[6+6]Photocycloadditions in face-to-face benzo/pyridazino substrates - En route to azapagodanes

Article abstract of DOI:10.1002/ejoc.200601075

In two specifically constructed rigid, proximate, "face-to-face" benzo/pyridazino systems (shortest π,π distances ca. 3 A) photoequilibration with the photo[6+6]cycloadducts has been established by 254-nm irradiation (ratios ca. 2:1). The failure to obser

Full text of DOI:10.1002/ejoc.200601075

FULL PAPER
DOI: 10.1002/ejoc.200601075
[
6+6]Photocycloadditions in Face-to-Face Benzo/Pyridazino Substrates – En
Route to Azapagodanes[
‡]
[
a]
[b]
[b]
[b]
[b]
Thomas Mathew,* Joern Tonne, Gottfried Sedelmeier, Clemens Grund,
[b]
[b]
[b]
Manfred Keller, Dieter Hunkler, Lothar Knothe, and Horst Prinzbach*
Dedicated to Prof. Dr. George A. Olah
Keywords: Photocycloadditions / Polycycles / Polyelectron cycloadditions / Heterocycles
In two specifically constructed rigid, proximate, “face-to-
spective pair of photoisomers as determined by their ac-
face” benzo/pyridazino systems (shortest π,π distances ca.
ceptor/donor substituents. The highly strained photo-
[6+6]cycloadducts are sufficiently thermally persistent to
enable the addition of standard dienophiles, thus opening
access to novel azapagodane-type cage molecules.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2007)
3
Å) photoequilibration with the photo[6+6]cycloadducts has
been established by 254-nm irradiation (ratios ca. 2:1). The
failure to observe such “benzene/heteroarene” photodimers
for differently substituted benzo/pyridazino analogues is re-
lated to unfavorable UV absorption characteristics of the re-
Introduction
thus conveniently amenable to physical and chemical stud-
ies. Most importantly, the equilibration 1 i 2 became a key
When the [6+6]photodimerization of 3,3Ј-o,oЈ-cy-
clophane 1 to give 2 was reported in 1978,[ the formation
of a highly strained four-membered ring between two ben-
zenoid rings, combined with a significant loss of aromati-
city, constituted a new addition to “aromatic photochemis-
[7,8]
step in the pagodane (3) Ǟ dodecahedrane (4) design
2,3]
and ultimately in the vapor-phase generation of the C20 ful-
[9]
lerene 6. A theoretically highly intriguing offspring of our
assorted attempts to effect the isomerization 3 Ǟ 4 was the
discovery of the surprisingly persistent 4C/2e in-plane
bis(homoaromatic) dication 5, which triggered multifaceted
[
4]
try”. The shortest π,π distance between the face-to-face
oriented benzenoid chromophores (dexp = 3.04 Å) is far be-
low the sum of the van der Waals radii (3.4 Å), the close-
to-rigid sandwich-type geometry between the chromophoric
units causing significant pyramidalization of the quaternary
carbon atoms (interorbital angle ωexp = 161.4°). This un-
usual degree of enforced “proximity” was denoted by signif-
icantly red-shifted charge-transfer absorptions in the UV/
Vis spectra and significant through-space π,π interactions
determined by photoelectron spectroscopy. Upon direct
[10]
investigations.
(254 nm) and xanthone-sensitized excitation, photoequilib-
ria were established at ratios of 70:30 and 87:13, respec-
tively. Under the given geometric restraint, the strongly
[
5]
through-space and through-bond homoconjugated “syn-
o,oЈ-benzene dimer” 2 proved to be highly stable kinetically
#
–1
[6]
(
∆H = 38.8 kcalmol for the cycloreversion to 1 ) and
1]
[
[
‡] Photochemical Transformations, 86. Part 85: Ref.[
a] Loker Hydrocarbon Research Institute and Department of
Chemistry, University of Southern California,
Los Angeles, CA 90089-1661, USA
[
b] Chemisches Laboratorium der Universität Freiburg i. Br., Insti-
Subsequent explorations disclosed a perplexing depen-
dence of the photoreaction, as well as of the dications of
tut für Organische Chemie und Biochemie,
Albertstr. 21, 79104, Freiburg, i. Br., Germany
Fax: +49-761-203-6048
[
11]
type 5, on seemingly small structural differences.
Only
E-mail: horst.prinzbach@orgmail.chemie.uni-freiburg.de
with one of nearly a dozen variously functionalized deriva-
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T. Mathew, H. Prinzbach et al.
FULL PAPER
tives of 1 and the homolog 8 could [6+6]photoequilibria
be observed. Isomer 7 and the higher homolog 9 remained
[
1,12,13]
unchanged.
Replacement of one or both[12c] benzene rings in 1 by
variously substituted pyridazine rings was part of our
continuing efforts to correlate structural and electronic sub-
strate properties with the photochemical response and
hopefully extend the preparative-synthetic potential of the
respective syn-o,o-(hetero)arene/(hetero)arene dimers as
Scheme 1.
[2]
intermediates to azacages of type 3, 4 and 5. Here we
detail our photochemical study with the benzo/pyridazino
systems (Scheme 2) and present explorative experiments
directed at novel (aza)cage molecules.[
14]
Results and Discussion
Syntheses
Figure 1. Space filling models of 13a and 24a (AM1, Schakal).
The reaction with parent 10e proved exceptional in that
The construction of the benzo/pyridazino-o,oЈ-cy-
clophanes 24 (Scheme 2) commenced from the benzo/ene
10, which had been prepared in the pagodane-dodecahe-
instead of 13e a ca. 2:1 mixture of the C symmetric trimer,
3
drane project in kg-quantities (from isodrin, at that time a
bulk chemical) (Scheme 1). The annelation of the pyridaz-
15a, and an unsymmetrical, non-identified trimer, 15b, were
[
8]
isolated, the rapid trimerization being in line with a number
[
15]
ino chromophore was approached in a standard way uti-
lizing the 1,2,4,5-tetrazines 11a–e[ whose functionaliza-
tion (R) provides access to a number of target oriented vari-
ations. It was expected that the sterically only feasible exo
addition to 10 (Ǟ) would have to overcome skeletal strain
and steric compression between the benzene ring and the
vinylic hydrogen atoms during rehybridization en route to
the extremely labile cycloadducts 12 and that in the derived
dihydropyridazines 13, the two sterically highly protected
inner hydrogen atoms (2-,7-H, Figure 1) would be hardly
open to normally rapid tautomerization,[ deprotonation
or oxidative elimination.
[
18,19]
of prior reports.
For 15a an X-ray crystal structural
16]
analysis performed at 100 K (Figure 2, numbering scheme
[
20]
of 15a) provided the ultimate structural proof and stereo-
chemical details such as the dihedral angles H2–C2–C7–H7
=
40.3°, H6–C6–C7–H7 = 91.4° (J2,7 = 6.2, J6,7 = 2.0 Hz)
and N4–N4 transannular distance [d = 3.187(3) Å].
17]
In practice, benzoene 10 reacted rather smoothly with
the tetrazines 11a–c,e in comparison to the very sluggish
addition of the electron-demanding diene (tetrachlorocyclo-
pentadienone dimethyl acetal) in the model case.[8] When
exposed at room temperature to equimolar amounts of rea-
gent under strictly anhydrous, aprotic conditions, 10 was
totally consumed within minutes (11b) or hours (11a,c,e).
Only with 11d was high pressure (9.5 kbar) needed, basi-
cally in line with the expected tendency in inverse Diels–
The use of equimolar amounts of 10 and the reagents 11
[
18]
Alder additions. Of the practically quantitatively formed was suggested when it was found that 13b reacted smoothly
,5-dihydropyridazines (Figure 1), 13b,c proved particularly with an excess of 10 to give virtually exclusively (TLC) the
4
prone to hydration; under not perfectly anhydrous condi- C symmetrical cycloadduct 16. The latter, isolated in 80%
s
tions the exo-/endo-hydrates 14b,c were isolated in addition. yield also after treating 11b with two equivalents of 10,
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[6+6]Photocycloadditions
FULL PAPER
ring (Figure 1, δ2(7)H = 2.68–2.25) indeed proved hardly ac-
cessible making dehydrogenation of the heterocyclic rings a
critical step (Scheme 2). Attempts with numerous common
oxidants (e.g. MnO , CrO , chloranil) under forcing condi-
2
3
tions, and likewise with our standard drastic catalytic dehy-
drogenation procedure (Pd/C, 250 °C) successfully applied
[
8]
to the dihydrobenzene/benzene systems, led to total de-
composition. Only from the CrO3 oxidation of 13a the
C H O (MS) compound 25 surfaced as a defined, minor
30
24
degradation product (ca. 10%); the isomer 26 most proba-
bly formed upon longer heating a [D ]pyridine solution of
5
2
“
5 to 100 °C was of interest in our search for proximate
face-to-face” benzo/naphtho system.
[
22]
Figure 2. ORTEP diagram of trimer 15a (T = 100 K).
proved thermally highly stable (m.p. 310–312 °C) and, like
diazabicyclooctene {λ
(ε) = 375 nm (85)}, typically
max
[
21]
®
“
photoreluctant”.
polychromatic light of a Hanau TQ 125-Watt lamp (λ Ͼ
80 nm) and ca. 50% conversion (2.5 h irradiation time),
the likewise thermally stable bicyclo[2.2.0]hexane derivative
7 (m.p. 289–291 °C) was the sole product. Typical for the
After exposure to the Pyrex -filtered
2
1
highly congested steric situation in the decacycle 16 are in-
ter alia the diamagnetic shielding effects of the N=N double
bond upon the proximate CH group (δ27a-H = –0.24, δ27s
-
2
H = –0.36, J = 12.6 Hz!) and of the 6,7-anellated benzene
ring upon the 2(11)-H hydrogen atoms (δ = 0.97 ppm). The
inversion of the combining radical centers implied by struc-
ture 17, though, has not been unequivocally established.
Scheme 2.
For 24a,b the desired aromatization was originally[14]
achieved when the normally rapid tautomerization of 4,5-
dihydro-1,2-pyridazines in 13a,b could be neatly brought-
about through extended boiling in p-dichlorobenzene
In the dihydropyridazines 13a–d, the two inner hydrogen (174 °C) providing 20a and 21a (notably no H-transfer to
atoms immersed into the π face of the opposing benzene give 18), followed by N-chlorination (20b, 21b) and l,4-HCl
Eur. J. Org. Chem. 2007, 2133–2146
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2135

T. Mathew, H. Prinzbach et al.
FULL PAPER
elimination, in the case of 20b with tBuOK, in case of 21b 11b. At room temperature, the adducts 30a,b underwent
–
only with Schwesinger’s very small and strong “naked” F
quantitatively, presumably dyotropic, hydrogen transfer
[
23]
[24]
[8,25]
base (P F).
Later,
the overall yields of 53% for 24a (Scheme 3).
2
and 69% for 24b (based on 10) could be considerably im-
proved to ca. 90% and the synthetic procedure considerably
shortened into a “one-pot” protocol {13a–c Ǟ 24a–c}
when it was found that generation of the anions 19a–c with
P2F followed by quenching with methanol and bromine ne-
atly yielded 20a–22a and 20c–22c, respectively, and that the
latter in the presence of excess base rapidly lost HBr to give
nearly quantitatively 24a–c. It is stressed that, particularly
for 24c, total exclusion of moisture was necessary for this
result. A second product occasionally isolated besides 24c
was identified as 28a and was related to the formation of
the hydrates 14 that were decarboxylated via 27 . For 24d
this highly economical procedure failed, when in 13d, poss-
ibly with the assistance of bromine, the nucleophilic substi-
–
tution of one methoxy group by F was much faster than
the formation of 24a (b). After flash chromatography, 28b
was isolated in high yield (88%). Reduction of 24c with
LAH generated smoothly bismethylol 24f (77%, not opti-
mized), a close substitute of 24e.
[
20]
Scheme 3.
The single-crystal X-ray analyses of 24a (Figure 3)
and 24c reveal nearly identical proximity effects, very close
to that of 1: Closest through-space π,π distances (d) of 3.003
(
3.03) Å, with the two (hetero)aromatic rings nevertheless
Benzo/Pyridazino[6+6]Photocycloadditions
remaining planar and with the π,π repulsion being levied
by 7–8° outward pyramidalization at the four annelated po-
sitions and by widening of the interplanar angles (ω).
From a thorough photomechanistic study with 1, 7, 8
and 9 it has been concluded that the tendency of such o,oЈ-
cyclophanes to undergo [6π+6π]photocycloaddition de-
pends on whether the geometry of the S1 state is close
enough to the geometry of the photoproduct. A heuristic
trend for this tendency is seen in the relative strain energies
[
13b,24]
of substrate and photoproduct.
It was recognized,
that the installation of preparatively useful photostationary
equilibria would depend much on the UV absorption char-
acteristics of the respective pair of photoisomers as deter-
mined by their acceptor/donor substituents. As in case of 1
no other reaction pathway (such as photometathesis to the
respective [12]diazaannulenes) would supposedly inter-
[
26]
Figure 3. ORTEP diagrams of 24a and 24c.
fere.
