Ninhydrin as a source of naphthoquinone acetals and benzocycloheptenetrione derivatives, and the trapping of an oxacarbene derived from a cyclopentanone

Article abstract of DOI:10.1002/1099-0690(200207)2002:14<2385::AID-EJOC2385>3.0.CO;2-S

1,3-Bis(ethylenedioxy)-2-indanone (2) was shown to react with some dienophiles to give naphthoquinone acetals under photochemical reaction conditions, presumably by photodecarbonylation via the corresponding ortho-quinodimethane. With maleic anhydride the highly oxygenated benzocycloheptane derivative rac-12 was obtained in good yield. In a similar manner, upon irradiation in the presence of acrylonitrile a 2:1 mixture of ring-expanded regioisomers rac-13 and rac-14 was obtained. Irradiation in the presence of fumarodinitrile unexpectedly gave the spirocyclic compound rac-15, which was characterized by X-ray crystallography, rac-15 is the trapping product of oxacarbene 16, thus demonstrating a rare case of a ring expansion of a cyclopentanone to give a six-membered ring oxacarbene, here leading to an orthoester. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.

Full text of DOI:10.1002/1099-0690(200207)2002:14<2385::AID-EJOC2385>3.0.CO;2-S

FULL PAPER
Ninhydrin as a Source of Naphthoquinone Acetals and Benzocycloheptenetrione
Derivatives, and the Trapping of an Oxacarbene Derived from a
Cyclopentanone
Dirk Leinweber,[a] Matthias Schnebel,[a] Rudolf Wartchow,[b] Hans G. Wey,[c] and
Holger Butenschön*[a]
Keywords: Ninhydrin / Oxygen heterocycles / Carbenes / Ring expansion / Photochemistry
1,3-Bis(ethylenedioxy)-2-indanone (2) was shown to react
nitrile unexpectedly gave the spirocyclic compound rac-15,
with some dienophiles to give naphthoquinone acetals under which was characterized by X-ray crystallography. rac-15 is
photochemical reaction conditions, presumably by photode- the trapping product of oxacarbene 16, thus demonstrating a
carbonylation via the corresponding ortho-quinodimethane.
rare case of a ring expansion of a cyclopentanone to give a
With maleic anhydride the highly oxygenated benzocy- six-membered ring oxacarbene, here leading to an orthoes-
cloheptane derivative rac-12 was obtained in good yield. In
a similar manner, upon irradiation in the presence of acrylon-
itrile a 2:1 mixture of ring-expanded regioisomers rac-13 and
rac-14 was obtained. Irradiation in the presence of fumarodi-
ter.
( Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany,
2002)
Introduction
Ninhydrin (1), which is frequently used for the analysis
of amino acids, can be transformed into 1,3-bis(ethylene-
dioxy)-2-indanone (2) in high yield. Recently we published
a short synthesis of benzocyclobutenedione (5) on the basis
of a photodecarbonylation of 2 giving bis(acetal) 3 only,
which was hydrolyzed to give 5.[1] Later, the phthalic acid
monoester 4 was identified as a side product of the reaction,
and the yield of 3 was raised to 57% by using benzene as
the solvent.
It is reasonable to consider that the reaction proceeds via
the corresponding ortho-quinodimethane 6 or the diradical
7.[2Ϫ9] The importance of 5 in organic chemistry has been
well documented in recent review articles.[10Ϫ16]
The intermediacy of 6 or 7 raises the question of whether
the presence of dienophiles during the irradiation might al-
low the formation of the respective [4ϩ2] cycloadducts.
Given the importance of naphthoquinone derivatives the
possibility of obtaining such compounds in a one-pot op-
eration from readily accessible 2 is particularly attractive.
The naphthoquinone building block can be found in many
[a]
Institut für Organische Chemie, Universität Hannover,
Schneiderberg 1B, 30167 Hannover, Germany
Fax: (internat.) ϩ49-(0)511/762-4616
E-mail: holger.butenschoen@mbox.oci.uni-hannover.de
[b]
natural products, for example vitamin K,[17] and 1,4-naph-
thoquinone is pharmacologically active to moderate Pneu-
mocystis carinii pneumonia (PCP).[18] Some 2-indanone de-
Institut für Anorganische Chemie, Universität Hannover,
Callinstraße 9, 30167 Hannover, Germany
[c]
Degussa AG,
Paul-Baumann-Straße 1, 45476 Marl, Germany
Eur. J. Org. Chem. 2002, 2385Ϫ2390  WILEY-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002 1434Ϫ193X/02/0713Ϫ2385 $ 20.00ϩ.50/0
2385

D. Leinweber, M. Schnebel, R. Wartchow, H. G. Wey, H. Butenschön
FULL PAPER
In the presence of 2.5 equivalents of propenal as the dien-
ophile a 67% yield of the cycloadduct rac-9 was achieved,
and, in a similar way, the reaction with four equivalents of
butenone gave the cycloadduct rac-10 in 58% yield.
