Preparation of polycyclic compounds by intramolecular photospirocyclization and photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives

Article abstract of DOI:10.1016/j.jphotochem.2016.01.005

Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4?+?2] cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.0^1,4]undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-linked cyanonaphthalenes. The observation demonstrates that π–π arene ring interactions, steric hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.

Full text of DOI:10.1016/j.jphotochem.2016.01.005

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Contents lists available at ScienceDirect
Journal of Photochemistry and Photobiology A:
Chemistry
journal homepage: www.elsevier.com/locate/jphotochem
Preparation of polycyclic compounds by intramolecular
photospirocyclization and photocycloaddition reactions of 4-alkenyl
-1-cyanonaphthalene derivatives
*
**
Hajime Maeda , Hidenori Wada, Hirofumi Mukae, Kazuhiko Mizuno
Department of Applied Chemistry, Graduate School of Engineering, Osaka Prefecture University, 1-1 Gakuen-cho, Naka-ku, Sakai, Osaka 599-8531, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Photoreactions of 4-pentenyl-1-cyanonaphthalenes yield spirocyclic products along with [4 + 2]
cycloadducts. Photoreactions of 5-phenyl derivatives produce a product having tricyclo[6.3.0.01,4
]
Received 1 October 2015
Received in revised form 6 January 2016
Accepted 7 January 2016
Available online xxx
undecadiene skeleton. Formation of angular triquinanes takes place in photoreactions of cycloalkene-
linked cyanonaphthalenes. The observation demonstrates that arene ring interactions, steric
p–p
hindrance, and suitable locations of reaction sites in syn and anti singlet exciplexes govern the modes
followed in intramolecular photoreactions of 4-alkenyl-1-cyanonaphthalenes.
ã 2016 Elsevier B.V. All rights reserved.
This paper is dedicated to Prof. Yoshihisa
Inoue for his retirement of Osaka Univer-
sity.
Keywords:
Photoreaction
Spirocyclization
Photocycloaddition
1-Cyano-4-alkenylnaphthalene
Angular triquinane
1. Introduction
synthesis of polycyclic compounds, such as spiro[4.5]decadienes,
tricyclo[6.3.0.01,4]undecadienes and angular triquinanes. The
Photocycloaddition reactions between alkenes and arenes serve
as useful methods for the preparation of polycyclic compounds
[1–7]. Although [3 + 2] photocycloaddition reactions of benzene
results of this effort are described below.
derivatives with alkenes is
a common reaction type, the
corresponding reactions of naphthalenes have been much less
explored [8–16]. In one study of these processes, we uncovered a
high yielding, one-pot method for the synthesis of benzotriquinane
derivatives that utilizes intramolecular [3 + 2] photocycloaddition
reactions of 2-alkenyl-1-cyanonaphthalenes [17,18]. The results of
this effort showed that intramolecular photocycloadditions have a
high potential for use as a general method for the preparation of
polycyclic compounds. In continuing studies in this area, we
demonstrated that intramolecular photoreactions of 4-alkenyl-1-
cyanonaphthalenes can be employed as methods for efficient
* Corresponding author. Present address: Division of Material Chemistry,
Graduate School of Natural Science and Technology, Kanazawa University,
Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan. Fax: +81 76 234 4800.
** Corresponding author. Present address: Graduate School of Materials Science,
Nara Institute of Science and Technology (NAIST), 8916-5, Takayama-cho, Ikoma,
Nara 630-0192, Japan. Fax: +81 76 234 4800.
Scheme 1. Photoreaction of 1a-b.
E-mail address: maeda-h@se.kanazawa-u.ac.jp (H. Maeda).
http://dx.doi.org/10.1016/j.jphotochem.2016.01.005
1010-6030/ã 2016 Elsevier B.V. All rights reserved.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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Table 1
Product ratio on photoreaction of 1a-b.
Substrate
Z
Irradiation time (h)
Product ratioa (isolated yields (%))
Conversion (%)
syn-2
anti-2
3
4
1a
1b
O
4
1
50 (43)
50
25
25
25
25 (24)
0
0
100
100
C(CN)2
Conditions: irradiated with a high pressure mercury lamp ([1a] = 30 mM, [1b] = 3 mM) and then treated with aq. CH3CN for 12 h.
a
Determined by 1H NMR.
Scheme 2. Experiments to investigate the mechanism.
were irradiated using a 300 W high pressure mercury lamp for 4
(1a) and 1 h (1b) (Scheme 1). The photolysates were diluted with
aqueous acetonitrile (CH3CN:H2O = 9:1) and let stand for 12 h. The
products generated in these reaction sequences were analyzed by
using 1H NMR and separated by using column chromatography on
silica gel followed by recycling preparative HPLC. The results show
that photoreactions of 1a-b produce syn- and anti-spiro[4.5]
decadienes 2a-b, and [4 + 2] cycloadducts 3a-b in ca. 2:1:1 ratios
(Table 1). The main product, syn-2a, formed by irradiation of 1a
was isolated in 43% yield and demonstrated by using X-ray
crystallographic analysis (Fig. 1) to have the assigned structure and
a stereochemistry in which the isopropenyl group is located in the
syn direction relative to the benzene ring. 1H NMR analysis of the
photolysates was utilized to show that syn- and anti-5a-b are the
Fig. 1. ORTEP drawing of syn-2a.
2. Results and discussion
2.1. Spirocyclization reactions
Dry acetonitrile solutions containing 1-cyanonaphthalene
derivatives 1a-b, containing 4-pentenyl and 2-oxa-4-pentenyl
groups at C-4 of the naphthalene ring, in Pyrex vessels (>280 nm)
Scheme 3. Isomerization from 5a-b to 2a-b.
Fig. 2. Time dependency in the photoreaction of 1b in dry CH3CN, determined by
1H NMR.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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Table 2
Effect of additives on the isomerization from 5b to 2b.
Additive
Time (h)
Conversion (%)
None
12
12
12
2
0
0
100
100
100
CH3COOH (5%)
H2O (10%)
Et3N (5%)
Pyridine (5%)
2
Scheme 4. Proposed mechanism for spirocyclization of 1.
Scheme 6. Photoreactions of 7a-b.
initially formed photoproducts and that these substances are
transformed to the corresponding syn- and anti-2a-b regioisomers
upon treatment with aqueous acetonitrile.
followed in formation of the spirocyclic products (Scheme 2).
Photoreactions of 1a-d6 and 1b-d6 in which the terminal methyl
groups in each are fully deuteriated, in dry CH3CN gave 5a-d6 and
The time dependence of the yields of products generated in the
photoreaction of 1b in dry acetonitrile were monitored by using
1H NMR spectroscopy. The results (Fig. 2) show that [2 + 2]
photocycloadduct 4b is produced at the initial stage of the
photoreaction and that this substance disappears upon prolonged
photoirradiation. Moreover, in concert with the disappearance of
4b the amounts of syn-5b,anti-5b and 3b in a ratio of 2:1:1 increase
with increasing irradiation time. The results of monitoring the
photoreaction of 1b in benzene showed that the same trends in
product formation and disappearance take place.
5b-d6 in which the carbon
a to the CN group in each is 100% mono-
deuteriated, respectively. Photoreactions of an equimolar mixture
of 1a and 1a-d6 produced 5a and 5a-d6 and none of the crossover
products 5a-d1 and 5a-d5. These results show that hydrogen
(perhaps proton) transfer from the methyl group in 1a to the
carbon
zwitterion intermediate 6a). Photoreactions of 1a-b in 9:1CH3CN:
D2O produced 5a-d1 and 5b-d1 in which the carbon to the CN
a to CN group occurs intramolecularly (perhaps via of
a
group in each is 100% mono-deuteriated. This result suggests that
D2O can mediate what must be an intramolecular proton transfer
process.
Several experiments using deuterium labeled substrates and
solvents were carried out to investigate the mechanistic pathways
In another experiment, the photolysates, containing 5a-b,
produced by photoreactions of 1a-b in dry CH3CN were treated
with D2O (10% vs CH3CN) (Scheme 3) and let stand for 12 h.
Analysis of the product mixtures showed that 2a-d1 and 2b-d1
having deuterium at the allylic positions, are generated in this
process. In order to clarify the role played by water, the effect of
additives on the isomerization reaction of 5b to form 2b was
studied (Table 2). The results show that the isomerization did not
occur when acetic acid (5%) was added and that addition of Et3N
(5%) or pyridine (5%) promotes the isomerization reaction. These
findings indicate that water acts as a base to abstract a-protons in
the isomerization reactions of 5a-b to form the more stable 2a-b.
The results described above enable formulation of the possible
mechanism for spirocyclization reactions of 1a-b shown in
Scheme 4. In the first step of this route, both syn 1(syn-1)* and
anti 1(anti-1)* singlet exciplexes are generated between the singlet
excited state of the cyanonaphthalene chromophore serving as an
electron acceptor and the side chain alkene group serving as an
electron donor. 1(Anti-1)* can serve as a precursor for the
Scheme 5. Formation of spiro compounds in photoreaction of 1c.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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cyclohexylidene group in the zwitterionic intermediate 6c, which
prevents formation of the [4 + 2] cycloadduct 3.
2.2. Formation of tricyclo[6.3.0.01,4]undecadienes
Photoreaction of Z-7a, possessing a phenyl group at the
terminal position of the alkene moiety, in CH3CN for 48 h gave
oligomeric products as a result of the presence of the styrene
moiety (Scheme 6). The sole isolable monomeric product (10%)
produced in this process was a single stereoisomer of the tricyclo
[6.3.0.01,4]undecadiene 8. The structure and stereochemistry of 8
were assigned using X-ray crystallographic analysis (Fig. 3).
Interestingly, photoreaction of E-7a led to production of 8 in 9%
yield. This observation suggests that E/Z isomerization takes place
under the photoreaction conditions to generate a mixture of Z-7a
and E-7a. Indeed, individual benzophenone triplet sensitized [19]
photoreactions of Z-7a and E-7a for 6 h were found to promote E/Z
photoisomerization to give in each case a 24:76 mixture of Z-7a
and E-7a. Finally, the diphenyl derivative 7b was observed to be
unreactive even when irradiated for long time periods.
