 0.08−0.03 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 195.1,
135.2, 134.3, 127.3, 47.5, 27.9, 9.4, 6.6; IR (ATR, neat) 3069, 3053,
G
dx.doi.org/10.1021/jo4008767 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
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1666, 1587, 1429, 1318, 1289, 1272, 1257, 1212, 1196, 1154, 1118,
1054, 1033, 1019, 955, 924, 889, 871, 791, 776, 753, 722, 679 cm−1;
MS (ESI+) m/z 239 [M + H]+; HRMS (ESI) m/z [M + Na]+ calcd
for C16H14O2Na 261.0891, found 261.0886.
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 9a (490 mg, 80%).
9a: 2′a,8′a-Dichloro-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-
1,1′-cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
1
6b: Dispiro[cyclopropane-1,1′-cyclopentane-2′,11″-(4″H)-
powder, mp 163−164 °C; H NMR (400 MHz, CDCl3) δ 8.24−8.19
1
naphthalene]-4″,5′-dione, white powder, mp 158−160 °C; H NMR
(m, 2H), 7.89−7.85 (m, 2H), 1.11 (ddd, J = 10.7, 7.6, 5.8 Hz, 2H),
0.74 (ddd, J = 10.7, 7.2, 5.8 Hz, 2H), 0.61 (ddd, J = 10.2, 7.2, 5.8 Hz,
2H), 0.33 (ddd, J = 10.2, 7.6, 5.8 Hz, 2H); 13C NMR (100 MHz,
CDCl3) δ 187.7, 135.3, 133.2, 128.5, 76.8, 34.5, 9.9, 9.8; IR (ATR,
neat) 3068, 3029, 2993, 1710, 1695, 1662, 1580, 1450, 1417, 1390,
1299, 1257, 1223, 1175, 1126, 1099, 1069, 1039, 1017, 966, 936, 842,
802, 780, 766, 725, 688, 636, 612 cm−1; MS (ESI+) m/z 307 [M +
H]+; HRMS (ESI) m/z [M + Na]+ calcd for C16H12O2Cl2Na
329.0112, found 329.0117.
(400 MHz, CDCl3) δ 8.17 (dd, J = 8.1, 1.4 Hz, 1H), 7.62 (td, J = 7.8,
1.5 Hz, 1H), 7.45−7.41 (m, 2H), 7.04 (d, J = 10.4 Hz, 1H), 6.43 (d, J
= 10.4 Hz, 1H), 2.85−2.70 (m, 2H), 2.62−2.46 (m, 2H), 1.36−1.26
(m, 2H), 0.74−0.70 (m, 1H), 0.55−0.51 (m, 1H); 13C NMR (100
MHz, CDCl3) δ 216.5, 184.3, 151.7, 146.0, 132.6, 131.6, 128.2, 127.4,
126.7, 126.4, 47.0, 38.5, 36.1, 35.6, 20.1, 18.5; IR (ATR, neat) 3074,
3029, 3005, 2963, 1710, 1661, 1600, 1452, 1417, 1396, 1316, 1299,
1171, 1093, 1072, 1033, 986, 972, 906, 838, 781, 764, 733, 691, 641
cm−1; MS (ESI+) m/z 239 [M + H]+; HRMS (ESI) m/z [M + Na]+
calcd for C16H14O2Na 261.0891, found 261.0889.
Photolysis of 10 with BCP in Anhydrous Benzene. A solution
of 10 (500 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 3 h to
reach a complete conversion of 10. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 10a (574 mg, 87%).
Photolysis of 7 with BCP in Anhydrous Benzene. A solution of
7 (344 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 7. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 7a (444 mg, 88%) and 7b (40 mg, 8%).
10a: 2′a-Phenoxy-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-1,1′-
cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
1
7a: 2′a-Methyl-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-1,1′-
powder, mp 156−157 °C; H NMR (400 MHz, CDCl3) δ 8.22−
cyclobuta[b]naphthalene-2′,1″-cyclopropane]-3′,8′-dione, white pow-
8.18 (m, 2H), 7.89−7.82 (m, 2H), 7.17−7.12 (m, 2H), 6.92−6.88 (m,
1H), 6.66−6.62 (m, 2H), 3.84 (s, 1H), 1.41−1.33 (m, 1H), 0.73−0.67
(m, 1H), 0.56−0.50 (m, 3H), 0.41−0.35 (m, 1H), 0.29−0.21 (m, 1H),
0.13−0.08 (m, 1H); 13C NMR (100 MHz, CDCl3) δ 193.7, 192.3,
154.7, 135.2, 134.9, 134.6, 134.0, 129.7, 128.1, 127.5, 121.7, 116.0,
80.8, 55.5, 31.7, 24.8, 9.4, 9.3, 7.2, 6.8; IR (ATR, neat) 3071, 2993,
2947, 2914, 1806, 1639, 1598, 1480, 1448, 1347, 1295, 1258, 1211,
1198, 1094, 1008, 966, 941, 891, 856, 837, 773, 751, 737, 722, 707,
695, 657 cm−1; MS (ESI+) m/z 331 [M + H]+, 353 [M + Na]+;
HRMS (ESI) m/z [M + Na]+ calcd for C22H18O3Na 353.1154, found
353.1152.
1
der, mp 115−116 °C; H NMR (400 MHz, CDCl3) δ 8.15−8.10 (m,
2H), 7.80−7.75 (m, 2H), 3.36 (s, 1H), 1.52 (s, 3H), 0.70−0.60 (m,
2H), 0.46−0.33 (m, 3H), 0.19 (ddd, J = 10.3, 6.9, 5.4 Hz, 1H), 0.07
(ddd, J = 10.2, 6.9, 5.2 Hz, 1H), 0.03 to −0.01 (m, 1H); 13C NMR
(100 MHz, CDCl3) δ 197.3, 195.5, 135.3, 135.1, 134.2, 134.0, 127.5,
126.9, 55.3, 48.2, 32.8, 25.9, 20.9, 9.5, 8.0, 5.9, 5.7; IR (ATR, neat)
3068, 3035, 2990, 2932, 1711, 1663, 1591, 1450, 1420, 1396, 1371,
1286, 1256, 1171, 1154, 1129, 1094, 1069, 1027, 986, 912, 836, 801,
782, 765, 733, 694, 636 cm−1; MS (ESI+) m/z 253 [M + H]+. Anal.
Calcd for C17H16O2: C, 80.93; H, 6.39. Found: C, 80.89; H, 6.43.