While rac-8Ϫrac-10 are dihydronaphthoquinone derivat-
ives, the photolysis of 2 in the presence of 1.5 equivalents
of dimethyl butynedioate gave the naphthoquinone diacetal
11 in 89% yield. Compound 11 is of interest because of the
electron-poor double bond in the anellated ring, which
might be used as a dienophile in another [4ϩ2] cycloaddi-
tion leading to anthraquinone derivatives.
rivatives have been used by Sustmann et al. for the genera-
tion of ortho-quinodimethanes followed by cycloadditions
with nitric oxide.[19,20]
With a number of dienophiles the intramolecular cycliza-
tion giving 3 prevailed over the desired cycloaddition: the
use of diphenylethyne, tetracyanoethene, ethyl propynoate,
and 3-sulfolene, resulted in the formation of the bis(acetal)
3 only. However, irradiation of 2 and 1.5 equivalents of di-
methyl fumarate in benzene at 20 °C resulted in a 62% yield
of the cycloadduct rac-8. This compound can also be ob-
tained by heating 3 and dimethyl fumarate (neat) at 240 °C
for 3 h; it was fully characterized. The reaction conditions
and the possibility to skip intermediate 3 clearly demon-
strate the value of the direct photolysis of 2 to give rac-8.
Interestingly, when maleic anhydride was tested as the di-
enophile, the highly oxygenated benzocycloheptene rac-12
was obtained in 85% yield. rac-12 is the product of a cyc-
lization reaction between the diradical formed by the first
photochemical α-cleavage and the dienophile. Apparently
the reactivity of maleic anhydride makes the cyclization
process faster than the second α-cleavage. In a similar fash-
ion, the use of five equivalents of acrylonitrile resulted in a
2:1 regioisomeric mixture of nitriles rac-13 and rac-14 in
67% overall yield.
2386
Eur. J. Org. Chem. 2002, 2385Ϫ2390

Ninhydrin as a Source of Naphthoquinone Acetals and Benzocycloheptenetrione Derivatives
FULL PAPER
Figure 1. Structure of one molecule of rac-15 in the crystal;[21] the structure of the other one does not significantly deviate from this;
˚
selected bond lengths [A] and angles [°]: O1ϪC3 1.392(2), O1ϪC5 1.444(2), O2ϪC5 1.383(2), O3ϪC5 1.384(2), C1ϪC2 1.519(2), C2ϪC3
1.505(2), C3ϪC8 1.506(2), C5ϪC6 1.502(2), C6ϪC7 1.388(2), C6ϪC9 1.389(2), C7ϪC8 1.511(2), C7ϪC12 1.391(2), C9ϪC10 1.367(3),
C10ϪC11 1.383(3), C11ϪC12 1.368(3); C3ϪO1ϪC5 113.33(12), O1ϪC5ϪC6 111.53(14), C5ϪC6ϪC7 122.21(14), C6ϪC7ϪC8
120.20(14), C3ϪC8ϪC7 107.92(14), O1ϪC3ϪC8 111.81(12), C1ϪC3ϪC2 60.76(11)
Fumarodinitrile was tested next; the spiro-anellated or- and H11 (bonded to C17) and is probably caused by the
thoester rac-15 was isolated in only 32% yield. Due to the slight disorder of C17.
number of directly connected quaternary carbon atoms an
There is no doubt that rac-15 is the result of a cycloaddi-
tion of the dienophile with the oxacarbene 16. The forma-
tion of cyclic oxacarbenes by photolysis of cycloalkanones
identification by NMR spectroscopy was not easy. An HR
mass spectrum could not be obtained because of the low
intensity of the molecular ion peak. The product was finally
was first reported by Yates et al. in 1964 upon photolysis
identified by an X-ray crystal structure analysis (Figure 1).