Fig. 3. ORTEP drawing of 8.
The mechanism proposed for photoreactions of E-7a and Z-7a is
shown in Scheme 7. In the route, photoexcitation of both E-7a and
Z-7a leads to formation of the syn and anti singlet exciplexes 1(syn-
E-7a)*, 1(anti-E-7a)*, 1(anti-Z-7a)* and 1(syn-Z-7a)*. The struc-
ture of 8 suggests that among the four possible exciplexes 1(syn-Z-
reversibly formed [2 + 2] photocycloadduct 4. Spirocyclization
reactions of both 1(syn-1)* and 1(anti-1)* generate syn and anti
zwitterionic intermediates 6, which can undergo CꢀꢀC bond
formation to produce [4 + 2] cycloadducts 3. Alternatively,
intramolecular proton transfer in 6 forms the primary photo-
products 5 which undergo base promoted isomerization to give the
final spirocyclic products 2.
7a)*, in which
p–p interactions occur between the phenyl group
and naphthalene ring, is the likely intermediate involved in
formation of [2 + 2] cycloadduct 9, which is the primary
With the aim of increasing the selectivity of photoproduct
formation, photoreaction of the cyclohexylidene derivative 1c was
performed (Scheme 5). The reaction was found to generate the
spirocyclic product 2c exclusively in a 91% yield and a 83:17 syn:
anti ratio. The increase of chemoselectivity seen in this process
might be consequence of steric hindrance provided by the
photoproduct. Thermally induced disrotatory, 6
ring opening of 9 then gives 10, which undergoes secondary
photochemical, disrotatory 4 ring closure to form 8. A possible
p electrocyclic
p
reasonwhy the diphenyl derivative 7b does not follow this reaction
pathway may be steric hindrance which blocks operation of the
Scheme 7. Proposed mechanism for the formation of tricyclo[6.3.0.01,4]undecadiene 8.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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5
Scheme 8. Photoreaction of 11a-b.
initial [2 + 2] photocycloaddition step, only photoinduced cis–trans
isomerization may take place.
2.3. Formation of angular triquinanes
It was anticipated that photoreactions of cycloalkene linked
cyanonaphthalenes would produce angular triquinanes, whose
basic skeleton is found in natural products contained in plants
[20,21]. Indeed, irradiation of acetonitrile solutions of cyanonaph-
thalenes 11a-b produced triquinanes 12a and 12b as single
stereoisomers in 71% and 69% respective isolated yields (Scheme 8).
The structure and stereochemistry of these substances were
assigned by using X-ray crystallographic analysis (Fig. 4). Impor-
tantly, spirocyclic and tricyclo[6.3.0.01,4]undecadiene products are
not produced in these processes.
Scheme 9. Proposed mechanism for the formation of angular triquinanes 12.
A likely mechanism for the high yielding formation of the
angular triquinanes is shown in Scheme 9. The singlet excited state
of 11 can form both syn and anti exciplexes, 1(syn-11)* and 1(anti-
11)*. The former exciplex is unable to undergo spirocyclization or
[2 + 2] photocycloaddition because of steric hinderance or some
structural reason. In contrast, the anti-type exciplexes 1(anti-11)*
can adopt a conformation that can undergo intramolecular [3 + 2]
photocycloaddition at the 2,4-positions of the naphthalene ring to
give the tertially benzylic a-CN containing biradical 13. It should be
noted that the orientation of the cycloalkene ring in 1(anti-11)* is
favorable for the biradical forming cycloaddition process. The
intramolecular bonding between the radical centers in biradical 13
then forms the angular triquinane 12.
Fig. 5. UV–vis absorption spectra of substrates in this study and 1-cyano-4-
methylnaphthalene (14) in aerated CH2Cl2 (1.0 ꢁ10ꢀ4 M).
to have absorption bands in the range of 260–360nm attributable to
2.4. Discussion
p–p* transitions of 1-cyanonaphthalene chromophore and absorp-
tion maxima at 301–305 nm (
e
= 8.2 ꢁ103–9.8 ꢁ 103 molꢀ1 dm3
cmꢀ1). These observations show that by using >280 nm light the
1-cyanonaphthalene moiety is excited exclusively. Fluorescence
Inspection of the UV–vis absorption spectra of the alkene linked
cyanonaphthalenes in CH2Cl2 (1 ꢁ10ꢀ4 M) (Figs. 5 and 6) were found
Fig. 4. ORTEP drawings of (a) 12a and (b) 12b.
Scheme 10. Photoreaction of 1-cyano-2-alkenylnaphthalene (Ref. [17]).
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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maximum and weak exciplex emission was also observed for 11a
at a longer wavelength (380–500 nm).
The results of many studies show that photocycloaddition
reactions of arenes with alkenes are synthetically useful processes
[1–7]. Moreover, it has been found that photoreactions of benzenes
with alkenes proceed mainly by [2 + 2](ortho) and [3 + 2](meta)
cycloaddition pathways, and to a lesser extent by [4 + 2](para)
cycloaddition modes. In photoreactions of naphthalenes with
alkenes, [2 + 2] cycloaddition at the 1,2-positions of the naphtha-
lene ring is the most common process taking place [22–53].
However, [2 + 2] cycloaddition at the 1,8a-positions [54–56], [3 + 2]
cycloaddition at the 1,3-positions [8–11] [3 + 2] cycloaddition at the
1,8-positions [12–16] and [4 + 2] [57–62] photocycloadditions
rarely occur.
McCullough et al. reported that intramolecular photoreactions
of 1-cyano-2-oxaalkenylnaphthalenes give 1,2-[2 + 2] photocy-
cloadducts [63,64]. In addition, in an earlier effort, we investigated
intramolecular photoreactions of the related compounds shown in
Scheme 10 [17]. In that study, we observed that photocycloadduct
17 forms exclusively in the initial stage of the photoreaction of 15,
but that the linear triquinane 16 is the main product (74% yield)
when irradiation is conducted for a prolonged time period (10 h).
This finding was explained by taking into account that 17 can be
reversibly photocleaved to form 15 while 16 is unreactive because
it does not absorb light at wavelengths >280 nm. Of the two
possible singlet exciplexes, 1(chair-15)* and 1(boat-15)*, formed in
the initial chemical step of this process, 1(chair-15)* appears to be
more thermodynamically favorable. A driving force for this
uncommon [3 + 2] photocycloaddition process is the extra
Fig. 6. Fluorescence spectra of substrates in this study and 1-cyano-4-methyl-
naphthalene (14) in aerated CH2Cl2 (excited at absorption maxima, fluorescence
intensity was adjusted to the absorbance at absorption maxima).
spectra of these substances (ca. 1 ꢁ10ꢀ4 M in aerated CH2Cl2)
contain maxima associated with monomer emission from the
1-cyanonaphthalene fluorophore that is partially quenched by the
internal alkene moiety. The fluorescence efficiencies were found to
decrease in the order of 1-cyano-4-methylnaphthalene
(14) > 11a > 1c > 11b > 1b > Z-7a > 7b > E-7a, phenomena again asso-
ciated with increasing intramolecular fluorescence quenching.
Typical exciplex emission was observed for 11b at 400 nm
Scheme 11. Summary of photoreaction pathways.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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7
stabilization of 18 provided by the presence of tertiary benzylic
-CN radical center. It is important to note that the linear
intramolecular [3 + 2] photocycloaddition. Finally, it is possible
to conclude that p–p arene ring interactions, steric hindrance, and
a
triquinane skeleton is also found in naturally occurring substances
[65,66]. In an additional investigation, McCullough found that
photoreactions of 1-cyano-4-alkenylnaphthalenes form intramo-
lecular [2 + 2] photocycloadducts at the 3,4-positions of the
naphthalene ring along with unidentified minor products [63,64].
The three types of photoreactions uncovered in this study are
summarized in Scheme 11. In these processes, both syn-type and
anti-type singlet exciplexes are likely formed from naphthalene
ring centered singlet excited states. Because each face of alkene
group can be oriented closer to naphthalene ring in these
exciplexes, these complexes have diastereomeric relationships.
When R1 and R2 in the alkene chain are cyclic and R3 = H, [3 + 2]
photocycloaddition reaction of the anti-exciplex to give biradicals
13 is energetically preferred because of steric reasons. Intramo-
lecular biradical coupling then affords the angular triquinane 12.
On the other hand, when R2 and R3 are part of acyclic alkyl groups,
both syn and anti-type exciplexes have similar energies. In these
cases the reaction follows a stepwise route producing zwitterionic
intermediates 6. Intramolecular proton transfer in 6 followed by
isomerization gives the spirocyclic product 2. When R2 or R3 is a
phenyl group, syn-type exciplexes are preferentially produced
suitable locations of reaction sites in syn and anti singlet exciplexes
govern the modes followed in intramolecular photoreactions of 4-
alkenyl-1-cyanonaphthalenes.
4. Experimental
4.1. Materials and equipment
Acetonitrile was distilled from CaH2 and then from P2O5.
Benzene was distilled from CaH2 and then from Na.1H and 13C NMR
spectra were recorded using a Varian MERCURY-300 (300 MHz and
75 MHz, respectively) spectrometer with Me4Si as an internal
standard. IR spectra were determined using
a Jasco FT/IR-
230 spectrometer. UV–vis spectra were recorded using a Jasco
V-530 spectrophotometer. Fluorescence spectra were recorded
using a Jasco FP-770 spectrophotometer. Mass spectra (EI) were
taken on a SHIMADZU GCMS-QP5050 operating in the electron
impact mode (70 eV) equipped with GC-17A and DB-5MS column
(J&W Scientific Inc., Serial: 8696181). HPLC separations were
performed on a recycling preparative HPLC equipped with Jasco
PU-2086 Plus, RI-2031 Plus differential refractometer, Megapak
GEL 201C columns (GPC) using CHCl3 as an eluent. Column
chromatography was conducted by using Kanto-Chemical Co., Ltd.,
silica gel 60 N (spherical, neutral, 0.063–0.200 mm). X-ray crystal-
lographic data for a single crystals were obtained using a Rigaku
RAXIS RAPID imaging plate area detector with graphite mono-
because of the intervention of stabilizing
p–p interactions
between the phenyl and naphthyl ring. In this case, intramolecular
[2 + 2] photocycloaddition reaction takes place to yield 9. Ring
cleavage of 9 followed by photochemical disrotatory ring closure
then produces the tricyclo[6.3.0.01,4]undecadiene derivative 8.
