Remarkable interaction effects of molecular packing on site- and stereoselectivity in photocycloaddition of 2-pyrones with maleimide in the solid state

Article abstract of DOI:10.1016/S0040-4020(00)01108-X

Solid-state photoirradiation of 1:1 complex crystals of 4-[ω-(2-furyl)alkyloxy]-6-methyl-2-pyrones 1b, 1c or 4-(ω-arylalkyloxy)-6-methyl-2-pyrones 1d-j with maleimide 2 gave [2+2]cycloadducts 3b-f, 3i, 3j with exclusive stereoselectivity. The high reaction selectivity was confirmed by X-ray structure analyses and MO method of the complex crystals, which were composed of two sets of a 1:1 complex between 1 and 2, arising from an CH-π interaction between 2 and the aromatic rings of 1, and/or π-π stacking between the aromatic rings in addition to four kinds of hydrogen bonding between the ground state 2-pyrone moieties and 2.

Full text of DOI:10.1016/S0040-4020(00)01108-X

TETRAHEDRON
Pergamon
Tetrahedron 57 (2001) 1531±1541
Remarkable interaction effects of molecular packing on site- and
stereoselectivity in photocycloaddition of 2-pyrones with
maleimide in the solid state
a,²
Toru Obata, Tetsuro Shimo, Mikio Yasutake, Teruo Shinmyozu, Masaru Kawaminami,
b
b
b
c
a
Ryosuke Yoshida and Kenichi Somekawa
a,p
a
Department of Applied Chemistry and Chemical Engineering, Faculty of Engineering, Kagoshima University, Korimoto 1-21-40,
Kagoshima 890-0065 Japan
b
Institute for Fundamental Research of Organic Chemistry (IFOC), Kyushu University, Hakozaki 6-10-1, Higashi-ku,
Fukuoka 812-8581 Japan
c
Department of Physics, Faculty of Science, Kagoshima University, Korimoto 1-21-35, Kagoshima 890-0065 Japan
Received 11 September 2000; accepted 20 November 2000
AbstractÐSolid-state photoirradiation of 1:1 complex crystals of 4-[v-(2-furyl)alkyloxy]-6-methyl-2-pyrones 1b, 1c or 4-(v-arylalkyl-
oxy)-6-methyl-2-pyrones 1d±j with maleimide 2 gave [212]cycloadducts 3b±f, 3i, 3j with exclusive stereoselectivity. The high reaction
selectivity was con®rmed by X-ray structure analyses and MO method of the complex crystals, which were composed of two sets of a 1:1
complex between 1 and 2, arising from an CH±p interaction between 2 and the aromatic rings of 1, and/or p±p stacking between the
aromatic rings in addition to four kinds of hydrogen bonding between the ground state 2-pyrone moieties and 2. q 2001 Elsevier Science Ltd.
All rights reserved.
1
. Introduction
surroundings for controlling the selectivity of photochemi-
cal reactions because of the tight and regular arrangement of
the molecules in the crystals, using a noncovalent inter-
3
Photochemical [212]cycloadditions in solution have been1
utilized to synthesize many kinds of important compounds.
The photoreactions were, however, not so regio- and stereo-
action like a hydrogen bond, charge transfer interaction,
or p±p stacking. Much attention has been paid to the
2
3
[212]- and [414] photodimerization reactions in the
selective. On the other hand, organic solid-state photo-
reactions are strictly controlled by their crystal structures
and can therefore be highly selective. Single- and two-
component organic crystals recently supplied ideal
crystals including the asymmetric synthesis in host±guest
inclusion complexes together with intramolecular cycli-
4
5
zation and valence isomerization, but only limited
6
Scheme 1.
Keywords: solid-state photochemistry; cycloaddition; 2-pyrones; hydrogen bonding; CH±p interaction; p±p stacking.
Corresponding author. Tel.: 181-99-285-8330; fax: 181-99-285-8334; e-mail: some@apc.kagoshima-u.ac.jp
Present address: National Institute of Materials and Chemical Research, Tsukuba-shi Higashi 1-1, 305-8565, Japan.
p
²
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020(00)01108-X

1
532
T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
Scheme 2.
3 4
Scheme 3. Conditions: (a) PPh , CCl ; (b) 4-hydroxy-6-methyl-2-pyrone, DBU.
investigation of [212] cycloaddition between two different
organic molecules has been reported.
between 4-[v-(2-furyl)alkyloxy]-6-methyl-2-pyrones (1b,
1c) or 4-(v-arylalkyloxy)-6-methyl-2-pyrones (1d±j) and
maleimides, using their intermolecular multiple interactions
to control the molecular packing. Correlation between the
mutual geometry of some groups in the complex crystals
and the photochemical behavior may be analyzed by X-ray
crystal analyses.
7
8
We have reported, as shown in Scheme 1, that the peri-
(
[212] or [412]), site-(3,4- or 5,6-addition) and regio-
selective photoadducts in the triplet photoreactions of
-pyrones with electron-de®cient or electron-rich alkenes
2
in solution were considered to be formed through the regio-
selective 3-b or 6-b two-center interaction at the ®rst-step,
and periselective ring-closure from the biradical inter-
mediates. The two-step cycloaddition selectivities were,
however, not so high. We showed recently that the solid-
state photocycloaddition reaction of 4-methoxy-6-methyl-2-
pyrone 1a with maleimide, gave a [212]cycloadduct, peri-,
site-, and stereo-selectively, by using hydrogen bonding
Table 1. Melting points of the starting materials and 1:1 complex crystals
prepared by the method
2 Pyrone (8C)
1:1 Complex crystal (8C)
1d (83±85)
1f (68±72)
1d´2 (99±101)
1f´2 (75±77)
9
between 1a and 2 (Scheme 2). Overlapping or short
1
1
i (142±143)
j (119±120)
1i´2 (140±141)
1j´2 (109±110)
distance between the two substrates and also some sub-
stituents of the substrates in the solid state may control the
cross-photocycloaddition. We planned photoreactions
Maleimide (mp 92±948C).

T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
1533
Scheme 4.
2
. Results and discussion
.1. Synthesis of compounds 1b±j
-Pyrones, 1b±j, were prepared by dehydrohalogenative
24 h gave [212]cycloadduct 3d in 70% yield as the sole
product together with recovery of 1d´2 (23%) (Scheme 4).