of cyclocamphanone.[22] Since then many cases of such ring
expansions have been reported, although the vast majority
describe the reactions of cyclobutanone derivatives.[23Ϫ26]
Ring expansions of cyclopentenone derivatives leading to
pyran systems via oxacarbene intermediates are rare. The
scarce reports include reactions of cyclocamphanone,[22,27]
a
stereochemical study using 3-oxacyclopentanones,[28]
photolysis of a spirocyclopropyl-anellated cyclopentanone
[29]
in a synthesis of thromboxane A2
and a similar step in
the synthesis of pederol,[30] and, finally, a photochemical
The asymmetric unit contains two molecules, which, in a ring expansion starting from a camphor derivative.[31] To the
first approximation, form an enantiomeric pair. The aniso- best of our knowledge the photolysis leading to rac-16 is not
tropic displacement ellipsoid of atom C17 in the first molec- only a rare case in that a cyclopentenone ring is expanded,
ule suggests a split position for this atom, although no split but also the first case of such a reaction leading to an ortho-
position was introduced in the refinement. The maximum ester; it is possible that the formation of side product 4 of
of the difference Fourier synthesis is in the vicinity of C17 the irradiation of 2 can be explained along similar lines.
Eur. J. Org. Chem. 2002, 2385Ϫ2390
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D. Leinweber, M. Schnebel, R. Wartchow, H. G. Wey, H. Butenschön
FULL PAPER
and dimethyl trans-butenedioate (831 mg, 5.8 mmol) was heated at
240 °C for 3 h. Dimethyl trans-butenedioate, which sublimed into
the condenser, was brought back into the reaction mixture by heat-
ing it with a heat gun. After the reaction time the temperature was
reduced to 130Ϫ140 °C, and unchanged dimethyl trans-butenedio-
ate was removed into a cold trap at 0.1 mbar. Residual dimethyl
trans-butenedioate was removed into a cold trap over 14 h at 50 °C
at 0.1 mbar. A brown, crystalline solid was obtained, which was
recrystallized from toluene, washed with pentane and dried at
0.001 mbar. Yield: 1370 mg (3.8 mmol, 76%) of rac-8 as colorless
crystals (m.p. 155 °C). IR (KBr): ν˜ ϭ 3440 cmϪ1 (br), 3060 (w),
2980 (m), 2950 (m,), 2900 (m), 1735 (s), 1600 (w), 1575 (w), 1482
(m), 1440 (s), 1430 (s), 1368 (s), 1340 (s), 1280 (s), 1235 (s), 1215
(s), 1170 (s), 1165 (s), 1100 (s), 1060 (s), 1020 (s), 980 (m), 965 (m),
950 (s), 900 (m), 775 (s) 708 (w), 660 (w), 605 (m), 570 (m). 1H
NMR (400 MHz, [D6]acetone): δ ϭ 3.69 (s, 6 H, CH3), 3.73 (s, 2
H, CH), 3.98 (m, 2 H, CH2), 4.13 (m, 4 H, CH2), 4.42 (m, 2 H,
CH2) 7.40 ϩ 7.46 (AAЈBBЈ system, 2 ϫ 2 H, arom. CH) ppm. 13C
NMR (100 MHz, [D6]acetone): δ ϭ 52.0 (d, 1JC,H ϭ 137 Hz, CH),
52.4 (q, 1JC,H ϭ 147 Hz, CH3), 65.8 (t, 1JC,H ϭ 150 Hz, CH2), 67.7
In summary, we have found a ready access to some naph-
thoquinone derivatives under rather mild reaction condi-
tions as well as an example of a cyclopentenone ring expan-
sion via an oxacarbene leading to the orthoester rac-15. We
are currently investigating the possibilities to exploit this
chemistry for the synthesis of naturally occurring or phar-
macologically interesting substances as phthiokol or vit-
amin K derived compounds.[17]
Experimental Section
General: Pentane, petroleum ether (PE), tert-butyl methyl ether
(TBME), diethyl ether (DEE), and THF were distilled under argon
from sodium-potassium alloy/benzophenone. 1H NMR: Bruker
WP 200 SY (200.1 MHz), AM 400 (400.1 MHz). 13C NMR: Bruker
WP 200 SY (50.3 MHz), AM 400 (100.1 MHz). Signal multiplicit-
ies were determined with APT and DEPT techniques. Chemical
shifts refer to δTMS ϭ 0 or to residual solvent signals.[32,33] IR:
PerkinϪElmer FT-IR 580 and 1710. MS: Finnigan MAT 112, 312
at 70 eV. HRMS: Finnigan MAT 312, VG Autospec, peak match-
ing with PFK. Combustion analyses: Heraeus CHN Rapid. Melt-
ing points (uncorr.) were determined in sealed glass tubes with an
apparatus according to Dr. Tottoli. Column chromatography (col.
chrom.): silica gel (J. T. Baker, 40 µm). Separations were performed
using flash chromatography.[34] Column length (l) and diameter (ø)
are given. Ninhydrin was a donation from Merck KGaA.