Non-exciplex mechanism such as photoinduced electron-
chromated Mo-Ka radiation. The structure was solved by direct
transfer (PET) [67–70] seems unlikely because
D
G for PET process
methods (SIR92) and expanded by using Fourier techniques. All
calculations were performed using the Crystal Structure crystallo-
graphic software package.
calculated by Rehm–Weller equation (
D
G = EOx(D) ꢀ Ered(A) ꢀ E0–
0 ꢀ e2/
er) [71] is positive in the photoreaction of trisubstituted
aliphatic alkenes or cycloalkenes (Ered (1-cyanonaphthalene) =
ꢀ2.33 V vs Ag/Ag+ [67], EOx (2-methyl-2-butene) = 1.47 V vs Ag/Ag+
[72], EOx (cyclopentene) = 2.19 V vs SCE [73], EOx (cyclohexene) =
2.31 V vs SCE [68], E0–0 (1-cyanonaphthalene) = 89.4 kcal/mol
[67]). However, oxidation potentials of phenyl-substituted alkenes
4.2. General procedure for photoreaction
A dry acetonitrile solution containing substrate (10–30 mM)
was placed in a cylindrical Pyrex vessel (f= 8 mm). The solution
are lower (EOx
diphenylethylene) = 1.22 V vs SCE [73]) and calculated
(
a
-methylstyrene) = 1.86 V vs SCE [74], EOx (1,1-
G becomes
was degassed by argon bubbling for 15 min and then the vessel was
sealed. The solution was irradiated by using a 300 W high pressure
mercury lamp (Eikosha, PIH-300) at room temperature. The
temperature of the solution was kept around room temperature
by circulated cooling water during irradiation.
D
negative, therefore PET mechanism in the photoreaction of 7a-b
may be partially involved, but it might not be a major pathway in
photoreaction in nonpolar solvent such as benzene.
3. Conclusion
4.3. Preparation of 1a
Photoirradiation of acetonitrile solutions containing dimethyl-
substituted alkene linked naphthalenes 1 followed by treatment of
the photolysate with aqueous CH3CN gives rise to formation of
spiro[4.5]decadiene derivatives 2 in 75% yield and a syn:anti
diastereomer ratio of 67:33. The results of experiments using a D2O
containing solvent and a per-deuteriated substrate demonstrate
A mixture of 1-methylnaphthalene (8.00 g, 56.3 mmol), Fe
powder (cat), I2 (cat), CCl4 (25 mL) was stirred and cooled to 0 ꢂC.
CCl4 (5 mL) solution of Br2 (9.01 g, 2.91 mL, 56.3 mmol) was slowly
added and stirred for 2 h. The organic phase was shaken with sat.
Na2S2O3 aq, 10% NaOH aq, and sat. NaCl aq. The organic layer was
dried over Na2SO4, filtered, and concentrated in vacuo. The
product, 1-bromo-4-methylnaphthalene (11.8 g, 53.2 mmol, 94%
yield) was used without purification. A mixture of 1-bromo-4-
methylnaphthalene (11.8 g, 53.2 mmol), CuCN (11.8 g, 131.6 mmol),
N-methyl-2-pyrrolidone (70mL) was heated to 200 ꢂC by an oil
bath and stirred for 30 min. After cooling to room temperature,10%
NH3 aq and CHCl3 was added and shaken. The organic layer was
concentrated in vacuo to give brown solid. Separation by column
chromatography on silica gel (eluent; hexane–AcOEt) gave 1-
cyano-4-methylnaphthalene (8.77 g, 52.5 mmol, 99% yield). Color-
that formation of
2 follows a mechanistic route in which
intramolecular proton transfer occurs in a zwitterionic intermedi-
ate. On the other hand, photoreactions of stereoisomeric phenyl-
substituted derivatives Z-7a and E-7a produce the same product,
tricyclo[6.3.0.01,4]undecadiene 8, whose structure was determined
by using X-ray crystallographic methods. Triplet sensitized
photoreactions of Z-7a and E-7a gave a photostationary state
mixture of Z-7a and E-7a in a 24:76 ratio. These results suggest that
[2 + 2] photocycloaddition at the 4,4a-positions of the naphthalene
ring takes place to form 8 through a pathway involving E–Z
less solid; 1H NMR (CDCl3, 300 MHz)
d 2.77 (s, 3H), 7.36–8.27 (m,
photoisomerization, formation of a singlet exciplex that has
p
–
p
6H) ppm. A CCl4 (60 mL) solution of 1-cyano-4-methylnaphthalene
(7.77 g, 46.5 mmol), N-bromosuccinimide (8.28 g, 46.5 mmol),
benzoyl peroxide (cat) was refluxed for 3 h. Solid was removed
by filtration, and solvent was removed in vacuo. The product,
1-cyano-4-(bromomethyl)naphthalene (10.9 g, 44.5 mmol, 96%
overlap between the arene rings, and thermal ring opening
followed by disrotatory ring closure. Cycloalkene linked cyano-
naphthalenes 11a-b undergo photoreactions to generate angular-
triquinanes 12a-b in high yields through a route involving
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

G Model
JPC 10103 No. of Pages 13
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yield) was used without purification. Yellow solid; 1H NMR (CDCl3,
300 MHz) 4.93 (s, 2H), 7.59–8.33 (m, 6H) ppm. To THF (10 mL)
(s, 1H), 6.83 (dd, J = 6.4, 3.0 Hz, 1H), 7.32–7.50 (m, 4H) ppm; 13C
NMR (CDCl3, 75 MHz) 23.5, 30.0, 34.9, 47.7, 56.8, 72.1, 78.4, 114.4,
115.1, 116.8, 125.0, 126.7, 127.7, 129.5, 135.4, 141.0, 141.3 ppm; IR
(KBr) 2222 (C
N) cmꢀ1; GC–MS (EI) m/z (%) = 251 (5, M+), 166
(100, C12H8N). Data for anti-2a: colorless solid; 1H NMR (CDCl3,
300 MHz) 1.72 (s, 3H), 2.47–2.56 (m, 2H), 2.87 (t, J = 6.3 Hz, 1H),
3.86–4.10 (m, 4H), 4.87 (s, 1H), 5.00 (t, J = 1.6 Hz, 1H), 6.85 (t,
J = 4.3 Hz, 1H), 7.30-7.54 (m, 4H) ppm; 13C NMR (CDCl3, 75 MHz)
d
d
solution of NaH (0.780 g,19.5 mmol) was added 3-methyl-2-buten-
1-ol (1.29 g, 15.0 mmol) under argon atmosphere. The solution was
refluxed for 30 min. THF (100 mL) solution of 1-cyano-4-(bromo-
methyl)naphthalene (3.69 g, 15.0 mmol) was added at 0 ꢂC and
stirred for 1 h. Then it was warmed to room temperature, and
stirred for 1 h. Sat. NaCl aq and Et2O were added and shaken. The
organic layer was dried over Na2SO4, filtered, and concentrated in
vacuo. Separation of the brown oil by column chromatography on
silica gel (eluent; hexane–AcOEt) gave 1-cyano-4-(5-methyl-2-
oxa-4-hexenyl)naphthalene (1a, 2.29 g, 9.12 mmol, 61% yield).
n
¼
d
d
23.9, 29.3, 48.1, 54.4, 71.6, 109.3, 114.5, 116.9, 125.3, 125.5, 127.6,
129.8, 138.9, 142.7, 143.8 ppm.
4.6. Photoreaction of 1b
Colorless oil; 1H NMR (CDCl3, 300 MHz)
4.13 (d, J = 6.9 Hz, 2H), 4.98 (s, 2H), 5.44 (m, 1H), 7.62–8.29 (m, 6H)
ppm; 13C NMR (CDCl3, 75 MHz)
18.5, 26.2, 67.4, 69.7, 110.2, 117.9,
d 1.68 (s, 3H), 1.78 (s, 3H),
A dry CH3CN (100 mL) solution of 1b (100.0 mg, 0.333 mmol)
was irradiated for 1 h. H2O (11 mL) was added and left it as it is for
12 h. The mixture contained syn-2b, anti-2b, and 3b. Separation by
column chromatography on silica gel (eluent; hexane:AcOEt = 5:1)
gave syn-2-(prop-1-en-2-yl)-20H-spiro[cyclopentane-1,10-naph-
d
120.5, 124.4, 124.5, 125.8, 127.6, 128.2, 131.0, 132.2, 132.4, 138.0,
140.3 ppm; GC–MS (EI) m/z (%) = 251 (9, M+), 166 (62, C12H8N), 85
(100, C5H9).
thalene]-4,4,40-tricarbonitrile
(syn-2b)
and
4,4-dimethyl-
3,3a,4,5-tetrahydro-5,9b-ethenocyclopenta[a]naphthalene-2,2,5
(1H)-tricarbonitrile (3b, 23.7 mg, 0.079 mmol, 24% yield). Data for
syn-2b: colorless solid; mp 154–156 ꢂC; 1H NMR (CDCl3, 300 MHz)
4.4. Preparation of 1b
To a mixture of THF (10 mL) and NaH (1.00 g, 25.0 mmol) was
added malononitrile (1.50 g, 22.7 mmol) at ꢀ78 ꢂC under argon
atmosphere, and stirred for 10 min. The solution was warmed to
d
1.27 (s, 3H), 2.55–2.87 (m, 6H), 3.17 (d, J = 15.0 Hz,1H), 4.30 (s,1H),
4.80 (s, 1H), 6.80 (dd, J = 5.9, 3.6 Hz, 1H), 7.17–7.54 (m, 4H) ppm; 13
NMR (CDCl3, 75 MHz) 23.4, 31.1, 38.7, 43.2, 48.5, 50.4, 56.8, 115.5,
C
d
room
temperature,
4-bromo-2-methyl-2-butene
(5.07 g,
115.7, 116.1, 116.3, 117.5, 125.9, 128.6, 129.5, 129.8, 135.1, 140.4,
140.8 ppm; GC–MS (EI) m/z (%) = 299 (2, M+), 166 (100, C12H8N).