7b: 3″-Methyldispiro[cyclopropane-1,1′-cyclopentane-2′,1″-(4″H)-
Photolysis of 11 with BCP in Anhydrous Benzene. A solution
of 11 (376 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 3 h to
reach a complete conversion of 11. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 11a (468 mg, 87%). Photolysis for 24 h gave 11b (457 mg,
85%).
1
naphthalene]-4″,5′-dione, white powder, mp 136−138 °C; H NMR
(400 MHz, CDCl3) δ 8.18 (dd, J = 7.8, 1.8 Hz, 1H), 7.59 (td, J = 7.8,
1.4 Hz, 1H), 7.43−7.39 (m, 2H), 6.83 (q, J = 1.4 Hz, 1H), 2.79−2.74
(m, 2H), 2.58−2.42 (m, 2H), 2.04 (d, J = 1.4, 3H), 1.30−1.27 (m,
2H), 0.71−0.67 (m, 1H), 0.53−0.49 (m, 1H); 13C NMR (100 MHz,
CDCl3) δ 217.0, 184.9, 147.4, 146.2, 132.7, 132.2, 131.5, 128.0, 127.3,
126.9, 46.6, 38.7, 36.2, 35.8, 20.1, 18.5, 16.3; IR (ATR, neat) 3077,
1794, 1709, 1653, 1632, 1602, 1459, 1383, 1370, 1314, 1286, 1235,
1196, 1175, 1093, 1018, 952, 934, 893, 790, 777, 757, 718, 670 cm−1;
MS (ESI+) m/z 253 [M + H]+; HRMS (ESI) m/z [M + Na]+ calcd
for C17H16O2Na 275.1048, found 275.1044.
11a: 2′a-Methoxy-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-1,1′-
cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
1
powder, mp 159−161 °C; H NMR (400 MHz, CDCl3) δ 8.21−
8.19 (m, 1H), 8.11−8.08 (m, 1H), 7.84−7.79 (m, 2H), 3.80 (s, 1H),
3.35 (s, 3H), 1.12 (ddd, J = 10.3, 5.0, 3.3 Hz, 1H), 0.69 (ddd, J = 10.3,
7.2, 5.8 Hz, 1H), 0.48−0.39 (m, 3H), 0.33 (ddd, J = 10.3, 7.0, 5.5,
1H), 0.18−0.13 (m, 1H), 0.06 (ddd, J = 10.3, 7.0, 5.5, 1H); 13C NMR
(100 MHz, CDCl3) δ 194.3, 194.3, 135.5, 134.9, 134.7, 134.2, 127.7,
127.1, 82.2, 54.1, 52.8, 31.5, 24.3, 8.7, 8.5, 7.0, 6.9; IR (ATR, neat)
3068, 3038, 2947, 2914, 1724, 1663, 1595, 1456, 1441, 1353, 1315,
1290, 1253, 1226, 1088, 1051, 977, 838, 728, 705, 667 cm−1; MS (ESI
+) m/z 269 [M + H]+; HRMS (ESI) m/z [M + Na]+ calcd for
C17H16O3Na 291.0997, found 291.0992.
Photolysis of 8 with BCP in Anhydrous Benzene. A solution of
8 (385 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 8. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 8a (473 mg, 87%).
8a: 2′a-Chloro-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-1,1′-
cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
1
powder, mp 122−124 °C; H NMR (400 MHz, CDCl3) δ 8.25−
11b: white powder, mp 169−171 °C; 1H NMR (300 MHz, CDCl3)
δ 8.09 (d, J = 7.9 Hz, 1H), 7.70−7.65 (m, 2H), 7.52−7.47 (m, 1H),
4.61−4.54 (m, 2H), 3.75 (s, 1H), 2.65 (s, 1H), 1.20−1.03 (m, 2H),
0.58−0.48 (m, 2H), 0.37−0.29 (m, 2H), 0.25−0.13 (m, 2H); 13C
NMR (75 MHz, CDCl3) δ 194.4, 144.1, 134.8, 129.9, 128.8, 127.1,
127.0, 89.1, 81.8, 72.9, 54.1, 30.9, 24.4, 6.3, 4.6, 4.2, 4.1; IR (ATR,
neat) 3377, 3062, 3002, 2953, 2875, 1662, 1598, 1447, 1383, 1318,
1297, 1278, 1262, 1194, 1160, 1096, 1066, 1020, 1004, 956, 930, 869,
812, 770, 752, 725, 687, 628 cm−1; MS (ESI+) m/z 269 [M + H]+;
HRMS (ESI) m/z [M + Na]+ calcd for C17H16O3Na 291.0997, found
291.0993.
Photolysis of 12 with BCP in Anhydrous Benzene. A solution
of 12 (404 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 3 h to
reach a complete conversion of 12. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
8.20 (m, 1H), 8.16−8.12 (m, 1H), 7.86−7.81 (m, 2H), 4.04 (s, 1H),
1.10 (ddd, J = 10.6, 7.7, 5.7 Hz, 1H), 0.77 (ddd, J = 10.6, 7.2, 5.7 Hz,
2H), 0.60 (ddd, J = 10.2, 7.2, 5.7 Hz, 1H), 0.51 (ddd, J = 10.2, 6.6, 5.7
Hz, 1H), 0.41 (ddd, J = 10.3, 6.6, 5.7 Hz, 1H), 0.30 (ddd, J = 10.3, 7.7,
5.7 Hz, 1H), 0.10 (ddd, J = 10.2, 7.2, 5.7 Hz, 1H); 13C NMR (100
MHz, CDCl3) δ 192.2, 189.6, 134.9, 134.8, 134.7, 133.5, 128.5, 127.3,
68.5, 59.4, 35.0, 26.1, 10.6, 10.2, 8.8, 6.1; IR (ATR, neat) 3074, 2999,
1710, 1680, 1585, 1456, 1399, 1302, 1274, 1244, 1094, 1026, 970, 927,
814, 798, 783, 766, 749, 726, 691, 606 cm−1; MS (ESI+) m/z 273 [M
+ H]+. Anal. Calcd for C16H13O2Cl: C, 70.46; H, 4.80. Found: C,
70.23; H, 4.92.
Photolysis of 9 with BCP in Anhydrous Benzene. A solution of
9 (454 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 9. Flash column chromatography on
H
dx.doi.org/10.1021/jo4008767 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
afforded 12a (479 mg, 85%). Photolysis for 24 h gave 12b (496 mg,
88%).