1
1
(t, JC,H ϭ 150 Hz, CH2), 107.8 (s, benzyl-C), 126.1 (d, JC,H
ϭ
161 Hz, arom. CHCHCq), 129.8 (d, 1JC,H ϭ 162 Hz, arom. CHCq),
139.0 (s, arom. Cq) 171.3 (s, CϭO) ppm. MS (CI, 70 eV, NH3): m/
z (%) ϭ 382 (100) [Mϩ ϩ NH4ϩ], 365 (16) [Mϩ ϩ Hϩ], 338 (3),
310 (9), 280 (3). C18H20O8 (364.36): calcd. C 59.34, H 5.53; found
C 59.18, H 5.50.
1,4-Bis(ethylenedioxy)-1,2,3,4-tetrahydronaphthalene-2-carb-
aldehyde (rac-9): In a photochemical immersion reactor (Pyrex, Hg
high-pressure lamp Philips HPK 125 W)
Irradiation of 1,3-Bis(ethylenedioxy)indan-2-one (2):[1] In a photo-
chemical immersion reactor (Pyrex, Hg high-pressure lamp Philips
HPK 125 W) a solution of 2[1] (1000 mg, 4.0 mmol) in 100 mL of
benzene was irradiated for 5 h at 20 °C with some argon bubbling
through the mixture. After solvent removal a colorless oil was ob-
tained, which was purified by column chromatography (l ϭ 25 cm,
ø ϭ 30 mm, TBME). Yield: 254 mg (1.2 mmol, 30%) of (2-hydroxy-
ethyl) phthalate (4), recrystallized from ethyl acetate, colorless solid
(m.p. 120 °C), and 422 mg (1.92 mmol, 48%) of 1,2-bis(ethylene-
dioxy)benzocyclobutene (3).[35]
a
solution of 2[1]
(1000 mg, 4.0 mmol) and propenal (580 mg, 10.3 mmol) in 100 mL
of benzene was irradiated for 5 h at 20 °C with some argon bub-
bling through the mixture. After solvent removal a yellowish solid
was obtained, which was purified by column chromatography (l ϭ
25 cm, ø ϭ 30 mm, TBME/PE, 1:1). Yield: 740 mg (2.7 mmol, 67%)
of rac-9 as a colorless oil. IR (film): ν˜ ϭ 2892 (m) cmϪ1, 1776 (m),
1720 (s), 1360 (m), 1316 (m), 1284 (m), 1228 (m), 1152 (m), 1116
(m), 1056 (s), 1008 (m), 944 (m), 892 (m). 1H NMR (400 MHz,
[D6]acetone): δ ϭ 2.24 (dd, 2J ϭ Ϫ13.7, 3J ϭ 11.2 Hz, trans-CHH),
2.41 (dd, 2J ϭ Ϫ13.7, 3J ϭ 3.3 Hz, cis-CHH), 3.19 (ddd, 3J ϭ 11.7,
3.3, 1.5 Hz, 1 H, CHCHO), 4.05Ϫ4.25 (m, 7 H, CH2), 4.44Ϫ4.53
(m, 1 H, CH2), 7.38Ϫ7.43 (m, 2 H, arom. CH), 7.45Ϫ7.53 (m, 2
H, arom. H), 9.87 (d, 3J ϭ 1.5 Hz, 1 H, CHO) ppm. 13C NMR
(BB, 100 MHz, [D6]acetone): δ ϭ 32.0 (CCH2CH), 54.1 (aliph.
CH), 64.3 (CH2 acetal), 64.4 (CH2 acetal), 65.3 (CH2 acetal), 66.7
(CH2 acetal), 105.3 (benzyl Cq), 106.7 (benzyl Cq), 124.9 (arom.
CH), 126.1 (arom. CH), 128.6 (arom. CH), 128.7 (arom. CH),
137.9 (arom. Cq), 138.4 (arom. Cq), 200.1 (CϭO) ppm. MS (70 eV):
m/z (%) ϭ 276 (1) [Mϩ], 248 (1) [Mϩ Ϫ CO or Mϩ Ϫ C2H4], 247
(2) [Mϩ Ϫ CHO], 220 (13) [Mϩ Ϫ CO Ϫ C2H4 or Mϩ Ϫ 2 C2H4],
149 (15), 148 (100) [C6H4C(O2C2H4)], 132 (11), 104 (64), 76 (31,
C6H4).