Data for 3b: colorless solid; mp 153–155 ꢂC; 1H NMR (CDCl3,
34.0 mmol) was slowly added, and stirred for 30 min. Sat. NaCl
aq and Et2O were added and shaken. The organic layer was dried
over Na2SO4, filtered, and concentrated in vacuo. Separation of the
brown oil by column chromatography on silica gel (eluent;
hexane–AcOEt) gave 5,5-dicyano-2-methyl-2-pentene (2.10 g,
300 MHz) d 1.34 (s, 3H),1.39 (s, 3H), 2.11 (dd, J = 3.6,1.8 Hz,1H), 2.50
(dd, J = 11.8, 6.5 Hz, 1H), 2.79 (dd, J = 13.7, 6.3 Hz, 1H), 2.95 (d,
J = 15.4 Hz, 1H), 3.34 (d, J = 15.2 Hz, 1H), 6.24 (d, J = 2.7 Hz, 1H), 6.41
(d, J = 2.7 Hz, 1H), 7.33–7.60 (m, 4H) ppm; 13C NMR (CDCl3, 75 MHz)
15.7 mmol, 69%). Colorless oil; 1H NMR (CDCl3, 300 MHz)
d 1.73
(s, 3H), 1.80 (s, 3H), 2.73 (dd, J = 6.6, 1.3 Hz, 2H), 3.67 (t, J = 6.6 Hz,
1H), 5.22 (t, J = 1.3 Hz, 1H) ppm. To THF (5 mL) solution of NaH
(0.400 g, 10.0 mmol) was added 5,5-dicyano-2-methyl-2-pentene
(0.580 g, 4.33 mmol) at 0 ꢂC under argon atmosphere, and stirred
for 1 h. THF (100 mL) solution of 1-cyano-4-(bromomethyl)
naphthalene (1.16 g, 4.72 mmol) was added at room temperature
and stirred for 1 h. Sat. NaCl aq and Et2O were added and shaken.
The organic layer was dried over Na2SO4, filtered, and concentrated
in vacuo. Separation of the brown oil by column chromatography
on silica gel (eluent; CHCl3) followed by recrystallization from
benzene gave 1-cyano-4-(2,2-dicyano-5-methyl-4-hexenyl)naph-
thalene (1b, 0.760 g, 2.54 mmol, 59% yield). Colorless solid; mp
d
29.7, 30.1, 30.8, 37.2, 41.1, 46.2, 49.4, 51.3, 59.0, 115.4, 117.4, 119.5,
126.5, 127.7, 128.5, 129.4, 129.9, 137.8, 140.7, 142.8 ppm; GC–MS (EI)
m/z (%) = 299 (5, M+), 166 (54, C12H8N).
4.7. Preparation of 1a-d6
A mixture of ethyl bromoacetate (11.3 g, 67.4 mmol) and P(OEt)3
(13.2 g, 79.7 mmol) was refluxed at 150 ꢂC for 3 h. Concentration in
vacuo gave ethyl 2-(diethylphosphoryl) acetate [75] (15.2 g,
67.4 mmol, 99% yield). Data for ethyl 2-(diethylphosphoryl)
acetate: colorless oil; 1H NMR (CDCl3, 300 MHz)
d 1.35 (m, 9H),
2.96 (d, J = 21.6 Hz, 2H), 4.18 (m, 6H) ppm. To a THF (150 mL)
solution of ethyl 2-(diethylphosphoryl) acetate (15.2 g, 67.4 mmol)
was slowly added n-BuLi (1.6 M hexane solution, 60 mL, 96 mmol)
at ꢀ78 ꢂC and stirred for 30 min. Acetone-d6 (15 mL, 200 mmol)
was added at ꢀ50 ꢂC and stirred for 30 min, then stirred at room
temperature for 2 h. Sat. NH4Cl aq and Et2O were added and
shaken. The organic layer was dried over Na2SO4, filtered, and
concentrated in vacuo. Distillation under reduced pressure (bp 69–
71 ꢂC/40 mmHg) gave ethyl 3,3-bis(trideuteriomethyl)-2-prope-
noate (6.69 g, 49.9 mmol, 74% yield). Colorless oil; 1H NMR (CDCl3,
225–226 ꢂC (benzene); 1H NMR (CDCl3, 300 MHz)
1.87 (s, 3H), 2.85 (d, J = 7.3 Hz, 2H), 3.75 (s, 2H), 5.39–5.42 (m, 1H),
7.69–8.36 (m, 6H) ppm; 13C NMR (CDCl3, 75 MHz)
18.9, 26.4, 37.5,
38.5, 39.2, 109.3, 111.8, 114.2, 115.0, 117.3, 124.1, 126.4, 128.1, 128.2,
d 1.75 (s, 3H),
d
128.9, 131.7, 131.8, 132.8, 134.5, 141.6 ppm; IR (KBr)
n
2223 (C N)
¼
cmꢀ1; GC–MS (EI) m/z (%) = 299 (8, M+), 166 (57, C12H8N), 69 (100,
C5H9); Anal. Calcd for C20H17N3 C: 80.24, H: 5.72, N: 14.04. Found C:
80.39, H: 5.65, N: 13.95.
4.5. Photoreaction of 1a
300 MHz) d 1.27 (t, J = 7.1 Hz, 3H), 4.14 (q, J = 7.1 Hz, 2H), 5.67 (s, 1H)
ppm. To THF (40 mL) solution of ethyl 3,3-bis(trideuteriomethyl)-
2-propenoate (3.35 g, 25.0 mmol) was slowly added iBu2AlH (1.0 M
hexane solution, 100 mL, 100 mmol) at ꢀ78 ꢂC, and stirred for
30 min. Then the solution was stirred at room temperature for 1 h.
After cooling to 0 ꢂC, wet Na2SO4 was added and stirred for 1 h. The
precipitated colorless solid was collected, washed with Et2O, and
concentrated in vacuo. Distillation under reduced pressure (bp 76–
77 ꢂC/50 mmHg) gave 3,3-bis(trideuteriomethyl)-2-propen-1-ol
(0.817 g, 8.88 mmol, 36% yield). Colorless oil; 1H NMR (CDCl3,
A dry CH3CN (30 mL) solution of 1a (226 mg, 0.900 mmol) was
irradiated for 4 h. H2O (3 mL) was added and left it as it is for 12 h.
The mixture contained syn-2a, anti-2a, and 3a. Separation by
column chromatography on silica gel (eluent; hexane:AcOEt = 5:1)
gave syn-4-(prop-1-en-2-yl)-4,5-dihydro-2H,20H-spiro[furan-3,10-
naphthalene]-40-carbonitrile (syn-2a, 97.1 mg, 0.387 mmol, 43%
yield) and anti-4-(prop-1-en-2-yl)-4,5-dihydro-2H,2'H-spiro[fu-
ran-3,10-naphthalene]-40-carbonitrile (anti-2a). Data for syn-2a:
colorless solid; mp 94–96 ꢂC; 1H NMR (CDCl3, 300 MHz)
d 1.26 (s,
300 MHz)
d 1.15 (br, 1H), 4.12 (br, 2H), 5.41 (t, J = 7.1, 1H) ppm. To a
3H), 2.55 (dd, J = 18.3, 6.4 Hz, 1H), 2.70 (dd, J = 18.3, 3.0 Hz, 1H), 2.83
(m, 1H), 3.81–4.11 (m, 3H), 4.25 (s, 1H), 4.39 (d, J = 8.7 Hz, 1H), 4.66
mixture of THF (10 mL) and NaH (0.540 g, 13.3 mmol) was added
3,3-bis(trideuteriomethyl)-2-propen-1-ol (0.817 g, 8.88 mmol) at
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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JPC 10103 No. of Pages 13
H. Maeda et al. / Journal of Photochemistry and Photobiology A: Chemistry xxx (2015) xxx–xxx
9
room temperature, and then refluxed for 30 min. THF (70 mL)
solution of 1-cyano-4-(bromomethyl)naphthalene (1.97 g,
washed with Et2O, and concentrated in vacuo. Distillation under
reduced pressure (bp 88–90 ꢂC/7 mmHg) gave (2-hydroxyethyli-
7.99 mmol) was added at 0 ꢂC and stirred for 1 h. Then the solution
was warmed to room temperature and stirred for 2 h. Sat. NaCl aq
and Et2O were added and shaken. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. Separation of the
brown oil by column chromatography on silica gel (eluent;
hexane–AcOEt) gave 1-cyano-4-{5,5-[bis(trideuteriomethyl)]-2-
oxa-4-pentenyl}naphthalene (1a-d6, 0.570 g, 1.87 mmol, 28%
dene) cyclohexane (1.33 g, 10.6 mmol, 42% yield). Colorless oil; 1
H
NMR (CDCl3, 300 MHz) d 0.89–1.61 (m, 7H), 2.11–2.21 (m, 4H), 4.13
(dd, J = 7.0 Hz, 0.4 Hz, 2H), 5.36 (m, 1H) ppm. A mixture of (2-
hydroxyethylidene) cyclohexane (0.750 g, 5.95 mmol) and HBr
(47% aq, 20 mL) was vigorously shaken. Upper layer was separated
to be identified as (2-bromoethylidene)cyclohexane. To a mixture
of THF (5 mL) and NaH (0.286 g, 7.15 mmol) was added malononi-
trile (0.786 g, 11.9 mmol) at 0 ꢂC under argon atmosphere, and
stirred for 1 h. THF (5 mL) solution of the (2-bromoethylidene)
cyclohexane was added at room temperature and stirred for 2 h.