As it turned out, 24a and 24b behaved as expected with
Thus the intrinsic deviations from perfect parallel orien- respect to rate and specificity of the photoreaction
tation of the two chromophores by ca. 9° (MM2, interor- (Scheme 4). Irradiation of ca. 10–
3(–4)
 carefully dried and
bital angles ω ca. 171°, Schakal plots) are enlarged by these degassed acetonitrile solutions at 0 °C with λ = 254 nm
pyramidalizations to ca. 20° resulting in ω = 163° (161° in light of low-pressure Hg lamps (Rayonet chamber, quartz
1
). This “face-to-face” orientation is clearly expressed in the tubes, room temperature, Figure 4) established neat ca. 2:1
1
H NMR spectra. The signals of the four benzenoid pro- equilibria with 32a and 32b, respectively (isosbestic points
tons appear at significantly higher field than those of the at 296 nm and 228, 249 nm, respectively). Prolonged irradi-
respective precursor 13 {e.g. ∆δ = +0.5 – +0.9 (ca. 0.5) for ation had no further measurable effect and NMR control
24a(b)}. The UV spectra of 24a,b (Figure 4), on the other shown for 24a in Figure 5, proved the neatness of these
hand, do not show the remarkable bathochromic shift of photoequilibrations. Irradiation of such solutions or of
the long-wavelength absorption which was noted for the di- solutions of pure 32a or 32b with polychromatic light (λ
®
benzo compound 1 (charge-transfer effect between the ben- Ͼ 280 nm, high-pressure Hg lamp, a Pyrex vessel) caused
[
8]
zene rings). Compared to the UV spectra of the model complete cycloreversion to 24a and 24b, respectively. Par-
pyridazines 31a,b only the intensities of the long-wavelength ticularly, the UV absorption curves (CH CN) of 24a/32a
3
absorptions are significantly enhanced. To obtain 31a,b, (λmax = 277/304 nm) displayed the degree of bathochromic
diene 29 was treated with equimolar amounts of 11a and displacement as seen for 1/2 and ascribed to cyclobutane-
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[6+6]Photocycloadditions
FULL PAPER
Scheme 4.
mediated σ-homoconjugation between the two dienic chro-
[
5]
mophores. In clear contrast, UV and NMR control of
irradiation experiments with 24c and 24f in carefully de-
gassed solvents using monochromatic (254 nm) and poly-
1
Figure 5. H NMR control of the equilibration 24a i 32a.
chromatic light (λ Ͼ 280 nm) furnished no evidence for the appreciable isomerization back to 24a(b) [typically ca. 25%
formation of 32c and 32f, only slow polymerization.
of pure 32a(b) isolated]. After crystallization the slightly
The benzo/pyridazino cyclodimers 32a and 32b are ex- colored crystals melted upon rapid heating without notice-
tremely acid-sensitive. Chromatography of the photoequili- able change at 183–185 °C and 140 °C, respectively.
brium mixtures even on deactivated silica gel (triethyl-
amine), unproblematic with benzo/benzo dimers,[ caused
1]
Thermal Cycloreversions
To account for the above cited high kinetic stability of
parent 2, an explanation in terms of a structurally enforced
concerted but symmetry-forbidden cycloreversion mecha-
nism via an antiaromatic transition state (cf. 34) – as op-
[6]
posed to a stepwise one (cf. 33) – has been presented. For
1
3
2a a qualitative, H NMR monitored kinetic study in [D ]-
6
benzene at 140 °C (sealed tube) confirmed a neat cyclore-
version to 24a with a half-life time of ca. 13 h. The frag-
mentation patterns in the 70-eV MS spectra of the pairs
2
3
4a/32a and 24b/32b indicate the rapid cycloreversion of the
2a and 32b ions.
·
+
·+
Cycloadditions
Inverse and standard [4+2]-additions to the dihydropy-
ridazine and cyclohexadiene parts of the photoproducts 32
were explored with novel cage structures as target mole-
cules. The attempts aiming at inverse additions can be
briefly summarized: not in the least for steric reasons (3,6-
disubstitution), with no electron-rich dienophile, not even
with the sterically rather undemanding (dimethylamino)eth-
Figure 4. UV (254 nm) control of the equilibrations 24a i 32a and
2
4b i 32b. Top: a: start, b: 10 s, c: 30 s, d: 2 min, e: change to
[
27]
300 nm, 8 min. Bottom: a: start, b: 20 s, c: 2 min, d: 4 min.
ylene, could addition be achieved, even under high pres-
Eur. J. Org. Chem. 2007, 2133–2146
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2137

T. Mathew, H. Prinzbach et al.
FULL PAPER
sure (9.5 kbar). Selected standard additions performed with
32a are listed in Scheme 5, Scheme 6, and Scheme 7.
The syn-o,oЈ-dibenzene 2 is thermally stable enough to
allow the sterically demanding addition of maleic anhydride
MA) and after prolonged boiling (12 h) of a benzene solu-
(
tion, the 1:1 “domino” adduct arising from external attack
was quantitatively secured. For 32a it was expected that its
lower thermal stability would complicate matters. In fact, a
1
H NMR-controlled experiment with a solution of 32a and
MA in [D ]benzene kept at 100 °C for 15 h in a sealed
6
NMR tube revealed the presence of only ca. 10% of the 1:1
“domino” product 36 besides 24a (no evidence for interme-
diate 35). The yield of 36 was raised to 45% when the reac-
tion solution was subjected to 9.5-kbar pressure at 80 °C
for 19 h.
Scheme 5.
In contrast, N-phenyl-triazoline-3,5-dione (NPTD)
added rapidly at room temperature to 32a providing after
chromatographic separation 45–48% of the colorless “dom-
ino” adduct 37 and the yellow “pincer” isomer 38.
cause 24a neither interfered with NPTD nor with the sepa- opening of the annelated cyclobutane ring, was too fast.
Scheme 6.
[
28]
Be- octadiene unit,[29] presumably promoted by the concerted
ration of 37 and 38, it was preparatively advantageous to For probably similar reasons, the photoelimination of N
use 32a as the original ca. 2:1 photoequilibrium mixture
2
with 24a. The principal features of the C -symmetrical skel-
s
etons 37 and 38 were unambiguously derived from the
NMR spectra. In this context, the at first sight surprising
structural assignment of 38 was confirmed by an X-ray
structural analysis (Figure 6) with crucial details such as
the through-space distance C4(7)–N19(18)
=
2.9354
[
20]
(2.8314) Å.
Oxidative hydrolysis of 37 to provide with
the bisazo[2.2.1.1]pagodane 39 a potential precursor of the
much desired [1.1.0.0]pagodane 41 required forcing condi-
tions. The highly strained yet thermally rather stable 39 was
nevertheless isolated in high yield {80%, colorless crystals,
λmax = 389 nm (ε = 129), 367 (106), 276 (1170), 246 (8700).
+
+
MS: m/z = 412 ([M – N ] ), 384 ([M – 2 N ] )}. Analogous
2
2
or even somewhat milder treatment of 38 did not result in
0 or the tetraaza[2.2.1.1]pagodadiene 43 but in 24a. In
spite of the seemingly very favorable steric situation in 40
intermediacy admittedly questionable) for a cycloaddition
to give 43, the expulsion of N from the diazabicyclo[2.2.2]- Figure 6. X-ray structure of 38.
4
(
2
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[6+6]Photocycloadditions
FULL PAPER
from 39 did not give access to 41. Hopes, that in both N2-
With the C3v symmetrical trimer 15a in hand, a potential
[
32]
elimination steps 1,4-radical recombination (cf. 16 Ǟ 17) tripodal N-donor ligand, a chance was seen to arrive at
could at least compete with ring-opening events[ were not hexaazaadamantanes (47) which, with their rigid-parallel
substantiated. Irradiation of “photoreluctant” 39 with fixation of three neighboring –NR–NR– bonds (through-
30]
2
54 nm light in dilute, deoxygenized CH CN at room tem- space N···N distances of ca. 3.2 Å), could have meant a
3
perature ended in a mixture of products (at least 3, TLC, highly attractive extension of our search for proximate, syn-
no 41) of which the major (80%), oxygen-sensitive compo- periplanar bishydrazines and the derived (radical) ions.[
nent was isolated through crystallization (hexane/CH Cl , In explorative experiments, however, the C=N double
33]
2
2
4
:1) and identified as tetraene 42.
The slim dimethyl acetylene dicarboxylate (DMA) has tion and bridging interconnections.[34]
been shown to expeditiously undergo “domino” – and
bonds in 15a proved resistant to their hydrogenative satura-
[28]
“
pincer”-type additions to 2 (ratio 97:3). 32a, in contrast,
[31]
like other N-heterocycles, behaved towards DMA as nu-
cleophile producing with an excess of reagent nearly quanti-
tatively the yellowish [λmax (CH CN) = 395 nm], crystalline
3
1:2 adduct (MS, TLC, 92% isolated besides 24a and an-
other trace component). Structure 46 arising from the inter-
ception of the primary dipole 44 and endo-cyclization in 45
is in line with the spectroscopic data. The high-field chemi-
With this 86th report on “Photochemical Transforma-
tions”, a series comes to an end which began in 1962,
[35]
cal shift of (presumably) 6Ј-H (δ = 4.68 ppm) and m/z =
in the earlier days of preparative, particularly mechanistic
+
6
19 [M – C H ] as mother peak in the MS spectrum are
[36]
6
5
organic photochemistry.
Over the years, the use of light
prominent features.
for the construction of molecules with unusual architecture,
with unusual photophysical and chemical properties, has re-
mained a major area of research performed in the group of
the senior correspondence author (H. P.). The latter takes
this opportunity to express his gratitude and sincere thanks
to all the students, technicians, postdoctoral fellows and
colleagues who along this long road have contributed their
time, skills, enthusiasm, advice and expertise, and to all the
institutions and agencies having generously provided finan-
cial support.
Experimental Section
General: Melting points (m.p.) were determined with a Monoskop
IV (Fa. Bock) and are uncorrected. Elemental analyses were per-
formed by the Analytische Abteilung des Chemischen Laboratori-
ums Freiburg i. Br. Analytical TLC: Merck silica gel plates with
F
254 indicator with detection by UV, KMnO
acid solution. IR spectra were recorded with Perkin–Elmer 457
KBr pellets), UV spectra with Perkin–Elmer Lambda 15, Mass
4
or phosphomolybdic
(
1
spectra with Finnigan MAT 44S and MAT 8200, H NMR spectra
1
3
with Bruker WM 250 and AM 400, C NMR spectra with Bruker
AM 400. If not specified otherwise, EI (70 eV) MS, 400/100.6 MHz
Scheme 7.
1
13
3
H/ C NMR spectra in CDCl are given. Chemical shifts were
recorded relative to TMS (δ = 0 ppm). Assignments were confirmed
by homo- and hetero-nuclear decoupling and HЈH, HЈX corre-
lation experiments; assignments indicated with an asterisk can be
interchanged. In the glove box used (M. Braun Labmaster 130),
the O and H O values were below 1 ppm. The silica gel used for
2 2
column chromatography was Merck (0.040–0.063 mm) or ICN Bio-
medicals GmbH (0.032–0.063 mm).
Concluding Remarks
With the photoequilibrations 24a,b i 32a,b, the primary
objective of this study was accomplished, the scope of ar-
ene/(hetero)arene [6+6]photocycloaddition reaction could
be extended. The limitations met with 24c,f are, as in case
(
1α,2α,7α,8α,9β,10α,13α,14β)-3,6-Diphenyl-11,12-benzo-4,5-diaza-
of a dibromo-derivative of 2,[
12a]
primarily ascribed to the
1
0,13 2,7 9,14
pentacyclo[6.6.1.1
.0 .0 ]hexadeca-3,5,11-triene (13a): A
Cl (10 mL) was added
to a stirred solution of 10 (208 mg, 1.0 mmol) in CH Cl (10 mL).
After 12 h, the color of the reaction mixture had changed from
of (aza)pagodane-type cage molecules has been further sub- violet to yellow (total conversion, TLC). Following concentration
absorption characteristics of starting materials and poten-
tial products. The preparative-synthetic utility of the syn-
solution of 11a (234 mg, 1.0 mmol) in CH
2
2
2
2
[
6+6]arene/(hetero)arene cyclodimers for the construction
stantiated.
in vacuo, the residue was chromatographed (silica gel, 12ϫ2 cm,
Eur. J. Org. Chem. 2007, 2133–2146
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2139

T. Mathew, H. Prinzbach et al.
FULL PAPER
CH
2
Cl
2
), 380 mg (92%) of yellow crystals were isolated (R
f
= 0.17); deeply red, dry solution of 10 (51 mg, 0.22 mmol) and 11d (51 mg,
®
m.p. 167–168 °C. UV (CH
3
CN): λmax (ε) = 358 nm (sh, 3700), 345 0.25 mmol) in toluene (1 mL) was sealed into a small Teflon hose.