The structure of 3d was established fully by spectroscopic
data (IR, MS and H and C NMR; see Section 4) and
determined by an X-ray structure analysis. Similar irradia-
tion of the 1:1 complex crystals 1f´2, 1i´2, and 1j´2 afforded
[212]cycloadducts 3f, 3i and 3j in 90, 52 and 65% yields,
respectively, with each recovery of 1´2. The structure of 3f
was also determined by single-crystal X-ray diffraction. It
was dif®cult to prepare the 1:1 complex crystals of 1b´2,
2
1
13
2
coupling between 4-hydroxy-6-methyl-2-pyrone and halo-
genated alkylaromatic compounds with a base in 27±71%
yields (Scheme 3).
2
.2. Preparation of 1:1 complex crystals
1
c´2, 1e´2, 1g´2 and 1h´2 by the crystallization method (a).
Irradiation of the mixtures of 1b and 2, 1c and 2, 1e and 2,
g and 2, and 1h and 2 prepared by method (b) gave
212]cycloadducts 3b, 3c and 3e in 100, 45 and 82% yields,
respectively, with recovery of 1c´2 and 1e´2. Neither method
b) nor (c) afforded photocycloadduct of 1g with 2 or 1h
1
:1 Complex crystals of 2-pyrones 1 with maleimide 2 were
prepared by three methods of the two equimolar substrates:
a) crystallization from an appropriate solvent; (b) evapo-
ration of the solvent from a solution containing the
substrates; (c) grinding the substrates with a mortar and
pestle. The melting points of the crystals obtained by
method (a) showed higher values than that of both or one
substrate (Table 1).
1
[
(
(
1
0
2.3. Photochemical results
Irradiation of a 1:1 complex crystal 1d´2 (1.0 mmol) (color-
less prisms, mp 99±1018C) between 1d (mp 83±858C) and 2
(mp 92±948C), which was prepared by the crystallization
method (a) from a CHCl solution, at room temperature for
3
Table 2. Grinding-time effect for photocycloadditions of the mixtures
between 2-pyrones and maleimide
a
Grinding time (min)
Yield of 3 (%)
3
d
3e
3f
3i
3j
5
1
3
81
89
96
66
72
74
81
90
90
59
63
89
39
43
89
0
0
All mixtures of 1d, 1e, 1f, 1i and 1j (0.50 mmol) with 2 (0.50 mmol) were
ground for 5±30 min and irradiated for 24 h.
Figure 1. Molecular packing diagram by hydrogen bondings, CH±p, and
p±p interactions in the 1:1 complex crystal of 1d with 2.
a
1
Yields were calculated by H NMR and no other product formed.

1
534
T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
Figure 2. Molecular packing diagram of the 1:1 complex crystal of 1d with 2.
Ê
Ê
with 2. The yields of the products 3d, 3e, 3f, 3i and 3j were
increased by longer irradiation and prolonged mixing time
of the mixtures using method (c) (Table 2). This means
intermolecular interactions in this system are very effective
for the molecular packing.
double bonds are 3.65 A (C(6)´´´C(13)) and 3.81 A
(C(5)´´´C(14)), which are within the normal photoreaction
1
3
distances in the solid state (Fig. 2). Such crystal structure
is inferred to be effectively brought about by four types of
hydrogen bondings, two-layer electrostatic interactions
between the 2-pyrone ring and 2, and p±p stacking between
two benzene rings, which is in contrast to the fact that pure
2.4. X-Ray analyses of the complex crystals and the
photochemical behavior
1
4
benzene adopts a CH±p interaction structure and the
structure of the benzene±hexa¯uorobenzene material is
composed of p±p stacking of alternating molecules in the
The reaction selectivity in the solid-state photoreactions of
1:1 complex crystals 1d´2, 1f´2, 1i´2 and 1j´2 can be viewed
1
5,16
solid state.
The p±p stacking arrangement of tethered
from X-ray crystallographic analyses of the single crystals,
which were prepared by crystallization from CHCl , CH Cl
2
benzene rings in this study is inferred to be caused by the
packing effect around the benzene rings. On the other hand,
a CH±p interaction was observed between 2 and the
benzene ring of 1 (Fig. 1). Although the CT complex
absorption band of 1d´2 was not observed from the UV
measurements in the solid phase and in solution, the over-
lapping structure of 1d with 2 in the crystal is inferred to be
formed by the electrostatic interaction. The solid-state
photoreaction of the complex crystal 1a with 2 gave
a [212]cycloadduct, but that of 4,6-dimethyl-2-pyrone
with 2 did not afford the cycloadduct. 2-Pyrone±
Ê
O(ether)´´´HCv(maleimide) (2.47 A) hydrogen bonding is
considered to be necessary for the photocycloaddition. It
may work to orient the two reactive double bonds sterically.
3
2
or MeCN, as a consequence of the crystal topology. In the
case of 1d´2, as can be seen in Fig. 1, the crystals contain
hydrogen bondings between the O±CvO and HN groups
Ê
with the O´´´H distance of 2.02 A, together with
Ê
C(4)vC(3)H´´´OvC±N (2.51 A), C(6)vC(5)H´´´OvC±N
Ê
Ê
(
(
2.48 A)
and
2.47 A) (the last two hydrogen bondings were recognized
2-pyrone±O(ether)´´´HCv(maleimide)
9
newly). The CH´´´O type of hydrogen bonding in the crystal
has been recognized as an important interaction in determin-
1
1
ing the molecular packing. CH±p interactions, which
have been suggested to play important roles in the crystal
1
2
structure of host±guest compounds,
Ê
between the
maleimide ole®n and benzene (3.0 A), and p±p stacking
Ê
between two benzene rings (3.8 A) were also observed.
X-ray crystallographic analyses of 1i´2 and 1j´2 showed
results similar to those of 1d´2 with respect to bond
distances between the reacting double bonds, hydrogen
bonds, CH±p interaction between 2 and the benzene ring,
and p±p stacking between the aromatic rings (Figs. 3 and
4). These results are summarized in Table 3. On the other
hand, as can be seen in Fig. 5, X-ray crystallographic analy-
sis of 1f´2 showed a CH±p interaction between the benzene
rings instead of the p±p stacking shown in 1d´2, 1i´2 and
1j´2. The fact that the calculated density value of the 1:1
These hydrogen bondings were suggested from the lower
wavelength shifts of the carbonyl groups in the IR spectra:
2
1
lactone and imide carbonyls showed 17 and 13 cm shifts,
respectively, from each original absorption band. It is
considered that these weak interactions afforded the higher
melting points of the 1:1 complex crystals than that of each
substrate. The angles between reactive ole®n carbons in 1d
and 2 are 102.78 (C(6)±C(5)±C(14)), 75.08 (C(5)±C(6)±
C(13)), 111.58 (C(6)±C(13)±C(14)), 68.88 (C(5)±C(14)±
C(13)), and intermolecular distances of the two reacting
2
3
complex crystal 1f´2 (1.280 g cm ) became smaller than

T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
1535
Figure 3. Molecular packing diagram by hydrogen bondings, CH±p, and p±p interactions in the 1:1 complex crystal of 1i with 2.