0.54−0.41 (m, 4H), 0.08 to −0.01 (m, 2H); 13C NMR (75 MHz,
CDCl3) δ 195.1, 135.3, 131.2, 130.0, 129.4, 129.3, 47.9, 28.1, 9.5, 6.7;
IR (ATR, neat) 3080, 2987, 2947, 2911, 1806, 1639, 1595, 1480, 1447,
1423, 1348, 1295, 1258, 1211, 1197, 1096, 1060, 1008, 966, 941, 891,
856, 838, 774, 752, 737, 724, 707, 695, 657 cm−1; MS (ESI+) m/z 289
[M + H]+; HRMS (ESI) m/z [M + Na]+ calcd for C20H16O2Na
311.1048, found 311.1043.
12a: 2′a-Ethoxy-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-1,1′-
cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
1
powder, mp 159−161 °C; H NMR (400 MHz, CDCl3) δ 8.21−
8.18 (m, 1H), 8.09−8.07 (m, 1H), 7.82−7.78 (m, 2H), 3.80 (s, 1H),
3.52 (dq, J = 8.7, 7.0 Hz, 1H), 3.41 (dq, J = 8.7, 7.0 Hz, 1H), 1.26 (t, J
= 7.0, 3H), 1.19−1.14 (m, 1H), 0.69−0.63 (m, 1H), 0.50−0.40 (m,
3H), 0.32−0.26 (m, 1H), 0.15−0.03 (m, 2H); 13C NMR (100 MHz,
CDCl3) δ 194.8, 194.5, 135.5, 134.9, 134.6, 134.2, 127.7, 127.0, 81.5,
61.0, 55.0, 31.8, 24.3, 15.5, 8.4, 8.3, 7.2, 7.0; IR (ATR, neat) 3071,
2987, 2941, 2905, 1806, 1713, 1639, 1595, 1574, 1483, 1441, 1420,
1347, 1308, 1295, 1257, 1208, 1193, 1093, 1008, 966, 941, 891, 856,
838, 774, 752, 737, 707, 695, 657 cm−1; MS (ESI+) m/z 283 [M +
H]+; HRMS (ESI) m/z [M + Na]+ calcd for C18H18O3Na 305.1154,
found 305.1159.
14b: Dispiro[cyclopropane-1,1′-cyclopentane-2′,1″-(4″H)-
1
anthracene]-4″,5′-dione, white powder, mp 172−174 °C; H NMR
(300 MHz, CDCl3) δ 8.75 (s, 1H), 8.02 (d, J = 8.2 Hz, 1H), 7.89 (d, J
= 8.2 Hz, 1H), 7.85 (s, 1H), 7.65−7.53 (m, 2H), 7.09 (d, J = 10.3 Hz,
1H), 6.51 (d, J = 10.3 Hz, 1H), 2.95−2.52 (m, 4H), 1.42−1.31 (m,
2H), 0.84−0.79 (m, 1H), 0.61−0.55 (m, 1H); 13C NMR (75 MHz,
CDCl3) δ 216.8, 184.6, 151.9, 141.4, 135.0, 131.6, 129.6, 129.1, 128.7,
128.3, 127.7, 127.5, 126.9, 126.9, 47.0, 39.7, 36.7, 36.1, 20.1, 18.8; IR
(ATR, neat) 3087, 3071, 2990, 2947, 1711, 1665, 1621, 1591, 1447,
1401, 1309, 1278, 1272, 1218, 1160, 1092, 1075, 1033, 979, 895, 834,
821, 756, 665, 642 cm−1; MS (ESI+) m/z 289 [M + H]+; HRMS
(ESI) m/z [M + H]+ calcd for C20H17O2 289.1229, found 289.1256.
Photolysis of 15 with BCP in Anhydrous Benzene. A solution
of 15 (416 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (200 mL) was photolyzed with nitrogen bubbling for 12 h to
reach a complete conversion of 15. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 15a (317 mg, 55%) and 15b (236 mg, 41%).
12b: white powder (with photolysis for 24 h), mp 155−157 °C; 1H
NMR (400 MHz, CDCl3) δ 8.09−8.06 (m, 1H), 7.69−7.65 (m, 1H),
7.56−7.54 (m, 1H), 7.49−7.45 (m, 1H), 4.67 (t, J = 6.3 Hz, 1H), 3.73
(s, 1H), 2.57 (s, 1H), 1.35 (d, J = 6.3 Hz, 3H), 1.09−0.98 (m, 2H),
0.55−0.46 (m, 2H), 0.34−0.27 (m, 2H), 0.22−0.12 (m, 2H); 13C
NMR (100 MHz, CDCl3) δ 194.7, 145.1, 134.8, 129.7, 128.6, 127.1,
126.5, 86.5, 85.5, 73.1, 54.3, 30.5, 24.5, 15.8, 6.3, 4.4, 4.2, 3.8; IR
(ATR, neat) 3401, 3083, 2984, 2947, 2908, 1806, 1653, 1638, 1595,
1574, 1477, 1447, 1348, 1314, 1295, 1259, 1211, 1198, 1099, 1081,
1108, 966, 941, 891, 856, 838, 773, 752, 737, 707, 695, 657 cm−1; MS
(ESI+) m/z 283 [M + H]+; HRMS (ESI) m/z [M + Na]+ calcd for
C18H18O3Na 305.1154, found 305.1150.
Photolysis of 13 with BCP in Anhydrous Benzene. A solution
of 13 (432 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 3 h to
reach a complete conversion of 13. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 13a (521 mg, 88%). Photolysis for 48 h gave 13a (36 mg,
6%), 13b (320 mg, 54%) and 6a (257 mg, 25%).
15a: Trispiro[biscyclopropane-1,2″:1′,3″-oxetane-4″,9‴-(10‴H)-
anthracene]-10‴-one, white powder, mp 156−158 °C; 1H NMR
(300 MHz, CDCl3) δ 8.35 (dd, J = 7.9, 1.3 Hz, 2H), 8.21 (dd, J = 7.9,
1.5 Hz, 2H), 7.79 (td, J = 7.9, 1.5 Hz, 2H), 7.52 (td, J = 7.9, 1.3 Hz,
2H), 1.29−1.24 (m, 2H), 0.67−0.62 (m, 2H), 0.35−0.31 (m, 2H),
0.00 to −0.04 (m, 2H); 13C NMR (75 MHz, CDCl3) δ 183.5, 143.9,
133.9, 130.3, 128.5, 127.6, 126.6, 83.2, 71.9, 39.9, 8.6, 8.5; IR (ATR,
neat) 3065, 3035, 2999, 1659, 1599, 1459, 1318, 1283, 1195, 1175,
1151, 1114, 1019, 1003, 966, 957, 930, 864, 817, 768, 751, 733, 686,
628 cm−1; MS (ESI+) m/z 289 [M + H]+; HRMS (ESI) m/z [M +
Na]+ calcd for C20H16O2Na 311.1048, found 311.1042.