Sat. NaCl aq and Et2O were added and shaken. The organic layer
was dried over Na2SO4, filtered, and concentrated in vacuo.
Separation of the brown oil by column chromatography on silica
gel (eluent; hexane–AcOEt) gave 3,3-dicyanopropylidenecyclo-
hexane (0.410 g, 2.36 mmol, 40% yield). Colorless oil; 1H NMR
yield). Colorless oil; 1H NMR (CDCl3, 300 MHz)
J = 6.9 Hz, 2H), 4.98 (s, 2H), 5.44 (m, 1H), 7.62–8.29 (m, 6H) ppm;
13C NMR (CDCl3, 75 MHz)
18.5, 26.2, 67.4, 69.7, 110.2, 117.9, 120.5,
d 4.13 (d,
d
124.4, 124.5, 125.8, 127.6, 128.2, 131.0, 132.2, 132.4, 138.0,
140.3 ppm; GC–MS (EI) m/z (%) = 257 (7, M+), 166 (62, C12H8N),
91 (98, C5H3D6).
4.8. Preparation of 1b-d6
(CDCl3, 300 MHz)
J = 7.6, 6.8 Hz, 2H), 3.66 (t, J = 6.8 Hz, 2H), 5.15 (m,1H) ppm; 13C NMR
(CDCl3, 75 MHz) 23.82, 26.82, 28.14, 28.64, 29.08, 29.39, 37.45,
d 1.43–1.58 (m, 6H), 2.16–2.19 (m, 4H), 2.74 (dd,
A mixture of 3,3-bis(trideuteriomethyl)-2-propen-1-ol (1.07 g,
11.6 mmol) and HBr (47% aq, 30 mL) was vigorously shaken. Upper
layer was separated to be identified as 1,1-bis(trideuteriomethyl)-
3-bromo-1-propene. To a mixture of THF (10 mL) and NaH (0.510 g,
12.8 mmol) was added malononitrile (3.83 g, 58.0 mmol) at 0 ꢂC
under argon atmosphere, and stirred for 1 h. THF (5 mL) solution of
the 1,1-bis(trideuteriomethyl)-3-bromo-1-propene was added at
room temperature and stirred for 2 h. Sat. NaCl aq and Et2O were
added and shaken. The organic layer was dried over Na2SO4,
filtered, and concentrated in vacuo. Separation of the brown oil by
column chromatography on silica gel (eluent; hexane–AcOEt) gave
d
111.83 (2C), 112.57, 148.39 ppm; GC–MS (EI) m/z (%) = 174 (17, M+),
109 (65, C8H13), 67 (100, C5H7). To a mixture of THF (2 mL) and NaH
(0.123 g, 3.07 mmol) was added 3,3-dicyanopropylidenecyclohex-
ane (0.410 g, 2.36 mmol) under argon atmosphere at room
temperature, and stirred for 1 h. THF (20 mL) solution of 1-
cyano-4-(bromomethyl)naphthalene (0.581 g, 2.36 mmol) was
added and stirred for 2 h. Sat. NaCl aq and Et2O were added and
shaken. The organic layer was dried over Na2SO4, filtered, and
concentrated in vacuo. Separation of the brown oil by column
chromatography on silica gel (eluent; CHCl3) followed by
recrystallization from EtOH gave 1-cyano-4-(2,2-dicyano-4-cyclo-
hexylidenebutyl)naphthalene (1c, 0.304 g, 0.842 mmol, 36% yield).
4,4-dicyano-1,1-bis(trideuteriomethyl)-1-butene
(0.386 g,
2.76 mmol, 24% yield). Colorless oil; 1H NMR (CDCl3, 300 MHz)
d
1.73 (s, 3H), 1.80 (s, 3H), 2.73 (dd, J = 6.6, 1.3 Hz, 2H), 3.67 (t,
J = 6.6 Hz, 1H), 5.22 (t, J = 1.3 Hz, 1H) ppm. To a mixture of THF
(10 mL) and NaH (0.144 g, 3.59 mmol) was added 4,4-dicyano-1,1-
bis(trideuteriomethyl)-1-butene (0.386 g, 2.76 mmol) under argon
atmosphere at room temperature, and stirred for 1 h. THF (30 mL)
solution of 1-cyano-4-(bromomethyl)naphthalene (0.883 g,
3.59 mmol) was added and stirred for 4 h. Sat. NaCl aq and Et2O
were added and shaken. The organic layer was dried over Na2SO4,
filtered, and concentrated in vacuo. Separation of the brown oil by
column chromatography on silica gel (eluent; CHCl3) followed by
recrystallization from benzene gave 1-cyano-4-{2,2-dicyano-5,5-
[bis(trideuteriomethyl)]-4-pentenyl}naphthalene (1b-d6, 0.102 g,
0.333 mmol, 12% yield). Colorless solid; mp 219–221 ꢂC; 1H NMR
Colorless solid; mp 179–181 ꢂC (EtOH); 1H NMR (CDCl3, 300 MHz)
d
1.60 (m, 6H), 2.22–2.24 (m, 4H), 2.87 (d, J = 7.5 Hz, 2H), 3.74 (s, 2H),
5.33 (m, 1H), 7.69–7.79 (m, 3H), 7.96 (d, J = 7.6, 1H), 8.18 (m, 1H),
8.35 (m,1H) ppm; 13C NMR (CDCl3, 75 MHz)
d 26.81, 28.12, 28.71,
29.71, 36.50, 37.71, 38.42, 39.38, 109.31, 110.81 (2C), 111.67, 115.04,
117.37, 124.08, 126.34, 128.86, 131.65, 131.79, 132.77, 134.52,
149.51 ppm; IR(KBr)
n
2222 (C ; GC–MS (EI) m/z
N) cmꢀ1
¼
(%) = 339 (3, M+), 166 (13, C12H8N), 109 (100, C8H13); Anal. Calcd
for C23H21N3 C: 81.38, H: 6.24, N: 12.38. Found C: 80.88, H: 6.27, N:
12.24.
4.10. Photoreaction of 1c
(CDCl3, 300 MHz) d 2.85 (s, 2H), 3.74 (s, 2H), 5.40 (m,1H), 7.68–8.36
(m, 6H) ppm; GC–MS (EI) m/z (%) = 305 (8, M+), 166 (100, C12H8N).
A dry CH3CN (80 mL) solution of 1c (271 mg, 0.800 mmol) was
irradiated for 3 h. H2O (9 mL) was added and left it as it is for 12 h.
The mixture contained syn-2c and anti-2c. Yields and syn/anti
ratio were determined by 1H NMR to be 91% and 83:17,
respectively. Separation by column chromatography on silica gel
(eluent; hexane–AcOEt), recycling preparative HPLC (eluent;
CHCl3), and recrystallization from hexane–MeOH gave syn-2c
(68.8 mg, 0.203 mmol, 25% yield). Colorless solid; mp 134–136 ꢂC;
4.9. Preparation of 1c
To a THF (100 mL) solution of ethyl 2-(diethylphosphoryl)
acetate (8.80 g, 39.1 mmol) was slowly added n-BuLi (1.6 M hexane
solution, 32.0 mL, 51.2 mmol) at ꢀ78 ꢂC under argon atmosphere
and stirred for 30 min. Cyclohexanone (8.0 mL, 77.2 mmol) was
added at ꢀ50 ꢂC and stirred for 30 min, then stirred at room
temperature for 2 h. Sat. NH4Cl aq and Et2O were added and
shaken. The organic layer was dried over Na2SO4, filtered, and
concentrated in vacuo. Distillation under reduced pressure (bp 78–
81 ꢂC/3 mmHg) gave ethyl cyclohexylideneacetate (5.91 g,
1H NMR (CDCl3, 300 MHz)
3.21 (d, J = 15.3 Hz, 1H), 4.80 (m, 1H), 6.78 (dd, J = 6.4, 3.0 Hz, 1H),
7.13–7.54 (m, 4H) ppm; 13C NMR (CDCl3, 75 MHz)
22.0, 23.1, 25.7,
d 1.21–1.82 (m, 8H), 2.48–2.92 (m, 6H),
d
29.5, 30.9, 38.8, 42.6, 48.3, 50.3, 58.0, 115.0, 116.3, 116.5, 117.7,
125.5, 125.9, 127.5, 128.5, 129.6, 129.8, 132.3, 135.3, 140.5 ppm; IR
35.2 mmol, 90% yield). Colorless oil; 1H NMR (CDCl3, 300 MHz)
d
(KBr)
(100, C12H8N).
n
2223 (C
N) cmꢀ1; GC–MS (EI) m/z (%) = 339 (6, M+), 166
¼
1.28 (t, J = 7.2 Hz, 3H), 1.60-1.65 (m, 6H), 2.18 (m, 2H), 2.81 (m, 2H),
4.14 (q, J = 7.1 Hz, 2H), 5.59 (s, 1H) ppm. To THF (100 mL) solution of
ethyl cyclohexylideneacetate (4.20 g, 25.0 mmol) was slowly added
iBu2AlH (1.0 M hexane solution, 100 mL, 100 mmol) at –78 ꢂC,
stirred for 30 min. Then the solution was stirred at room
temperature for 1 h. After cooling to 0 ꢂC, wet Na2SO4 was added
and stirred for 1 h. The precipitated colorless solid was collected,
4.11. Preparation of Z-7a
To THF (80 mL) solution of ethyl acetoacetate (3.95 g,
30.4 mmol) was slowly added (Me3Si)2NLi (1.0 M THF solution,
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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H. Maeda et al. / Journal of Photochemistry and Photobiology A: Chemistry xxx (2015) xxx–xxx
36.5 mL, 36.5 mmol) at –60 ꢂC under argon atmosphere, and stirred
for 2 h. p-Toluenesulfonic anhydride was added and stirred for 12 h.