2
3
that of 1d´2 (1.330 g cm ) from the X-ray crystal data. A
comparison of the packing diagram of the 1f´2 with the other
complex crystals suggested an enlargement of the vacant
space between 1f and 2 owing to the steric hindrance of a
p-methyl group at the benzene ring. The p-phenyl group of
2
3
1i´2 (1.387 g cm ) stacked with another molecule of 1i
prefer steric hindrance to give a tight packing structure
(Fig. 3). Preparation of the 1:1 complex crystal of 1g
Figure 4. Molecular packing diagram by hydrogen bondings, CH±p, and p±p interactions in the 1:1 complex crystal of 1j with 2.

1
536
T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
Table 3. Features of 1:1 complex crystals 1d´2, 1f´2, 1i´2 and 1j´2 from the X-ray structure analyses
Distances between two reacting
Ê
double bonds (A)
Hydrogen
Ê
bonds (A)
Interaction of aromatic±
Ê
aromatic rings (distance, A)
Interaction of aromatic ring±
Ê
maleimide (distance, A)
a
1d´2
1f´2
1i´2
1j´2
3.65, 3.81
3.65, 3.77
3.52, 3.70
3.49, 3.57
2.02
p±p (3.8)
CH±p (3.0)
CH±p (3.0)
CH±p (3.0)
CH±p (2.9)
b
2
2
2
.51
c
.48
d
.47
a
2.02
CH±p
b
2
2
2
.42
c
.51
d
.55
a
1.91
p±p (3.8)
p±p (3.6)
b
2
2
2
.39
c
.48
d
.45
a
2.06
b
c
2
2
2
.47
.37
d
.49
a
b
c
d
C(2)vO´´´HN.
C(3)±H´´´CvO.
vC(5)±H´´´OvC(maleimide).
Pyrone±O´´´HCv(maleimide).
(
2
p-methoxyphenyl group) or 1h (p-nitrophenyl group) with
was dif®cult despite many crystallization trials and the
adduct 5i in 13% yield, which was formed through
decarboxylation of the [412]cycloadduct followed by addi-
tion of another molecule of 2, in addition to 3i (9%) and
unidenti®ed compounds. Similar sensitized photoreactions
of 1b, 1d with 2 gave bis-adducts 5b, 5d as major products.
These results suggest that the arrangement in parallel orien-
tation by the CvO´´´HN hydrogen bonding control the
photocycloaddition reaction in the solid state.
9
mixtures of 1g and 2, and 1h and 2 were also found to be
completely photostable, even after photolysis for 48 h.
Since the crystal packing depends on numerous polar inter-
actions, the change in the crystal structure owing to the polar
nature of the methoxy or nitro group seems to prevent the
favorable parallel orientation of the two sets of 1:1 complex
between 1 and 2 such that a photocycloaddition reaction is
precluded.
The arrangement of 1 and 2 in the crystal is explained by
some electrostatic interactions including hydrogen bonding
of the two substrates at the ground state. The interactions are
con®rmed by the calculated atomic charges of the ground
states of 1d and 2 as shown in Fig. 6. It shows four kinds of
hydrogen bonding interactions, a CH±p interaction
between 2 and the benzene ring, and overlapping between
electronegative C(5) of 1d and an electropositive carbonyl
carbon of 2. The overlapping distance is observed to be
The photoreactions of 1b±j with N-methylmaleimide and
N-phenylmaleimide, whose substrates gave no 1:1 complex
crystals with 1b±j, did not afford cycloadduct in the solid
state. The substrates were also almost inactive with 1b±j in
solution photoreaction. On the other hand, sensitized photo-
irradiation to a solution of 1i and maleimide 2, whose solid-
state photoreaction afforded only 3i, gave exo±endo bis-
Figure 5. Molecular packing diagram by hydrogen bondings, CH±p interactions in the 1:1 complex crystal of 1f with 2.

T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
1537
HX110A (FAB MS) using m-nitrobenzyl alcohol as matrix.
Elemental analyses were made using a Yanaco MT-5.
Photoirradiations were carried out in a Pyrex tube by
using Riko 400 W high pressure mercury lamp equipped
with a merry-go-round apparatus.
4-[3-(2-Furylpropoxy)]-6-methyl-2-pyrone (1c) was pre-
pared according to the method described in the literature.
1
7
Single crystal X-ray diffraction analysis of 1d´2 was
performed on an Enraf±Nonius CAD4 diffractometer, and
those of 1f´2, 1i´2, 1j´2, 3d, 3e, 3f were performed on a
Rigaku RAXIS-RAPID Imaging diffractometer with
graphite-monocromated Mo Ka radiation. Lorentz and
polarization corrections were applied to the intensity data.
1
8
The structures were solved by direct methods using SIR92
1
9
or SIR88 and re®ned by a full-matrix least-squares
method. The non-hydrogen atoms were re®ned isotropi-
2
0
cally. All calculations were performed using the teXsan
crystallographic software package.
²
Figure 6. Calculated atomic charges of the two ground states of 1d and 2,
and their interactions.
4.1.1. 4-(2-Furyloxy)-6-methyl-2-pyrone (1b). A solution
of furfuryl alcohol (6.6 g, 67 mmol) and triphenylphosphine
(21 g, 80 mmol) in CCl (60 ml) was re¯uxed for 70 min
4
Ê
3.89 A from the X-ray crystallographic analysis. On the
basis of these results, photocycloaddition reactions of 1
with 2 in the solid state shown in Scheme 4 are con®rmed
to be exclusively peri-, site- and stereo-selective.
under nitrogen atmosphere. The solution was allowed to
cool to room temperature, and hexane (100 ml) was
added. Resulting solid was ®ltered and the ®ltrate was
evaporated. A solution of the concentrate in MeCN
(
50 ml) was added to 4-hydroxy-6-methyl-2-pyrone (6.3 g,
3
. Conclusions
50 mmol), then DBU (9.7 g, 64 mmol) was added dropwise
and re¯uxed for 19.5 h. The solution was evaporated and
submitted to column chromatography (silica gel, ethyl
acetate±hexaneˆ1:1) to give 1b, which was puri®ed by
recrystallization from hexane. 1b (2.7 g, 27% yield): mp
This work revealed interesting multiple factors of 1:1
complex crystals 1´2, which served as photoreactive
molecules in the solid state. The combination of four
kinds of hydrogen bondings, CH±p interaction, p±p
stacking and electrostatic interaction in the ground state
arranged the two sets of molecules between two layers
and oriented the reactive C5±C6 double bond of the
2
1
1
110±111.58C; IR (KBr) 1734 cm ; H NMR (CDCl ) d
3
2.20 (3H, s), 4.96 (2H, s), 5.55 (1H, s), 5.79 (1H, s), 6.41
(1H, m), 6.48 (1H, m), 7.47 (1H, m); LR MS m/z 206 (M ).