13a: 2′a-Isopropoxy-1′,2′,2′a,8′a-tetrahydrodispiro[cyclopropane-
1,1′-cyclobuta[b]naphthalene-2′,11″-cyclopropane]-3′,8′-dione, white
15b: white powder, mp 154−156 °C; 1H NMR (300 MHz, CDCl3)
δ 7.91 (dt, J = 7.6, 1.1 Hz, 1H), 7.64 (td, J = 7.4, 1.1 Hz, 1H), 7.54 (td,
J = 7.5, 1.1 Hz, 1H), 7.37−7.31 (m, 2H), 7.15 (td, J = 7.5, 1.2 Hz, 1H),
6.91 (dt, J = 7.6, 0.9 Hz, 1H), 6.82 (dt, J = 7.6, 0.9 Hz, 1H), 1.07−0.98
(m, 2H), 0.92−0.87 (m, 1H), 0.79−0.63 (m, 2H), 0.50−0.33 (m, 3H);
13C NMR (75 MHz, CDCl3) δ 169.8, 150.0, 148.9, 140.7, 134.1, 130.1,
129.4, 126.8, 126.5, 125.2, 123.8, 123.4, 119.0, 96.0, 33.9, 29.9, 13.9,
11.7, 9.1, 6.3; IR (ATR, neat) 3074, 3038, 3008, 1744, 1704, 1610,
1466, 1417, 1338, 1284, 1236, 1187, 1157, 1113, 1090, 1020, 940, 916,
900, 820, 757, 751, 724, 691, 662, 650 cm−1; MS (ESI+) m/z 289 [M
+ H]+, 311 [M + Na]+. Anal. Calcd for C20H16O2: C, 83.31; H, 5.59.
Found: C, 83.06; H, 5.60.
Photolysis of 16 with BCP in Anhydrous Benzene. A solution
of 16 (693 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 16. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 16a (750 mg, 88%).
1
powder, mp 158−159 °C; H NMR (400 MHz, CDCl3) δ 8.24−8.19
(m, 1H), 8.10−8.05 (m, 1H), 7.82−7.78 (m, 2H), 3.89 (s, 1H), 3.80
(m, 1H), 1.20 (ddd, J = 9.8, 6.9, 4.4 Hz, 1H), 1.18 (d, J = 6.1 Hz, 3H),
1.13 (d, J = 6.1 Hz, 3H), 0.60 (ddd, J = 10.3, 7.1, 5.7, 1H), 0.52−0.35
(m, 3H), 0.23 (ddd, J = 10.3, 6.6, 5.6 Hz, 1H), 0.12−0.01 (m, 2H);
13C NMR (100 MHz, CDCl3) δ 195.2, 194.7, 135.4, 134.6, 134.6,
134.1, 127.8, 127.0, 80.5, 69.2, 56.7, 33.0, 24.4, 23.8, 23.7, 8.0, 7.7, 7.6,
7.3; IR (ATR, neat) 3068, 2987, 2938, 2902, 1806, 1707, 1639, 1595,
1477, 1447, 1347, 1307, 1291, 1257, 1211, 1198, 1095, 1081, 1008,
966, 941, 891, 856, 837, 774, 752, 722, 707, 695, 657 cm−1; MS (ESI+)
m/z 297 [M + H]+, 319 [M + Na]+; HRMS (ESI) m/z [M + Na]+
calcd for C19H20O3Na 319.1310, found 319.1313.
13b: white powder, mp 147−149 °C; 1H NMR (300 MHz, CDCl3)
δ 8.10−8.07 (m, 1H), 7.69−7.63 (m, 1H), 7.56−7.53 (m, 1H), 7.49−
7.44 (m, 1H), 3.68 (s, 1H), 2.68 (s, 1H), 1.41 (s, 3H), 1.12−0.96 (m,
2H), 0.94 (s, 3H), 0.53−0.44 (m, 2H), 0.32−0.11 (m, 4H); 13C NMR
(75 MHz, CDCl3) δ 194.6, 143.4, 134.4, 130.8, 128.5, 127.4, 126.8,
88.3, 83.8, 75.4, 54.5, 30.7, 27.4, 24.8, 23.7, 6.5, 4.3, 4.1, 3.8; IR (ATR,
neat) 3413, 3368, 3074, 2999, 1807, 1695, 1639, 1598, 1574, 1480,
1444, 1348, 1314, 1293, 1208, 1193, 1033, 1007, 941, 890, 856, 837,
770, 752, 737, 721, 707, 695, 657 cm−1; MS (ESI+) m/z 297 [M +
H]+. Anal. Calcd for C19H20O3: C, 77.00; H, 6.80. Found: C, 76.92; H,
6.82.
Photolysis of 14 with BCP in Anhydrous Benzene. A solution
of 14 (416 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 10 h to
reach a complete conversion of 14. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 14a (451 mg, 78%) and 14b (146 mg, 15%).
16a: yellow powder, mp 130−131 °C; 1H NMR (300 MHz,
CDCl3) δ 8.20−8.17 (m, 1H), 8.10−8.07 (m, 1H), 7.89−7.79 (m,
2H), 7.76−7.73 (m, 2H), 7.47−7.37 (m, 3H), 4.26−4.16 (m, 2H),
1.48−1.43 (m, 1H), 1.26−1.18 (m, 1H), 1.21 (t, J = 7.2 Hz, 3H),
0.69−0.53 (m, 3H), 0.29−0.18 (m, 3H); 13C NMR (75 MHz, CDCl3)
δ 191.9, 189.6, 166.2, 164.7, 136.8, 135.3, 134.1, 133.6, 130.6, 129.6,
129.2, 127.7, 127.5, 106.0, 87.8, 64.5, 60.4, 33.6, 33.4, 29.7, 13.9, 9.5,
7.9, 7.8, 6.2; IR (ATR, neat) 3071, 1794, 1708, 1632, 1602, 1480,
1453, 1414, 1371, 1337, 1315, 1269, 1235, 1094, 1062, 1030, 950, 934,
866, 840, 777, 758, 748, 719, 704, 671, 622 cm−1; MS (ESI+) m/z 427
[M + H]+, 449 [M + Na]+; HRMS (ESI) m/z [M + Na]+ calcd for
C27H22O5Na 449.1365, found 449.1358.