(
sh, 8400), 327 (sh, 14400), 315 (16100), 280 (sh, 8200), 273 (sh,
Using PE 60/70 as a pressure source, the sample was exposed to
3
7
1
7
2
1
J
000), 259 (sh, 6000), 220 (sh, 4400). IR: ν˜ = i.a. 3032, 2952, 2882,
9.5 kbar at 65 °C for 2 d in a 10-cm high-pressure autoclave. Con-
–1
1
1
580, 1553, 1460 cm . H NMR: δ = 7.85–7.80 (m, 4 H), 7.50– centration in vacuo yielded colorless crystals (69 mg, 97%). H
.40 (6 H), 7.45 (m, 4Ј-, 5Ј-H), 7.14 (3Ј-,6Ј-H), 3.43 (s, 10-,13-H), NMR: δ = 7.25 (m, 4Ј-,5Ј-H), 7.10 (m, 3Ј-,6Ј-H), 3.68 (s, 2 OCH
.76 (m, 9-,14-H), 2.68 (br. s, 2-,7-H), 2.43 (m, 1-,8-H), 2.18 (dm, 3.35 (m, 10-,13-H), 2.79 (m, 9-,14-H), 2.52 (br. s, 2-,7-H), 2.22 (m,
6a-H), 2.02 (dm, 16s-H), 1.56 (dm, 15a-H), 1.47 (dm, 15s-H) ppm; 1-,8-H), 2.18 (dm, 16s-H), 2.09 (dm, 15s-H), 1.63 (dm, 16a-H), 1.60
15a,s = 9.4, J16a,s = 8.6 Hz. 13C NMR: δ = 159.5 (C-3,-6), 143.7 (2 (dm, 15a-H) ppm. C NMR: δ = 174.2 (C-3,-6) 147.0 (C-11,-12),
3
),
13
C), 136.3 (C-11,-12), 130.2, 128.3, 127.0 (10 C), 126.2 (C-4Ј,-5Ј), 126.0 (C-4Ј,-5Ј), 123.3 (C-3Ј,-6Ј), 60.4 (C-16), 51.4 (C-2,-7), 46.9
122.8 (C-3Ј,-6Ј), 60.9 (C-16), 48.3 (C-2,-7), 47.5 (C-10,-13), 46.4 (C-
3
(C-10,-13), 46.3 (C-9,-14), 44.1 (C-15), 44.0 (2 OCH ), 43.2 (C-1,-
9
+
,-14), 42.8 (C-15), 33.8 (C-1,-8) ppm. MS: m/z (%) = 415 (23) [M
8) ppm. HRMS: calcd. for C20 322.1683; found 322.1678.
Compound 13d remained unchanged after refluxing a solution in
p-dichlorobenzene (174 °C) for 8 h.
22 2 2
H N O
+
+
1] , 414 (70) [[M] ], 233 (46), 165 (22), 116 (100). C30
H
26
N
2
(414.6): calcd. C 86.82, H 6.32; found: C 86.84, H 6.35.
(
4
1α,2α,7α,8α,9β,10α,13α,14β)-3,6-Bis(trifluoromethyl)-11,12-benzo-
(
1
5
CH
1α,2α,7α,8α,9β,10α,13α,14β)-3,6-Bis(trifluoromethyl)-3-hydroxy-
,5-diazapentacyclo[6.6.1.11 .0 .0 ]hexadeca-3,5,11-triene
0,13
2,7 9,14
10,13 2,7 9,14
1,12-benzo-4,5-diazapentacyclo[6.6.1.1
,11-diene (14bendo/exo). 14bendo: Colorless crystals (R
Cl ). UV (CH CN): λmax (ε) = 276 nm (610), 268 (770), 261
sh, 980), 240 (sh, 2880), 215 (sh, 11050). IR: ν˜ = inter alia
.0 .0 ]hexadeca-
(
13b): Upon addition of an orange-red, dry solution of 11b
312 mg, 1.5 mmol) in CH Cl (5 mL) to a stirred dry solution of
0 (327 mg, 1.5 mmol) in CH Cl (5 mL) the color rapidly disap-
peared. After 15 min of concentration in vacuo, the greenish resi-
due crystallized from CH Cl /petroleum ether (1:9). 540 mg (90%)
of light green crystals were collected, m.p. 110 °C (R = 0.39,
CH Cl /petroleum ether, 1:1). UV (CH CN): λmax (ε) = 282 nm
1100), 275 (1530), 268 (1560), 250 (1670), 243 (sh, 1550), 213 (sh,
f
= 0.20,
(
1
2
2
2
2
3
2
2
(
–1
1
3
450 cm (br., O–H), 2962, 1499 (C=C), 1463, 1146 (C-F). H
O-exch.
NH), 3.33 (s 10-H)*, 3.31 (s, 13-H)*, 2.81–2.70 (m, 9-,14-H), 2.55
s, 1-H)*, 2.58 (s,8-H)*, 2.17–2.09 (m, 2-,7-H), 1.97 (d, 16a-H),
.67–1.58 (m, 16s-,15a-H) 1.56 (br. s, D O-exch. OH), 1.52 (dm,
2
2
NMR: δ = 7.27–7.18 (m, 3Ј-,4Ј-,5Ј-,6Ј-H), 6.03 (br. s, D
2
f
2
2
3
(
(
1
1
1
3
1
1
2
–1
1
7
530). IR: ν˜ = i.a. 2948 cm , 1464, 1201, 1142, 1125. H NMR: δ
7.18 (m, 4Ј,-5Ј-H)*, 7.05 (m, 3Ј-,6Ј-H)*, 3.35 (s, 10-,13-H), 2.88
m, 9-,14-H), 2.68 (m, 1-,8-H), 2.25 (br. s, 2-,7-H), 2.12 (dm, 16a-
H), 1.98 (dm, 16s-H), 1.84 (dm, 15a-H), 1.35 (dm, 15s-H) ppm;
15a,s = 10.8, J16a,s = 8.8 Hz. 13C NMR: δ = 156.8 (q, J = 32.4 Hz,
C-3,-6), 145.8 (C-11,-12), 126.6 (C-4Ј,-5Ј), 123.3 (C-3Ј,-6Ј), 120.3
q, J = 279.1 Hz, 2 CF ), 60.4 (C-16), 47.7 (C-2,-7), 46.2 (C-10,-
3), 46.0 (C-9,-14), 43.3 (C-15), 33.0 (C-1,-8) ppm. MS: m/z (%) =
13
5s-H) ppm; J15a,s = 10.4, J16a,s = 8.6 Hz. C NMR: δ = 147.6,
46.1 (C-11, C-12), 146.2 (q, J = 32.4 Hz, C-6), 126.1, 125.8 (C-
=
(
3 3
Ј,-4Ј), 125.0 (q, J = 335.1 Hz, CF ) 123.5 (q, J = 286.0 Hz, CF ),
23.3 (C-5Ј,-6Ј), 80.0 (q, J = 30.0 Hz, C-3), 60.3 (C-16), 47.7 (C-
J
3), 47.0 (C-10), 46.3 (C-7), 46.2, 46.1 (C-9,-14), 42.4 (C-15), 40.7
+
(
C-2), 40.4 (C-8), 34.2 (C-1) ppm. MS: m/z (%) = 416 (15) [M] ,
(
1
3
3
1
81 (15), 167 (9), 166 (9), 165 (11), 143 (87), 142 (21), 141 (19), 130
(
28), 128 (15), 117 (32), 116 (100). C20 O (416.4): calcd. C
18 2
H N
+
98 (12) [M] , 143 (33), 141 (12), 117 (23), 116 (100), 115 (31), 67
(398.4): calcd. C 60.31, H 4.05; found: C 60.37,
5
7.70, H 4.36; found C 57.68, H 4.40.
(
22). C20
H
16
F
6
N
2
1
4bexo: Colorless crystals (R = 0.16, CH Cl ). UV (CH CN): λmax
f
2 2 3
H 4.06
(
ε) = 276 nm (575), 268 (815), 261 (sh, 1170), 241 (3040), 215 (sh,
Occasionally, if moisture was not completely excluded, besides 13b,
two hydrates were isolated chromatographically (silica gel,
1
–
1
1
1
s, D
9
2
0430). IR: ν˜ = i.a. 3430 cm (br., O–H), 2954, 2880, 1462 (C=C),
1
180 (C-F). H NMR: δ = 7.23–7.05 (m, 3Ј-,4Ј-,5Ј-,6Ј-H), 5.94 (br.
2ϫ2 cm, CH
2
Cl
2
/petroleum ether, 1:1), which resulted from exo/
O to a C=N double bond (14bendo/exo).
2
O-exch. NH), 3.35 (s, 10-H)*, 3.30 (s, 13-H)*, 2.87–2.72 (m,
-,14-H), 2.57 (1-H)*, 2.64 (s, 8-H)*, 2.37 (br. s, D O-exch -OH),
.12 (dm, 16a-H), 2.06–2.01 (m 2-,7-H), 1.99 (dm, 16s-H), 1.62
endo addition of H
2
2
Dimethyl (1α,2α,7α,8α,9β,10α,13α,14β)-11,12-Benzo-4,5-diazapen-
tacyclo[6.6.1.11 .0 .0 ]hexadeca-3,5,11-triene-3,6-dicarboxyl-
0,13
2,7 9,14
(
dm, 15a-H), 1.55 (dm, 15s-H) ppm; J15a,s = 10.2, J16a,s = 8.6 Hz.
ate (13c): Upon stirring a deeply red solution of 10 (107 mg,
13
C NMR: δ = 146.8, 146.0 (C-11, C-12) 144.5 (q, J = 32.3 Hz, C-
), 126.2, 126.1 (C-3Ј,-4Ј), 124.4 (q, J = 286.4 Hz, CF ) 124.4 (q, J
), 123.3 (C-5Ј,-6Ј), 78.5 (q, J = 29.3 Hz, C-3), 60.4
0
.52 mmol) and 11c (104 mg, 0.52 mmol) in benzene (4 mL) for 1 h,
conversion was complete (TLC). Concentration in vacuo and flash
chromatography (silica gel, ethyl acetate, R = 0.48) delivered
91 mg (98%) of yellowish crystals. H NMR: δ = 7.35 (m, 4Ј-,5Ј-
6
=
(
4
4
3
290.4 Hz, CF
3
f
C-16), 47.3 (C-13), 47.0 (C-10), 46.3 (C-7), 46.2, 46.0 (C-9,-14),
1
1
3.7 (C-15), 40.0 (C-2), 36.9 (C-8), 35.3 (C-1) ppm. MS: m/z (%) =
H), 7.12 (m, 3Ј-,6Ј-H), 3.86 (s, 2 OCH
3
), 3.38 (br. s, 10-,13-H), 2.85
+
16 (20) [M] , 347 (8), 283 (6), 165 (15), 143 (74), 142 (20), 130
(m, 9-,14-H), 2.48 (br. s, 2-,7-H), 2.42 (m, 1-,8-H), 2.12 (dm, 16a),
(
27), 128 (17), 118 (5), 117 (39), 116 (100), 115 (52), 91 (10), 83 (5),
7 (6), 69 (6), 67 (13). C20 O (416.4): calcd. C 57.70, H 4.36;
found: C 57.63, H 4.39.
1
=
.98 (dm, 16s-H), 1.79 (dm, 15a-H), 1.29 (dm, 15s-H) ppm; J15a,s
7
18 2
H N
+
10.6, J16a,s = 9.0 Hz. MS: m/z (%) = 379 (9) [M + 1] , 378 (18)
+
+
3
[M] , 320 (13), 319 (58) [M – COOCH ] , 318 (14), 260 (4) [M – 2
]+, 203 (13), 197 (85), 188 (17), 181 (12), 165 (27), 143
Dimethyl (1α,2α,7α,8α,9β,10α,13α,14β)-3-Hydroxy-11,12-benzo-
COOCH
3
1
0,13 2,7 9,14
4
,5-diazapentacyclo[6.6.1.1
carboxylate (14cendo(?)): Colorless crystals, 182 °C. H NMR: δ =
.40 (br. s, NH), 7.32 (m, 1 H), 7.15 (m, 3 H), 6.08 (s, OH), 3.90
s, OCH ), 3.80 (s, OCH ), 3.40 (br. s, 7-H)*, 3.31 (br. s, 2-H)*,
.75–2.70 (m, 2 H), 2.45–2.38 (m, 2 H), 2.15 (m, 1-H), 1.95–1.90
.0 .0 ]hexadeca-5,11-diene-3,6-di-
(14), 128 (18), 117 (30), 116 (100). C22
H
22
N
2
O
4
(378.4): calcd. C
1
6
9.83, H 5.86; found C 69.44, H 5.50. 13c remained unchanged
7
(
2
(
after refluxing a solution in p-dichlorobenzene (174 °C) for 8 h.