1
Anal. Calcd for C11
63.97; H, 4.87.
H O : C, 64.07; H, 4.89. Found: C,
10 4
2
-pyrone ring with the ole®nic moiety of maleimide.
Thus, highly stereoselective photocycloaddition reactions
were possible (the two ole®ns were nearly parallel and
4.1.2. 4-Benzyloxy-6-methyl-2-pyrone (1d). 1d was
prepared according to a similar method mentioned above
by using benzyl alcohol (7.2 g, 67 mmol), triphenylphos-
Ê
separated by less than 4.0 A). Of the nine crystalline
materials prepared by three methods (crystallization,
evaporation of the solvent, and grinding of the two
substrates), all but two (1g and 1h with 2) underwent the
anticipated photocycloaddition reactions. The stereo-
chemistry of the photocycloadduct and/or X-ray structural
analysis of the 1:1 complex crystals 1´2 revealed the
stacked interaction between 1 and 2 in the crystals. This
favorable molecular feature should prove promising in the
application of this concept to other ole®n systems for stereo-
chemically controlled [212]photocycloadditions in the
solid state.
phine (21 g, 81 mmol), CCl
2-pyrone (6.3 g, 50 mmol) and DBU (9.7 g, 64 mmol). 1d
(60 ml), 4-hydroxy-6-methyl-
4
2
1 1
(3.8 g, 35% yield): mp 83±848C; IR (KBr) 1735 cm ; H
NMR (CDCl ) d 2.21 (3H, s), 5.01 (2H, s), 5.50 (1H, s),
5.84 (1H, s), 7.3±7.5 (5H, m); LR MS m/z 216 (M ). Anal.
3
1
Calcd for C13
5.60.
H O : C, 72.21; H, 5.59. Found: C, 72.27; H,
12 3
4.1.3. 4-(3-Phenylpropoxy)-6-methyl-2-pyrone (1e). 1e
was prepared by a method similar to that of 1b by using
3
-phenyl-1-propanol (9.1 g, 67 mmol), triphenylphosphine
21 g, 81 mmol), CCl4 (60 ml), 4-hydroxy-6-methyl-2-
pyrone (6.3 g, 50 mmol) and DBU (9.7 g, 64 mmol). 1e
(
4. Experimental
2
1 1
(4.0 g, 32% yield): mp 79±808C; IR (KBr) 1708 cm ; H
NMR (CDCl
4.1. General
3
) d 2.08 (2H, quint, Jˆ6.8 Hz), 2.21 (3H, s),
All melting points are uncorrected. NMR spectra were
measured at 400 MHz on the JNM GSX-400 (TMS as an
internal standard). IR spectra were recorded with a JASCO
IR Report-100 spectrometer as KBr disks. Mass spectra
were recorded with a JEOL LMS-OISG or a JEOL JMS-
²
Crystallographic data have been deposited at the CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK and copies can be obtained on request, free of
charge, by quoting the publication citation and deposition numbers
151239-151245 for 1d´2, 1f´2, 1i´2, 1j´2, 3d, 3e and 3f, respectively.

1
538
T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
2
.76 (2H, t, Jˆ6.8 Hz), 3.92 (2H, t, Jˆ6.8 Hz), 5.34 (1H, s),
4.2. Typical procedures of 1:1 complex crystal
preparation.
1
.79 (1H, s), 7.16±7.32 (5H, m); LR MS m/z 244 (M ).
5
Anal. Calcd for C H O : C, 73.75; H, 6.60. Found: C,
1
5
16
3
73.68; H, 6.60.
(a) 2-pyrone 1 (0.50 mmol) and maleimide 2 (0.50 mmol)
were dissolved in hot CHCl , CH Cl or MeCN. The solu-
3
2
2
4.1.4. 4-(4-Methylbenzyloxy)-6-methyl-2-pyrone (1f). A
solution of p-methylbenzyl chloride (7.0 g, 50 mmol), 4-hy-
droxy-6-methyl-2-pyrone (6.3 g, 50 mmol) and DBU (9.7 g,
64 mmol) in MeCN (50 ml) was re¯uxed for 19.5 h. The
tion was allowed to cool slowly to room temperature, during
which ®ne crystals were formed. (b) Acetone solution of 1
(0.50 mmol) and 2 (0.50 mmol) in a Pyrex tube was evapo-
rated using rotary evaporator at room temperature. (c) A
mixture of 1 (0.50 mmol) and 2 (0.50 mmol) was ground
together in a mortar and for 30 min.
solution was allowed to cool to room temperature, and
was evaporated. The concentrate was submitted to column
chromatography (silica gel, ethyl acetate±hexaneˆ 1:1) to
give 1f, which was puri®ed by recrystallization from
hexane±ethanol (1:1). 1f (4.6 g, 40% yield): mp 68±728C;
4.3. 1b´2 1:1 Complex crystal
2
1 1
IR (KBr) 1730 cm ; H NMR (CDCl ) d 2.20 (3H, s), 2.37
3
Since the preparation of 1:1 complex crystal by method (a)
is dif®cult, treatment of a solution of 1b (41 mg, 0.20 mmol)
and 2 (20 mg, 0.20 mmol) in acetone (5 ml) by method (b)
gave 1b´2. Mp 101±1048C.
(
3H, s), 4.97 (2H, s), 5.52 (1H, s), 5.82 (1H, s), 7.20 (2H, d,
1
Jˆ7.6 Hz), 7.26 (2H, d, Jˆ7.6 Hz); LR MS m/z 230 (M ).
Anal. Calcd for C H O : C, 73.03; H, 6.13. Found: C,
14
1
4
3
73.13; H, 6.12.