3: IR (KBr): ν˜ ϭ 3388 (s, OH) cmϪ1, 3248 (w), 3132 (w), 2984 (w),
2940 (w), 2828 (w), 2640 (m), 2552 (m), 1740 (s), 1684 (s), 1580
(w), 1492 (w), 1408 (w), 1364 (w), 1308 (m), 1280 (s), 1260 (s), 1072
(m), 768 (w), 748 (w). 1H NMR (400.1 MHz, [D6]DMSO): δ ϭ
3
3
3.67 (t, J ϭ 5.3 Hz, 2 H, 9-H), 4.23 (t, J ϭ 5.3 Hz, 2 H, 10-H),
4.88 (br, 1 H, OH), 7.58Ϫ7.82 (m, 4 H, arom. H), 13.31 (br, 1 H,
COOH) ppm. 13C NMR (100.6 MHz, [D6]DMSO): δ ϭ 58.8 (CH2,
C-9), 66.9 (CH2, C-10), 128.4 (CH), 128.9 (CH), 131.1 (CH), 131.4
(CH), 132.2 (Cq), 132.5 (Cq), 167.7 (CϭO), 168.2 (CϭO) ppm. MS
(70 eV, 120 °C): m/z (%) ϭ 180 (6), 149 (100) [Mϩ Ϫ OCH2-
CH2OH], 121 (9), 104 (29), 93 (10), 76 (20, C6H4). C10H10O5
(210.19): calcd. C 57.14, H 4.80; found C 57.15, H 4.68.
Dimethyl
1,4-Bis(ethylenedioxy)-trans-1,2,3,4-tetrahydronaph-
thalene-2,3-dicarboxylate (rac-8): a) In a photochemical immersion
reactor (Pyrex, Hg high-pressure lamp Philips HPK 125 W) a solu-
tion of 2[1] (1000 mg, 4.0 mmol) and dimethyl trans-butenedioate
(860 mg, 6.0 mmol) in 100 mL of benzene was irradiated for 5 h at
20 °C with some argon bubbling through the mixture. After solvent
removal a yellowish solid was obtained, which was purified by col-
umn chromatography (l ϭ 25 cm, ø ϭ 30 mm, TBME/PE, 1:1).
Yield: 920 mg (2.5 mmol, 62%) of rac-8 as a colorless solid (m.p.
156 °C).
2-Acetyl-1,4-bis(ethylenedioxy)-1,2,3,4-tetrahydronaphthalene (rac-
10): In a photochemical immersion reactor (Pyrex, Hg high-pres-
sure lamp Philips HPK 125 W) a solution of 2[1] (1000 mg,
4.0 mmol) and butanone (1130 mg, 16.0 mmol) in 100 mL of ben-
zene was irradiated for 5 h at 20 °C with some argon bubbling
through the mixture. After solvent removal a yellow oil was ob-
tained, which was purified by column chromatography (l ϭ
250 mm, ø ϭ 30 mm, TBME/PE, 1:2). Yield: 634 mg (1.8 mmol,
58%) of rac-10 as a colorless solid (m.p. 113 °C). IR (ATR): ν˜ ϭ
2963 cmϪ1 (w), 2890 (w), 1704 (m), 1452 (w), 1372 (w), 1356 (w),
1304 (m), 1217 (m), 1180 (m), 1144 (m), 1061 (s), 1045 (s), 1026
b) In a Schlenk flask equipped with a Liebig condenser a mixture
of 1,2-bis(ethylenedioxy)benzocyclobutene (3) (1090 mg, 5.0 mmol)
2388
Eur. J. Org. Chem. 2002, 2385Ϫ2390

Ninhydrin as a Source of Naphthoquinone Acetals and Benzocycloheptenetrione Derivatives
(s), 946 (s), 927 (s), 853 (w), 775 (s). 1H NMR (200.1 MHz, CDCl3): ated for 5 h at 20 °C with some argon bubbling through the mix-