Occasionally, if moisture was not completely excluded, chromato-
3
3
graphically (silica gel, 12ϫ2 cm, CH
sides 13c a mixture of two hydrates (14cendo/exo) was isolated re-
sulting from exo/endo addition of H O to a C=N double bond (MS,
(396.4): calcd. C 66.65, H 6.10; found C 66.25,
2 2
Cl /petroleum ether, 1:1), be-
m, 2 H), 1.70 (m, 1 H), 1.65 (m, 1 H), 1.40 (1 H) ppm. MS (EI):
+
+
2
m/z (%) = 396 (58) [M] , 278 (14) [M – H O] , 337 (100) [M –
CO
2
+
2 3
CH ] , 197 (30), 116 (29).
NMR). C22
H 6.21.
24 2 5
H N O
(
1α,2α,7α,8α,9β,10α,13α,14β)-11,12-Benzo-4,5-diazapentacyclo[6.6.
1
0,13 2,7 9,14
(
1α,2α,7α,8α,9β,10α,13α,14β)-3,6-Dimethoxy-11,12-benzo-4,5-di- 1.1
.0 .0 ]hexadeca-3,5,11-triene [13e (C18
18 2
H N , 262.4)]-Tri-
1
0,13 2,7 9,14
azapentacyclo[6.6.1.1
.0 .0 ]hexadeca-3,5,11-triene (13d): A
mer (15a): A red solution of 10 (107 mg, 0.52 mmol) and 11e
2140
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 2133–2146

[
6+6]Photocycloadditions
FULL PAPER
–
1
(
43 mg, 0.52 mmol) in CH
2
Cl
2
(5 mL) was stirred at room temp.,
267 (1330), 261 (sh, 990), 217 (9300). IR: ν˜ = i.a. 3000 cm , 2950,
1
and the color disappeared after 5 h to give two products (TLC).
Concentration in vacuo and crystallization of the residue from
CH Cl provided 85 mg (62%) of pure trimer 15a. These crystals
2 2
proved suitable for the X-ray structural analysis (Figure 2). The
second product (15b, MS) could not be obtained pure, because un-
der various separation procedures it rapidly equilibrated with 15a
and (protonated) 13e.
2890, 1450, 1345, 1300, 1260, 1214, 1120, 1065. H NMR: δ = 7.24
(m, 2 H), 7.13 (m, 2 H), 7.04 (br. s, 4 H), 3.27 (m, 2 H), 3.23 (m,
2 H), 2.72 (m, 2 H), 2.40 (m, 2 H), 2.23 (dm, J = 11.1 Hz, 1 H),
2.06 (dm, J = 8.1 Hz, 1 H), 1.95–1.88 (m, 2+2+1 H), 1.76 (m, 2
H), 1.73 (dm, J = 8.5 Hz, 1 H), 1.58 (dm, J = 11.1 Hz), 1.53 (dm,
J = 8.1 Hz, 1 H), 1.48 (m, 2 H), 0.96 (dm, J = 12.5 Hz, 1 H), –1.13
1
(dm, J = 12.5 Hz, 1 H) ppm. H NMR (C
6
D
6
): δ = 6.55 (m, 4 H),
6
.52 (m, 4 H), 2.69 (m, 7-,10-H)*, 2.51 (m, 18-,21-H)*, 2.13 (dm,
1
1
5a: Colorless crystals, melting with decomposition Ն195 °C. H
J = 11.3 Hz, 1 H), 2.06 (br. s, 2 H), 1.93 (m, 2 H), 1.77 (m, 2 H),
NMR (C
H), 6.50 (d, 3-H), 3.37 (d, 6-H), 3.04 (m, 10-H), 3.01 (m, 13-H),
.5–2.4 (m, 9-,14-H), 2.37 (m, 2-H), 2.15 (br. s, 8-H), 2.08 (br. s, 1-
H), 1.91 (dq, 16s-H), 1.81 (dq, 15s-H), 1.64 (dt, 16a-H), 1.53 (dt,
-H), 1.32 (dm, 15a-H) ppm; J2,3 = 2.0, J2,7 = 6.2, J6,7 = 2.0, J7,8
1.5 Hz. 13C NMR: δ = 147.2, 146.3, 146.3 (C-3,-11,-12), 125.9,
25.5, 123.6, 122.9 (C-3Ј,-4Ј,-5Ј,-6Ј), 78.8 (C-6), 60.5 (C-16), 48.3
C-14), 47.7 (C-9), 46.8 (C-13), 46.7 (C-10), 45.9 (C-1), 45.7 (C-8),
6 6
D ): δ = 7.15 (m, 1 H), 7.05 (m, 1 H), 6.95–6.85 (m, 2
1
2
1
1
2
.62 (m, 2 H), 1.48 (dm, J = 7.8 Hz, 1 H), 1.33 (m, 2 H), 1.30 (m,
H), 1.25–1.20 (m, 2+1 H), 1.15 (dm, J = 8.6 Hz, 1 H), 1.08 (dm,
H), 1.01 (dm, 1 H), 0.95 (dm, J = 12.8 Hz, 1 H), –1.13 (dm, J =
2
13
2.8 Hz, 1 H) ppm. C NMR: δ = 148.1 (C-8,-9)*, 145.7 (C-19,-
7
=
1
(
4
+
(
(
0)*, 126.1 (2 CЈ), 126.2 (q, J = 282.1 Hz, CF
3
), 125.0 (2 CЈ), 123.5
),
), 48.9 (2 CH), 47.9 (2 CH), 47.7 (2 CH),
7.6 (2 CH), 46.3 (2 CH), 42.0 (CH ), 41.8 (2 CH), 39.5 (2 CH),
6.8 (CH ) ppm. MS: m/z (%) = 578 (8) [M] , 149 (10), 143 (16),
42 (22), 141 (10), 129 (7), 128 (6), 117 (25), 116 (100). C36
(
2 CЈ), 122.1 (2 CЈ), 76.7, (q, J = 25.4 Hz, C-3,-14), 60.4 (CH
2
5
4
2
1
4.3 (2 CH), 52.4 (CH
2
2
3.9 (C-15), 35.9 (C-2), 35.4 (C-7) ppm. MS: m/z (%) = 787 (5) [M
1] , 786 (9) [M] , 525 (8), 524 (17) [15a – 13e] , 379 (21), 263
50), 262 (71) [13e, HR], 208 (39), 167 (36), 165 (25), 143 (26), 142
39), 141 (45), 117 (56), 116 (100). C54 (648.6): calcd. C
+
2
+
+
+
32 6
H F
(
578.7): calcd. C 74.73, H 5.57; found C 74.67, H 5.69.
54 6
H N
(
1α,7α,8α,9β,10α,13α,14β)-3,6-Diphenyl-11,12-benzo-4,5-diazapen-
82.41, H 6.92; found C 82.01, H 6.77.
1
0,13 2,7 9,14
tacyclo[6.6.1.1
.0 .0 ]hexadeca-2,5,11-triene (20a): A mixture
1
,12-Bis(trifluoromethyl)-6,7;17,18-dibenzo-23,24-diaza-
of 13a (207 mg, 0.5 mmol) and carefully dried p-dichlorobenzene
1.0 g) was refluxed for 2 h (total conversion, TLC). After removal
of p-dichlorobenzene in vacuo, the residue was chromatographed
3
,10 5,8 14,21 16.19 2,11 4,9 13,22 15,20
decacyclo[10.10.2.1 .1 .1
6
.1
.0 .0 .0
.0
]octacosa-
(
,17,23-triene (16): Cf. 13b; upon addition of a deeply orange-red,
dry solution of 11b (109 mg, 0.5 mmol) in CH
stirred dry solution of 10 (208 mg, 1.0 mmol)/P
CH Cl
concentrated in vacuo for 30 min, the colorless residue crystallized
after addition of CH Cl /petroleum ether (1:1). 240 mg (80%, not
optimized) of colorless crystals (CH Cl ) were isolated, m.p. 310–
12 °C. UV (CH CN): λmax (ε) = 375 nm (85), 278 (sh, 860), 273
1800), 267 (1820), 262 (sh, 1400), 216 (sh, 16400). IR: ν˜ = i.a.
000, 2946, 2896, 1487, 1461, 1333, 1275, 1214, 1153, 1057, 939
2
Cl
2
(5 mL) to a
(
(
silica gel, 9 ϫ 2 cm, CH
CH Cl ), 155 mg (74%) of light yellow, oxygen-sensitive crystals
CN): λmax (ε) = 300 nm
2 2 f
Cl , R = 0.25). With crystallization
2
O
5
(100 mg) in
2
2
2
2
(5 mL), the color rapidly disappeared. The mixture was
were isolated, m.p. 161–162 °C. UV (CH
3
(
5500), 292 (5800), 285 (6300), 278 (4200), 258 (1800), 251 (950),
–1
2
2
2
1
43 (11800). IR: ν˜ = i.a. 3296 cm , 3040, 2954, 1659, 1590, 1488,
1
2
2
460. H NMR: δ = 7.45 (br. s, N–H), 7.40–7.15 (m, 10 H, 3Ј-,6Ј-
3
(
3
3
H), 6.90–6.85 (m, 4Ј-,5Ј-H), 3.40–3.43 (m, 10-,13-H), 2.95–2.80 (m,
-,9-,14-H), 2.70 (d, 7-H), 2.14 (dm, 16a-H), 2.04 (dm, 16s-H), 1.72
m, 1-H), 1.52 (dm, 15a-H), 0.93 (dm, 15s-H) ppm; J7,8 = 3.2, J15a,s
8
(
=
1
1
3
1
=
–1 1
cm . H NMR: δ = 7.28 (m, 2 H) 7.17 (m, 2 H), 6.98 (br. s, 4 H),
.27 (m, 5-,8-H), 3.23 (m, 16-,19-H), 2.65 (m, 4-,9-H), 2.52 (m, 15-,
0-H), 2.11 (m, 26-Ha,s), 2.09 (dm, J = 8.6 Hz, 28-Ha), 1.88 (dm,
J = 8.6 Hz, 28-Hs), 1.79 (m, 14-,21-H,), 1.77 (m, 3-,10-H), 1.75
dm, J = 8.3 Hz, 25-Ha), 1.57 (dm, J = 8.3 Hz, 25-Hs), 1.25 (m,
3-,22-H), 0.97 (m, 2-,11-H), –0.24 (dm, J = 12.6 Hz, 27-Ha), –0.36
dm, J = 12.6 Hz, 27-Hs) ppm. 13C NMR: δ = 147.6 (C-6,-7)*,
13
8.9, J16a,s = 8.3 Hz. C NMR: δ = 159.5, 154.3 (C-3,-6), 142.6,
3
2
41.6 (C-11,-12), 136.3, 136.2, 134.4, 131.2, 131.1, 128.6, 128.4,
28.1, 127.9, 127.5, 126.6, 125.7, 124.8, 123.2, 121.7 (10 C, C-2,-
Ј,-4Ј,-5Ј,-6Ј), 60.0 (C-16), 49.3 (C-15), 48.4 (C-7), 47.0, 46.7 (C-
0,-13), 46.3, 43.8 (C-9,-14), 41.0, 37.8 (C-1,-8) ppm. MS: m/z (%)
(
1
(
1
1
1
+
+
415 (31) [M + 1] , 414 (96) [M] , 348 (42), 298 (79), 297 (100),
71 (38). C30 (414.6): calcd. C 86.90, H 6.32; found C 86.79,
2
26 2
H N
45.2 (C-17,-18)*, 126.3 (q, J = 282.1 Hz, 2 CF
25.6 (2 CЈ), 123.4 (2 CЈ), 122.0 (2 CЈ), 76.8 (q, J = 25.4 Hz, C-1,-
2), 60.1 (CH ), 52.8 (CH ), 50.7 (C-3,-10), 50.3 (C-14,-21), 47.9
),
) ppm. MS (FAB): m/z
%) = 607 (25) [M + 1] , 606 (3) [M] , 400 (19), 399 (70) [13b +
3
), 126.2 (2 CЈ),
H 6.29
(
1α,7α,8α,9β,10α,13α,14β)-3,6-Bis(trifluoromethyl)-11,12-benzo-4,5-
2
2
1
0,13 2,7 9,14
diazapentacyclo[6.6.1.1
Cf. 20a; A solution of 13b (398 mg, 1.0 mmol) in p-dichlorobenzene
(1.5 g) was refluxed for 2 h. After removal of the solvent the solid
.0 .0 ]hexadeca-2,5,11-triene (21a):
(
C-4,-9), 47.5 (C-15,-20), 46.1 (C-5,-8), 43.3 (C-16,-19), 41.9 (CH
2
41.5 (C-13,-24), 39.6 (C-2,-11), 27.4 (CH
2
+
+
(
+
residue was chromatographed (silica gel, 10ϫ2 cm; CH
leum ether, 1:4). 340 mg (85%) of 21a (R = 0.15) were isolated
after crystallization from CH Cl /petroleum ether (1:9) as colorless
needles, m.p. 167 °C. UV (CH CN): λmax (ε) = 288 nm (sh, 1880),
78 (2250), 274 (sh, 2180), 238 (sh, 4200), 216 (sh, 10920). IR: ν˜ =
2 2
Cl /petro-
H] , 307 (23), 304 (27), 289 (25), 273 (11), 257 (13), 246 (13), 242
11), 217 (100). C36 (606.7): calcd. C 71.28, H 5.32; found
C 71.06, H 5.27. Occasionally, if moisture was not completely ex-
cluded, chromatographically (silica gel, 12ϫ2 cm, CH Cl /petro-
leum ether, 1:1), besides 16 the two hydrates of 13b were found.