14a: 1′,2′,2′a,10′a-Tetrahydrodispiro[cyclopropane-1,1′-cyclobuta-
Photolysis of 17 with BCP in Anhydrous Benzene. A solution
of 17 (468 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 17. Flash column chromatography on
[b]anthracene-2′,11″-cyclobutane]-3′,10′-dione, white powder, mp
1
176−178 °C; H NMR (300 MHz, CDCl3) δ 8.70 (s, 2H), 8.12−
8.07 (m, 2H), 7.73−7.67 (m, 2H), 3.82 (s, 2H), 0.75−0.68 (m, 2H),
I
dx.doi.org/10.1021/jo4008767 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 17a (713 mg, 98%).
Synthesis of 8c. To a solution of 8b (236 mg, 1 mmol) in xylene
(10 mL) was added isoprene (82 mg, 1.2 mmol). The mixture was
heated at 130 °C overnight. TLC monitoring showed complete
conversion of 8b. The reaction mixture was cooled, the solvent was
evaporated under a vacuum, and the crude product was separated by
flash column chromatography on 300−400 mesh silica gel with
petroleum ether/ethyl acetate as eluents to give the final product 8c
(283 mg, 93%).
17a: white powder, mp 175−177 °C; 1H NMR (300 MHz, CDCl3)
δ 8.16−8.13 (m, 1H), 8.05−8.02 (m, 1H), 7.87−7.77 (m, 2H), 4.28
(q, J = 7.2 Hz, 2H), 2.36 (s, 3H), 1.34 (t, J = 7.2 Hz, 3H), 1.30−1.25
(m, 1H), 1.12 (ddd, J = 9.8, 6.8, 4.8 Hz, 1H), 0.64−0.48 (m, 3H),
0.22−0.11 (m, 3H); 13C NMR (75 MHz, CDCl3) δ 191.9, 189.7,
170.5, 165.1, 137.2, 135.3, 133.9, 133.3, 127.6, 127.3, 105.9, 88.3, 62.8,
60.0, 33.3, 32.7, 14.9, 14.3, 9.4, 7.8, 7.6, 5.8; IR (ATR, neat) 3065,
2984, 2950, 2905, 1806, 1639, 1594, 1483, 1453, 1414, 1347, 1299,
1258, 1210, 1198, 1087, 1059, 1008, 966, 941, 891, 856, 838, 774, 751,
722, 695, 657, 639 cm−1; MS (ESI+) m/z 365 [M + H]+, 387 [M +
Na]+; HRMS (ESI) m/z [M + Na]+ calcd for C22H20O5Na 387.1208,
found 387.1240.
8c: white powder, mp 144−145 °C; 1H NMR (400 MHz, CDCl3) δ
8.13−8.09 (m, 2H), 7.79−7.75 (m, 2H), 5.76−5.72 (m, 1H), 2.45−
2.22 (m, 4H), 1.88 (s, 3H), 0.52−0.46 (m, 2H), 0.30−0.23 (m, 2H),
0.17−0.09 (m, 2H), 0.05 to −0.01 (m, 2H); 13C NMR (100 MHz,
CDCl3) δ 197.0, 196.9, 135.3, 135.2, 135.2, 134.0, 133.9, 127.2, 120.1,
53.1, 52.4, 32.0, 29.4, 29.3, 27.1, 24.0, 9.0, 8.6, 6.4, 5.8; IR (ATR, neat)
3071, 2917, 2845, 1713, 1668, 1625, 1590, 1444, 1308, 1272, 1163,
1093, 1022, 1002, 948, 939, 859, 836, 794, 763, 724, 708, 670, 621
cm−1; MS (ESI+) m/z 305 [M + H]+; HRMS (ESI) m/z [M + H]+
calcd for C21H21O2 305.1542, found 305.1568.
Photolysis of 18 with BCP in Anhydrous Benzene. A solution
of 18 (508 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 18. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 18b (454 mg, 68%).
Synthesis of 8d. To a solution of 8b (236 mg, 1 mmol) in xylene
(10 mL) was added 1,3-cyclohexadiene (96 mg, 1.2 mmol). The
mixture was heated at 130 °C overnight. TLC analysis showed
complete conversion of 8b. The reaction mixture was cooled, the
solvent was evaporated under a vacuum, and the crude product was
separated by flash column chromatography on 300−400 mesh silica
gel with petroleum ether/ethyl acetate as eluents to give the final
product 8d (272 mg, 86%).
18b: white powder, mp 162−163 °C; 1H NMR (400 MHz, CDCl3)
δ 8.15 (dd, J = 7.9, 1.5 Hz, 1H), 7.51 (ddd, J = 8.1, 7.1, 1.5 Hz, 1H),
7.35 (ddd, J = 7.9, 7.1, 1.0 Hz, 1H), 6.93 (dd, J = 8.1, 1.0 Hz, 1H), 3.11
(ddd, J = 16.3, 9.0, 7.3 Hz, 1H), 2.66 (ddd, J = 12.4, 9.4, 3.1 Hz, 1H),
2.54 (s, 3H), 2.46 (ddd, J = 14.1, 9.4, 7.3 Hz, 1H), 2.37−2.31 (m, 1H),
2.30 (s, 3H), 2.03−1.84 (m, 4H); 13C NMR (100 MHz, CDCl3) δ
192.4, 181.1, 178.4, 169.8, 161.9, 146.4, 136.2, 133.0, 132.3, 126.3,
126.0, 122.7, 121.1, 59.8, 33.8, 33.0, 30.3, 25.4, 24.2, 23.7, 15.5; IR
(ATR, neat) 3068, 1794, 1654, 1632, 1603, 1477, 1459, 1411, 1378,
1336, 1300, 1272, 1231, 1197, 1120, 1023, 972, 949, 933, 839, 790,
747, 727, 709, 680 cm−1; MS (ESI+) m/z 335 [M + H]+, 357[M +
Na]+; HRMS (ESI) m/z [M + Na]+ calcd for C21H18O4Na 357.1103,
found 357.1099.
1
8d: white powder; mp 217−220 °C; H NMR (400 MHz, CDCl3)
δ 8.08−8.05 (m, 2H), 7.74 - 7.71 (m, 2H), 6.32−6.30 (m, 2H), 3.25
(ddd, J = 4.5, 3.0, 1.5 Hz, 2H), 2.58−2.53 (m, 2H), 1.30−1.26 (m,
2H), 0.77−0.73 (m, 2H), 0.54−0.49 (m, 2H), 0.28−0.24 (m, 2H),
0.01 to −0.03 (m, 2H); 13C NMR (100 MHz, CDCl3) δ 196.8, 135.5,
135.4, 133.8, 127.2, 56.7, 33.6, 25.6, 19.6, 8.8, 8.3; IR (ATR, neat)
3068, 3038, 2944, 2914, 1723, 1662, 1596, 1450, 1417, 1359, 1315,
1260, 1223, 1087, 1054, 976, 838, 827, 809, 722, 695, 672, 625 cm−1;
MS (ESI+) m/z 317 [M + H]+; HRMS (ESI) m/z [M + Na]+ calcd
for C22H20O2Na 339.1361, found 339.1341.