Sat. NaCl aq and AcOEt were added and shaken. The organic layer
was dried over Na2SO4, filtered, and concentrated in vacuo.
Separation of the brown oil by column chromatography on silica
gel (eluent; hexane–AcOEt) gave ethyl 3-(toluene-4-sulfonyloxy)-
but-2-enoate [76] (8.40 g, 29.6 mmol, 97% yield). Colorless oil; 1H
4.12. Preparation of E-7a
To a THF (100 mL) solution of ethyl 2-(diethylphosphoryl)
acetate (15.8 g, 70.0 mmol) was added n-BuLi (1.6 M hexane
solution, 52.5 mL, 84 mmol) slowly at ꢀ78 ꢂC under argon
atmosphere and stirred for 30 min. Acetophenone (12.3 mL,
105 mmol) was added at ꢀ50 ꢂC and stirred for 30 min, then
stirred at room temperature for 2 h. Sat. NH4Cl aq and Et2O were
added and shaken. The organic layer was dried over Na2SO4,
filtered, and concentrated in vacuo. Distillation under reduced
pressure (bp 131–132 ꢂC/8 mmHg) gave ethyl (E)-3-phenylbut-2-
enoate (8.69 g, 45.7 mmol, 65% yield). Colorless oil; 1H NMR (CDCl3,
NMR (CDCl3, 300 MHz) d 1.20 (t, J = 7.2 Hz, 3H), 2.10 (m, 3H), 2.44 (s,
3H), 4.04 (q, J = 7.2 Hz, 2H), 5.48 (m, 1H), 7.34 (d, J = 8.0 Hz, 2H), 7.89
(d, J = 8.4 Hz, 2H) ppm. To THF (80 mL) solution of 3-(toluene-4-
sulfonyloxy)-but-2-enoate (8.40 g, 29.6 mmol), PhB(OH)2 (5.41 g,
44.4 mmol), and PdCl2(PPh3)2 (1.04 g, 1.48 mmol) was added
Na2CO3 aq (2 M, 45 mL, 90 mmol), and stirred at 60 ꢂC for 15 h.
AcOEt was added, and the organic layer was washed with NaOH aq
and then sat. NaCl aq. The organic layer was dried over Na2SO4,
filtered, and concentrated in vacuo. Distillation under reduced
pressure (bp 121–124 ꢂC/7 mmHg) gave ethyl (Z)-3-phenyl-but-2-
enoate (4.71 g, 24.8 mmol, 84% yield). Colorless oil; 1H NMR (CDCl3,
300 MHz)
d 1.32 (t, J = 7.0 Hz, 3H), 2.58 (d, J = 1.2 Hz, 3H), 4.22 (q,
J = 7.0 Hz, 2H), 6.13 (q, J = 1.3 Hz, 1H), 7.32–7.49 (m, 5H) ppm. To THF
(110 mL) solution of ethyl (E)-3-phenylbut-2-enoate (8.69 g,
45.7 mmol) was slowly added iBu2AlH (1.0 M hexane solution,
110 mL, 110 mmol) at ꢀ78 ꢂC under argon atmosphere, and stirred
for 30 min. Then the solution was stirred at room temperature for
1 h. After cooling to 0 ꢂC, wet Na2SO4 was added and stirred for 1 h.
The precipitated colorless solid was collected, washed with Et2O,
and concentrated in vacuo. The product, (E)-3-phenylbut-2-en-1-
ol (6.70 g, 45.2 mmol, 99% yield) was used without purification.
300 MHz) d 1.08 (t, J = 7.1 Hz, 3H), 2.18 (s, 3H), 4.00 (q, J = 7.1 Hz, 2H),
5.90 (m, 1H), 7.16–7.35 (m, 5H) ppm. To THF (60 mL) solution of
ethyl (Z)-3-phenyl-but-2-enoate (4.71 g, 24.8 mmol) was slowly
i
added Bu2AlH (1.0 M hexane solution, 65 mL, 65 mmol) at ꢀ78 ꢂC
under argon atmosphere, and stirred for 30 min. Then the solution
was stirred at room temperature for 1 h. After cooling to 0 ꢂC, wet
Na2SO4 was added and stirred for 1 h. The precipitated colorless
solid was collected, washed with Et2O, and concentrated in vacuo.
The product, (Z)-3-phenylbut-2-en-1-ol (2.68 g, 18.1 mmol, 73%
yield) was used without purification. Colorless oil; 1H NMR (CDCl3,
Colorless oil; 1H NMR (CDCl3, 300 MHz)
d 1.35 (br, 1H), 2.08 (s, 3H),
4.36 (m, 2H), 6.00 (m,1H), 7.26–7.41 (m, 5H) ppm. A mixture of (E)-
3-phenylbut-2-en-1-ol (6.70 g, 45.2 mmol) and HBr (47% aq,
30 mL) was vigorously shaken. Upper layer was separated to be
identified as (E)-4-bromo-2-phenyl-2-butene. To a mixture of THF
(30 mL) and NaH (2.19 g, 54.8 mmol) was added malononitrile
(6.03 g, 91.4 mmol) at 0 ꢂC under argon atmosphere, and stirred for
1 h. THF (5 mL) solution of the (E)-4-bromo-2-phenyl-2-butene
was added at room temperature and stirred for 2 h. Sat. NaCl aq and
Et2O were added and shaken. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. Separation of the
brown oil by column chromatography on silica gel (eluent;
hexane–AcOEt) gave (E)-5,5-dicyano-2-phenyl-2-pentene (5.62 g,
300 MHz)
d 1.25 (br, 1H), 2.10 (s, 3H), 4.08 (m, 2H), 5.72 (m, 1H),
7.16–7.37 (m, 5H) ppm. A Et2O (20 mL) solution of (Z)-3-phenylbut-
2-en-1-ol (2.68 g,18.1 mmol), PPh3 (4.72 g,18.0 mmol), CBr4 (5.97 g,
18.0 mmol) was stirred at room temperature for 2 h. The
precipitated solid was removed by filtration. The solution was
concentrated in vacuo. The product, (Z)-2-phenyl-4-bromo-2-
butene was used without purification. To a mixture of THF (5 mL)
and NaH (0.869 g, 21.7 mmol) was added malononitrile (2.39 g,
36.2 mmol) at 0 ꢂC under argon atmosphere, and stirred for 1 h. THF
(5 mL) solution of (Z)-2-phenyl-4-bromo-2-butene was added, and
stirred for 2 h. Sat. NaCl aq and Et2O were added and shaken. The
organic layer was dried over Na2SO4, filtered, and concentrated in
vacuo. Separation of the brown oil by column chromatography on
silica gel (eluent; hexane–AcOEt) gave (Z)-5,5-dicyano-2-phenyl-
2-pentene [77] (1.52 g, 7.76 mmol, 43% yield). Colorless oil; 1H NMR
28.7 mmol, 63% yield). Colorless oil; 1H NMR (CDCl3, 300 MHz)
2.16 (m, 3H), 2.97 (m, 2H), 3.80 (t, J = 6.8 Hz, 1H), 5.75 (m, 1H), 7.30-
7.40 (m, 5H) ppm; 13C NMR (CDCl3, 75 MHz)
17.0, 23.3, 30.5,112.4,
d
d
117.9,125.9,127.9,128.4,142.1,142.8 ppm; GC–MS (EI) m/z (%) = 196
(10, M+), 131 (100, C10H11). To THF (10 mL) solution of NaH (0.331 g,
8.27 mmol) was added (E)-5,5-dicyano-2-phenyl-2-pentene
(1.35 g, 6.89 mmol) at room temperature under argon atmosphere,
and stirred for 1 h. THF (30 mL) solution of 1-cyano-4-(bromo-
methyl)naphthalene (1.69 g, 6.89 mmol) was added at room
temperature and stirred for 2 h. Sat. NaCl aq and Et2O were added
and shaken. The organic layer was dried over Na2SO4, filtered, and
concentrated in vacuo. Separation of the brown oil by column
chromatography on silica gel (eluent; CHCl3) followed by
recrystallization from benzene gave (E)-1-cyano-4-(2,2-dicyano-
5-phenyl-4-hexenyl)naphthalene (E-7a, 0.859 g, 2.38 mmol, 35%
yield). Pale yellow solid; mp 178–180 ꢂC; 1H NMR (CDCl3, 300 MHz)
(CDCl3, 300 MHz)
d 2.12 (m, 3H), 2.67 (m, 2H), 3.60 (t, J = 6.8 Hz,1H),
5.53 (m, 1H), 7.30–7.45 (m, 5H) ppm; 13C NMR (CDCl3, 75 MHz)
d
17.0, 23.3, 30.5, 112.4, 117.9, 125.9, 127.9, 128.4, 142.1, 142.8 ppm;
GC–MS (EI) m/z (%) = 196 (10, M+), 131 (100, C10H11). To THF (5 mL)
solution of NaH (0.398 g, 9.95 mmol) was added (Z)-5,5-dicyano-2-
phenyl-2-pentene (1.50 g, 7.65 mmol) at room temperature under
argon atmosphere, and stirred for 1 h. THF (30 mL) solution of 1-
cyano-4-(bromomethyl)naphthalene (1.88 g, 7.65 mmol) was
added at room temperature and stirred for 2 h. Sat. NaCl aq and
Et2O were added and shaken. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. Separation of the
brown oil by column chromatography on silica gel (eluent; CHCl3)
followed by recrystallization from EtOH gave (Z)-1-cyano-4-(2,2-
dicyano-5-phenyl-4-hexenyl)naphthalene (Z-7a,1.16 g, 3.21 mmol,
42% yield). Pale yellow solid; mp 161–163 ꢂC; 1H NMR (CDCl3,
d
2.16 (m, 3H), 3.07 (d, J = 7.1 Hz, 2H), 3.83 (s, 2H), 5.93 (m, 1H),
7.32–8.37 (m,11H) ppm; 13C NMR (CDCl3, 75 MHz)
17.4, 37.9, 38.6,
39.1, 111.9, 114.9, 116.9, 117.3, 124.0, 126.0, 126.4, 128.0, 128.2, 128.3,
128.5, 128.9, 131.7, 131.8, 132.8, 134.3, 142.1, 143.8 ppm; IR(KBr)
2222 (C
N) cmꢀ1; GC–MS (EI) m/z (%) = 361 (3, M+), 166 (16,
12H8N), 131 (100, C10H11).