FULL PAPER
2
3
δ ϭ 2.22 (dd, Jcis-3,trans-3 ϭ Ϫ13.8, Jcis-3,2 ϭ 3.1 Hz, 1 H, cis-3-
ture. After solvent removal a red oil was obtained, which was puri-
fied by column chromatography (l ϭ 250 mm, ø ϭ 30 mm, TBME/
PE, 1:1). Yield: 806 mg (2.7 mmol, 67%) of a 2:1 mixture of rac-13
2
3
H), 2.31 (s, 3 H, CH3), 2.61 (dd, Jtrans-3,cis-3 ϭ Ϫ13.8, Jtrans-3,2
11.7 Hz, 1 H, trans-3-H), 3.50 (ddd, J2,trans-3 ϭ 11.7, J2,cis-3
ϭ
3
3
ϭ
3.1 Hz, 1 H, 2-H), 4.01Ϫ4.30 (m, 8 H, acetal-H), 7.36Ϫ7.46 (m, 4 and rac-14 as a colorless solid.
H, arom. H) ppm. 13C NMR (100.6 MHz, CDCl3, APT): δ ϭ 31.3 rac-13 and rac-14: IR (ATR): ν˜ ϭ 2970 cmϪ1 (w), 2892 (w), 2118
(Ϫ, CH3), 34.1 (ϩ, CH2CH), 54.6 (Ϫ, CH), 64.5 (ϩ, acetal CH2),
(w, CN), 1703 (m, ketone), 1679 (m, ketone), 1599 (m), 1456 (w),
64.6 (ϩ, acetal CH2), 65.8 (ϩ, acetal CH2), 66.6 (ϩ, acetal CH2), 1402 (w), 1357 (m), 1286 (s), 1252 (m), 1221 (m), 1175 (m), 1140
106.1 (ϩ, CqCH2), 107.6 (ϩ, CqCH), 124.4 (Ϫ, arom. C), 126.2 (Ϫ, (m), 1083 (s), 1027 (s), 986 (m), 947 (s), 893 (w), 767 (s), 653 (w),
arom. C), 129.1 (Ϫ, arom. C), 129.2 (Ϫ, arom. C), 137.1 (ϩ, arom
Cq), 138.8 (ϩ, arom. Cq), 207.9 (ϩ, CϭO) ppm. MS (70 eV, 60 °C): ϩ 1], 301 (3) [Mϩ], 271 (4), 248 (2), 237 (7), 220 (70), 201 (18), 187
m/z (%) ϭ 290 (2) [Mϩ], 247 (3) [Mϩ Ϫ CH3CO], 220 (42), 203 (3),
(65), 162 (39), 148 (100) [C6H4C(O2C2H4)], 133 (53), 104 (60), 76
577 (m), 537 (m) ppm. MS (70 eV, 130 °C): m/z (%) ϭ 302 (1) [Mϩ
176 (9), 148 (100) [C6H4C(O2C2H4)], 133 (17), 104 (41), 76 (16) (52, C6H4). HRMS C16H15NO5: calcd. 301.0950; found. 301.0950.
[C6H4]. HRMS C16H18O5: calcd. 290.1154; found. 290.1158.
rac-13: 1H NMR (400.1 MHz, CDCl3): δ ϭ 2.81 (m, 2 H, CH2Cϭ
O), 3.40 (dd, J ϭ 7.65 Hz, 1 H, CH), 3.89Ϫ4.30 (m, 8 H, acetal
3
Dimethyl 1,4-Dihydro-1,4-bis(ethylenedioxy)naphthalene-2,3-dicarb-
H), 7.40Ϫ7.80 (m, 4 H, arom. H) ppm. 13C NMR (100.6 MHz,
CDCl3, APT): δ ϭ 36.6 (ϩ, CH2CO), 37.6 (Ϫ, CHCN), 65.8 (ϩ,
acetal CH2), 65.9 (ϩ, acetal CH2), 66.2 (ϩ, acetal CH2), 66.6 (ϩ,
acetal CH2), 106.6 (ϩ, CqCH), 106.9 (ϩ, CqCO), 117.3 (ϩ, CN),
125.7 (Ϫ, arom. C), 128.4 (Ϫ, arom. C), 129.7 (Ϫ, arom. C), 129.9
(Ϫ, arom. C), 134.8 (ϩ, arom. Cq), 135.4 (ϩ, arom. Cq), 197.4 (ϩ,
CϭO).
oxylate (11): In a photochemical immersion reactor (Pyrex, Hg
high-pressure lamp Philips HPK 125 W)
a
solution of 2[1]
(1000 mg, 4.0 mmol) and dimethyl butynedioate (850 mg,
6.0 mmol) in 100 mL of benzene was irradiated for 7 h at 20 °C
with some argon bubbling through the mixture. After solvent re-
moval a yellowish solid was obtained, which was purified by col-
umn chromatography (l ϭ 25 cm, ø ϭ 30 mm, TBME/PE, 1:1).