Photolysis of 19 with BCP in Anhydrous Benzene. A solution
of 19 (757 mg, 2 mmol) and BCP (320 mg, 4 mmol) in anhydrous
benzene (100 mL) was photolyzed with nitrogen bubbling for 24 h to
reach a complete conversion of 19. Flash column chromatography on
300−400 mesh silica gel with petroleum ether/ethyl acetate as eluents
afforded 19b (632 mg, 69%).
CCDC 932973−932979 contain the supplementary crystallographic
data for compounds 5a, 6a, 8d, 13b, 15b, 17a, and 19b in this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/
cif.
19b: white powder, mp 234−236 °C; 1H NMR (400 MHz, CDCl3)
δ 8.18 (dd, J = 8.1, 1.5 Hz, 1H), 7.60−7.57 (m, 2H), 7.48 (ddd, J =
8.1, 7.2, 1.5 Hz, 1H), 7.39−7.37 (m, 2H), 7.33 (ddd, J = 8.1, 7.2, 1.2
Hz, 1H), 7.24−7.19 (m, 2H), 7.14−7.05 (m, 4H), 6.89 (dd, J = 8.1,
1.2 Hz, 1H), 3.23−3.14 (m, 1H), 3.01−2.94 (m, 1H), 2.75−2.64 (m,
2H), 2.01−1.80 (m, 4H); 13C NMR (100 MHz, CDCl3) δ 193.0,
181.3, 178.5, 170.4, 158.0, 146.3, 137.8, 135.8, 133.1, 132.4, 132.3,
130.7, 129.5, 129.2, 128.1, 127.9, 127.9, 126.5, 126.1, 121.0, 119.4,
62.6, 35.0, 32.9, 25.4, 24.5, 23.7; IR (ATR, neat) 3074, 1805, 1710,
1662, 1639, 1594, 1483, 1448, 1417, 1396, 1347, 1297, 1281, 1253,
1208, 1196, 1094, 1008, 966, 940, 891, 855, 837, 773, 751, 737, 695,
656 cm−1; MS (ESI+) m/z 459 [M + H]+, 481 [M + Na]+; HRMS
(ESI) m/z [M + H]+ calcd for C31H23O4 459.1596, found 459.1590.
Synthesis of 8b. To a solution of 8a (272 mg, 1 mmol) in
CH3CN (10 mL) was added K2CO3 (166 mg, 1.2 mmol). The mixture
was stirred at room temperature overnight. TLC analysis showed
complete conversion of 8a; the reaction mixture was filtered. The
filtrate was evaporated under a vacuum, and the crude product was
separated by flash column chromatography on 300−400 mesh silica
gel with petroleum ether/ethyl acetate as eluents to give the final
product 8b (231 mg, 98%).
ASSOCIATED CONTENT
■
S
* Supporting Information
Crystal structure of compounds 5a, 6a, 8d, 13b, 15b, 17a, and
19b. NMR spectra of all compounds. CIF files of 5a, 6a, 8d,
13b, 15b, 17a, and 19b. This material is available free of charge
via the Internet at http://pubs.acs.org.
AUTHOR INFORMATION
■
Corresponding Author
*E-mail: xujh@nju.edu.cn; njuzy@nju.edu.cn.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
The authors would like to acknowledge financial support from
the National Natural Science Foundation of China (21121091)
and the Natural Science Foundation of Jiangsu Province
(BK2012012). H.K.F. thanks the Universiti Sains Malaysia
(USM) for a Research University Grant (No. 1001/PFIZIK/
811160). C.K.Q. thanks USM for APEX DE2012 Grant (No.
1002/PFIZIK/910323) and RUC Grant (No. 1001/PSKBP/
8630013). The authors extend their appreciation to The
Deanship of Scientific Research at King Saud University for the
8b: 1′,2′-Dihydrodispiro[cyclopropane-1,1′-cyclobuta[b]-
naphthalene-2′,1″-cyclopropane]-3′,8′-dione, yellow powder, mp
1
104−106 °C; H NMR (300 MHz, CDCl3) δ 8.02−7.99 (m, 2H),
7.68−7.65 (m, 2H), 1.43−1.39 (m, 4H), 0.86−0.82 (m, 4H); 13C
NMR (75 MHz, CDCl3) δ 177.5, 157.6, 133.9, 133.0, 126.3, 36.4, 9.2;
IR (ATR, neat) 3068, 1806, 1639, 1595, 1483, 1444, 1347, 1287, 1210,
1193, 1096, 1084, 1008, 941, 891, 855, 838, 774, 751, 737, 722, 707,
695, 657 cm−1; MS (ESI+) m/z 237 [M + H]+. Anal. Calcd for
C16H12O2: C, 81.34; H, 5.12. Found: C, 81.25; H, 5.18.
J
dx.doi.org/10.1021/jo4008767 | J. Org. Chem. XXXX, XXX, XXX−XXX

The Journal of Organic Chemistry
Article
(11) For reviews, see (a) Gilbert, A. In CRC Handbook of Organic
Photochemistry and Photobiology, 2nd ed.; Horspool, W., Lenci, F., Eds;
CRC Press: Boca Raton, FL, 2004; pp 87/1−87/12. (b) Goerner, H.
In CRC Handbook of Organic Photochemistry and Photobiology, 3rd ed.;
Griesbeck, A., Oelgemoller, M., Ghetti, F., Eds; CRC Press: Boca
Raton, FL, 2012; Vol. 1, pp 683−714.
funding the work through the research group Project No. RGP-
VPP-207.
DEDICATION
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Dedicated to the memory of Professor Howard E. Zimmerman.
(12) (a) Maruyama, K.; Otsuki, T.; Tai, S. J. Org. Chem. 1985, 50,
52−60. (b) Maruyama, K.; Imahori, H. J. Org. Chem. 1989, 54, 2692−
2702. (c) Eckert, G.; Goez, M. J. Am. Chem. Soc. 1994, 116, 11999−
12009. (d) Cleridou, S.; Covell, C.; Gadhia, A.; Gilbert, A.;
Kamonnawin, P. Perkin 1 2000, 1149−1155.
(13) (a) Bosch, E.; Hubig, S. M.; Kochi, J. K. J. Am. Chem. Soc. 1998,
120, 386−395. (b) Kokubo, K.; Masaki, T.; Oshima, T. Org. Lett.