d
n
¼
C
300 MHz)
d
2.17 (m, 3H), 2.80 (d, J = 7.3 Hz, 2H), 3.60 (s, 2H), 5.69
26.5,
4.13. Photoreaction of Z-7a and E-7a
(m, 1H), 7.12–8.33 (m, 11H) ppm; 13C NMR (CDCl3, 75 MHz)
d
38.0, 38.4, 38.8, 111.7, 114.9, 116.6, 117.3, 124.0, 126.3, 127.5, 127.6,
127.9, 128.1, 128.6, 128.8, 131.6, 132.7, 134.3, 140.1, 146.0 ppm; IR
CH3CN (28 mL) solution of Z-7a (100 mg, 0.277 mmol) was
irradiated for 48 h. CH3CN (28 mL) solution of E-7a (100 mg,
0.277 mmol) was also irradiated under the same conditions. From
1H NMR spectra, yields (10% from Z-7a, 9% from E-7a) were
determined. Mixture obtained by photoreaction from E-7a was
separated by column chromatography on silica gel (eluent;
(KBr)
n
2222 (C
N) cmꢀ1; GC–MS (EI) m/z (%) = 361 (8, M+),166 (22,
¼
C12H8N), 131 (100, C10H11); Anal. Calcd for C25H19N3 C: 83.08, H:
5.30, N: 11.63. Found C: 83.08, H: 5.42, N: 11.50.
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

G Model
JPC 10103 No. of Pages 13
H. Maeda et al. / Journal of Photochemistry and Photobiology A: Chemistry xxx (2015) xxx–xxx
11
hexane–AcOEt), recycling preparative HPLC (eluent; CHCl3),
recrystallization from EtOH to give (2aR*,5aS*,6R*,10bS*)-6-meth-
yl-6-phenyl-5a,6-dihydrocyclobuta[a]cyclopenta[b]naphthalene-
4,4,10b(3H,5H,10bH)-tricarbonitrile (8, 2.0 mg, 0.006 mmol, 2%
0.980 mmol, 35% yield). Pale green solid; mp 178–179 ꢂC; 1H
NMR (CDCl3, 300 MHz) d 2.95 (d, J = 7.4 Hz, 2H), 3.68 (s, 2H), 6.25 (t,
J = 7.4 Hz, 1H), 7.15–7.41 (m, 10H), 7.59 (d, J = 7.4 Hz, 1H), 7.69–7.76
(m, 2H), 7.90 (d, J = 7.4 Hz, 1H), 8.06-8.34 (m, 2H) ppm; 13C NMR
yield). Colorless solid; 1H NMR (CDCl3, 300 MHz)
d
1.86 (s, 3H),
(CDCl3, 75 MHz)
126.4, 127.5, 128.0, 128.2, 128.4, 128.7, 128.9, 129.5, 131.7, 132.7,
134.1, 138.2, 140.6, 149.4 ppm; IR(KBr) 2222 (C
N) cmꢀ1; GC–MS
(EI) m/z (%) = 423 (3, M+), 193 (100, C15H13); Anal. Calcd for
C30H21N3 C: 85.08, H: 5.00, N: 9.92. Found C: 84.83, H: 5.30, N: 9.80.
d 38.5, 38.8, 111.7 (2C), 114.8, 117.3, 117.7, 124.0,
2.51–2.55 (m, 2H), 2.79 (d, J = 14.1 Hz, 1H), 3.01 (d, J = 14.1 Hz, 1H),
3.15 (m,1H), 5.57 (d, J = 2.8 Hz,1H), 6.01 (d, J = 2.8 Hz,1H), 6.71–6.74
(m, 2H), 7.17–7.19 (m, 3H), 7.39–7.71 (m, 4H) ppm; 13C NMR (CDCl3,
n
¼
75 MHz)
d
29.2, 31.0, 39.9, 45.7, 46.6, 48.4, 52.3, 57.4, 116.7, 116.7,
118.9, 126.9, 127.6, 128.3, 128.3, 129.1, 129.2, 129.9, 132.2, 137.3,
141.2, 141.9, 142.0 ppm; GC–MS (EI) m/z (%) = 361 (14, M+), 166 (11,
4.16. Photoreaction of 7b
C12H8N), 131 (100, C10H11).
CH3CN (0.7 mL) solution of 7b (8.9 mg, 0.021 mmol) was
irradiated for 24 h. NMR spectrum indicated that no reaction took
place.
4.14. Photoreaction of Z-7a and E-7a in the presence of benzophenone
CH3CN (8.0 mL) solution of Z-7a (10.0 mg, 0.028 mmol) and
benzophenone (50.4 mg, 0.277 mmol) was irradiated for 6 h.
CH3CN solution of E-7a was also irradiated under the same
conditions. Both solutions reached to the photostationary state (E:
Z = 76:24). The ratio was determined by 1H NMR.
4.17. Preparation of 11a
CCl4 (50 mL) solution of cyclopentene (3.40 g, 50.0 mmol), N-
bromosuccinimide (8.90 g, 50.0 mmol), benzoyl peroxide (cat) was
refluxed for 1 h. The precipitated solid was removed by filtration.
The solution was concentrated in vacuo. The product, 3-bromo-
cyclopentene was used without purification. To a mixture of THF
(10 mL) and NaH (2.00 g, 50.0 mmol) was added malononitrile
(3.30 g, 50.0 mmol) at 0 ꢂC under argon atmosphere, and stirred for
1 h. 3-Bromocyclopentene was added at room temperature, and
stirred for 2 h. Sat. NaCl aq and Et2O were added and shaken. The
organic layer was dried over Na2SO4, filtered, and concentrated in
vacuo. Separation of the brown oil by column chromatography on
silica gel (eluent; hexane–AcOEt) gave 3-(dicyanomethyl)cyclo-
pentene (3.64 g, 27.6 mmol, 55% yield). Colorless oil; 1H NMR
4.15. Preparation of 7b
THF (70 mL) solution of ethyltriphenylphosphonium iodide
(13.5 g, 32.5 mmol) and tBuOK (3.37 g, 30.0 mmol) was stirred
under argon atmosphere for 5 min. The color of solution turned
orange due to the formation of ylide. THF (40 mL) solution of
benzophenone (4.56 g, 25.0 mmol) was added, and stirred at room
temperature for 2 h, and refluxed overnight. Sat. NaCl aq and
benzene were added and shaken. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. Separation of the
colorless oil by column chromatography on silica gel (eluent;
hexane) gave 1,1-diphenylpropene (4.44 g, 22.9 mmol, 92% yield).
(CDCl3, 300 MHz)
d 1.79 (m, 1H), 2.28–2.65 (m, 3H), 3.34 (m, 1H),
3.66 (d, J = 6.2 Hz, 1H), 5.73 (m, 1H), 6.14 (m, 1H) ppm. To THF
(10 mL) solution of NaH (2.30 g, 33.1 mmol) was added 3-
(dicyanomethyl)cyclopentene (3.64 g, 27.6 mmol) at room tem-
perature under argon atmosphere, and stirred for 1 h. THF (50 mL)
solution of 1-cyano-4-(bromomethyl)naphthalene (6.79 g,
27.6 mmol) was added at room temperature and stirred for 2 h.
Sat. NaCl aq and Et2O were added and shaken. The organic layer
was dried over Na2SO4, filtered, and concentrated in vacuo.
Separation of the brown oil by column chromatography on silica
gel (eluent; CHCl3) followed by recrystallization from EtOH gave 1-
cyano-4-[2,2-dicyano-2-(2-cyclopentenyl)ethyl]naphthalene (11a,
1.68 g, 5.66 mmol, 21% yield). Colorless solid; mp 168–169 ꢂC; 1H
Colorless solid; 1H NMR (CDCl3, 300 MHz)
d 1.77 (d, J = 7.0 Hz, 3H),
6.18 (q, J = 7.0 Hz, 1H) 7.17–7.40 (m, 10H) ppm. CCl4 (30 mL) solution
of 1,1-diphenylpropene (2.08 g, 10.7 mmol), N-bromosuccinimide
(1.91 g,10.7 mmol), benzoyl peroxide (cat) was refluxed for 2 h. The
precipitated solid was removed by filtration. The solution was
concentrated in vacuo. The product, 3-bromo-1,1-diphenylpropene
(2.91 g, 10.6 mmol, 99% yield) was used without purification.
Yellow solid; 1H NMR (CDCl3, 300 MHz)
d 4.06 (d, J = 8.5 Hz, 2H),
6.34 (t, J = 8.5 Hz, 1H), 7.22–7.42 (m, 10H) ppm. To a mixture of THF
(10 mL) and NaH (0.700 g, 17.5 mmol) was added malononitrile
(1.05 g, 15.9 mmol) at 0 ꢂC under argon atmosphere, and stirred for
1 h. THF (20 mL) solution of 3-bromo-1,1-diphenylpropene was
added, and stirred for 2 h. Sat. NaCl aq and Et2O were added and
shaken. The organic layer was dried over Na2SO4, filtered, and
concentrated in vacuo. Separation of the brown oil by column
chromatography on silica gel (eluent; hexane–AcOEt) gave 4,4-
dicyano-1,1-diphenyl-1-butene (1.39 g, 5.40 mmol, 51% yield).