4
.3.1. 11-(2-Furfuryloxy)-7-methyl-8-oxa-4-azatricyclo-
2
,6
4
1
.1.5. 4-(4-Methoxybenzyloxy)-6-methyl-2-pyrone (1g).
g was prepared by a method similar to that of 1b by
[5.4.0.0 ]undec-10-en-3,5,9-trione (3b) from the photo-
lysis of 1b´2. Crystals of 1b´2 (60 mg, 0.20 mmol) were
photolyzed in a Pyrex tube for 24 h under nitrogen atmos-
using 4-methoxybenzyl alcohol (9.2 g, 67 mmol), tri-
phenylphosphine (21 g, 80 mmol), CCl (60 ml), 4-hydroxy-
1
phere at room temperature. H NMR revealed quantitative
4
6
6
-methyl-2-pyrone (6.3 g, 50 mmol) and DBU (9.7 g,
4 mmol). 1g (4.0 g, 32% yield): mp 109±1128C; IR
conversion to cycloadduct 3b, which was recrystallized
from MeCN. Mp 170±1738C; IR (KBr) 3450, 1780,1735,
1710 cm ; H NMR (DMSO-d ) d 1.58 (3H, s), 3.41 (1H,
2
1
1
21 1
(
(
KBr) 1730 cm ; H NMR (CDCl ) d 2.20 (3H, s), 3.83
3
3H, s), 4.93 (2H, s), 5.50 (1H, s), 5.80 (1H, s), 6.92 (2H, d,
6
d, Jˆ6.0 Hz), 3.51 (1H, dd, Jˆ6.0, 9.2 Hz), 3.64 (1H, d,
Jˆ9.2 Hz), 4.82 (1H, d, Jˆ12.4 Hz), 5.02 (1H, d,
Jˆ12.4 Hz), 5.46 (1H, s), 6.50 (1H, m), 6.60 (1H, m),
1
Jˆ8.4 Hz), 7.30 (2H, d, Jˆ8.4 Hz); LR MS m/z 246 (M ).
Anal. Calcd for C H O : C, 68.28; H, 5.73. Found: C,
1
4
14
4
1
6
8.29; H, 5.76.
7.73 (1H, m); LR MS m/z 303 (M ). Anal. Calcd for
C H NO : C, 59.41; H, 4.32, N, 4.62. Found: C, 59.65;
6
1
5
13
4.1.6. 4-(4-Nitrobenzyloxy)-6-methyl-2-pyrone (1h). 1h
H, 4.37; N, 4.55.
was prepared by a method similar to that of 1f by using
p-nitrobenzyl bromide (6.48 g, 30 mmol), 4-hydroxy-6-
methyl-2-pyrone (3.78 g, 30 mmol) and DBU (5.6 g,
4.4. 1c´2 1:1 Complex crystal
3
6 mmol). 1h (2.7 g, 34% yield): mp 164±1678C; IR
Treatment of a solution of 1c (1.0 mmol) and 2 (1.0 mmol)
in acetone (5 ml) by method (b) gave 1c´2 as a colorless oil,
which was solidi®ed at 2158C.
2
1 1
KBr) 1740 cm ; H NMR (CDCl ) d 2.24 (3H, s), 5.12
(
(
8
3
2H, s), 5.46 (1H, s), 5.88 (1H, s), 7.55 (2H, Jˆ8.0 Hz),
.28 (2H, d, Jˆ8.0 Hz); LR MS m/z 262 (M11). HR FAB
MS (M11) Calcd for C H NO 262.0175. Found
13 12 5
4.4.1. 11-(2-Furfurylpropoxy)-7-methyl-8-oxa-4-azatri-
2
,6
262.0174.
cyclo[5.4.0.0 ]undec-10-en-3,5,9-trione (3c) from the
photolysis of 1c´2. Crystals of 1c´2 (330 mg, 1.0 mmol)
were photolyzed in a Pyrex tube at 2158C for 24 h. The
4.1.7. 4-(4-Biphenyloxy)-6-methyl-2-pyrone (1i). 1i was
prepared by a method similar to that of 1b by using 4-bi-
phenylmethanol (5.5 g, 30 mmol), triphenylphosphine
reaction solid was washed with CHCl (5 ml) to remove the
3
starting materials and the resulting solid was ®ltered to give
3c (149 mg, 45% yield), which was recrystallized from
MeCN. The starting material 1c´2 was recovered from the
(
9.5 g, 36 mmol), CCl4 (50 ml), 4-hydroxy-6-methyl-2-
pyrone (3.8 g, 30 mmol) and DBU (5.6 g, 36 mmol). 1i
2
2.4 g, 27% yield): mp 142±1438C; IR (KBr) 1720 cm ;
1
(
concentration of the CHCl ®ltrate (47%). Mp 226±2288C;
3
1
1
21
H NMR (CDCl ) d 2.22 (3H, s), 5.04 (2H, s), 5.52 (1H, s),
3
IR (KBr) 3400, 1780, 1730, 1700 cm ; H NMR (DMSO-
1
.85 (1H, s), 7.3±7.6 (9H, m); LR MS m/z 292 (M ). Anal.
5
Calcd for C H O : C, 78.06; H, 5.52. Found: C, 78.04; H,
5
d ) d 1.59 (3H, s), 1.93 (2H, quint, Jˆ7.8 Hz), 2.72 (2H, t,
6
Jˆ7.8 Hz), 3.41 (1H, d, Jˆ6.2 Hz), 3.53 (1H, dd, Jˆ6.2,
9.2 Hz), 3.63 (1H, d, Jˆ9.2 Hz), 3.83 (1H, dt, Jˆ7.8,
1
9
16
3
.54.
1
0.2 Hz), 3.95 (1H, dt, Jˆ7.8, 10.2 Hz), 5.24 (1H, s), 6.15
4
1
.1.8. 4-(1-Naphthylmethyloxy)-6-methyl-2-pyrone (1j).
j was prepared by a method similar to that of 1f by using
(1H, m), 6.35 (1H, m), 7.52 (1H, m), 11.44 (1H, s); LR MS
m/z 332 (M11). Anal. Calcd for C17 : C, 61.63; H,
5.17; N, 4.23. Found: C, 61.47; H, 5.21; N, 4.30.