2000, 2, 1979−1981. (c) Xue, J.; Xu, J.-W.; Yang, L.; Xu, J.-H. J. Org.
Chem. 2000, 65, 30−40.
(14) (a) Xu, J.-H.; Song, Y.-L.; Zhang, Z.-G.; Wang, L.-C.; Xu, J.-W.
Tetrahedron 1994, 50, 1199−1210. (b) Xu, J.-H.; Wang, L.-C.; Xu, J.-
W.; Yan, B.-Z.; Yuan, H.-C. J. Chem. Soc., Perkin Trans. 1 1994, 571−
577. (c) Miyashi, T.; Konno, A.; Takahashi, Y.; Kanecko, A.; Suzuki,
T.; Mukai, T.; Koga, N.; Iwamura, H. Tetrahedron Lett. 1989, 30,
5297−5300. (d) Christl, M.; Braun, M.; Deeg, O.; Wolff, S. Eur. J. Org.
Chem. 2011, 968−982.
(15) Rehm, D.; Weller, A. Isr. J. Chem. 1970, 8, 259−271.
(16) (a) Bunce, N. J.; Hadley, M. Can. J. Chem. 1975, 53, 3240−
3246. (b) Haga, N.; Takayanagi, H.; Tokumaru, K. J. Chem. Soc., Perkin
Trans. 2 2002, 734−745. (c) Kuboyama, A. Bull. Chem. Soc. Jpn. 1978,
51, 2771−2775.
(17) (a) Abe, M. In Handbook of Synthetic Photochemistry; Albini, A.,
Fagnoni, M., Eds.; Wiley-VCH: Weinheim, 2009; pp 217−239.
(b) Griesbeck, A. G.; Fiege, M. In Molecular and Supramolecular
Photochemistry; Ramamurthy, V., Schanze, K. S., Eds.; Marcel Dekker:
New York, 2000; Vol. 6, pp 33−100. (c) Fleming, S. A.; Bradford, C.
L.; Gao, J. J. In Molecular and Supramolecular Photochemistry;
Ramamurthy, V., Schanze, K. S., Eds.; Marcel Dekker: New York,
1997; Vol. 1, pp 187−243. (d) Bach, T. Synthesis 1998, 683−703.
(e) Jones, G. In Organic Photochemistry; Padwa, A., Ed.; Marcel
Dekker: New York, 1981; Vol. 5, pp 1−122.
(18) (a) Herre, W.; Weis, P. Spectrochim. Acta, Part A 1973, 29, 203−
205. (b) Kemp, D. R.; Porter, G. Proc. R. Soc. London, Ser. A 1971, 326,
117−130.
(19) Ogino, K.; Minami, T.; Kozuka, S.; Kinoshita, T. J. Org. Chem.
1980, 45, 4694−4698.
REFERENCES
■
(1) For reviews, see: (a) Bach, T.; Hehn, J. P. Angew. Chem., Int. Ed.
2011, 50, 1000−1045. (b) Hoffmann, N. Chem. Rev. 2008, 108, 1052−
1103. (c) Griesbeck, A. G.; Hoffmann, N.; Warzecha, K.-D. Acc. Chem.
Res. 2007, 40, 128−140. (d) Hoffmann, N. Pure Appl. Chem. 2007, 79,
1949−1958. (e) Yucel, B.; Valentic, N.; Noltemeyer, M.; de Meijere,
A. Eur. J. Org. Chem. 2007, 4801−4090. (f) Winkler, J. D.; Bowen, C.
M.; Liotta, F. Chem. Rev. 1995, 95, 2003−2020. (g) Muller, F.; Mattay,
̈
J. Chem. Rev. 1993, 93, 99−117.
(2) (a) Thibodeaux, C. J.; Chang, W.-C.; Liu, H.-W. Chem. Rev. 2012,
112, 1681−1709. (b) Brackmann, F.; de Meijere, A. Chem. Rev. 2007,
107, 4493−4537.
(3) (a) Chen, D. Y.-K.; Pouwer, R. H.; Richard, J.-A. Chem. Soc. Rev.
2012, 41, 4631−4642. (b) Donaldson, W. A. Tetrahedron 2001, 57,
8589−8627. (c) Carson, C. A.; Kerr, M. A. Chem. Soc. Rev. 2009, 38,
3051−3060. (d) Rubin, M.; Rubina, M.; Gevorgyan, V. Chem. Rev.
2007, 107, 3117−3179.
(4) (a) Brandi, A.; Cicchi, S.; Cordero, F. M.; Goti, A. Chem. Rev.
2003, 103, 1213−1269. (b) Shi, M.; Shao, L.-X.; Lu, J.-M.; Wei, Y.;
Mizuno, K.; Maeda, H. Chem. Rev. 2010, 110, 5883−5913.
(5) (a) Ciufolini, M. A.; Rivera-Fortin, M. A.; Zuzukin, V.; Whitmire,
K. H. J. Am. Chem. Soc. 1994, 116, 1272−1277. (b) Ciufolini, M. A.;
Rivera-Fortin, M. A.; Byrne, N. E. Tetrahedron Lett. 1993, 34, 3505−
3508.
(6) For reviews, see: (a) de Meijere, A.; Schill, H.; Kozhushkov, S. I.;
Walsh, R.; Muller, E. M.; Grubmuller, H. Russ. Chem. Bull. 2004, 53,
̈
̈
947−959. (b) de Meijere, A.; von Seebach, M.; Zollner, S.;
̈
Kozhushkov, S. I.; Belov, V. N.; Boese, R.; Haumann, T.; Benet-
Buchholz, J.; Yufit, D. S.; Howard, J. A. K. Chem.Eur. J. 2001, 7,
4021−4034. (c) de Meijere, A.; Kozhushkov, S. I. Eur. J. Org. Chem.
2000, 3809−3822. (d) de Meijere, A.; Kozhushkov, S. I.; Spath, T.;
̈
von Seebach, M.; Lohr, S.; Nuske, H.; Pohlmann, T.; Es-Sayed, M.;
̈
̈
Brase, S. Pure Appl. Chem. 2000, 72, 1745−1756.
̈
(7) (a) Traetteberg, M.; Simon, A.; Peters, E. M.; de Merjere, A. J.
Mol. Struct. 1984, 118, 333−343. (b) Boese, R.; Haumann, T.; Jemmis,
E. D.; Kiran, B.; Kozhushkov, S. I.; de Meijere, A. Liebigs Ann. 1996,
913−919. (c) Eckert-Maksic,
P. N. J. Phys. Chem. 1987, 91, 2786−2790.
́ ́
M.; Maksic, Z. B.; Skancke, A.; Skancke,
(20) (a) Marshall, J. A.; Brady, S. F.; Andersen, N. H. Fortschr. Chem.
