Allenyl(vinyl)methane photochemistry. Photochemistry of γ-(3-methyl-1-phenyl-1,2-butadienyl)-substituted α,β-unsaturated ester and nitrile derivatives

Article abstract of DOI:10.1016/S0040-4020(01)00426-4

The direct photolyses of the γ-(3-methyl-1-phenyl-1,2-butadienyl)-substituted α,β-unsaturated esters and nitriles gave the bicyclo[2.1.0]pentanes, cross-conjugated trienes, and several intramolecular products, while the triplet-sensitization led to the former two compounds. It was found that the photochemoselectivity depended on the substituents on the vinyl group and would be controlled by the energy using the triplet sensitizers.

Full text of DOI:10.1016/S0040-4020(01)00426-4

TETRAHEDRON
Pergamon
Tetrahedron 57 &2001) 4831±4840
Allenylꢀvinyl)methane photochemistry. Photochemistry of
g-ꢀ3-methyl-1-phenyl-1,2-butadienyl)-substituted
a,b-unsaturated ester and nitrile derivatives
Takashi Tsuno,p Hidetaka Hoshino, Rieko Okuda and Kunio Sugiyama
Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Narashino, Chiba 275-8575, Japan
Received 5 March 2001; accepted 16April 2001
AbstractÐThe direct photolyses of the g-&3-methyl-1-phenyl-1,2-butadienyl)-substituted a,b-unsaturated esters and nitriles gave the
bicyclo[2.1.0]pentanes, cross-conjugated trienes, and several intramolecular products, while the triplet-sensitization led to the former two
compounds. It was found that the photochemoselectivity depended on the substituents on the vinyl group and would be controlled by the
energy using the triplet sensitizers. q 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
the photochemistry of 1,1-dicyano-3,3-dimethyl-1,4,5-
hexatriene 7 and 1,1-dicyano-3,3,6-trimethyl-1,4,5-hepta-
triene 8 in comparison with that of 6.
The photochemistry of the divinylmethanes1 in which one
vinyl is a,b-unsaturated esters2,3 or ylidenemalononitrile4
has been found to undergo regioselective di-p-methane
rearrangement by multiplicity of the excited state. Such
photochemoselectivity by multiplicity control is interesting.
We then noted the photochemistry of allenyl&vinyl)-
methanes in which the vinyl is an electron-de®cient
alkene.5±9 Previously, we reported the photochemistry of
g-allenyl-substituted alkylidenemalonates 1,6 a,b-unsatu-
rated esters 2,6 and alkylidene Meldrum's acids 3 &Scheme
1).7 In the photolyses of 1 and 2, the intramolecular [212]
cycloaddition predominantly occurred under the direct and
sensitized photolyses to yield the bicyclo[2.1.0]pentanes.6
On the other hand, the direct photolyses of 3 gave the
alkenylidenecyclopropanes, while the sensitized photolyses
afforded the bicyclo[2.1.0]pentanes. Further, the photo-
chemistry of 3 presented the possibility of new multiplicity
control of the photochemistry of the divinylmethanes.7
Furthermore, for the triplet excited state, we con®rmed
that the activated chromophore was the vinyl chromophore
based on the estimated triplet energy.5±7
2. Results and discussion
2.1. Preparation of esters and nitriles ꢀ4±8)
The phenyl-substituted allenic aldehyde 9 was initially
prepared by the reaction of 2-methyl-4-phenyl-3-butyn-2-
ol with isobutyraldehyde in the presence of a catalytic
amount of p-toluenesulfonic acid &Scheme 2). The diester
4 was obtained by the condensation of 9 with dimethyl
malonate using Lehnert's method.10 The monoester 5 was
We found that newly prepared allenyl&vinyl)methanes 4±6
&Scheme 1) each have a triplet excited state of the allene or
vinyl moiety and their states produced different photo-
products: a cross-conjugated triene from the excited state
of the allenyl chromophore and an intramolecular [212]
cycloadduct from that of the vinyl chromophore.8 In this
paper, we report the photochemistry of 4±6 and also present
Keywords: allenes; cycloadditions; photochemistry; rearrangement.
Corresponding author. Tel.: 181-474-74-2569; fax: 181-474-74-2579;
e-mail: t5tuno@cit.nihon-u.ac.jp
p
Scheme 1.
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020&01)00426-4

4832
T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
Scheme 2.
prepared by the reaction of 9 with methyl diethylphos-
phonoacetate in the presence of sodium hydride in DMF.
The dinitriles 6±8 were prepared by the condensation of the
allenic aldehydes with malononitrile in pyridine.
2.2. Photochemistry of esters ꢀ4 and 5)
The direct photolysis of the diester 4 in hexane gave a cross-
conjugated triene 10, bicyclo[2.1.0]pentane 11, pyran 12,
Scheme 3.
Table 1. Direct and sensitized photolyses of 4±8
Substrate
Solvent
Additive
Irradiation time/h
Products &isolated yield/%)
4
Hexane
Acetone
Benzene
33a
5b
10 &4)
&12)
&19)
11 &15)
&3)
12 &18)
13 &4)
17 &2)
21 &9)
Anthraquinone
None
6.5c
5
6
Hexane
Acetone
25a
15b
14 &1)
&14)
15 &25)
&7)
16 &15)
20 &0.5)
Acetonitrile
Acetone
Acetonitrile
None
30a
4.5b
1c
18 &53)
&38)
19 &26)
Michler's ketone
None
&64)
7
8
a
Acetonitrile
Acetone
5d
22 &11)
25 &57)
23 &6)
&53)
24 &0.7)
1.2b
Acetonitrile
Acetone
55a
26 &8)
&59)
13.5b
The direct photolyses were performed using a 6-W low-pressure mercury lamp with a quartz jacket under argon atmosphere.
b
c
d
The sensitized photolyses were performed using a 100-W high-pressure mercury lamp with a pyrex jacket under argon atmosphere.
The solution of the substrate and sensitizer in a pyrex tube was irradiated using a 100-W high-pressure mercury lamp through a pyrex ®lter.
The direct photolysis was performed using a 100-W high-pressure mercury lamp with a quartz jacket under argon atmosphere.

T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
Table 2. Quantum yields for the isomerization of 4 and 5
4833
a
)
Substrate
l/nm
Additive &ET/kJ mol21
Quantum yields
4
254
None
2-Methyl-1,3-butadiene &251)b,c
Acetone &377±334)b
F10ˆ0.013
0.0085
0.25
0.37
0.29
0.16
0.082
0.012
0.0031
F11ˆ0.043
F12ˆ0.030
F
13,0.0001
,0.0001
0.041
0.027
0.016
0.028
313
365
Acetophenone &310)b
Benzophenone &287)b
0.0018
2-Benzoylpyridine &279)b
Anthraquinone &259)c
,0.0001
,0.0001
,0.0001
,0.0001
4-Phenylacetophenone &254)b
1-Acenaphthone &236)b
5
254
Noneb
F14ˆ0.0065
0.0040
F15ˆ0.14
F16ˆ0.0096
F
17,0.014
0.012
2-Methyl-1,3-butadiene &251)b,d
Acetone &377±334)b
Acetophenone &310)b
Benzophenone &287)b
2-Benzoylpyridine &279)b
Anthraquinone &259)e
4-Phenylacetophenone &254)b
1-Acenaphthone &236)b
0.15
0.0095
313
365
0.0260.054
0.045
0.040
0.021
0.0066
0.016
0.0022
,0.0001
,0.0001
,0.0001
,0.0001
0.0055
0.0028
Total quantum yields for the formation of the photoproducts corresponding with the quantum yield for the disappearance of 4 or 5 below the conversion of
20%.
a
Sensitizers absorb .95% of incident light.
In hexane.
b
c
Quencher concentration: 0.03 mol dm23
.
d
e
Quencher concn.: 0.07 mol dm23
In benzene.