Yield: 1290 mg (3.6 mmol, 89%) of 11 as a colorless solid (m.p. 184
°C). IR (KBr): ν˜ ϭ 2956 (w) cmϪ1, 2908 (w), 1716 (s), 1664 (w),
1488 (w), 1436 (m), 1332 (m), 1284 (s), 1224 (s), 1208 (s), 1160 (m),
1140 (m), 1064 (s), 1024 (s), 976 (m), 960 (s), 780 (m), 724 (w), 612
rac-14: 1H NMR (400.1 MHz, CDCl3): δ ϭ 3.13 (m, 2 H, CH2CH),
3
3
3.70 (dd, Jtrans ϭ 14.2, Jcis ϭ 6.9 Hz, 1 H, CH), 3.89Ϫ4.30 (m, 8
H, acetal H), 7.40Ϫ7.80 (m, 4 H, arom. H) ppm. 13C NMR
(100.6 MHz, CDCl3, APT): δ ϭ 30.9 (Ϫ, CH), 45.0 (ϩ, CH2CH),
65.6 (ϩ, acetal CH2), 65.8 (ϩ, acetal CH2), 65.9 (ϩ, acetal CH2),
67.2 (ϩ, acetal CH2), 108.4 (ϩ, CqCH2), 109.6 (ϩ, CqCO), 118.8
(ϩ, CN), 126.8 (Ϫ, arom. C), 127.4 (Ϫ, arom. C), 128.2 (Ϫ, arom.
C), 129.7 (Ϫ, arom. C), 131.1 (ϩ, arom. Cq), 135.6 (ϩ, arom. Cq),
199.0 (ϩ, CO).
1
(w). H NMR (400.1 MHz, CDCl3): δ ϭ 3.81 (s, 6 H, CH3), 4.26
(m, 8 H, CH2), 7.39 ϩ 7.50 (AAЈBBЈ, 2 ϫ 2 H, arom. H) ppm. 13
C
NMR (100.6 MHz, CDCl3): δ ϭ 52.5 (CH3), 66.8 (CH2), 101.9 (Cq,
OCO), 124.7 (CH, arom. CHCHCq), 128.9 (CH, arom. CHCHCq),
137.0 (Cq, arom. Cq), 140.7 (Cq, CqCϭO), 165.1 (Cq, CϭO) ppm.
MS (70 eV, 140 °C): m/z (%) ϭ 363 (6) [Mϩ ϩ1], 362 (13) [Mϩ],
331 (7), 319 (17), 303 (40), 287 (12), 274 (77), 259 (21), 244 (17),
231 (57), 215 (26), 187 (21), 148 (100) [C6H4C(O2C2H4)], 133 (17),
104 (44).
6:7-Benzo-Anellated 4-Oxaspiro[2.5]octane-trans-1,2-dicarbonitrile
(rac-15): In a photochemical immersion reactor (Pyrex, Hg high-
pressure lamp Philips HPK 125 W) a solution of of 2[1] (1000 mg,
4.0 mmol) and fumarodinitrile (1570 mg, 20.0 mmol) in 100 mL of
benzene was irradiated for 5 h at 20 °C with some argon bubbling
through the mixture. After solvent removal a red oil was obtained,
which was purified by column chromatography (l ϭ 250 mm, ø ϭ
30 mm, TBME/PE, 1:1). Yield: 404 mg (1.3 mmol, 32%) of rac-15
as a colorless solid (m.p. 123 °C). IR (ATR): ν˜ ϭ 3043 cmϪ1 (w),
2977 (w), 2906 (w), 2251 (w), 1477 (w), 1452 (w), 1318 (m), 1210
(m), 1146 (m), 1049 (s), 1033 (s), 976 (m), 945 (s), 871 (w), 763 (m),
732 (w), 653 (w). 1H NMR (400.1 MHz, CDCl3): δ ϭ 2.44 (d, 3J ϭ
4,9-Bis(ethylenedioxy)-3a,4,9,10a-tetrahydro-2-oxabenzo[f]-
azulene-1,3,10-trione (rac-12): In a photochemical immersion re-
actor (Pyrex, Hg high-pressure lamp Philips HPK 125 W) a solu-
tion of 2[1] (1000 mg, 4.0 mmol) and maleic anhydride (784 mg,
8.0 mmol) in 100 mL of benzene was irradiated for 4 h at 20 °C
with some argon bubbling through the mixture. After solvent re-
moval a colorless solid was obtained, which was purified by column
chromatography (l ϭ 25 cm, ø ϭ 30 mm, TBME). Yield: 1180 mg
(3.4 mmol, 85%) of rac-12 as a colorless solid. IR (KBr): ν˜ ϭ 2904
(m) cmϪ1, 1872 (m, CϭO cycl. anhydride) 1796 (s, cycl. CϭO an-
hydride), 1732 (m, CϭO, ketone), 1236 (m), 1216 (m), 1048 (m),
1020 (m), 988 (m), 944 (m), 908 (m). 1H NMR (200 MHz, [D6]ace-
tone): δ ϭ 3.5Ϫ4.6 (m, 10 H, CH, CH2), 7.3Ϫ7.9 (m, 4 H, arom.