NMR (CDCl3, 300 MHz)
d 2.12 (m, 1H), 2.39–2.72 (m, 3H), 3.52 (m,
1H), 3.73 (s, 2H), 5.90 (m, 1H), 6.27 (m, 1H), 7.69–7.78 (m, 3H), 7.95
(d, J = 7.4 Hz, 1H), 8.17 (m, 1H), 8.33 (m, 1H) ppm; 13C NMR (CDCl3,
75 MHz)
d 26.8, 32.7, 37.1, 43.8, 54.5, 111.6, 114.6, 114.7, 117.4, 124.0,
126.0, 126.3, 128.0, 128.1, 128.8, 131.6, 131.8, 132.8, 134.6,
138.8 ppm; IR(KBr)
n
2221 (C ; GC–MS (EI) m/z
N) cmꢀ1
¼
(%) = 297 (11, M+), 166 (70, C12H8N), 67 (100, C5H7).
Colorless oil; 1H NMR (CDCl3, 300 MHz)
6.8 Hz, 2H), 3.73 (t, J = 6.8 Hz, 1H), 6.09 (t, J = 7.4 Hz, 1H), 7.18–7.43
(m, 10H); 13C NMR (CDCl3, 75 MHz)
23.3, 31.2, 112.2 (2C), 118.5,
d 2.86 (dd, J = 7.3 Hz,
4.18. Preparation of 11b
d
127.4, 128.0, 128.2, 128.3, 128.7, 129.4, 148.7 ppm; GC–MS (EI) m/
z = 258 (6, M+), 193 (46, C15H13), 115 (100, C9H7). To THF (5 mL)
solution of NaH (0.168 g, 4.19 mmol) was added 4,4-dicyano-1,1-
diphenyl-1-butene (0.721 g, 2.79 mmol) at room temperature
under argon atmosphere, and stirred for 1 h. THF (20 mL) solution
of 1-cyano-4-(bromomethyl)naphthalene (0.687 g, 2.79 mmol)
was added at room temperature and stirred for 2 h. Sat. NaCl aq
and Et2O were added and shaken. The organic layer was dried over
Na2SO4, filtered, and concentrated in vacuo. Separation of the
brown oil by column chromatography on silica gel (eluent; CHCl3)
followed by recrystallization from EtOH gave 1-cyano-4-(2,2-
CCl4 (20 mL) solution of cyclohexene (5.18 g, 63.1 mmol), N-
bromosuccinimide (11.4 g, 64.1 mmol), benzoyl peroxide (cat) was
refluxed for 1 h. The precipitated solid was removed by filtration.
The solution was concentrated in vacuo. The product, 3-bromo-
cyclohexene was used without purification. To a mixture of THF
(20 mL) and NaH (2.68 g, 67.0 mmol) was added malononitrile
(4.02 g, 60.9 mmol) at 0 ꢂC under argon atmosphere, and stirred for
1 h. 3-Bromocyclohexene was added at room temperature, and
stirred for 2 h. Sat. NaCl aq and Et2O were added and shaken. The
organic layer was dried over Na2SO4, filtered, and concentrated in
vacuo. Separation of the brown oil by column chromatography on
silica gel (eluent; hexane–AcOEt) gave 3-(dicyanomethyl)
dicyano-5,5-diphenyl-4-pentenyl)naphthalene
(7b,
0.418 g,
Please cite this article in press as: H. Maeda, et al., Preparation of polycyclic compounds by intramolecular photospirocyclization and
photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

G Model
JPC 10103 No. of Pages 13
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H. Maeda et al. / Journal of Photochemistry and Photobiology A: Chemistry xxx (2015) xxx–xxx
cyclohexene (1.33 g, 9.10 mmol, 15% yield). Colorless oil; 1H NMR
(CDCl3, 300 MHz) 1.58–1.63 (m, 2H), 1.86 (m, 1H), 2.07-2.13 (m,
was also supported by Kanazawa University SAKIGAKE Project. The
authors also thank Dr. Akihiro Nomoto for X-ray crystallographic
analysis of compound 8.
d
3H), 2.84 (m, 1H), 3.64 (d, J = 3.3 Hz, 1H), 5.65 (m, 1H), 6.07 (m, 1H)
ppm. To THF (5 mL) solution of NaH (0.390 g, 9.76 mmol) was added
3-(dicyanomethyl)cyclohexene (1.19 g, 8.13 mmol) at room tem-
perature under argon atmosphere, and stirred for 1 h. THF (50 mL)
solution of 1-cyano-4-(bromomethyl)naphthalene (2.00 g,
8.13 mmol) was added at room temperature and stirred for 2 h.
Sat. NaCl aq and Et2O were added and shaken. The organic layer
was dried over Na2SO4, filtered, and concentrated in vacuo.
Separation of the brown oil by column chromatography on silica
gel (eluent; CHCl3) followed by recrystallization from EtOH gave 1-
cyano-4-[2,2-dicyano-2-(2-cyclohexenyl)ethyl]naphthalene (11b,
1.59 g, 5.11 mmol, 62% yield). Colorless solid; mp 164–166 ꢂC; 1H
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the
online
version,
at
http://dx.doi.org/10.1016/j.
jphotochem.2016.01.005.
References
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[5] J. Cornelisse, Chem. Rev. 93 (1993) 615–669.
[6] K. Mizuno, H. Maeda, A. Sugimoto, K. Chiyonobu, in: V. Ramamurthy, K.S.
Schanze (Eds.), Molecular and Supramolecular Photochemistry:
Understanding and Manipulating Excited-State Processes, vol. 8, Marcel
Dekker, Inc., New York, 2001, pp. 127–241.
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Photobiology, in: A. Griesbeck, M. Oelgemöller, F. Ghetti (Eds.), third edition,
CRC Press, Boca Raton, 2012, pp. 489–509.
NMR (CDCl3, 300 MHz)
d 1.74 (m, 2H), 2.02-2.33 (m, 4H), 3.00 (m,
1H), 3.74 (s, 2H), 5.89 (m, 1H), 6.23 (m, 1H), 7.70–7.79 (m, 3H), 7.96
(d, J = 7.4 Hz, 1H), 8.16 (m, 1H), 8.34 (m, 1H) ppm; 13C NMR (CDCl3,
75 MHz)
d 21.4, 25.0, 25.9, 35.9, 43.8, 44.0, 111.6, 114.3, 114.6, 117.4,
122.1, 124.1, 126.3, 128.0, 128.1, 128.8, 131.6, 131.8, 132.8, 134.8,
135.0 ppm; IR(KBr)
n
2220 (C
N) cmꢀ1; GC–MS (EI) m/z (%) = 311
¼
(3, M+), 166 (89, C12H8N), 81 (100, C6H9); Anal. Calcd for C21H17N3
C: 81.00, H: 5.50, N: 13.49. Found C: 80.88, H: 5.65, N: 13.25.
[8] D. Bryce-Smith, A. Gilbert, B.H. Orger, J. Chem. Soc. Chem. Commun. (1966)
512–514.
[9] Y. Inoue, K. Nishida, K. Ishibe, T. Hakushi, N. Turro, J. Chem. Lett. (1982)
471–474.
4.19. Photoreaction of 11a
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A dry CH3CN (80 mL) solution of 11a (238 mg, 0.800 mmol) was
irradiated for 20 h. Separation by column chromatography on silica
gel (eluent; hexane–AcOEt), recycling preparative HPLC (eluent;
CHCl3), and recrystallization from EtOH gave (2aR*,2a1-
R*,2b1S*,6bR*,8aS*)-1,2,2a,2c,7,8a-hexahydrobenzo[a]cyclopropa
[cd]pentaleno[1,6-fg]pentalene-2c,8,8(2a1H,2bH,2b1H)-tricarboni-
trile (12a, 60.5 mg, 0.204 mmol, 25% yield). Colorless solid; mp
201–202 ꢂC; 1H NMR (CDCl3, 300 MHz)
d 1.95 (m, 1H), 2.12–2.30
(m, 3H), 2.49 (d, J = 6.4 Hz, 1H), 2.74–2.82 (m, 2H), 3.12–3.19 (m,
3H), 3.60 (d, J = 6.4 Hz, 1H), 6.99 (m, 1H), 7.23–7.33 (m, 2H), 7.49 (m,
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d
27.3, 30.8, 36.7, 38.6, 43.9,
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47.0, 49.7, 51.3, 53.9, 66.7, 72.7,115.0,116.8,119.1, 119.6,125.0,128.3,
128.5, 134.2, 146.7 ppm; IR (KBr)
n
2234 (C
N) cmꢀ1; GC–MS (EI)
¼
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4.20. Photoreaction of 11b
A dry CH3CN (80 mL) solution of 11a (249 mg, 0.800 mmol) was
irradiated for 8 h. Separation by column chromatography on silica
gel (eluent; hexane–AcOEt), recycling preparative HPLC (eluent;
CHCl3), and recrystallization from EtOH gave 12b (73.0 mg,
0.235 mmol, 29% yield). Colorless solid; mp 232–233 ꢂC; 1H NMR
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d 1.48–2.01 (m, 6H), 2.49–2.70 (m, 4H), 2.97 (d,
J = 4.7 Hz, 1H), 3.09 (d, J = 4.7 Hz, 1H), 3.51 (d, J = 6.7 Hz, 1H), 7.11 (m,
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d
16.8, 21.6, 23.5, 29.4, 35.5, 41.3, 43.9, 46.3, 49.2, 54.1, 64.2, 66.5,
114.3, 116.7, 119.0, 120.3, 124.6, 128.2, 128.6, 134.2, 147.6 ppm; IR
(KBr) 2233 (C
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n
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Acknowledgements
This study was partially supported financially by Grants-in-Aid
for Scientific Research on Priority Areas “Advanced Molecular
Transformations of Carbon Resources” (18037063, 19020060 in the
Area No. 444 to K.M.) and Scientific Research (C) (23550058 to K.
M., 20550049, 23550047, 26410040 to H.M.) from the Ministry of
Education, Culture, Sports, Science, and Technology (MEXT) of
Japan. H.M. is grateful for financial support from Mitsubishi
Chemical Corporation Fund and The Mazda Foundation. This work
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photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
10.1016/j.jphotochem.2016.01.005

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photocycloaddition reactions of 4-alkenyl-1-cyanonaphthalene derivatives, J. Photochem. Photobiol. A: Chem. (2016), http://dx.doi.org/
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