.
and cyclopropene 13 &Scheme 3). On the other hand, the
direct photolysis of the monoester 5 afforded 14±17
&Scheme 3). An induction period was found for the forma-
tion of the cyclopropenes 13 and 16, and moreover, the
isolated [212] cycloadducts 11 and 15 were irradiated to
afford the cyclopropenes 13 and 16. Though the acetone-
sensitized photolyses of 4 or 5 afforded the triene 10 or 14
and the [212] cycloadduct 11 or 15, polymeric materials
were signi®cantly produced. The yields from their photo-
lyses are described in Table 1.
of the bicyclo[2.1.0]pentanes, pyran, and Z-form are within
experimental error in comparison with the non-additive
conditions, whereas the quantum yields for the formation
of the trienes 10 and 14 decrease by ca. 35% &4!10) and
38% &5!14) in the presence of the quencher. Acetone
&ETˆ377,334 kJ mol21) and acetophenone &ETˆ310 kJ
mol21) are good sensitizers for the isomerization to the
trienes 10 and 14 and to the [212] cycloadducts 11 and
15. Benzophenone &ETˆ287 kJ mol21) has an effect on
their isomerization, though the quantum yields of the for-
mation of the [212] cycloadducts 11 and 15 are smaller
than those obtained with the use of acetone or aceto-
phenone. 2-Benzoylpyridine &ETˆ279 kJ mol21), anthra-
quinone &ETˆ259 kJ mol21), 4-phenylacetophenone &ETˆ
Table 2 shows the quantum yields for the isomerization of 4
and 5 under the direct and sensitized irradiation. In the direct
photolyses, the isomerization of the cyclopropene 13 or 16
has very low quantum ef®ciency. For the direct photolyses
in the presence of 2-methyl-1,3-butadiene &ETˆ251 kJ
mol21) as a quencher, the quantum yields for the formation
254 kJ mol21) and 1-acetonaphthone &ETˆ236kJ mol 21
)
having a triplet energy less than that of benzophenone
show sensitizing effects for the formation of the trienes 10
Scheme 4.

4834
T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
while Michler's ketone &ETˆ259 kJ mol21
)
or 4-
Table 3. Quantum yields for the isomerization of 6
phenylbenzophenone &ETˆ249 kJ mol21) scarcely affected
the formation of 18. We then carried out Michler's ketone-
sensitization of 6 on the basis of their results, and compound
19 was obtained in 64% yield.
a
l/nm
Additive &ET/kJ mol21
)
Quantum yields
254
313
365
None
Acetone &377±334)
Acetophenone &310)
Benzophenone &287)
Thioxanthen-9-one &274)
Michler's ketone &259)
F18ˆ0.18
F19ˆ0.073
0.039
0.093
0.29
0.14
0.11
0.052
0.15
0.057
0.14
The direct photolysis of 7 in acetonitrile afforded an allenyl-
cyclopropane 22, bicyclo[2.1.0]pentane 23, and 1,3-phenyl
rearrangement compound 24 as intramolecular photo-
products &Scheme 4) and further led to considerably poly-
meric compounds and very small amounts of unidenti®ed
intramolecular compounds. On the other hand, the dinitrile 8
under direct photolysis underwent mainly a di-p-methane
rearrangement to yield 25, and further the intramolecular
[212] cycloadduct 26 was obtained as a by-product
&Scheme 4). The acetone-sensitization of 7 or 8 gave the
intramolecular [212] cycloadduct 23 or 26 in good yields
&Table 1).
0.051
,0.0001
,0.0001
4-Phenylbenzophenone &249)
Total quantum yields for the formation of the photoproducts corresponded
with the quantum yield for the disappearance of 6 below a conversion of
20%.
a
Sensitizers absorb .95% of incident light.
and 14 only and the latter two sensitizers have a slight
quantum ef®ciency. By these sensitized ef®ciencies, we
considered that the trienes 10 and 14 would be prepared
chemoselectively using sensitizers which have triplet
energies in the range of 280 to 235 kJ mol21, and we then
examined the anthraquinone-sensitization of 4. As the
result, the triene 10 was obtained only in 19% isolated yield.
The structures of the photoproducts were established by
spectroscopic data and microanalyses or HRMS.11
2.4. Reaction mechanisms of photochemistry of esters
and nitriles
2.3. Photochemistry of nitriles ꢀ6±8)
The direct photolysis of 6 in acetonitrile gave mainly cross-
conjugated triene 18 and bicyclo[2.1.0]pentane 19, and the
by-product was obtained as 1,3-allyl rearrangement product
20 in a very low yield &Scheme 4). In the case of the
acetone-sensitization of 6, the bicyclo[2.1.0]pentane 19
and indene 21 were obtained. Although GLC analysis
showed the formation of 18 and 19 during the acetone-sensi-
tization of 6, after prolonged irradiation, 18 decreased with
increasing 21. The yields from their photolyses are
described in Table 1. The quantum yields for the isomeri-
zation of 6 are described in Table 3. Acetone, acetophenone,
The sensitizing effects of esters 4 and 5 and nitrile 6 suggest
that the trienes and [212] cycloadducts are derived from the
triplet excited state of a different chromophore in the
substrates. The triplet energy required for the formation of
the [212] cycloadduct from ester 4 or 5 is estimated to be
ca. 300 kJ mol21, while that from the nitrile 6 is ca.
250 kJ mol21. Based on our previous reports of the photo-
chemistry on the g-allenyl-substituted a,b-unsaturated
esters,5±8 the triplet energy required for the formation of
the [212] cycloadduct is estimated to be ca. 300 kJ mol21
and the activated chromophore is the vinyl moiety. The
estimated triplet energies of esters 4 and 5 correspond
with those of the reported a,b-unsaturated esters.5±8
benzophenone, and thioxanthen-9-one &ETˆ274 kJ mol21
)
show sensitizing effects for the formation of 18 or 19,
Scheme 5.

T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
4835
Scheme 6.
Furthermore, the triplet energy of the ylidenemalononitrile
has been reported to be ca. 250 kJ mol21 4a
The reported
Michler's ketone, and the intramolecular [212] cyclo-
addition takes place. Thus, the photochemoselectivity for
the formation of the trines and bicyclo[2.1.0]pentanes on
the substituents on vinyl group would be controlled by the
energy using triplet sensitizers.
.
triplet energy corresponds with the estimated values for 6.