f
(
32 6 2
H F N
2
2
3
2
2
2
–
1
1
inter alia 3328 cm (N–H), 2960, 1468, 1399, 1372, 1198, 1150. H
3
,14-Bis(trifluoromethyl)-8,9;19,20-dibenzodecacyclo- NMR: δ = 7.35 (br. s, N–H), 7.3–7.25 (m, 3Ј-,4Ј-H), 7.2–7.1 (m,
14.6.1.15 .1 .1
,12
7,10 18,21 2,15 3,14 4,13 6,11 17,22
.0 .0 .0 .0 .0
]hexacosa-8,19-
CN
150 mL) was irradiated in a Pyrex vessel with polychromatic light
5Ј-,6Ј-H), 3.35 (m, 10-H), 3.30 (m, 13-H), 3.19 (br. s, 1-H), 2.92–
[
diene (17): A degassed solution of 16 (61 mg, 0.1 mmol) in CH
(
3
3.03 (m, 9-,14-H), 2.88 (d, 7-H), 2.09 (dm, 16a-H), 2.01 (dm, 16s-
®
H), 1.93 (dm, 15a-H), 1.60 (m, 8-H), 1.19 (dm, 15s-H) ppm; J7,8 =
1
3
from a Hanau TQ 125-W high-pressure lamp (λ Ͼ280 nm) until
ca. 50% conversion (TLC, 2.5 h, one product). After concentration
1.6, J15a,s = 9.9, J16a,s = 8.6 Hz. C NMR: δ = 147.1, 144.7 (C-
11,-12), 129.8 (q, J = 34.2 Hz, C-6), 127.0, 125.3, 125.2, 122.4 (C-
in vacuo, the residue was chromatographed (silica gel, CH
troleum ether, 1:3) giving 30 mg (52%) of colorless crystals, m.p.
89–291 °C (CH Cl /petroleum ether, 1:9, R = 0.83), and then re-
sidual 16. UV (CH CN): λmax (ε) = 277 nm (sh, 400), 273 (1280),
2
Cl
2
/pe-
2,-3Ј,-4Ј,-5Ј,-6Ј), 121.2 (q, J = 273.4 Hz, CF
272.3 Hz, CF )*, 120.9 (q, J = 35.0 Hz, C-3), 59.6 (C-16), 49.3 (C-
15), 47.1 (C-7), 46.6, 46.3 (C-10,-13), 46.1, 43.4 (C-9,-14), 39.5, 35.5
3
)*, 120.7 (q, J =
3
2
2
2
f
+
+
3
(C-1,-8) ppm. MS: m/z (%) = 399 (13) [M + 1] , 398 (59) [M] , 329
Eur. J. Org. Chem. 2007, 2133–2146
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2141

T. Mathew, H. Prinzbach et al.
FULL PAPER
(
(
4
87), 213 (27), 167 (16), 143 (33), 142 (22), 141 (36), 129 (32), 128
(414 mg, 1.0 mmol) in anhydrous toluene (5 mL). After 30 min (to-
43), 117 (55), 116 (100). C20
.05; found C 60.38, H 4.10.
H
16
F
6
N
2
(398.4): calcd. C 60.31, H tal conversion, 20b, MS) tBuOK (220 mg) was added and stirring
continued for 30 min. Upon standard workup the product was
crystallized from CH
light-yellow crystals were collected, m.p. 205–206 °C. UV
CH CN): λmax (ε) = 338 nm (sh, 390), 274 (19800), 214 (sh, 25100).
IR: ν˜ = inter alia 3032 cm , 2948, 1548, 1488, 1463. H NMR: δ
8.00–7.90 (m, 4 H), 7.60–7.45 (m, 6 H), 6.72 (m, 3Ј-,6Ј-H), 6.50
m, 4Ј-,5Ј-H), 3.61 (br. s, 3-,6-H), 3.56 (br. s, 2-,7-H), 3.45 (br. s, 1-,
-H), 2.19 (dm, 12a-H), 2.05 (dm, 11a-H), 2.03 (dm, 12s-H), 1.80
2 2
Cl /petroleum ether (1:4), 345 mg (84%) of
(
1α,7α,8α,9β,10α,13α,14β)-3,6-Bis(trifluoromethyl)-4-chloro-11,12-
1
0,13 2,7 9,14
benzo-4,5-diazapentacyclo[6.6.1.1
ene (21b): tBuOCl (0.13 mL, 1.0 mmol) was added dropwise to a
stirred solution of 21a (250 mg, 0.63 mmol) in anhydrous toluene
.0 .0 ]hexadeca-3,5,11-tri-
(
3
–
1
1
=
(
8
(
3 mL) at room temperature (under N
2
). After 30 min tBuOK
(220 mg) was added and stirring was continued for 30 min. After
concentration in vacuo the residue was dissolved in CHCl
20 mL), washed with water and dried (MgSO ). The product ob-
tained after concentration in vacuo was chromatographed (silica
gel, 10ϫ2 cm, petroleum ether, R = 0.25). After crystallization
from petroleum ether 245 mg (90%) of yellow needles were iso-
lated, m.p. 97–98 °C. UV (CH CN): λmax (ε) = 438 nm (210), 317
2140), 270 (sh, 1970), 255 (2450), 217 (sh, 5840). IR: ν˜ = i.a.
3
1
3
(
(
dm, 11s-H) ppm; J11a,s = 8.8, J12a,s = 9.1 Hz. C NMR: δ = 152.8
C-3Ј,-6Ј), 143.3 (2 C), 142.4 (C-4,-5), 136.6 (C-9,-10), 128.9, 128.7,
(
4
1
1
4
28.4 (10 C), 126.5 (C-4ЈЈ,-5ЈЈ), 122.0 (C-3ЈЈ,-6ЈЈ), 58.9, 58.8 (C-11,-
f
2), 46.2 (C-3,-6), 46.0 (C-2,-7), 45.2 (C-1,-8) ppm. MS: m/z (%) =
+
+
13 (33) [M + 1] , 412 (100) [M] , 295 (75), 116 (70). HRMS: calcd.
412.1939; found 412.1946. C30 (412.6): calcd.
3
for C30
H
24
N
2
24 2
H N
(
C 87.34, H 5.86; found: C 86.57, H 6.85. Crystal structural analysis,
Figure 3.
–1
3
052 cm , 2960, 2913, 2873, 1469, 1375, 1330, 1269, 1196, 1175.
1
H NMR: δ = 7.11 (m, 3Ј-,4Ј-H), 6.95 (m, 5Ј-,6Ј-H), 3.37 (m, 10-
H), 3.34 (m, 13-H), 3.29 (m, 1-H), 3.21 (m 9-H)*, 3.02 (m, 14-H)*,
b) cf. 24c: 13a (212 mg, 0.5 mmol)/benzene (30 mL)/P
2
F (1.6 g,
2
2
.70 (d, 7-H), 2.65 (dm, 16a-H), 2.34 (m, 8-H), 2.16 (dm, 16s-H),
4.5 mmol)/benzene (15 mL)/Br (320 mg, 2.0 mmol). 190 mg (92%)
of 24a.
2
1
3
.0–2.1 (dm, 15s-,15a-H) ppm; J7,8 = 2.1, J16a,s = 9.8 Hz.
C
NMR: δ = 147.7, 143.4 (C-11,-12), 128.0 (q, J = 34.8 Hz, C-3)*,
(
9
2
1α,2β,3α,6α,7β,8α)-4,5-(3Ј,6Ј-Bis(trifluoromethyl-4Ј,5Ј-pyridazino)-
1
4
CF
4
23.0 (q, J = 35.0 Hz, C-6)*, 126.9, 126.7, 125.6, 122.9 (C-2,-3Ј,-
Ј,-5Ј,-6Ј), 123.9 (q, J = 281.8 Hz, CF ), 121.0 (q, J = 272.2 Hz,
), 58.6 (C-16), 48.8 (C-7), 48.2, 46.0 (C-10,-13), 47.3 (C-15),
5.8, 43.0 (C-9,-14), 39.0, 34.45 (C-1,-8) ppm. MS: m/z (%) = 432
3
,6 2,7
,10-benzotetracyclo[6.2.1.1 .0 ]dodeca-4,9-diene (24b): a) Cf.
4a; in a glove box, P F (520 mg, 1.45 mmol) was added to a solu-
3
2
3
tion of 21b (150 mg, 0.35 mmol) in anhydrous benzene (5 mL). Af-
ter being stirred for 2 min, the now colorless solution was washed
+
(5) [M] , 143 (12), 142 (38), 141 (43), 129 (23), 128 (19), 117 (37),
with water, dried (MgSO
graphically (silica gel, 8 ϫ 2 cm, CH
30 mg (95%) were recovered (R = 0.25) and crystallized from
CH Cl /petroleum ether (1:8); m.p. 208–210 °C. UV (CH CN):
max (ε) = 312 nm (sh, 440), 293 (sh, 560), 258 (2520), 252 (sh,
4
), and concentrated in vacuo. Chromato-
116 (100). C20
6 2
H15ClF N (432.2): calcd. C 55.51, H 3.49; found C
2
2
Cl /petroleum ether, 1:1),
55.64, H 3.54.
1
f
Dimethyl (1α,7α,8α,9β,10α,13α,14β)-11,12-Benzo-4,5-diazapentacy-
2
2
3
clo[6.6.1.11 .0 .0 ]hexadeca-2,5,11-triene-3,6-dicarboxylate
22a): P F (488 mg, 1.36 mmol) was added to a stirred solution of
3c (243 mg, 0.64 mmol) in benzene (10 mL) in a glove box. After
min the reaction was quenched with methanol (5 mL), the clear
0,13
2,7 9,14
λ
–
1
(
2
2200), 223 (sh, 3610), 217 (sh, 8270). IR: ν˜ = inter alia 3004 cm ,
2968, 1455, 1403, 1259, 1215, 1200, 1180. H NMR: δ = 6.77, 6.66
(3ЈЈ-,4ЈЈ-,5ЈЈ-,6ЈЈ-H), 3.65 (m, 1-,8-H), 3.50 (q, 2-,7-H), 3.29 (q, 3-,
1
1
3
yellowish solution concentrated in vacuo, and the residue was flash-
6-H), 2.23 (dt, 12a-H), 2.08 (dt, 11a-H), 1.97 (dq, 11s-H), 1.90 (dq,
chromatographed (silica gel, 10ϫ2 cm, cyclohexane/ethyl acetate,
12s-H) ppm; J11a,s = J12a,s = 9.4, J11a(s),1(8) = 1.5, J12a(s),3(6) =
1.6 Hz. C NMR: δ = 147.4 (q, J = 34.8 Hz, C-3Ј,-6Ј), 145.7 (C-
1
3
1
:1); 231 mg (95%) of colorless crystals (R
f
= 0.60) were isolated.
): δ = 8.3 (br. s, N–H), 7.00 (m, 3Ј-H)*, 6.86 (m, 4,-5), 143.4 (C-9,-10), 127.2 (C-3ЈЈ,-6ЈЈ), 123.6 (C-4ЈЈ,-5ЈЈ), 121.5 (q,
Ј-H)*, 6.83–6.72 (m, 5Ј-,6Ј-H)*, 3.75 (br. s, 1-H), 3.47 (d, 7-H), J = 275.0 Hz, C–CF ), 59.1 (C-12), 58.5 (C-11), 45.8 (C-1,-8)*, 45.9
.40 (s, OCH ),3.42 (m, 13-H), 3.32 (s, OCH ), 3.10 (br. s, 10-H), (C-2,-7), 44.6 (C-3,-6)* ppm. MS: m/z (%) = 396 (11) [M] , 167
1
6 6
H NMR (C D
4
3
2
1
3
+
3
3
.98 (br. s, 14-H), 2.56–2.60 (8-,9-H), 1.92 (dm, 16s-H), 1.85 (dm,
5s-H), 1.65 (dm, 16a-H), 1.58 (dm, 15a-H) ppm; J7,8 = 2.6 Hz.
C NMR: δ = 164.5 (CO), 161.3 (CO), 147.4, 145.3 (C-11,-12),
30.0 (C-6), 128.6 (C-2), 126.2, 125.1, 124.0, 123.0 (C-3Ј,-4Ј,-5Ј,-
(12), 143 (31), 142 (37), 141 (100). C20
60.61, H 3.56; found C 60.41, H 3.55.
14 6 2
H F N (396.3): calcd. C
13
b) Cf. 24c; compound 13b (200 mg, 0.5 mmol)/benzene (30 mL)/
F (1.6 g, 4.5 mmol)/benzene (15 mL)/Br (320 mg, 2.0 mmol).
80 mg (90%) of 24b.