H17NO
6
(
1-chloromethyl)naphthalene (8.8 g, 50 mmol), 4-hydroxy-
6
6
-methyl-2-pyrone (6.3 g, 50 mmol) and DBU (9.7 g,
4 mmol). 1j (4.1 g, 30% yield): mp 119±1208C; IR
4.5. 1d´2 1:1 Complex crystal
2
1 1
(
(
KBr) 1708 cm ; H NMR (CDCl ) d 2.20 (3H, s), 5.44
3
2H, s), 5.67 (1H, s), 5.82 (1H, s), 7.4±7.9 (7H, m); LR MS
A mixture of 1d (109 mg, 0.50 mmol) and 2 (49 mg,
0.50 mmol) was dissolved in 5 ml of hot CHCl . The solu-
tion was allowed to cool at room temperature, during which
1
m/z 266 (M ). Anal Calcd for C H O : C, 76.68; H, 5.30.
1
Found: C, 76.69; H, 5.30.
7
14
3
3

T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
1539
1
3
®ne white crystals were formed. After crystallizing over-
night, the crystal were collected by ®ltration, then dried in
C NMR (DMSO-d ) d 26.1, 28.2, 29.7, 39.2, 39.3, 51.0,
6
66.7, 75.2, 89.1, 124.4, 126.8, 139.7, 161.8, 166.7, 173.3,
175.1; LR MS m/z 341 (M ); HR FAB MS (M11) Calcd for
C H NO 342.1341, Found 342.1343.
1
1
vacuo to give 1d´2 (148 mg, 94% yield, mp 99±1018C) as
colorless prisms. H NMR con®rmed a 1:1 ratio of 1d´2.
1
9
20
5
4
.6. Single crystal X-ray diffraction analysis of 1d´2
4.8. Single crystal X-ray diffraction analysis of 3e
Crystal structure data for 3e: formula C19
Crystal structure data for 1d´2: formula C H NO .
1
H19NO
5
, Mˆ
7
15
5
Mˆ313.31, crystal dimensions 0.07£0.20£0.55 mm, tri-
341.36, crystal dimensions 0.50£0.05£0.40 mm, mono-
Ê
Ê
clinic, space group P2 /n (#14), aˆ13.3182(6) AÊ , bˆ
clinic, space group P-1 (#2), aˆ6.5888 A, bˆ11.2920 A,
1
Ê
6.35582(2) AÊ , cˆ19.1422(7) AÊ , bˆ102,8125(7)8, Vˆ
cˆ11.8837 A, aˆ64.88838, bˆ78.12228, gˆ82.26228,
3
23
ˆ1.330 g cm , 2u ˆ49.28,
max
Ê
3
23
ˆ1.435 g cm , 2u ˆ54.98, Tˆ
max
Ê
1579.9(1) A , Zˆ4, r
Vˆ782.3323 A , Zˆ2, r
calcd
calcd
Tˆ296.0 K, R (R )ˆ0.063 (0.099) for 1119 re¯ection data
93.0 K, R (R
I.3.00s(I) and 302 variables, GOFˆ1.21.
w
)ˆ0.035 (0.049) for 2589 re¯ection data with
w
with I.3.00s(I) and 269 variables, GOFˆ1.36.
2,6
4
.6.1. 11-Benzyloxy-7-methyl-8-oxa-4-azatricyclo[5.4.0.0 ]-
undec-10-en-3,5,9-trione (3d) from the photolysis of
d´2. Crystals of 1d´2 (148 mg, 0.48 mmol) prepared by
4.9. 1f´2 1:1 Complex crystal
1
A mixture of 1e (0.50 mmol) and 2 (0.50 mmol) was
dissolved in 5 ml of MeCN, and following the same workup
as mentioned in the 1d´2 preparation gave 1f´2 (96% yield,
method (a) were sandwiched with two Pyrex glass plates
and photolyzed for 24 h under nitrogen atmosphere at room
temperature. The same workup, as mentioned above,
afforded 3d (105 mg, 70% yield) together with recovery
of 1d´2 (23%). Similar irradiations to the crystals 1d´2
1
mp 75±778C) as colorless prisms. H NMR con®rmed a 1:1
ratio of 1f´2.
(
gave 3d in 96% yield. Mp 266±2688C; IR (KBr) 3300,
0.50 mmol) prepared by method (c), grinded for 30 min
4.10. Single crystal X-ray diffraction analysis of 1f´2
Crystal structure data for 1f´2: formula C H NO , Mˆ
21 1
775, 1720, 1690 cm ; H NMR (DMSO-d ) d 1.60 (3H,
1
6
18 17
5
s), 3.42 (1H, d, Jˆ6.4 Hz), 3.54 (1H, dd, Jˆ6.4, 9.8 Hz),
327.34, crystal dimensions 0.20£0.20£0.40 mm, orthor-
Ê
3
.69 (1H, d, Jˆ9.8 Hz), 4.84 (1H, d, Jˆ7.8 Hz), 5.00 (1H, d,
hombic, space group Pnma (#62), aˆ11.2390(3) A,
1
3
3
Ê
Ê
Ê
Jˆ7.8 Hz), 5.40 (1H, s), 7.3±7.5 (5H, m), 11.48 (1H, s); C
bˆ6.6086(2) A, cˆ22.8667(7) A, Vˆ1698.4(2) A , Zˆ4,
2
3
NMR (DMSO-d ) d 26.1, 39.2, 39.4, 51.1, 69.4, 75.4, 89.9,
6
r
1.280 g cm , 2u ˆ55.08, Tˆ297.0 K, R (R )ˆ
calcd
max
w
1
3
3
26.8, 126.9, 133.5, 161.7, 166.6, 173.3, 175.3; LR MS m/z
14 (M11); HR FAB MS (M11) Calcd for C H NO
14.1029. Found 314.1029.
0.065 (0.092) for 1392 re¯ection data with I.3.00s(I)
and 140 variables, GOFˆ1.34.
1
7
15
5
4
.10.1. 11-p-Methylbenzyloxy-7-methyl-8-oxa-4-azatri-
2
,6
4.6.2. Single crystal X-ray diffraction analysis of 3d.
Crystal structure data for 3d: formula C H NO .
cyclo[5.4.0.0 ]undec-10-en-3,5,9-trione (3f) from the
photolysis of 1f´2. Crystals of 1f´2 (164 mg, 0.50 mmol)
were sandwiched with two Pyrex glass plates and photo-
lyzed for 24 h. The same workup gave 3f (147 mg, 90%
yield) as colorless plates together with recovery of 1f´2
1
7
15
5
Mˆ313.31, crystal dimensions 0.07£0.20£0.10 mm, triclinic,
Ê
Ê
space group P-1 (#2), aˆ10.769(2) A, bˆ11.796(2) A, cˆ
Ê
6
.381(1) A, aˆ101.192(4)8, bˆ105.520(6)8, gˆ68.591(7)8,
Ê
calcd max
3
23
21
Vˆ723.0(2) A , Zˆ2, r ˆ1.439 g cm , 2u ˆ55.08,
(3%). Mp 255±2588C; IR (KBr) 1780, 1720, 1710 cm ;
H NMR (DMSO-d ) d 1.59 (3H, s), 2.32 (3H, s), 3.41
1
Tˆ93.0 K, R (R )ˆ0.055 (0.091) for 1929 re¯ection data
w
6
with I.3.00s(I) and 269 variables, GOFˆ1.31.