Hence, the intramolecular [212] cycloaddition of 4±6
under the sensitized photolyses occurs from the triplet of
the vinyl chromophore. On the other hand, the triplet energy
required for the formation of trienes 10, 14 or 18 from 4±6 is
estimated to be ca. 260 kJ mol21. It has been reported that
the triplet of 3-phenyl-1,2-butadiene is quenched by 1,3-
pentadiene &ETˆ247 kJ mol21),12 while the triplet of thiox-
anthen-9-one &ETˆ274 kJ mol21) is quenched by 1-phenyl-
1,2-propadiene.13 Therefore, these reports suggest that the
triplet energy of the monophenyl-substituted allene lies in
the range of 250±270 kJ mol21. Because this range includes
the estimated triplet energy of the phenyl-substituted allenyl
chromophore in 4±6, for esters 4 and 5, acetone and aceto-
phenone having higher triplet energy competitively affect
both chromophores in 4 and 5, although the sensitizers such
as benzophenone, 2-benzoylpyridine and thioxanthen-9-one
in the range of 260±290 kJ mol21 can reach the excited state
for the allenyl chromophore. Consequently, the anthra-
quinone would be sensitized selectively by the allenyl
chromophore in 4 to yield the triene 10 &Scheme 5). For
nitrile 6, both of the allenyl and vinyl chromophores were
excited by the sensitizers having a triplet energy of more
than 260 kJ mol21 to afford the triene 18 and bicyclo[2.1.0]-
pentane 19. However, for the preparative scale of the ace-
tone-sensitized photochemistry of 6, the resulting triene 18
further undergoes the acetone-sensitized photoreaction to
give the indene 21. The triplet energy of the vinyl chromo-
phore in esters 4 and 5 lies at a higher level than that of the
allenyl chromophore, whereas the levels of the energy of the
chromophores in 6 are the reverse &Scheme 6). Therefore,
the vinyl chromophore of 6 is selectively excited by
Recently, we proved the reaction mechanism of the intra-
molecular [212] cycloaddition of the allenyl&vinyl)-
methanes by trapping experiments of
a
biradical
intermediate using hydrogen selenide.5,6b Accordingly, in
the same pathway, the excited state of the vinyl chromo-
phore in 4±6 initially bonds between 2-C and 6-C to afford a
cyclopenta-1,3-diyl radical 27 or 28 from which ring closure
yields the intramolecular [212] cycloadducts &Schemes 5
and 6). On the other hand, for the formation of the trienes, it
is considered that the excited state of the allenyl chromo-
phore bonds between 3-C and 5-C to yield 29 or 30, which
undergoes a 1,2-phenyl migration to yield the trienes. This
reaction pathway was supported by a PM3 MO calculation;
the optimal structure of biradical 31 corresponded to
the structure of 14. 2-Methyl-1,3-butadiene under direct
photolyses was recognized to have a quenching effect on
the formation of the trienes but not on the formation of the
[212] cycloadducts. Because we have proposed that the
intramolecular [212] cycloaddition of the allenyl&vinyl)-
methanes occurs via both the singlet and triplet pathways,
in the cases of the photochemistry of 4 and 5, the intramo-
lecular [212] cycloadducts 11 and 15 are produced not only
from the triplet pathway but also the singlet one, and further,
due to the quenching effects, the trienes are derived via the
triplet excited state.
The direct photolysis of 4 gave pyran 12. Pyran 12 was not
obtained from sensitized photolyses, and its formation did

4836
T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
bichromophoric compounds takes place with the lower
triplet of either chromophore by an intramolecular energy
transfer. Previously, we reported that the compounds 1 and 2
underwent a photoreaction via the excited state of the vinyl
chromophore.6 However, the triene and [212] cycloadducts
are derived from the triplet excited state of the different
chromophores of the reported allenyl&vinyl)methanes 4±6,
and the control of the photochemoselectivity can be subject
to the use of triplet sensitizers and the substituents on the
vinyl group.
Scheme 7.
not show the quenching effect by 2-methyl-1,3-butadiene.
Therefore, 12 is derived from the photochemical intramo-
lecular oxa-Diels±Alder reaction via the singlet-excited
state of a Z-carbonyl in 4 &Scheme 5). Such an intramolec-
ular oxa-Diels±Alder reaction has been found in the photo-
chemistry of several allenyl&vinyl)methanes5,7a,9 and 3,6-
heptadien-2-ones.14
4. Experimental
4.1. General
The melting points were determined on a micro hot stage
&Yazawa) and are uncorrected. The NMR spectra were
measured in a CDCl3 solution using JEOL JNM-EX 90,
Bruker Avance-400, and JEOL Lamda-400 spectrometers.
The IR spectra were obtained with a BIO-RAD FTS-60A
spectrophotometer. The MS and HRMS spectra were
obtained with a JEOL JMS AX-500 spectrometer using
GCMS at an ionization voltage of 70 eV; the gas chromato-
graph connected to the MS spectrometer was a Hewlett-
Packard 5890 equipped with a capillary column &OV-1,
0.24 fmm£25 m). The UV-absorption spectra were
measured on a Shimadzu UV-160A spectrophotometer.
Spectroscopic-grade acetonitrile, hexane, and commercial
acetone were stored over molecular sieve 4A. The sensi-
tizers used were recrystallized or distilled.
The direct photolyses of 7 and 8 gave the allenylcyclo-
propanes 22 and 25, i.e. di-p-methane rearrangement
compounds, while the diesters which have the same allenyl
chromophore in 7 or 8 led mainly to the [212] cyclo-
adducts.5,6 Such a difference is explainable by the MO
coef®cients of the vinyl chromophore. In our previous
report,6b the MO coef®cient for the a-carbon of
2,2-dimethylpropylidenemalonate is larger than that of the
b-one. Hence, g-allenyl-substituted a,b-unsaturated esters
undergo preferential interaction between the allene center
and the a-carbon. However, the PM3 MO calculation for
2,2-dimethylpropylidenemalononitrile as a model of the
vinyl moiety in 6±8 indicates that the MO coef®cient
&0.68) of the b-carbon is larger than that &0.50) of the
a-carbon. In the photochemistry of 7 and 8, therefore, the
di-p-methane rearrangement occurred by preferential MO
interaction between the 5-C and 3-C &Scheme 6). On the
other hand, it seems that the minor compounds 20 and 24
were produced by the MO interaction between 5-C and 2-C
in the nitriles 6 and 7 &Scheme 6).
4.2. Preparation of the esters and nitriles
4.2.1. 2,2,5-Trimethyl-3-phenyl-3,4-hexadienal ꢀ9). 2-
Methyl-4-phenyl-3-butyn-2-ol &8.0 g, 50 mmol), isobutyr-
aldehyde &30 cm3, 0.33 mol), and TsOH &12 mg) were
dissolved in benzene &30 cm3) in a round glass vessel. The
vessel was joined to a water separator with a condenser, and
the mixture was re¯uxed for 120 h under an argon atmos-
phere. The reaction mixture was washed with sodium
acetate solution &1 mol dm23, 50 cm3), dried over MgSO4,
and evaporated in vacuo. The residual oil was distilled under
reduced pressure to give the aldehyde 9 in 41% &4.4 g) yield:
bp 90±1108C &2.0 Torr); IR &neat) 1951 &CvCvC), 1731
It is apparent that the cyclopropenes 13 and 16 were derived
via the photochemical pathway of the [212] cycloadducts
11 and 15 by the GLC analyses. Moreover, the indene 21 is
also the photoproduct from the triene 18. Because these
compounds are secondary photoproducts, a detailed reac-
tion mechanism has not been fully examined, but we
consider the following. The resulting bicyclo[2.1.0]pentane
11 or 15 was further excited to undergo cleavage of the
cyclopropane ring, and subsequently a cyclobutane ring
opening gave the cyclopropene 13 or 16 &Scheme 7). On
the other hand, the indene 21 is derived from the interaction
between the p-orbitals of the phenyl and vinyl moieties in
the triplet excited state of 18 &Scheme 8).
1
&CvO) cm21; H NMR &CDCl3, 90 MHz) d 1.23 &s, 6H,
CH3-2£2), 1.81 &s, 6H, CH3-6£2), 7.20±7.35 &m, 5H,
ArH), 9.56&s, 1H, CHO); 13C NMR &CDCl3, 22.5 MHz) d
20.6&q, 2C), 21.9 &q, 2C), 49.7 &s, C-2), 98.9 &s), 106.6&s),
126.7 &d), 128.0 &d, 2C), 128.2 &d, 2C), 136.9 &s), 203.5 &s),
203.7 &d); MS m/z &rel. intensity) 214 &M1, 9), 200 &17), 199
&100), 143 &19), 129 &12). HRMS Found: m/z 214.1337.
Calcd for C15H18O: M, 214.1358.
3. Conclusions
4.2.2. 1,1-Bismethoxycarbonyl-3,3,6-trimethyl-4-phenyl-
1,4,5-heptatriene ꢀ4). The TiCl4 method described by
Lehnert was used.10 A mixture of TiCl4 &5.0 cm3,
0.05 mol) and CCl4 &30 cm3) was slowly added to THF
&50 cm3) at 258C under argon. To the THF±TiCl4 suspen-
sion was added a mixture of aldehyde &2.1 g, 98 mmol),
dimethyl malonate &1.3 g, 98 mmol) in THF &30 cm3) and
then a solution of pyridine &5.0 cm3) in THF &30 cm3) was
added slowly dropwise over 1 h at 08C. The mixture was
Generally, the photochemistry via the triplet excited state of
Scheme 8.