CH) ppm. 13C NMR (50 MHz, [D6]acetone): δ ϭ 52.0 (aliph. CH),
52.9 (aliph. CH), 106.1 (aliph. Cq), 106.5 (aliph. Cq), 125.6 (arom.
CH), 129.3 (arom. CH), 129.7 (arom. CH), 129.9 (arom. CH),
134.1 (arom. Cq), 138.0 (arom. Cq), 165.7 (anhydride CϭO), 166.2
(anhydride CϭO), 193.9 (ketone CϭO) ppm. MS (70 eV): m/z
(%) ϭ 347 (4) [Mϩ ϩ 1], 346 (18) [Mϩ], 220 (47), 176 (12), 149
(23), 148 (100) [C6H4C(O2C2H4)], 133 (17), 104 (29), 76 (15) [C6H4],
66 (16).
3
7.0 Hz, 1 H, CH), 2.63 (d, J ϭ 7.0 Hz, 1 H, CH), 4.25Ϫ4.41 (m,
8 H, acetal H), 7.37Ϫ7.48 (m, 4 H, arom. H) ppm. 13C NMR
(100.6 MHz, CDCl3, BB): δ ϭ 14.5 (CH), 15.2 (CH), 65.1 (acetal
CH2), 65.6 (acetal CH2), 66.2 (acetal CH2), 66.7 (acetal CH2), 68.1
(CqCHCN), 101.3 (OCqCqCHCN), 114.1 (CN), 114.6 (CN), 119.6
(CqO3), 123.6 (arom. C), 127.4 (arom. C), 129.9 (arom. C), 130.4
(arom. C), 131.1 (arom. Cq), 135.5 (arom. Cq).) ppm. MS (70 eV,
140 °C): m/z (%) ϭ 326 (2) [Mϩ], 283 (2), 253 (2), 220 (27), 200
(6), 176 (10), 148 (100) [C6H4C(O2C2H4)], 104 (31), 76 (15) [C6H4].
Crystal Structure Analysis of rac-15:[21] C17H14N2O5, crystal size
0.85 ϫ 0.63 ϫ 0.15 mm, a ϭ 9.984(2), b ϭ 21.952(4), c ϭ 28.004(6)
3
˚
˚
rac-5,9-Bis(ethylenedioxy)-5,7,8,9-tetrahydro-6-oxobenzocyclo-
hepten-8-carbonitrile (rac-13) and rac-5,9-Bis(ethylenedioxy)-
5,7,8,9-tetrahydro-6-oxobenzocyclohepten-7-carbonitrile (rac-14): In Pcab (No. 61), Stoe IPDS diffractometer, λMo-K ϭ 0.71073 A,
A, α ϭ β ϭ γ ϭ 90°, V ϭ 6138(2) A , Z ϭ 16, dcalcd. ϭ 1.413
gcmϪ3, T ϭ 300(2) K, crystal system orthorhombic, space group
˚
α
a photochemical immersion reactor (Pyrex, Hg high-pressure lamp
θmax ϭ 26.01, 68463 measured reflections, 6014 independent
Philips HPK 125 W) a solution of 2[1] (1000 mg, 4.0 mmol) and (Rint ϭ 0.0895) and 3491 observed reflections [I Ͼ 2σ(I)], 434 re-
acrylonitrile (1130 mg, 8.0 mmol) in 100 mL of benzene was irradi-
fined parameters, Rgt(F) ϭ 0.0378, wR(F2) ϭ 0.0777.
Eur. J. Org. Chem. 2002, 2385Ϫ2390
2389

D. Leinweber, M. Schnebel, R. Wartchow, H. G. Wey, H. Butenschön
FULL PAPER
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H.-G. Korth, S. Sustmann, P. Lommes, T. Paul, A. Ernst, H.
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This work was supported by the Deutsche Forschungsgemeinsch-
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D. L. thanks the Land Niedersachsen for a graduate fellowship.
We are indebted to Merck KGaA for a donation of ninhydrin.
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Received January 31, 2002
[O02053]
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