(1H, d, Jˆ6.4 Hz), 3.52 (1H, dd, Jˆ6.4, 9.4 Hz), 3.66
(
1H, d, Jˆ9.4 Hz), 4.78 (1H, d, Jˆ11.6 Hz), 4.95 (1H, d,
4.7. 1e´2 1:1 Complex crystal
Jˆ11.6 Hz), 5.38 (1H, s), 7.21 (2H, d, Jˆ8.0 Hz), 7.31 (2H,
1
3
d, Jˆ8.0 Hz), 11.48 (1H, s); C NMR (DMSO-d ) d 19.3,
6
Treatment of a solution of 1e (1.0 mmol) and 2 (1.0 mmol)
in acetone (5 ml) by method (b) gave 1e´2 (mp 74±768C).
26.1, 39.2, 39.4, 51.1, 69.3, 75.3, 89.8, 126.9, 127.5, 130.4,
136.2, 161.7, 173.3, 175.2; LR MS m/z 327 (M ). Anal.
1
Calcd for C H NO : C, 66.05; H, 5.23; N, 4.28. Found
5
1
6
17
4
.7.1. 11-(3-Phenylpropyloxy)-7-methyl-8-oxa-4-azatri-
C, 65.42; H, 5.21; N, 4.67.
2
,6
cyclo[5.4.0.0 ]undec-10-en-3,5,9-trione (3e) from the
photolysis of 1e´2. Crystals of 1e´2 (343 mg, 1.0 mmol)
prepared by method (b) were photolyzed in a Pyrex tube
for 24 h at room temperature. The same workup afforded 3e
4.11. Single crystal X-ray diffraction analysis of 3f
Crystal structure data for 3f: formula
C H17NO ,
18 5
(
279 mg, 82% yield) and recovery of 1e´2 (10%). Similar
Mˆ327.34, crystal dimensions 0.50£0.20£0.50 mm, mono-
Ê
irradiation to the crystals 1e´2 (0.50 mmol) prepared by
method (c), grinded for 30 min gave 3e (74% yield),
which was recrystallized from DMF, together with recovery
of 1e´2 (18%). Mp 235±2378C; IR (KBr) 3250, 1770, 1720,
clinic, space group P2
1
/n (#14), aˆ7.3266(4)) A, bˆ
Ê
Ê
Ê
20.745(1) A, cˆ10.3288(8) A, bˆ105.666(2)8, Vˆ
3
23
1511.6(2) A , Zˆ4, rcalcd 1.438 g cm , 2umaxˆ55.08, Tˆ
93.0 K, R (R
with I.3.00s(I) and 286 variables, GOFˆ1.27.
4.12. 1i´2 1:1 Complex crystal
)ˆ0.045 (0.069) for 2806 re¯ection data
w
2
1 1
1
695 cm , H NMR (DMSO-d ) d 1.59 (3H, s), 1.91 (2H,
6
quint, Jˆ6.4 Hz), 3.41 (1H, d, Jˆ6.2 Hz), 3.53 (1H, dd,
Jˆ6.2, 9.2 Hz), 3.63 (1H, d, Jˆ9.2 Hz), 3.81 (1H, dt,
Jˆ6.4, 10.0 Hz), 3.93 (1H, dt, Jˆ6.4, 10.0 Hz), 4.01 (2H,
t, Jˆ6.4 Hz), 5.23 (1H, s), 7.2±7.3 (5H, m), 11.45 (1H, s);
A mixture of 1i (0.50 mmol) and 2 (0.50 mmol) was

1
540
T. Obata et al. / Tetrahedron 57 (2001) 1531±1541
21 1
dissolved in 5 ml of hot CH Cl , and following the same
2
3300, 1767, 1712, 1685 cm ; H NMR (DMSO-d ) d 1.60
6
2
workup as mentioned in the 1d´2 preparation afforded 1i´2
(
con®rmed a 1:1 ratio of 1i´2.
(3H, s), 3.43 (1H, d, Jˆ6.4 Hz), 3.51 (1H, dd, Jˆ6.4, 9.6 Hz),
1
96% yield, mp 140±1418C) as colorless plates. H NMR
3.68 (1H, d, Jˆ9.6 Hz), 5.30 (1H, d, Jˆ11.6 Hz), 5.45 (1H, d,
1
3
Jˆ11.6 Hz), 5.64 (1H, s), 7.5±8.2 (7H, m), 11.52 (1H, s); C
NMR (DMSO-d ) d 26.1, 38.7, 39.7, 51.0, 67.7, 75.9, 89.9,
6
4.13. Single crystal X-ray diffraction analysis of 1i´2
122.7, 123.8, 124.6, 125.1, 126.1, 126.9, 127.3, 129.0, 129.7,
1
1
31.7, 161.8, 166.6, 173.3, 175.4; LR MS m/z 363 (M ).
Crystal structure data for 1i´2: formula C H NO ,
5
Anal. Calcd for C21H17NO : C, 69.41; H, 4.72; N, 3.85.
5
2
3
19
Mˆ389.41, crystal dimensions 0.08£0.20£0.40 mm, tri-
Found: C, 69.14; H, 4.73; N, 3.87.
Ê
clinic, space group P-1 (#2), aˆ11.290(2) A, bˆ
Ê
Ê
1
9
1
3.861(1) A, cˆ6.2880(7) A, aˆ102.420(3)8, bˆ
4.16. Photoreaction of 1b with 2 in solution
3
Ê
2.655(5)8, gˆ76.000(5)8, Vˆ932.4(2) A , Zˆ4, r
calcd
2
3
.387 g cm , 2u ˆ55.08, Tˆ93.0 K, R (R )ˆ0.048
A solution of 1b (206 mg, 1.0 mmol), 2 (98 mg, 1.0 mmol),
and benzophenone (73 mg, 0.40 mmol) in MeCN (30 ml) was
irradiated for 5 h under nitrogen atmosphere at room tempera-
ture. After evaporating the solvent, the resulting residue was
submitted to column chromatography (silica gel, ethyl ace-
tate±hexaneˆ1:1) to give a mixture of 3b (10% yield) and 5b
max
w
(
0.073) for 2925 re¯ection data with I.3.00s(I) and 391
variables, GOFˆ1.31.