T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
4837
stirred for 24 h at room temperature and then quenched with
water &50 cm3) and ether &50 cm3). The solution was sepa-
rated and the aqueous layer was extracted with ether
&50 cm3£2). The combined organic fractions were dried
over MgSO4 and evaporated in vacuo. The residue was
chromatographed on silica gel &150 g) using hexane/
EtOAc &98:2, v/v) to give the ester 4 in 65% &2.1 g) yield:
IR &neat) 1965 &CvCvC), 1734 &CvO), 1638
and 1,1-dicyano-3,3-dimethyl-1,4,5-hexatriene ꢀ8). In a
manner similar to that described above for the preparation
of 6, a condensation of 2,2,5-trimethyl-3,4-hexadienal7aor
2,2-dimethyl-3,4-pentadienal7a with malononitrile gave the
nitrile 7 or 8.
Data for 7. A yellow oil, bp 90±958C &2 Torr); IR &neat)
2250 &CN), 1970 &CvCvC) cm21 1H NMR &CDCl3,
;
1
&CvC) cm21; H NMR &CDCl3, 400 MHz) d 1.31 &s, 6H,
90 MHz) d 1.37 &s, 6H, CH3-3£2), 1.74 &d, 6H, Jˆ1.3 Hz,
CH3-6£2), 5.04 &septet, 1H, Jˆ1.3 Hz, CH-4), 7.21 &s, 1H,
CH-2); 13C NMR &CDCl3, 22.5 MHz) d 20.2 &q, 2C), 27.2
&q, 2C), 40.7 &s, C-3), 86.9 &s, C-1), 94.9 &d, C-4), 100.5 &s,
C-6), 111.1 &s, CN), 113.3 &s, CN), 175.9 &d, C-2), 201.0 &s,
C-5); MS m/z &rel. intensity) 186&M 1, 2), 171 &35), 67
&100), 41 &45). HRMS Found: m/z 186.1155. Calcd for
C12H14N2: M, 186.1158.
CH3-3£2), 1.81 &s, 6H, CH3-6£2), 3.68 &s, 3H, OCH3), 3.77
&s, 3H, OCH3), 7.20 &s, 1H, vCH), 7.25±7.28 &m, 5H, ArH);
13C NMR &CDCl3, 22.5 MHz) d 20.4 &q, 2C), 27.5 &q, 2C),
40.5 &s), 52.5 &q), 54.6&q), 98.9 &s), 110.8 &s), 125.0 &s),
126.4 &d), 127.9 &s), 128.3 &d, 2C), 136.9 &s), 154.7 &d),
166.9 &s, 2C), 201.5 &s); MS m/z &rel. intensity) 328 &M1,
6), 296 &10), 196 &12), 144 &12), 143 &100), 128 &24). HRMS
Found: m/z 328.1650. Calcd for C20H24O4: M, 328.1675.
Data for 8. A yellow oil, 85±908C &3 Torr); IR &neat) 2245
&CN), 1960 &CvCvC) cm21; 1H NMR &CDCl3, 90 MHz) d
1.38 &s, 6H, CH3-3£2), 4.94 &d, 2H, Jˆ7.0 Hz,
CvCvCH2), 5.24 &dd, 1H, Jˆ6.2, 7.0 Hz, CHvCvC),
7.26&s, 1H, CH-2); 13C NMR &CDCl3, 22.5 MHz) d 27.4
&q, 2C), 39.4 &s, C-3), 79.2 &t, C-6), 87.6 &s, C-1), 96.2 &d, C-
4), 110.9 &s, CN), 113.2 &s, CN), 175.1 &d, C-2), 207.5 &s, C-
5); MS m/z &rel. intensity) 158 &M1, 16), 157 &35), 143 &91),
116 &100), 93 &40), 92 &90), 65 &45), 39 &69). HRMS Found:
m/z 158.0836. Calcd for C10H10N2: M, 158.0845.
4.2.3. Methyl ꢀE)-4,4,7-trimethyl-5-phenyl-2,5,6-octatri-
enoate ꢀ5). Methyl diethylphosphonoacetate &6.31 g,
30 mmol) was dissolved in DMF &30 cm3). To the mixture
was added sodium hydride &0.72 g, 30 mmol) which was
washed with pentane. The solution was stirred for 10 min
at room temperature under argon and then the aldehyde &9:
5.36g, 25 mmol) was added. The mixture was stirred for
24 h at room temperature and then quenched with water
&50 cm3). The solution was extracted with ether &50 cm3£
2). The combined organic fractions were dried over MgSO4
and evaporated in vacuo. The residue was chromatographed
on silica gel &150 g) using hexane/ether &99:1, v/v) to give
the ester in 59% &4.0 g) yield as a colorless oil: IR &neat)
4.3. Photolyses of 4
4.3.1. Direct photolysis of 4. A solution of 4 &657 mg,
2.00 mmol) in hexane &400 cm3) was irradiated under
argon at room temperature for 33 h using a 6-W low-
pressure mercury lamp with a quartz jacket. After evapo-
ration of the solvent, the residual oil was subjected to
medium-pressure silica gel chromatography using 2%
ether±hexane as an eluent to give 3-isopropylidene-1,1-
bismethoxycarbonyl-5-methyl-4-phenyl-1,4-hexadiene &10:
26mg, 4%), 3-isopropylidene-2,2-bismethoxycarbonyl-5,5-
dimethyl-4-phenylbicyclo[2.1.0]pentane &11: 99 mg, 15%),
2-isopropylidene-3-oxa-4-methoxy-5-methoxycarbonyl-7,7-
dimethyl-1-phenylbicyclo[4.1.0]hept-4-ene &12: 118 mg,
18%), and methyl 2-methoxycarbonyl-3-methyl-1-&3,3-
dimethyl-2-phenylcyclopropen-1-yl)-2-pentenoate &13: 25 mg,
4%).
1
1972 &CvCvC), 1725 &CvO), 1649 &CvC) cm21; H
NMR &CDCl3, 90 MHz) d 1.23 &s, 6H, CH3-3£2), 1.82 &s,
6H, CH3-6£2), 3.71 &s, 3H, OCH3), 5.83 &d, 1H, J15.8 Hz,
vCH), 7.18 &d, 1H, Jˆ15.8 Hz, vCH), 7.20 &s, 5H, ArH);
13C NMR &CDCl3, 22.5 MHz) d 20.6&q, 2C), 27.4 &q, 2C),
40.5 &s), 51.4 &q), 97.7 &s), 110.4 &s), 118.0 &d), 126.4 &d),
127.8 &d, 2C), 128.8 &d, 2C), 137.7 &s), 157.9 &d), 167.4 &s),
201.8 &s); MS m/z &rel. intensity) 270 &M1, 7), 211 &15), 195
&10), 144 &13), 143 &100), 128 &29). HRMS Found: m/z
270.1584. Calcd for C18H22O2: M, 270.1621.
4.2.4. 1,1-Dicyano-4-phenyl-3,3,6-trimethyl-1,4,5-hepta-
triene ꢀ6). Malononitrile &2.0 g, 30 mmol) and 9 &6.4 g,
30 mmol) were dissolved with pyridine &5 cm3). The
mixture was stirred for 24 h at room temperature and then
acidi®ed with HCl &6mol dm 23). The mixture was extracted
with ether &50 cm3). The ethereal solution was dried over
MgSO4 and evaporated in vacuo. The residue was chroma-
tographed on silica gel with EtOAc/Hexane &5:95, v/v) as an
eluent to give 6 in 46% &3.5 g) yield as yellow crystals:
mp 958C &ether/hexane); IR &KBr) 2237 &CN) 1961
Data for 10. An oil; IR &neat) 1737 &CvO), 1597
1
&CvC) cm21; H NMR &400 MHz, CDCl3) d 1.66 &s, 3H,
CH3), 1.69 &s, 3H, CH3), 1.85 &s, 3H, CH3), 2.02 &s, 3H,
CH3), 3.51 &s, 3H, OCH3), 3.75 &s, 3H, OCH3), 7.24 &s,
5H, ArH), 7.85 &s, 1H, CH-2); 13C NMR &22.5 MHz,
CDCl3) d 21.2 &q), 22.0 &q), 23.1 &q), 23.3 &q), 51.9 &q,
OCH3), 52.5 &q, OCH3), 122.6&s), 12.60 &d), 127.3 &d,
2C), 129.3 &s), 129.8 &d, 2C), 131.9 &s), 133.2 &s), 135.0
&s) 140.5 &d), 147.6 &s), 165.9 &s, CO), 166.5 &s, CO); MS
m/z &rel. intensity) 328 &M1, 63), 296 &100). HRMS Found:
m/z 328.1725. Calcd for C20H24O4: 328.1675.