1
6
1
P
2
2
Ј), 124.1 (C-3), 59.5 (C-16), 51.5 (OCH
3 3
), 51.2 (OCH ), 49.8 (C-
1
5), 47.8 (C-7), 46.7, 46.5 (C-10,-13), 46.5, 45.5 (C-9,-14), 40.0, 38.2
+
(
(
(
C-1,-8) ppm. MS: m/z (%) = 379 (4), 378 (17) [M] , 329 (56), 318
19), 218 (16), 203 (26), 202 (14), 189 (17), 188 (36), 165 (15), 128
40), 116 (98), 115 (100). HRMS: calcd. for C22
78.1580; found: 378.1574.
Dimethyl (1α,2β,3α,6α,7β,8α)-4Ј,5Ј-Pyridazino-9,10-benzotetra-
3
,6 2,7
cyclo[6.2.1.1 .0 ]dodeca-4,9-diene-3Ј,6Ј-dicarboxylate (24c): A
Cl (50 mL)
was added to a solution of 10 (294 mg, 1.41 mmol) in CH Cl
10 mL) within 20 min. After concentration in vacuo, the yellowish
residue (525 mg, 1.4 mmol, of 13c) was transferred into a glove box
and dissolved in benzene (30 mL). Within 3 min, a solution of P
3.52 g, 9.80 mmol) in benzene (40 mL) was added, then the re-
sulting brown solution was removed from the glove box. Under N
H
22
N
2
O
4
(378.4): deeply red solution of 11c (285 mg, 1.44 mmol) in CH
2
2
3
2
2
(
Dimethyl (1α,7α,8α,9β,10α,13α,14β)-4-Chloro-11,12-benzo-4,5-diaza-
pentacyclo[6.6.1.11 .0 .0 ]hexadeca-2,5,11-triene-3,6-dicarb-
oxylate (22b): After stirring a solution of 22a (26 mg, 0.07 mmol)
and sodium dichloroisocyanurate (16 mg, 0.07 mmol) in benzene
0,13
2,7 9,14
2
F
(
2
(10 mL) and six drops of water (clear solution) for 12 h at 70 °C,
bromine (684 mg, 4.28 mmol) was added, and the orange solution
was extracted with water (4ϫ50 mL) after 10 min. The organic
conversion was complete (TLC). MS: m/z (%) = 414 (21), 413 (77),
+
+
4
12 (10) [M] , 377 (100) [M – Cl] , 295 (13), 294 (17), 279 (23), 245
phase was dried (Na
residue flash-chromatographed (silica gel, CH
2
2
SO
4
), concentrated in vacuo, and the solid
Cl /ethyl acetate,
:1); 510 mg, (96 %) of colorless crystals were isolated. UV
(
12), 243 (11). HRMS: calcd. for C22 21ClN (412.9): 412.1191;
H
2 4
O
2
2
found 412.1181.
(
1α,2β,3α,6α,7β,8α)-4,5-(3Ј-,6Ј-Diphenyl-4Ј,5Ј-pyridazino)-9,10-ben-
3
(CH CN, qual.): λmax (ε) = 340–330 nm (br. sh, ca. 200), 310–260
3
,6 2,7
1
zotetracyclo[6.2.1.1 .0 ]dodeca-4,9-diene (24a): a) tBuOCl
0.13 mL, 0.1 mmol) was added to a stirred solution of 20a
(ca. 600). H NMR: δ = 6.68, 6.55 (3ЈЈ-,4ЈЈ-,5ЈЈ-,6ЈЈ-H), 4.10 (s, 2
OCH ) 4.00 (m, 3-,6-H), 3.50 (m, 2-,7-H), 3.32 (m, 1-,8-H), 2.15
(
3
2142
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 2133–2146

[6+6]Photocycloadditions
FULL PAPER
(
dm, 11a-H), 2.05 (dm, 12a-H), 1.92 (dm, 11s-H), 1.90 (dm, 12s-
H) ppm; J11a,s = J12a,s = 9.2 Hz. HRMS: calcd. for C22
76.1423; found 376.1401. X-ray crystal structure, Figure 3.
(1α,2α,7α,8α,9β,10α,13α,14β)-6-Methoxy-11,12-benzo-4,5-di-
1
0,13 2,7 9,14
H
20
N
2
O
4
azapentacyclo[6.6.1.1
Cf. 24c. A solution of P
.0 .0 ]hexadeca-5,11-dien-3-one (28b):
2
F (710 mg, 2.0 mmol) in benzene (5 mL)
3
was added over 3 min to a solution of 13d (97 mg, 0.30 mmol) in
benzene (5 mL) in a glove box . The brownish solution (19d) was
Under not totally anhydrous conditions a second product besides
4c was isolated in various amounts and identified as 28a.
2
removed from the box and under N
was added. After 30 min the orange solution (one product, TLC)
was thoroughly washed with water, dried (Na SO ) and concen-
trated in vacuo. The solid residue was flash-chromatographed (sil-
ica gel, CH Cl /ethyl acetate, 3:1) and 81 mg (88%) of crystalline
8b were isolated. H NMR: δ = 7.52 (br. s, NH), 7.32 (m, 1 H),
.25 (m, 1 H), 7.06 (m, 2 H), 3.54 (s, OCH ), 3.30 (m, 10-,13-H),
.85–2.70 (m, 2-,7-,8-H), 2.66 (m, 1-H), 2.1–2.0 (m, 9-,14-H), 1.98
2
, bromine (218 mg, 1.36 mmol)
(
1α,2β,3α,6α,7β,8α)-4,5-[3Ј,6Ј-Bis(hydroxymethyl)pyridazino]-9,10-
3,6 2,7
2
4
benzotetracyclo[6.2.1.1 .0 ]dodeca-4,9-diene (24f): At room tem-
perature and under N , 24c (103 mg, 0.27 mmol) was added to a
suspension of LiAlH (78 mg, 2.05 mmol) in anhydrous THF
5 mL). After being stirred for 45 min at 50 °C, the suspension was
cooled to 0 °C, hydrolyzed with water (0.5 mL)/NaOH (0.1 mL,
0%), and the stirring was continued for 15 min at room temp.
Following concentration in vacuo, the residue was extracted with
CH Cl (5ϫ10 mL), the organic phase dried (Na SO ), concen-
2
2
2
4
1
2
7
2
(
3
1
1
3
(
dm, 16s-H) 1.6–1.4 (m, 15s-,16a-H), 1.52 (md, 15a-H) ppm.
C
NMR: δ = 167.7 (C-6), 157.1 (C-3), 146.7, 146.5 (C-11,-12), 126.0,
2
2
2
4
1
7
26.1, 123.9, 123.2 (C-3Ј,-4Ј,-5Ј,-6Ј), 60.6 (C-15), 53.7, 47.0 (C-2,-
), 46.7, 46.3 (C-10,-3), 46.3 (C-9,-14), 46.2 (OCH ), 43.3 (C-16),
trated in vacuo, and the residue flash-chromatographed (silica gel,
ethyl acetate/methanol, 7:1); 64 mg (73%) of crystals were isolated.
3
+
1
40.2, 37.5 (C-1,-8) ppm. MS (EI): m/z (%) = 308 (100) [M] , 307
H NMR (CD
OH), 3.60 (m, 3-,6-H), 3.48 (m, 2-,7-H), 3.30 (t, 2 OH), 3.2
m, 1-,8-H) 2.15 (dm, 11a-H)*, 2.10 (dm, 12a-H)*, 1.98–194 (dm,
3
OD): δ = 6.76, 6.54 (3ЈЈ-,4ЈЈ-,5ЈЈ-,6ЈЈ-H), 4.70 (d, 2
(
(
4), 267 (12), 179 (13), 167 (11), 166 (16), 165 (34), 128 (10), 127
45). C19 (308.4): calcd. C 74.00, H 6.54; found C 73.79,
CH
(
1
2
20 2 2
H N O
1s-,12s-H) ppm. 13C NMR (CD
OD): δ = 156.3 (C-3Ј,-6Ј), 146.4
H 6.33.
3
(
(
(
(
(
C-4,-5), 145.2 (C-9,-10), 127.5 (C-3ЈЈ,-6ЈЈ), 123.3 (C-4ЈЈ,-5ЈЈ), 63.6
(
1α,4α,5β,6α,9α,10β)-2,3-(3Ј,6Ј-Diphenyl-4Ј,5Ј-pyridazino)tetracy-
CH OH) 60.3 (C-12), 59.3 (C-11), 47.4 (C-1,-8), 46.8 (C-2,-7), 44.8
2
3,6 2,7
clo[6.2.1.1 .0 ]dodec-2-ene (31a): A carefully dried, violet solu-
tion of 29 (158 mg, 1.0 mmol) and 11a (234 mg, 1.0 mmol) in
CH
single product, TLC). After standard workup 320 mg (88%) of col-
orless crystals were isolated. UV (CH CN): λmax (ε) = onset ca.
+
C-3,-6) ppm. MS: m/z (%) = 320 (4) [M] , 291 (10), 179 (6), 161
8), 142 (18), 141 (38), 129 (19), 128 (28), 127 (11), 117 (18), 116
2 2
Cl (10 mL) was stirred until total conversion (TLC, 12 h, a
67), 115 (100). HRMS: calcd. for C20
20.1508.
20 2 2
H N O 320.1525; found
3
3
1
3
4
30 nm, 327 (450), 272 (2600), 249 (2100). H NMR: δ = 8.05 (m,
H), 7.65 (m, 4 H), 7.53 (m, 2 H), 3.55 (m, 3-,6-H), 3.00 (m, 2-,7-
(1α,2α,8α,9β,10α,13α,14β)-6-Phenyl-4,5;11,12-dibenzopentacyclo[6.6.
3
,6 2,7 9,14
1
.1 .0 .0 ]hexadeca-4,6,11-trien-3-one (25): Yellowish crystals
H), 2.48 (1-,8-H), 1.94 (m, 12-Ha,s), 1.83 (dm, 11-Ha), 1.55 (dm,
1
=
C), 128.5 (4 C), 127.3 (4 C), 59.8 (C-12), 46.8 (2 C), 46.4 (C-11),
4
=
–1
4
(CCl ), m.p. 205–207 °C. IR: ν˜ = inter alia 2980 cm , 2900, 2880,
1-Hs), 1.15 (m, 9-,10-Ha), 0.72 (m, 9-,10-Hs) ppm; J11a,s = J12a,s
–1 1
1
690, 1590, 1460, 1440, 1220, 775 cm . H NMR: δ = 7.58 (m, 2
1
3
9.2 Hz. C NMR: δ = 156.6 (C-3Ј,-6Ј), 144.5 (C-4,-5), 135.4 (2
H), 7.50 (m, 1 H), 7.41 (m, 1 H), 7.36–7.31 (m, 3 H), 7.16 (m, 1
H), 7.07 (m, 1 H), 7.01 (m, 1 H), 6.89 (m, 1 H), 6.75 (m, 2 H), 3.48
(
2
1
6.2 (2 C), 44.2 (2 C), 39.2 (2 C), 21.8 (C-9,-10) ppm. MS: m/z (%)
m, 10-H), 3.34 (m, 13-H), 3.0–2.9 (m, 1-,9-,14-H), 2.81 (m, 8-H),
+
+
24 2
365 (22) [M + 1] , 364 (100) [M] , 323 (15), 283 (32). C26H N
.47 (br. s, 2-H), 2.17 (dm, 16s-H), 2.06 (dm, 16a-H), 1.77 (dm,
(
364.5): calcd. C 85.68, H 6.64; found C 85.62, H 6.70.
1
5a-H), 1.50 (dm, 15s-H) ppm; J15a,s = 10.5, J16a,s = 11.0 Hz. H
NMR ([D
5
]pyridine): δ = 7.79–6.74 (m, 13 H), 3.34 (m, 1 H), 3.20
(1α,4α,5β,6α,9α,10β)-2,3-(3Ј,6Ј-Trifluoromethyl-4Ј,5Ј-pyridazino)tetra-
3
,6 2,7
(
m, 1 H), 3.15 (m, 1 H), 2.85 (m, 2 H), 2.72 (m 1 H), 2.02 (dm, cyclo[6.2.1.1 .0 ]dodec-4-ene (31b): Preparation according to
1
6s-H), 1.89 (dm, 16a-H), 1.63 (dm, 15a-H), 1.50 (dm, 15s-H) ppm.