Org. Naturst. 1974, 31, 283−376. (b) Daniel, M.; Purkayastha, R. P. In
Handbook of Phetoalexin Metablism and Action; Marcel Dekker: New
York, 1995. (c) Afzal, M.; Al Oriquat, G. Heterocycles 1986, 24, 2943−
2961.
(8) (a) Hofland, A.; de Boer, T. J. Recl. Trav. Chim. Pays-Bas 1987,
106, 558−562. (b) Gleiter, R.; Haider, R.; Conia, J. M.; Barnier, J. P.;
de Meijere, A.; Weber, W. J. Chem. Soc., Chem. Commun. 1979, 130−
132. (c) Gleiter, R.; Spanget-Larson, J. In Advances in Strain in Organic
Chemistry; Halton, B., Ed.; JAI Press, Ltd.: London, 1992; Vol. 2, pp
143−189.
(21) (a) Iwata, C.; Miyashita, K.; Imao, T.; Masuda, K.; Kondo, N.;
Uchida, S. Chem. Pharm. Bull. 1985, 33, 853−855. (b) Fivush, A. M.;
Strunk, S. R. Synth. Commun. 1996, 26, 1623−1627. (c) Swenton, J. S.;
Callinan, A.; Wang, S. P. J. Org. Chem. 1992, 57, 78−85. (d) Swenton,
J. S.; Bradin, D.; Gates, B. D. J. Org. Chem. 1991, 56, 6156−6163.
(e) Iwata, C.; Yamada, M.; Ida, Y.; Imao, T.; Miyagawa, H.; Miyashita,
K. Chem. Pharm. Bull. 1988, 36, 2864−2871. (f) Iwata, C.; Yamada,
M.; Shinoo, Y.; Kobayashi, K.; Okada, H. Chem. Pharm. Bull. 1980, 28,
1932−1934. (g) Iwata, C.; Yamada, M.; Shinoo, Y.; Kobayashi, K.;
Okada, H. J. Chem. Soc., Chem. Commun. 1977, 888−889.
(22) (a) Otsuki, T. Bull. Chem. Soc. Jpn. 1976, 2596−2605.
(b) Bryce-Smith, D.; Evans, E. H.; Gilbert, A.; McNeill, H. S. J.
Chem. Soc., Perkin Trans. 1 1992, 485−489.
(23) (a) Ochiai, M.; Arimoto, M.; Fujita, E. J. Chem. Soc. Chem.
Commun. 1981, 460−461. (b) Liu, H.-J.; Chan, W. H. Can. J. Chem.
1980, 58, 2196−2198. (c) Maruyama, K.; Tai, S. Chem. Lett. 1985,
681−684. (d) Maruyama, K.; Narita, N. Bull. Chem. Soc. Jpn. 1980, 53,
757−763.
(24) Naito, T.; Makita, Y.; Yazaki, S.; Kaneko, C. Chem. Pharm. Bull.
1986, 34, 1505−1517.
(9) For recent examples, see: (a) Cordero, F. M.; Salvati, M.;
Vurchio, C.; de Meijere, A.; Brandi, A. J. Org. Chem. 2009, 74, 4225−
4231. (b) Zanobini, A.; Brandi, A.; de Meijere, A. Eur. J. Org. Chem.
2006, 1251−1255. (c) Zhao, L.-G.; de Meijere, A. Adv. Synth. Catal.
2006, 348, 2484−2492. (d) Molchanov, A. P.; Diev, V. V.; Magull, J.;
́
Vidovic, D.; Kozhushkov, S. I.; de Meijere, A.; Kostikov, R. R. Eur. J.
Org. Chem. 2005, 593−599. (e) Schelper, M.; de Meijere, A. Eur. J.
Org. Chem. 2005, 582−592. (f) Yucel, B.; Arve, L.; de Meijere, A.
̈
Tetrahedron 2005, 61, 11355−11373. (g) Hoyte, S. A.; Spencer, J. L.
Organometallics 2011, 30, 5415−5423. (h) Kozhushkov, S. I.; Yufit, D.
S.; Ackermann, L. Org. Lett. 2008, 10, 3409−3412.
(10) (a) Wu, D.-D.; Wang, L.; Xu, K.; Song, J.; Fun, H.-K.; Xu, J.-H.;
Zhang, Y. Chem. Commun. 2012, 48, 1168−1170. (b) Wu, D.-D.; He,
M.-T.; Liu, Q.-D.; Wang, W.; Zhou, J.; Wang, L.; Fun, H.-K.; Xu, J.-H.;
Zhang, Y. Org. Biomol. Chem. 2012, 10, 3626−3635. (c) Wu, D.-D.;
Huang, C.-M.; Wu, Y.-H.; H.-, K.; Xu, J.-H.; Zhang, Y. RSC Adv. 2013,
3, 7529−7536. (d) Huang, C.-M.; Zheng, M.-M.; Xu, J.-H.; Zhang, Y.
Molecules 2013, 18, 2942−2966.
K
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The Journal of Organic Chemistry
Article
(25) (a) Burger, U.; Lottaz, P.-A.; Millasson, P.; Bernardinelli, G.
Helv. Chim. Acta 1994, 77, 850−858. (b) Maruyama, K.; Imahori, H. J.
Chem. Soc., Perkin Trans. 2 1990, 257−265.
(26) Li, X. M.; Wang, L.; Xu, J. H.; Zhang, S. S.; Fun, H.-K. Acta
Crystallogr., Sect. E: Struct. Rep. Online 2003, E59, o1742−ol744.
(27) (a) Kuboyama, A. Bull. Chem. Soc. Jpn. 1960, 33, 1027−1030.
(b) Stevenson, P. E. J. Mol. Spectrosc. 1965, 17, 58−85.
(28) Yoshihara, T.; Yamaji, M.; Itoh, T.; Nishimura, J.; Shizuka, H.;
Tobita, S. J. Photochem. Photobiol., A 2001, 140, 7−13.
(29) (a) Lamola, A. A.; Hammond, G. S. J. Chem. Phys. 1965, 43,
2129−2135. (b) Zander, M. Ber. Bunsen-Ges. 1967, 71, 424−429.
(30) (a) Griesbeck, A. G.; Abe, M.; Bondock, S. Acc. Chem. Res. 2004,
37, 919−928. (b) Griesbeck, A. G.; Mauder, H.; Stadtmuller, S. Acc.
̈
Chem. Res. 1994, 27, 70−75.
L
dx.doi.org/10.1021/jo4008767 | J. Org. Chem. XXXX, XXX, XXX−XXX