1
&CvCvC) cm21; H NMR &CDCl3, 90 MHz) d 1.48 &s,
6H, CH3-3£2), 1.83 &s, 6H, CH3-6£2), 7.11±7.40 &s, 5H,
ArH), 7.43 &s, 1H, CH-2); 13C NMR &CDCl3, 22.5 MHz) d
20.1 &q, 2C), 28.0 &q, 2C), 43.0 &s, C-3), 87.8 &s), 100.7 &s,
C-1), 109.1 &s), 110.7 &s, CN), 113.8 &s, CN), 127.1 &d, C-2),
128.3 &ds, 3C), 128.4 &d, 2C), 176.4 &d, C-2), 201.7 &s, C-5);
MS m/z &rel. intensity) 262 &M1, 8), 248 &21), 247 &100), 232
&46), 231 &18). Anal. calcd for C18H18N2: C, 82.41; H, 6.92;
N, 10.68. Found: C, 82.20; H, 7.06; N, 10.57.
Data for 11. Colorless crystalline solid: mp 102±1058C
1
&hexane); IR &neat) 1733 &CvO), 1602 &CvC) cm21; H
NMR &400 MHz, CDCl3) d 0.93 &s, 3H, CH3), 1.27 &s, 3H,
CH3), 1.57 &s, 3H, CH3), 1.73 &s, 3H, CH3), 2.29 &s, 1H,
1-CH), 3.77 &s, 3H, OCH3), 3.84 &s, 3H, OCH3),
4.2.5. 1,1-Dicyano-3,3,6-trimethyl-1,4,5-heptatriene ꢀ7)

4838
T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
7.22±7.50 &m, 5H, aromatic H); 13C NMR &22.5 MHz,
CDCl3) d 18.0 &q), 19.1 &q), 20.1 &q), 23.7 &q), 29.2 &s,
C-5), 36.4 &d, C-1), 48.1 &s, C-4), 52.1 &q, OCH3), 52.6&q,
OCH3), 57.4 &s, C-2), 126.7 &d), 127.9 &d, 2C), 129.0 &s),
130.2 &s), 131.2 &d, 2C), 137.7 &s), 170.9 &s, CO), 171.3 &s,
CO); MS m/z &rel. intensity) 328 &M1, 67), 193 &100). HRMS
Found: m/z 328.1731. Calcd for C20H24O4: 328.1675.
dimethyl-2-phenylcyclopropen-1-yl)-3-pentenoate &16: 81 mg,
15%), and methyl &Z)-4,4,7-trimethyl-5-phenyl-2,5,6-octa-
trienoate &17: 10 mg, 2%).
Data for 14. A colorless oil; IR &neat) 1720 &CvO), 1612
1
&CvC) cm21; H NMR &90 MHz, CDCl3) d 1.62 &s, 3H,
CH3), 1.77 &s, 3H, CH3), 1.83 &s, 3H, CH3), 2.01 &s, 3H,
CH3), 3.71 &s, 3H, OCH3), 5.79 &d, 1H, Jˆ15.4 Hz,
2-CH), 7.20 &s, 5H, ArH), 7.82 &d, 1H, Jˆ15.4 Hz, CH-3);
13C NMR &22.5 MHz, CDCl3) d 20.2 &q), 21.4 &q), 22.1 &q),
23.4 &q), 51.4 &q, OCH3), 117.7 &d, C-2), 126.1 &d), 127.7 &d,
2C), 129.4 &d, 2C), 132.3 &s), 132.9 &s), 135.1 &s), 141.1 &s)
142.0 &d, C-3), 142.9 &s), 168.4 &s, CO); MS m/z &rel. inten-
sity) 270 &M1, 64), 195 &56), 32 &100). HRMS Found: m/z
270.1565. Calcd for C18H22O2: 270.1621.
Data for 12. An oil: IR &neat) 1720 &CvO), 1682
1
&CvC) cm21; H NMR &400 MHz, CDCl3) d 1.04 &s, 3H,
CH3-7), 1.27 &s, 3H, CH3-7), 1.68 &s, 3H, CH3), 1,73 &3H, s,
CH3), 1.78 &s, 1H, CH-6), 3.70 &s, 3H, OCH3), 3.98 &s, 3H,
OCH3), 7.21±7.36&m, 5H, ArH); 13C NMR &22.5 MHz,
CDCl3) d 17.5 &q), 19.9 &q), 24.4 &q), 29.4 &q), 29.7 &s,
C-7), 32.1 &d, C-6), 50.9 &q, OCH3), 55.6&q, CH ), 79.4
3
&s, C-1), 118.2 &s), 126.1 &d), 128.3 &d and s, 3C), 130.2
&s), 142.4 &d, 2C), 144.6 &s), 163.5 &s, CO), 167.8 &s); MS
m/z &rel. intensity) 328 &M1, 10), 143 &100). HRMS Found:
m/z 328.1693. Calcd for C20H24O4: 328.1675.
Data for 15. A colorless oil; IR &neat) 1733 &CvO), 1602
1
&CvC) cm21; H NMR &90 MHz, CDCl3) d 0.92 &s, 3H,
CH3-5), 1.23 &s, 3H, CH3-5), 1.27 &s, 3H, CH3), 1.53 &s,
3H, CH3), 1.94 &s, 1H, CH-4), 3.16&br s, 1H, CH-3),
3.78&s, 3H, OCH3), 7.21±7.56&m, 5H, ArH); 13C NMR
&22.5 MHz, CDCl3) d 16.8 &q), 18.1 &q), 19.4 &q), 23.2 &q),
28.7 &s, C-5), 32.4 &d, C-4), 43.5 &d, C-3), 49.0 &s, C-1), 51.6
&q, OCH3), 125.5 &s, .Cv), 126.5 &d), 127.9 &d, 2C), 130.7
&s, .Cv), 131.3 &d, 2C), 138.3 &s), 174.3 &s, CO); MS m/z
&rel. intensity) 270 &M1, 28), 211 &100), 195 &63). HRMS
Found: m/z 270.1565. Calcd for C18H22O2: 270.1621.
Data for 13. An oil: IR &neat) 1824 &cyclopropene), 1741
1
&CvO) cm21; H NMR &400 MHz, CDCl3) d 1.32 &s, 6H,
CH3), 1.54 &d, Jˆ0.8 Hz, 3H, CH3), 1.82 &d, Jˆ1.1 Hz, 3H,
CH3), 3.78 &s, 6H, OCH3), 6.08 &septet, 1H, Jˆ1.1 Hz, 1H,
vCH), 7.26±7.49 &m, 5H, ArH); 13C NMR &22.5 MHz,
CDCl3) d 19.0 &q), 23.1 &s), 24.7 &q, 2C), 26.5 &q), 53.0
&q, 2C, OCH3), 58.3 &s), 120.3 &s), 123.4 &s), 125.1 &s),
128.3 &d), 128.5 &d, 2C), 129.1 &s), 129.6&d, 2C), 138.6
&s) 169.3 &s, 2C, CO); MS m/z &rel. intensity) 328 &M1,
17), 143 &100). HRMS Found: m/z 328.1670. Calcd for
C20H24O4: 328.1675.