C NMR: δ = 203.2 (C=O) 148.0, 147.1, 145.1, 144.8, 140.7, 138.2,
32.9, 131.2, 130.3, 129.0, 128.9, 128.3, 128.0, 126.9, 126.3, 126.1,
compound 31a from 29 (158 mg, 1.0 mmol) and 11b (218 mg,
1
3
1.0 mmol) in CH Cl (10 mL); after stirring for 15 min provided
2
2
1
1
4
2
310 mg (89%) of colorless crystals. UV (CH CN): λ
ca. 345 nm, 313 (450), 257 (sh, 1460), 233 (4050). H NMR: δ =
max
(ε): onset
3
1
26.0, 125.6, 125.0, 124.6, 122.2, 59.3, 53.9, 48.9, 47.7, 46.8, 46.7,
6.5, 46.2, 37.4 ppm. MS (EI): m/z (%) = 400 (100) [M] , 285 (22), 3.70 (m, 3-,6-H), 2.99 (m, 2-,7-H), 2.30 (1-,8-H), 2.19 (br. s, 12-
84 (64), 283 (45), 259 (20), 258 (32), 257 (21). C30H24O (400.5): Ha,s), 1.72 (dm, 11-Ha), 1.42 (dm, 11-Hs), 1.05 (m, 9-,10-Ha), 0.07
+
1
3
calcd. C 89.96, H 6.03; found C 89.29, H 6.25. Dissolved in [D
5
]
(m, 9-,10-Hs) ppm; J11a,s = 9.5 Hz. C NMR: δ = 149.4 (C-4,-5),
pyridine, 25 at 100 °C was slowly transformed (completely after
148.5 (q, J = 33.9 Hz, C-3Ј,-6Ј), 120.8 (q, J = 285.7 Hz, CF ), 57.7
3
1
5
1
h) to (most probably) 26. H NMR ([D
H), 7.97 (m, 1 H), 7.8–7.3 (m, 8 H), 6.82 (d, 1 H), 6.42 (m, t, 1 (C-9,-10) ppm. MS: m/z (%) = 340 (85) [M] , 320 (27), 280 (31),
5
]pyridine): δ = 8.51 (m,
(C-12), 46.8 (2 C), 46.4 (1 C), 45.6 (1 C),44.4 (2 C), 39.3 (2 C), 21.8
+
H), 6.06 (t, 1 H), 5.6 (br., OH), 3.85 (m, 1 H), 3.37 (m, 1 H), 3.20 95 (100). C16H14F N (340.3): calcd. C 55.18, H 4.05; found C
6
2
(m, 1 H), 3.16–3.0 (3 H), 2.10–1.85 (m, 3 H), 1.81 (dm, 1 H) ppm. 55.08, H 4.05.
(
1α,2α,7α,8α,9β,10α,13α,14β)-6-Methoxycarbonyl-11,12-benzo-4,5-
3,6-Diphenyl-4,5-diazaoctacyclo[12.5.1.02,7.O2,13.07,18.08,13
.
1
0,13 2,7 9,14
8,16 17,20
diazapentacyclo[6.6.1.1
.0 .0 ]hexadeca-5,11-dien-3-one
O
,0
]eicosa-3,5,9,11-tetraene (32a): A degassed solution of
1
(28a): Colorless crystals. H NMR: δ = 7.52 (br. s, NH), 7.32 (m,
24a (206 mg, 0.5 mmol) in CH CN (150 mL) was irradiated with
3
1
H), 7,25 (m, 1 H), 7.06 (m, 2 H), 3.54 (s, OCH
3
), 3.30 (m, 10-,
monochromatic 254 nm light (Rayonet reactor, quartz tubes) for
3 h (ratio 24a/32a ca. 2:1, no further change, H NMR control, see
1
13-H), 2.85–2.70 (m, 2-,7-,8-H), 2.66 (m, 1-H), 2.1–2.0 (m, 9-,14-
H), 1.98 (dm, 16s-H) 1.6–1.4 (m, 15s-,16a-H), 1.52 (dm, 15a-H) Figures 4 and 5). After concentration in vacuo, the residue was
ppm. 13C NMR: δ = 167.5 (C-6), 163.8 (CO), 146.6, 146.0 (C-11,-
chromatographically (deactivated silica gel, 10ϫ2 cm, CH Cl /pe-
troleum ether, 1:5) separated into 32a (R = 0.1, 62 mg, 30%) and,
after changing to CH Cl /CH OH (2 %), residual 24a (150 mg).
Compound 32a crystallized from CH Cl /petroleum ether (1:5) in
orange needles, melting at 183–185 °C without change. UV
(CH CN): λmax (ε) = 351 nm (sh, 5460), 304 (sh, 11300), 294 (sh,
2
2
1
4
4
2), 126.1, 126.0, 123.8, 123.4 (C-3Ј,-4Ј,-5Ј,-6Ј), 60.5 (C-15), 52.7,
f
7.8 (C-2,-7), 47.0, 46.9 (C-10,-3), 46.4 (C-9,-14), 46.3, 46.2 (C-15),
2
2
3
+
3.2, 40.1 ppm. MS (EI): m/z (%) = 336 (58) [M] , 323 (14), 277
2
2
+
(26) [M – CO
2
CH
3
] , 193 (18), 155 (95), 116 (100). C20
H
22
N
2
O
3
(336.4): calcd. C 71.41, H 5.99; found: C 71.02, H 5.81.
3
Eur. J. Org. Chem. 2007, 2133–2146
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2143

T. Mathew, H. Prinzbach et al.
FULL PAPER
–
1
1
2
1700), 286 (sh, 11500), 214 (sh, 7000). IR: ν˜ = inter alia 3046 cm , was chromatographed (silica gel, 8ϫ1.5 cm, CH
2
Cl
= 0.85), then, 56 mg (48%) of 38 [with CH
3
OH (2%)] were eluted.
2
). First 52 mg
1
934, 2858, 1534, 1503, 1447, 1434. H NMR: δ = 8.12–7.90 (m, 4
(45%) of 37 (R
f
2
2
Cl /
H), 7.50–7.35 (m, 6 H), 5.51 (m, 9-,12-H), 5.34 (m, 10-,11-H), 3.17 CH
(
m, 1-,18-H), 2.88 (m, 17-,20-H), 2.75 (m, 14-,16-H), 2.10 (dm, 15a-
3
3
2
7: Colorless crystals, m.p. 234–236 °C. UV (CH
3
CN): λmax(ε) =
H), 1.99 (dm, 15s-H), 1.74 (dm, 19a-H), 1.60 (dm, 19s-H) ppm;
J
1
88 nm (90), 376 (80), 258 (sh, 5200). IR (KBr): ν˜ = inter alia 3050,
15a,s = 10.7, J19a,s = 11.3 Hz. 13C NMR: δ = 156.7 (C-3,-6), 135.9,
30.5, 128.4, 128.1 (10 C), 124.7 (C-10,-11), 123.7 (C-9,-12), 64.0
–
1 1
968, 2864, 1762, 1716, 1497, 1440 cm . H NMR: δ = 7.75–7.50
(
10 H), 7.40–7.30 (5 H, N-phenyl), 4.92 (m, 3-,6-H), 2.98 (m, 18-,
(C-2,-7), 59.9 (C-8,-13), 54.9 (C-1,-8), 54.8 (C-17,-20), 54.6 (C-14,-
1
1
1
1
9-H), 2.84 (m, 20-,22-H), 2.81 (m, 15-,17-H), 2.46 (m, 7-,8-H),
.94 (dm, 21s-H), 1.65 (dm, 21a-H), 1.43 (dm, 16s-H),0.96 (dm,
+
1
4
6), 38.4, 38.1 (C-15,-19) ppm. MS: m/z (%) = 413 (6) [M + 1] ,
+
24 2
12 (34) [M] , 295 (55), 116 (100). HRMS: calcd. for C30H N
1
3
6a-H) ppm; J16a,s = J21a,s = 11.0 Hz. C NMR: δ = 165.9 (C=O),
(412.55) 412.1939; found 412.1942.
51.4, 140.6, 131.4, 129.2, 129.0, 128.8, 128.2, 125.5 (15 C), 73.7
,6-Bis(trifluoromethyl)-4,5-diazaoctacyclo-[12.5.1.02,7.O2,13.07,18
(C-9,-12), 61.2 (C-13,-14), 59.4 (C-3,-6), 58.6 (C-1,-2), 52.1 (C-18,-
19), 49.1 (C-20,-22), 42.7 (C-15,-17), 42.0 (C-7,-8), 41.8 (C-21), 39.6
3
0
2
2
.
8,13 8,16 17,20
.O ,0
]eicosa-3,5,9,11-tetraene (32b): Cf. 32a. Compound
+
(
C-16) ppm. MS (FAB): m/z (%) = 589 (45) [M + 2] , 588 (100)
4b (65 mg, 0.16 mmol) in CH
54 nm light for 2 h: ratio 24b/32b, ca. 2:1 ( H NMR). The residue
Cl /pe-
= 0.25, 18 mg, 28%), then residual
= 0.40, 45 mg) were eluted. Compound 32b crystallized
from CH Cl /petroleum ether (1:9) in light-green needles, melting
at 140 °C without change. UV (CH CN): λmax (ε) = 354 nm (120),
04 (sh, 780), 291 (sh, 1715), 278 (sh, 2440), 266 (2725), 212 (sh,
3
CN (150 mL) was irradiated with
+
+
+
1
[M + 1] , 587 (3) [M] , 560 (58), 559 (99) [M – N ] , 441 (21), 440
– PhNCO] , 413 (31), 307 (39), 289 (37), 279 (16),
71 (21), 258 (17). MS (EI): m/z (%) = 559 (100) [M – N
2
+
(
12) [M – N
2
was chromatographed (deactivated silica gel, 8ϫ2 cm, CH
troleum ether, 1:1). First 32b (R
4b (R
2
2
+
2
2
] , 440
f
+
(
14) [M – N
2
– PhNCO] , 303 (21). C38
H N O (587.7): calcd. C
29 5 2
2
f
77.66, H 4.97; found C 77.59, H 4.80.
2
2
3
38: Colorless crystals, m.p. 331–332 °C. UV (CH
3
CN): λmax (ε) =
3
3
1
(
1
3
42 nm (5450), 392 (4700), 241 (4150). 204 (sh, 10050). IR (KBr):
–1
400). IR: ν˜ = inter alia 3040 cm , 2976, 2940, 2872, 1577, 1347,
–1
1
ν˜ = inter alia 3068 cm , 2986, 1769, 1706, 1530, 1490. H NMR:
δ = 8.1–7.4 (10 H), 7.32–7.20 (5 H, N-phenyl), 6.32 (m, 20-,21-H),
1
278, 1243, 1197, 1174, 1156. H NMR: δ = 5.80 (m, 9-,12-H), 5.38
m, 10-,11-H), 3.04 (m, 1-,18-H), 2.82 (m, 17-,20-H), 2.51 (m, 14-,
6-H), 2.04 (dm, 19a-H), 1.96 (dm, 15a-H), 1.97 (dm, 15s-H), 1.57
dm, 19s-H) ppm; J15a,s = 11.7, J19a,s = 11.4 Hz. 13C NMR: δ =
4.97 (m, 1-,17-H), 3.03–3.07 (m, 12-,22-H), 3.0–2.9 (m, 9-,11-H),
2
.79 (m, 13-,15-H), 2.1–1.95 (m, 10a-,10s-,14a-H), 1.79 (dm, 14s-
(
13
H) ppm; J14a,s = 11.3 Hz. C NMR: δ = 170.0 (C=O), 157.3, 134.7,
1
1
1
55.9 (q, J = 33.5 Hz, C-3,-6), 126.0 (C-10,-11), 121.9 (C-9,-12),
20.1 (q, J = 278.8 Hz, CF ), 66.4 (C-2,-7), 58.7 (C-8,-13), 55.2 (C-
,-8), 54.7 (C-17,-20), 52.3 (C-14,-16), 38.8, 36.6 (C-15,-19) ppm.
(
C-20,-21), 130.9, 128.8, 128.7, 128.6, 127.8, 127.7, 125.2 (14 C),
3
7
1
7.2 (C-4,-7), 63.36 (C-3,-8), 54.9 (C-1,-17), 53.8 (C-2,-16), 52.3 (C-
2,-22), 52.0 (C-13,-15), 47.6 (C-9,-11), 40.3 (C-10)*, 40.2 (C-14)*
+
+
MS: m/z (%) = 397 (2) [M + 1] , 396 (6) [M] , 143 (12), 142 (41),
+
+
ppm. MS: m/z (%) = 588 (20) [M + 1] , 587 (33) [M] , 297 (17),
1
6
41 (100). C20
0.55, H 3.54.
14 6 2
H F N (396.3): calcd. C 60.61, H 3.56; found C
2
1
96 (32), 295 (68), 271 (16), 202 (16), 165 (19), 141 (29), 128 (18),
19 (24), 117 (23), 116 (100). C38 (587.7): calcd. C 77.66,
29 5 2
H N O
,12-Diphenyl-10,11-diazaundecacyclo[11.9.0.01,6.02,14.02.20.03.8
H 4.97; found C 77.55, H 4.75. X-ray crystal structure, Figure 6.
9
0
.
7
.12 9,14 13,17 15,19 18,22
.0 .0
.0
.0
]docos-10-ene-anti-4,anti-5-dicarboxylic
,6-Diphenyl-4,5,10,11-tetraazaundecacyclo[11.9.0.01,6.02,14.02,20
3
0
.