4
.13.1. 11-(4-Biphenylmethyloxy)-7-methyl-8-oxa-4-aza-
2
,6
tricyclo[5.4.0.0 ]undec-10-en-3,5,9-trione (3i) from the
photolysis of 1i´2. Crystals of 1i´2 (117 mg, 0.30 mmol)
prepared by method (a) were sandwiched with two Pyrex
glass plates and photolyzed for 24 h. The same workup
afforded 3i (61 mg, 52% yield) and recovery of 1i´2
1
(12% yield) whose yields were obtained from H NMR analy-
1
sis, together with unidenti®ed compounds. 5b: H NMR
(DMSO-d ) d 1.65 (3H, s), 2.59 (1H, d, Jˆ8.0 Hz), 2.64
6
(1H, d, Jˆ9.6 Hz), 2.84 (1H, dd, Jˆ3.2, 8.0 Hz), 2.97 (1H,
m), 3.07 (1H, dd, Jˆ3.2, 9.6 Hz), 4.54 (1H, s), 4.59 (1H, d,
Jˆ12.4 Hz), 4.66 (1H, d, Jˆ12.4 Hz), 6.33 (1H, d, Jˆ2.8 Hz),
6.38 (1H, m), 7.60 (1H, m), 11.20 (1H, s), 11.36 (1H, s).
(
39%). Similar irradiation to the crystals 1i´2 prepared by
method (c), grinded for 30 min gave 3i (64% yield) together
with recovery of 1i´2 (27%). Mp 252±2548C; IR (KBr)
2
1
1
300, 1765, 1715, 1690 cm ; H NMR (DMSO-d ) d
3
1
9
5
1
4
1
6
.61 (3H, s), 3.43 (1H, d, Jˆ6.8 Hz), 3.56 (1H, dd, Jˆ6.8,
.6 Hz), 3.70 (1H, d, Jˆ9.6 Hz), 4.89 (1H, d, Jˆ11.8 Hz),
.06 (1H, d, Jˆ11.8 Hz), 5.42 (1H, s), 7.3±7.7 (9H, m),
4
.17. Photoreaction of 1d with 2 in solution
Similar photoirradiation to a solution of 1d (217 mg,
1.0 mmol), 2 (98 mg, 1.0 mmol), and benzophenone
1
3
1.49 (1H, s); C NMR (DMSO-d ) d 26.1, 39.2, 39.4,
6
1.0, 51.1, 69.1, 75.4, 89.9, 125.2, 126.1, 127.4, 132.6,
38.2, 138.7, 161.7, 166.6, 173.3, 175.3, 176.1; LR MS
m/z 389 (M ); HR FAB MS (M11) Calcd for C H NO
3
(74 mg, 0.41 mmol) in MeCN (40 ml), and same workup
afforded a mixture of 3d (10% yield) and 5d (18% yield)
1
1
( H NMR analysis) together with unidenti®ed compounds.
2
20
5
1
390.1341. Found 390.1342.
5
8
d: H NMR (DMSO-d ) d 1.63 (3H, s), 2.60 (1H, d, Jˆ
6
.0 Hz), 2.64 (1H, d, Jˆ9.6 Hz), 2.88 (1H, dd, Jˆ2.8,
4.14. 1j´2 1:1 Complex crystal
8.0 Hz), 3.06 (1H, m), 3.15 (1H, dd, Jˆ3.6, 9.6 Hz), 4.64
(
1H, d, Jˆ12.4 Hz), 4.72 (1H, s), 4.76 (1H, d, Jˆ12.4 Hz),
7.2±7.5 (5H, m), 11.21 (1H, s), 11.36 (1H, s).
A mixture of 1j (0.50 mmol) and 2 (0.50 mmol) was
dissolved in 5 ml of hot CH Cl , and following the same
2
2
workup as mentioned in the 1d´2 preparation afforded, using
method (a), 1j´2 (95% yield, mp 109±1108C) as colorless
plates. H NMR con®rmed a 1:1 ratio of 1j´2.
4
.18. Photoreaction of 1i with 2 in solution
1
Similar photoirradiation to a solution of 1i (586 mg,
.0 mmol), 2 (195 mg, 2.0 mmol), and benzophenone
(158 mg, 0.87 mmol) in MeCN (60 ml), and same workup
2
4.15. Single crystal X-ray diffraction analysis of 1j´2
1
afforded a mixture of 3i (9% yield) and 5i (13% yield) ( H
NMR analysis) together with unidenti®ed compounds. 5i: H
1
Crystal structure data for 1j´2: formula C H NO , Mˆ
2
1
17
5
3
63.37, crystal dimensions 0.10£0.40£0.50 mm, triclinic,
NMR (DMSO-d ) d 1.64 (3H, s), 2.60 (1H, d, Jˆ8.0 Hz),
6
Ê
Ê
space group P-1 (#2), aˆ10.302(2) A, bˆ12.236(2) A,
2.65 (1H, d, Jˆ9.4 Hz), 2.90 (1H, dd, Jˆ2.8, 8.0 Hz), 3.09
(1H, m), 3.16 (1H, dd, Jˆ7.0, 9.4 Hz), 4.70 (1H, d,
Jˆ12.4 Hz), 4.74 (1H, s), 4.82 (1H, d, Jˆ12.4 Hz), 7.4±
7.7 (9H, m), 11.23 (1H, s), 11.37 (1H, s).
Ê
cˆ7.6812(9) A, aˆ105.095(8)8, bˆ105.383(7)8, gˆ
3
23
1.410 g cm ,
Ê
6
2
8.270(4)8, Vˆ855.9(2) A , Zˆ2, r
calcd
u
ˆ54.98, Tˆ93.0 K, R (R )ˆ0.042 (0.071) for 2421
max
w
re¯ection data with I.3.00s(I) and 312 variables, GOFˆ
1
.31.
References
4
.15.1. 11-(1-Naphthylmethyloxy)-7-methyl-8-oxa-4-aza-
2
,6
tricyclo[5.4.0.0 ]undec-10-en-3,5,9-trione (3j) from the
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