Data for 16. A colorless oil; IR &neat) 1824 &cyclopropene),
1
1735 &CvO) cm21; H NMR &90 MHz, CDCl3) d 1.29 &s,
6H, CH3£2), 1.73 &d, 3H, Jˆ1.3 Hz, CH3), 1.80 &d, 3H, Jˆ
1.3 Hz, CH3), 3.74 &s, 3H, OCH3), 4.52 &d, 1H, Jˆ8.8 Hz,
CH-2), 5.52 &d septet, 1H, Jˆ8.8, 1.3 Hz, CH-3), 7.17±7.56
&m, 5H, ArH); 13C NMR &22.5 MHz, CDCl3) d 18.2 &q),
21.7 &q), 25.0 &s), 25.1 &q), 25.7 &q), 42.9 &d), 52.2 &q,
CH3O), 119.2 &d, CHv), 123.6&s, C-1), 127.8 &d), 128.5
&d, 2C), 129.1 &d, 2C), 129.6&s), 129.8 &s), 135.6&s), 172.2
&s, CO); MS m/z &rel. intensity) 270 &M1, 26), 211 &100).
HRMS Found: m/z 270.1574. Calcd for C18H22O2:
270.1621.
4.3.2. Acetone-sensitized photolysis of 4. A solution of 4
&657 mg, 2.00 mmol) in acetone &400 cm3) was irradiated
under argon at room temperature for 5 h using a 100-W
high-pressure mercury lamp with a pyrex jacket. After
evaporation of the solvent, the residual oil was subjected
to medium-pressure silica gel chromatography using 2%
ether±hexane as an eluent to give 10 &79 mg, 12%) and 11
&20 mg, 3%).
4.3.3. Anthraquinone-sensitized photolysis of 4. A ben-
zene solution &50 cm3) of 4 &155 mg, 0.472 mmol) and
anthraquinone &43 mg) in a pyrex tube was degassed with
argon and then irradiated for 6.5 h using a 100-W high-
pressure mercury lamp through a pyrex glass ®lter. The
ester 4 was consumed by 12% according to GLC analysis.
After evaporating solvent, the residue was subjected to
preparative TLC to give 11 in 19% &26mg) yield.
Data for 17. A colorless oil; IR &neat) 1983 &CvCvC),
1732 &CvO), 1639 &CvC) cm21 1H NMR &90 MHz,
;
CDCl3) d 1.41 &s, 6H), 1.79 &s, 6H), 3.64 &s, 3H, OCH3),
5.72 &d, 1H, Jˆ13.2 Hz, vCH), 6.22 &d, 1H, Jˆ13.2 Hz,
vCH), 7.25±7.29 &m, 5H, ArH); MS m/z &rel. intensity) 270
&M1, 9), 143 &100). HRMS Found: m/z 270.1569. Calcd for
C18H22O2: 270.1621.
4.4.2. Acetone-sensitized photolysis of 5. A solution of 5
&543 mg, 2.00 mmol) in acetone &400 cm3) was irradiated
under argon at room temperature for 15 h using a 100-W
high-pressure mercury lamp with a quartz jacket. After
evaporation of the solvent, the residue was subjected to
medium-pressure silica gel chromatography using ether/
hexane &2/98, v/v) as an eluent to give 14 &76mg, 14%)
and 15 &38 mg, 7%).
4.4. Photolyses of methyl ꢀE)-4,4,7-trimethyl-5-phenyl-
2,5,6-octatrienoate ꢀ5)
4.4.1. Direct photolysis of 5. A solution of 5 &543 mg,
2.00 mmol) in hexane &400 cm3) was irradiated under
argon at room temperature for 25 h using a 6-W low-pres-
sure mercury lamp with a quartz jacket. After evaporation of
the solvent, the residual oil was subjected to medium-pres-
sure silica gel chromatography using 2% ether±hexane as an
eluent to yield methyl &E)-4-isopropylidene-6-methyl-5-
phenyl-2,5-heptadienoate &14: 5 mg, 1%), trans-2-isopropyl-
idene-3-methoxycarbonyl-5,5-dimethyl-1-phenylbicyclo-
[2.1.0]pentane &15: 136mg, 25%), methyl 4-methyl-2-[&3,3-
4.5. Photolyses of 6
4.5.1. Direct photolysis of 6. A solution of 6 &996mg,
3.8 mmol) in acetonitrile &400 cm3) was irradiated under
an argon atmosphere using a 6-W low-pressure mercury

T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
4839
lamp with a quartz jacket. After evaporation of the solvent,
the residue was subjected to medium-pressure silica gel
chromatography using EtOAc/hexane &5:95, v/v). The ®rst
fraction gave 5,5-dicyano-2,7-dimethyl-4-phenyl-2,3,6-
octatriene &20) in 0.5% &5 mg) yield: IR &neat) 2200
205 &100), 204 &10), 203 &10), 194 &24), 190 &18), 165 &12),
43 &21), 28 &26). Anal. calcd for C18H18N2: C, 82.41; H,
6.92; N, 10.68. Found: C, 82.29; H, 7.09; N, 10.61.
4.5.3. Michler's ketone-sensitized photolysis of 6. An
acetonitrile solution &50 cm3) of 6 &134 mg, 0.52 mmol)
and Michler's ketone &30 mg) in a pyrex tube was degassed
with argon and then irradiated for 1 h using a 100-W high-
pressure mercury lamp through a pyrex glass ®lter. After
evaporated of the solvent, the residue was subjected to
preparative TLC using EtOAc/hexane &5:95, v/v) to give
19 in 64% &86 mg) yield.
1
&CN) cm21; H NMR &90 MHz, CDCl3) d 1.45 &s, 6H,
CH3£2), 1.88 &d, 3H, Jˆ1.4 Hz, vCCH3), 2.00 &d, 3H,
Jˆ1.4 Hz, vCCH3), 5.38 &septet, 1H,Jˆ1.4 Hz, vCH),
7.20±7.66 &m, 5H, ArH); MS m/z &rel. intensity) 262 &M1,
7), 248 &11), 247 &55), 232 &19), 144 &13), 143 &100), 128
&49), 127 &15), 115 &16), 103 &11) 91 &10), 77 &15). HRMS
Found: m/z 262.1491. Calcd for C18H18N2: 262.1471. The
next fraction gave 2,2-dicyano-3-isopropylidene-5,5-di-
methyl-4-phenylbicyclo[2.1.0]pentane &19) in 26% &255
mg) yield: colorless crystals &ether/hexane), mp 85±868C;
4.6. Photolyses of 7 and 8
1
IR &KBr) 2242 &CN) cm21; H NMR &CDCl3, 90 MHz) d
4.6.1. Direct photolysis of 7. A solution of 7 &761 mg,
4.1 mmol) in acetonitrile &400 cm3) was irradiated under
an argon atmosphere at room temperature for 5 h with a
100-W high-pressure mercury lamp with a quartz jacket.