Anhydride (36): A solution of 32a (103 mg, 0.25 mmol) and freshly
sublimed maleic anhydride (62 mg, 0.63 mmol) in anhydrous tolu-
ene (2 mL) was heated to 80 °C under a pressure of 9.5 kbar for
3,8 7,12 9,14 13,17 15,19 18,22
.0 .0 .0
.0
.0
]docosa-4,10-diene (39): A solution
of 37 (20 mg, 0.035 mmol) and NaOH (24 mg) in dry iPrOH
2 mL) was heated under reflux for 22 h (N , total conversion,
TLC). The solution was cooled to 0 °C, then HCl (10%, 0.4 mL)
and a solution of CuCl (45 mg) in water (2.5 mL) were added.
After stirring at room temp. for 2 h, concd. NH OH solution was
added dropwise till a blue color persisted. The solution was ex-
tracted with CH Cl , the organic phase washed and dried (MgSO ),
then concentrated in vacuo. The solid residue crystallized from
CH Cl in colorless needles (12 mg, 80%). UV (CH CN): λmax (ε)
389 nm (130), 367 (110), 276 (1170). 246 (8700). H NMR: δ =
.9–7.5 (10 H), 6.06 (9-,12-H), 2.88 (m, 18-,19-H), 2.70 (m, 15-,17-
H), 2.64 (m, 20-,22-H), 1.65 (m, 7-,8-H), 1.58 (dm, 21s-H), 1.37
(
2
1
9 h. After concentration in vacuo, residual maleic anhydride was
–3
sublimed away at 10 Torr and the residue chromatographed (silica
gel, 8ϫ2 cm, ethyl acetate/petroleum ether, 3:7). First 36 (R = 0.3,
8 mg, 45%), then 24a (R = 0.8, 50 mg, 49%) were eluted. Com-
pound 36 crystallized from CH Cl /petroleum ether (1:4) in color-
2
f
4
5
f
2
2
2
2
4
1
less needles, m.p. 258 °C. H NMR: δ = 7.69 (m, 4 H), 7.53 (m, 4
H), 7.43 (m, 2 H), 3.05 (m, 4-,5-H), 2.96 (m, 3-,6-H),2.93 (m, 7-,8-
H), 2.79 (m, 20-,22-H), 2.69 (m, 18-,19-H), 2.03 (m, 15-,17-H), 1.93
2
2
3
1
=
7
(
dm, 21a-H), 1.52 (dm, 21s-H), 1.42 (dm, 16a-H), 0.98 (dm, 16s-
H) ppm; J16a,s = J21a,s = 10.5 Hz. 13C NMR: δ = 172.4 (CO), 141.8
(
(
2
(
(
2 C), 129.2, 128.6, 127.9 (10 C), 75.4 (C-9,-12), 62.9 (C-1,-2), 59.6
2 C), 57.4 (C-13,-14), 49.8 (2 C), 42.5 (2 C), 42.1 (2 C), 41.8 (C-
1), 39.6 (C-16), 37.4 (2 C), 30.6 (2 C) ppm. MS: m/z (%) = 513
13
(
dm, 16s-H), 1.14 (dm, 21a-H), 0.96 (dm, 16a-H) ppm. C NMR:
δ = 141.4, 128.9, 128.8, 128.0 (10 C), 74.6 (C-9,-12), 65.1 (C-3,-6),
1.3 (C-13,-14), 59.6 (C-7,-8), 56.7 (C-1,-2), 50.2 (C-15,-17), 42.6
6
+
+
+
29), 512 (39), 511 (100) [M + 1] , 510 (9) [M] , 482 (8) [M – N
HR: calcd. 482.1882; found 482.1880), 483 (17), 440 (10), 439 (22),
04 (10), 85 (15). C34 (510.6): calcd. C 79.98, H 5.13;
found C 79.77, H. 5.01.
2
]
(
(
(
C-18,-19), 41.7 (C-20,-22), 40.8 (C-16), 39.8 (C-21) ppm. MS
+
+
FAB): m/z (%) = 441 (9) [M + 1] , 413 (100) [M + 1 – N
2
] , 385
1
H
26
N
2
O
3
+
22), 384 (95) [M + 1–2 N
2
] , 318 (12), 307 (29), 289 (21). MS (EI):
+
+
m/z (%) = 412 (9) [M – N
2
] , 385 (33), 384 (100) [M – 2 N
19), 318 (54), 317 (21), 241 (15), 239 (12), 215 (11), 202 (11), 191
14), 178 (14), 165 (12), 115 (17). C30 (440.6): calcd. C 81.79,
2
] , 319
(
(
9
0
,12-Diphenyl-4,5,10,11-tetrazaazaundecacyclo[11.9.0.01,6.02,14
.
24 4
H N
2
.20 3.8 7.12 9,14 13,17 15,19 18,22
.0 .0 .0 .0
.0
.0
]docos-10-ene-4,5-dicarbox-N-
H 5.49; found C 81.51, H 5.36.
phenylimide (37) and 4,7-Diphenyl-5,6,18,19-tetraazadeca-
cyclo[15.2.2.19 .0 .0 .0 .0
,15
2,13 2,13 3,11 8,16 9,22 12,22 15,22
.0
.0
.0
]docosa-
3,10-Diphenylheptacyclo[10.5.1.02,6.06,16.07,11.07,14.013,17]octadeca-
4,6,20-trien-18,19-dicarbox-N-phenylimide (38): A solution of 32a
2,4,8,10-tetraene (42): A degassed solution of 39 (50 mg,
(
3
82 mg, 0.20 mmol) and N-phenyltriazoline-3,5-dione (36 mg, 0.11 mmol) in CH CN (50 mL) was irradiated with monochromatic
0
.20 mmol) in CH
2
Cl
2
(6 mL) was stirred for 30 min (total conver-
light (254 nm, quartz tube) for 1 h (complete conversion, one major
product, two traces, TLC). After concentration in vacuo, the resi-
sion, two products, TLC). After concentration in vacuo, the residue
2144
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 2133–2146

[6+6]Photocycloadditions
FULL PAPER
due was crystallized from hexane/CH
colorless, oxygen-sensitive crystals were isolated. H NMR: δ =
2
Cl
2
(4:1); 30 mg (80%) of
T. A. McCormack, J. L. King, Z. Gasyna, G. Chen, R. Gleiter,
N. C. Yang, J. Am. Chem. Soc. 2000, 122, 12098.
6] W. v. E. Doering, W. R. Roth, R. Breuckmann, L. Figge, H.-
1
[
7.5–7.2 (10 H), 6.56 (d, 4-,9-H), 6.22 (d, 5-,8-H), 3.48 (m, 1-,12-H),
W. Lennartz, W.-D. Fesner, H. Prinzbach, Chem. Ber. 1988,
3.25 (m, 13-,17-H), 2.56 (m, 18a-H), 2.46 (m, 18s-H), 2.37 (m, 15a-
1
21, 1; for the thermolytic cleavage of the parent syn-o,oЈ-di-
H), 2.22 (m, 14-,16-H), 2.15 (m, 15s-H) ppm; J4,5 = J8,9 = 5.4 Hz.
–
1
benzene an activation enthalpy of 27.2 Ϯ0.6 kcal mol has
been reported: H. Gan, G. Horner, B. Hrnjez, T. A. McCorm-
ack, J. L. King, Z. Gasyna, G. Chen, R. Gleiter, N. C. Yang,
J. Am. Chem. Soc. 2000, 122, 12098.
1
3
C NMR: δ = 162.0 (2 C), 135.7 (C-3,-10), 138.5, 132.5, 128.3 (10
C), 126.6 (C-4,-9), 126.3 (C-5,-8), 75.6 (C-2,-11), 62.1 (C-1,-,12),
0.3 (C-13,-17), 43.4 (C-18), 42.4 (C-14,-16), 41.1 (C-15) ppm. MS:
5
+
+
m/z (%) = 385 (12) [M + 1] , 384 (9) [M] , 319 (16), 318 (37), 317
14), 241 (13), 239 (9), 191 (9), 178 (10), 165 (7), 115 (9), 91 (12).
HRMS: calcd. for C30 24 384.1878; found 384.1855.
Tetramethyl (1α,12α,13β,14α,17α,18β)-3,10-Diphenyl-15,16-benzo-
[
7] a) W.-D. Fessner, H. Prinzbach, G. Rihs, Tetrahedron Lett.
1983, 24, 5857; b) W.-D Fessner, H. Prinzbach, The Pagodane
Route to Dodecahedrane in Cage Carbons, G. A. Olah (Ed.),
Wiley, New York, 1990; c) H. Prinzbach, K. Weber, Angew.
Chem. 1994, 106, 2329; Angew. Chem. Int. Ed. Engl. 1994, 33,
(
H
1
4,17 2,11 5,10 13,18
4
2
3
,5-diazahexacyclo[10.6.1.1
(11),3,6,8,15-pentaene-6,7,8,9-tetracarboxylate (46): A mixture of
2a (206 mg, 0.5 mmol) and dimethyl acetylenedicarboxylate
.0
.0
,0
]eicosa-
2239.
[
8] a) W.-D. Fessner, G. Sedelmeier, P. R. Spurr, G. Rihs, H.
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(2 mL, 16.3 mmol) was heated at 100 °C for 72 h (total conversion,
one major product two traces, TLC). Excess reagent was removed
in vacuo, the residue was chromatographed (silica gel, petroleum
ether/ethyl acetate, 7:3); 320 mg of yellow crystals (92%) were iso-
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02 (sh, 4780), 265 (sh, 11900), 236 (sh, 20680), 222 (21080). H
NMR: δ = 7.75–7.35 (10 H), 6.55 (m, 1 H), 6.45 (m, 1 H), 6.32 (m
3
CN): λmax (ε) = 395 nm (10760),
1
3
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3
3
1
H), 4.68 (m, 1 H), 4.0 (s, OCH
3
), 3.74 (s, OCH
3
), 3.71 (dm, J =
9
9, 488; Angew. Chem. Int. Ed. Engl. 1987, 26, 457; b) G. K. S.
.5 Hz, 12-H), 3.65 (s, OCH ), 3.60 (s, OCH
3
3
), 3.38 (dt, 19a-H),
Prakash, V. V. Krishnamurty, R. Herges, R. Bau, H. Yuan,
.35 (dm, J = 3.2 Hz, 1-H), 3.25 (dt, 19s-H), 3.23 (br. d, J = 3.8 Hz,
4-H)*, 2.70 (br. d, J = 3.7 Hz, 17-H)*, 2.03 (dt, 20s-H), 1.98–1.94
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(
m, 13-,18-H), 1.82 (dt, 20a-H) ppm; J19a,s = 10.5, J20as = 9.8 Hz.
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13
C NMR: δ = 166.9 (CO), 166.3 (CO), 164.5 (CO), 163.6 (CO),
47.3 (C=N), 146.5, 143.8, 143.2, 142.3, 138.0, 134.6, 131.1, 129.1,
28.5, 128.0, 127.9, 127.8, 127.1 126.5, 124.8, 123.1, 122.7, 121.7,
1
1
1
5
01.9, 65.6, 60.6, 60.2, 53.0 (OCH
3 3 3
), 52.8 (OCH ), 52.5 (OCH ),
1.8 (OCH ), 48.2, 47.5, 46.4, 46.1, 46.0 ppm. MS: m/z (%) = 696
3
+
+
(
4) [M] , 638 (11), 637 (15) [M – CO
2
CH
] , 477 (2), 445 (2), 141 (2), 116 (2), 77 (3). C42
696.8): calcd. C 72.40, H 5.21; found C 72.01, H 5.09.
3
] , 621 (7), 619 (100)
+
[M – C
6
H
5
36 2 8
H N O
1
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Acknowledgments
Support by the Deutsche Forschungsgemeinschaft, the Fonds der
Chemischen Industrie, and BASF AG is gratefully acknowledged.
We thank Prof. Dr. J. Sauer for valuable information, Prof. Dr. R.
Schwesinger for generous gifts of bases, Dr. J. Geier for calcula-
tions, C. Warth for help with MS analyses, G. Fehrenbach for art-
work, and Dr. P. R. Spurr for help with the manuscript. T. M.
sincerely thanks Professor Dr. George A. Olah and Professor Dr.
G. K. Surya Prakash for their constant encouragement, the Alexan-
der von Humboldt Foundation and the Loker Hydrocabon Re-
search Institute for financial support.
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2
2
Eur. J. Org. Chem. 2007, 2133–2146
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjoc.org
2145

T. Mathew, H. Prinzbach et al.
FULL PAPER
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2
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[36] Still expected is the detailed report of the photoacoustic mea-
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marbeit of M. Schottelius and the Dissertation of J. Tonne per-
[
[
24]
formed in J. Michel’s laboratory (Boulder, Colorado, USA).
In the latter, the above-cited kinetic analysis of the photophysi-
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reference compounds (absorption, transient absorption, fluo-
rescence emission, fluorescence excitation, fluorescence life-
times, fluorescence quantum yields, phosphorescence, picose-
cond-resolved transient absorption measurements) and of the
photochemical characteristics of the reversible reaction 1 i 4
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[
[
[
[
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Received: December 12, 2006
2002, 1, 105.
Published Online: March 13, 2007
2146
www.eurjoc.org
© 2007 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Eur. J. Org. Chem. 2007, 2133–2146