After solvent removal, the residual oil was separated by
medium-pressure silica gel chromatography using EtOAc/
hexane &10:90, v/v). The ®rst fraction gave 3,3-dicyano-2,7-
dimethyl-2,5,6-octatriene &24: 5 mg, 0.7%); a yellow oil, IR
&neat) 2250 &CN) cm21; 1H NMR &90 MHz, CDCl3) d 1.83
[d, 6H, Jˆ2.7 Hz, CvCvC&CH3)2], 1.84 &d, 3H, Jˆ1.3 Hz,
1.03 &s, 3H, CH3), 1.36&s, 3H, CH 3), 1.60 &s, 3H, vCCH3),
1.84 &s, 3H, vCCH3), 2.37 &s, 1H, CH-1), 7.36&s, 5H, ArH);
13C NMR &CDCl3, 22.5 MHz) d 17.5 &q), 18.2 &q), 18.9 &q),
22.6&q), 29.3 &s), 29.8 &s), 34.2 &d), 50.2 &s), 113.8 &s), 115.1
&s), 125.6&s), 127.9 &d), 128.5 &d, 2C), 130.4 &d, 2C), 132.8
&s), 134.3 &s); MS m/z &rel. intensity) 262 &M1, 30), 248 &20),
247 &100), 233 &12), 232 &44), 231 &10), 220 &22), 219 &16),
206&11), 205 &19), 190 &10), 143 &10), 128 &19), 115 &13), 91
&11), 77 &14), 41 &11). Anal. calcd for C18H18N2: C, 82.41; H,
6.92; N, 10.68. Found: C, 82.58; H, 7.05; N, 10.69. The third
fraction gave 1,1-dicyano-3-isopropylidene-5-methyl-4-
phenyl-1,4-hexadiene &18) in 53% &524 mg) yield; yellow
crystals &ether/hexane); mp 82±868C; IR &KBr) 2224 &CN),
1583, 1560 cm21; 1H NMR &CDCl3, 90 MHz) d 1.54 &s, 3H,
CH3), 1.70 &s, 3H, CH3), 1.98 &s, 3H, CH3), 2.13 &s, 3H,
CH3), 7.10±7.45 &m, 5H, ArH), 7.83 &s, 1H, vCH); 13C
NMR &CDCl3, 22.5 MHz) d 21.3 &q, 2C), 22.7 &q), 24.2
&q), 80.3 &s), 112.4 &s), 115.5 &s), 126.6 &d), 127.8 &d, 2C),
128.6&s), 129.2 &d, 2C), 134.9 &s), 138.0 &s), 139.4 &s), 159.2
&d), 158.4 &s); MS m/z &rel. intensity) 263 &M111, 16), 262
&M1, 74), 248 &21), 247 &100), 233 &10), 232 &40), 231 &12),
230 &13), 220 &23), 219 &32), 218 &11), 207 &10), 106&16),
205 &22), 190 &10), 185 &48), 165 &13), 143 &16), 129 &10),
128 &17), 119 &14), 116&13), 115 &27), 103 &10), 91 &34), 77
&19), 51 &11), 41 &19), 39 &14). Anal. calcd for C18H18N2: C,
82.41; H, 6.92; N, 10.68. Found: C, 82.50; H, 7.08; N,
10.60.
CvCCH3), 1.98 &d, 3H, Jˆ1.3 Hz, CvCCH3), 5.23 &m, 2H,
1
CHvC and CHvCvC); MS m/z &rel. intensity) 186&M
,
1), 185 &6), 171 &13), 120 &13), 119 &20), 105 &6), 67 &100),
65 &15), 41 &30). HRMS Found: m/z 186.1153. Calcd for
C12H14N2: 186.1158. The second fraction gave 2,2-dicyano-
3-isopropylidene-5,5-dimethylbicyclo[2.1.0]pentane
&23:
1
47 mg, 6%): a yellow oil, IR &neat) 2243 &CN) cm21; H
NMR &90 MHz, CDCl3) d 1.06&s, 3H, CH ), 1.35 &s, 3H,
3
CH3), 1.69 &s, 3H, CH3), 1.81 &s, 3H, CH3), 2.17 &d, 1H,
Jˆ5.3 Hz, CH-1), 2.51 &d, 1H, Jˆ5.3 Hz, CH-4); 13C NMR
&22.5 MHz, CDCl3) d 16.1 &q), 18.1 &q), 18.5 &q), 23.2 &q),
26.5 &d), 27.8 &d), 29.4 &s, 2-C), 36.4 &s, C-5), 113.7 &s, CN),
114.9 &s, CN), 121.8 &s), 131.5 &s); MS m/z &rel. intensity)
186&M 1, 7), 172 &11), 171 &97), 169 &10), 156 &32), 155
&11), 145 &16), 144 &100), 143 &20), 130 &13), 117 &25), 116
&18), 91 &13), 77 &14), 67 &23), 65 &12), 51 &13), 43 &17), 41
&43), 38 &37). HRMS Found: m/z 186.1176. Calcd for
C12H14N2: 186.1158. The ®nal fraction gave 1,1-dicyano-
3-&3-methyl-1,2-butadienyl)-2,2-dimethylcyclopropane &22:
1
84 mg, 11%): a yellow oil, IR &neat) 2250 &CN) cm21; H
4.5.2. Acetone-sensitized photolysis of 6. The acetone
solution &400 cm3) of 6 &996mg, 3.8 mmol) was irradiated
under an argon atmosphere at room temperature for 4.5 h
using a 100-W high-pressure mercury lamp with a pyrex
jacket. After evaporation of the solvent, the residue was
subjected to medium-pressure silica gel chromatography
using 5% EtOAc±hexane as an eluent. The ®rst fraction
gave 19 in 38% &380 mg) yield. Next fraction gave 2-&1,1-
dicyanoethen-2-yl)-3-isopropyl-1,1-dimethylindene &21) in
9% &87 mg) yield: yellow crystals &ether); mp 91±928C; IR
&KBr) 2218 &CN) cm21; 1H NMR &CDCl3, 90 MHz) d 1.39
&s, 6H, CH3-1£2), 1.42 &d, 6H, Jˆ8.5 Hz, CH3£2), 3.27
&septet, 1H, Jˆ8.5 Hz, CH), 7.26±7.44 &m, 3H, aromatic
H, and vCH), 7.66±7.78 &m, 2H, ArH); 13C NMR
&CDCl3, 22.5 MHz) d 20.1 &q, 2C), 24.5 &q, 2C), 28.6&d),
49.8 &s), 82.1 &s), 114.1 &s), 114.9 &s), 122.0 &d), 124.3 &d),
127.0 &d), 129.3 &d), 138.6&s), 142.3 &s), 153.1 &d), 156.7 &s),
161.0 &s); MS m/z &rel. intensity) 262 &M1, 42), 247 &18),
232 &15), 231 &10), 221 &12), 220 &67), 219 &35), 206 &20),
NMR &90 MHz, CDCl3) d 1.39 &s, 3H, CH3), 1.48 &s, 3H,
CH3), 1.74 &d, 3H, Jˆ2.6Hz, C vCvCCH3), 1.75 &d, 3H,
Jˆ2.6Hz, C vCvCCH3), 2.35 &d, 1H, Jˆ7.6Hz, CH-3),
4.88 &dqq, 1H, Jˆ7.6, 2.6, and 2.6 Hz, CHvCvC); 13C
NMR &22.5 MHz, CDCl3) d 16.0 &s, C-1), 17.3 &q), 20.1
&q), 20.2 &q), 23.8 &q), 35.1 &s, C-2), 41.3 &d, C-3), 80.4 &d,
CHvCvC), 99.2 &s, CHvCvC), 113.0 &s, CN), 114.6&s,
CN), 205.9 &s, CHvCvC); MS m/z &rel. intensity) 186
&M1, 8), 171 &99), 156 &35), 144 &41), 80 &34), 79 &36), 67
&100), 41 &61), 38 &45). HRMS Found: m/z 186.1176. Calcd
for C12H14N2: 186.1158.
4.6.2. Direct Photolysis of 8. A solution of 8 &633 mg,
4.0 mmol) in acetonitrile &400 cm3) was irradiated under
an argon atmosphere at room temperature for 55 h with a
6-W low-pressure mercury lamp with a quartz jacket. After
solvent removal, the residual oil was separated by medium-
pressure silica gel chromatography using EtOAc/hexane

4840
T. Tsuno et al. / Tetrahedron 57 (2001) 4831±4840
&10:90, v/v) to yield 2,2-dicyano-5,5-dimethyl-3-methyl-
enebicyclo[2.1.0]pentane &26: 50 mg, 8%) and 1,1-di-
cyano-2,2-dimethyl-3-&1,2-propadienyl)cyclopropane &25:
363 mg, 57%).
actinometry.15 The photolyses were performed at conver-
sions of less than 20% of 4±6. The data are described in
Tables 2 and 3.
References
Data for 25. A yellow oil, IR 2242 &CN), 1954
1
&CvCvC) cm21; H NMR &90 MHz, CDCl3) d 1.40 &s,
1. For reviews on the photochemistry of the divinylmethanes,
see: &a) Zimmerman, H. E.; Armesto, D. Chem. Rev. 1996,
96, 3065±3112. &b) Zimmerman, H. E. In CRC Handbook of
Photochemistry and Photobiology, Horspool, W., Song, P.-S.,
Eds.; CRC: New York, 1995; pp 185±193. &c) Zimmerman,
H. E. Org. Photochem. 1991, 11, 1±36. &d) Zimmerman, H. E.
Acc. Chem. Res. 1982, 15, 312±317. &e) Zimmerman, H. E. In
Rearrangements in Ground and Excited States, DeMayo, P.,
Ed.; Academic: New York, 1980; pp 131±166. &f) Hixson,
S. S.; Mariano, P. S.; Zimmerman, H. E. Chem. Rev. 1973,
73, 531±551.
3H, CH3), 1.49 &s, 3H, CH3), 2.43 &ddd, 1H, Jˆ1.8, 4.2,
6.2 Hz, CH-3), 5.20 &m, 3H, CHvCvCH2); 13C NMR
&22.5 MHz, CDCl3) d 16.2 &s, C-1), 17.4 &q), 23.7 &q),
34.9 &s, C-2), 40.2 &d, C-3), 78.3 &t, CHvCvCH2), 82.4
&d, CHvCvCH2), 112.7 &s, CN), 114.3 &s, CN), 211.9 &s,
CHvCvCH2),; MS m/z &rel. intensity) 158 &M1, 16), 157
&38), 143 &100), 116 &95), 93 &36), 92 &57), 65 &32), 51 &38),
39 &61). HRMS Found: m/z 158.0836. Calcd for C10H10N2:
158.0845.
1
Data for 26. A yellow oil, IR 2245 &CN) cm21; H NMR
2. Zimmerman, H. E.; Factor, R. E. Tetrahedron 1981, 37
&Suppl. 1), 125±141.
&90 MHz, CDCl3) d 1.08 &s, 3H), 1.41 &s, 3H), 2.37 &d, 1H,
Jˆ4.9 Hz, CH-1), 2.63 &br d, 1H, Jˆ4.9 Hz, CH-4), 5.22 &d,
1H, Jˆ2.6Hz, vCH), 5.34 &dd, 1H, Jˆ1.4, 2.6Hz, vCH);
13C NMR &22.5 MHz, CDCl3) d 16.1 &q), 23.2 &q), 27.2 &s),
30.5 &sd, 2C), 38.5 &d), 111.1 &t, vCH2), 113.3 &s, CN),
115.1 &s, CN), 138.8 &s, C-3); MS m/z &rel. intensity) 158
&M1, 4), 143 &87), 116&100), 93 &30), 38 &32). HRMS
Found: m/z 158.0858. Calcd for C10H10N2: 158.0845.
È
3. &a) Baeckstrom, P. Tetrahedron 1978, 34, 3331±3335.
È
&b) Baeckstrom, P. J. Chem. Soc., Chem. Commun. 1976,
476±477. &c) Bullivant, M. J.; Pattenden, G. J. Chem. Soc.,
Perkin Trans. 1 1976, 256±258.
4. &a) Zimmerman, H. E.; Armesto, D.; Amezua, M. G.; Gannett,
T. P.; Johnson, R. P. J. Am. Chem. Soc. 1979, 101, 6367±6383.
&b) Zimmerman, H. E.; Cassel, J. M. J. Org. Chem. 1989, 54,
3800±3816.
4.6.3. Acetone-sensitized photolysis of 7 and 8. The
acetone solution &400 cm3) of 7 or 8 &0.01 mol dm23) was
irradiated under an argon atmosphere at room temperature
using a 100-W high-pressure mercury lamp with a pyrex
jacket. After evaporation of the solvent, the residue was
subjected to medium-pressure silica gel chromatography
to yield 23 or 26. The yields of the products are described
in Table 1.
5. We have published recently on the `Allenyl&vinyl)methane
Photochemistry'; Tsuno, T.; Sugiyama, K. In Recent Research
Developments in Organic Chemistry; Pandalai, S. G.; Ed.;
1999; Vol. 3, pp 435±453.
6. &a) Sugiyama, K.; Tsuno, T. Chem. Express 1992, 7, 929±932.
&b) Tsuno, T.; Sugiyama, K. Bull. Chem. Soc. Jpn 1999, 72,
519±531.
7. &a) Tsuno, T.; Sugiyama, K. Bull. Chem. Soc. Jpn 1995, 68,
3175±3188. &b) Tsuno, T.; Sugiyama, K. Chem. Lett. 1991,
503±507.
4.7. MO calculation
8. Tsuno, T.; Hoshino, H.; Sugiyama, K. Tetrahedron Lett. 1997,
38, 1581±1584.
MO calculation was performed using the UHF method for
the biradical intermediate 31 and the RHF method for 14
and 2,2-dimethylpropylidenemalononitrile of Mac Spartan
Plus of Wavefunction, Inc.
9. Sugiyama, K.; Yoshida, M.; Tsuno, T. Heterocycles 1994, 38,
1721±1726.
10. Lehnert, W. Tetrahedron 1973, 29, 635±638.
11. An ortep drawing of 11 was summarized in our previous
communication8 and its crystallographic data for the structure
have been deposited at the Cambridge Crystallographic Data
Centre as refcode RUHCAY. Copies of the data can be
obtained free of charge on application to CCDC, 12 Union
Road, Cambridge CB2 1EZ, UK &fax: 144-&0)1223-336033,
e-mail: deposit@ccdc.cam.ac.uk).
4.8. Measurements of quantum yields
The quantum yields for the isomerization of 4±6 to the
photoproducts were measured by GCL or NMR analyses,
and the photolyses were carried out by a merry-go-round
method. A 6-W low-pressure mercury lamp with a quartz-
glass ®lter was used as a 254-nm irradiation source. On the
other hand, a 450-W high-pressure mercury lamp with a
combination of a K2CrO4 solution and a pyrex glass ®lter
was used as a 313-nm irradiation source; the same lamp with
a combination of a CuSO4 solution and a Corning 7-37 glass
®lter was used as a 365-nm irradiation source. Argon was
bubbled into a solution &10 cm3) of 4±6 &0.01 mol dm23) in
a quartz or pyrex tube. The solution was irradiated at room
temperature using each of the above lamps. The light inten-
sity of the 254- and 365-nm irradiation sources was deter-
mined by tris&oxalato)ferrate&III) actinometry,15 while that
of the 313-nm radiation source was determined by stilbene
12. Fujita, K.; Matsui, K.; Shono, T. J. Am. Chem. Soc. 1975, 97,
6256±6257.
13. Kamphuis, J.; Bos, H. J. T.; Visser, R. J.; Huizer, B. H.;
Varma, C. A. G. O. J. Chem. Soc., Perkin Trans. 2 1986,
1867±1874.
14. &a) Scheider, R. A.; Meinwald, J. J. Am. Chem. Soc. 1967, 89,
2023±2032. &b) Meinwald, J.; Kobzina, J. W. J. Am. Chem.
Soc. 1969, 91, 5177±5178.
15. Kuhn, H. J.; Braslavsky, S. E.; Schmid, R. Pure Appl. Chem.
1989, 61, 187±210.