One-pot electrosynthesis of 2,3-bis(spiro-2-indanyl-1,3-dione)-indeno[1,2-b]furan-4-one

Article abstract of DOI:10.1016/j.tetlet.2007.07.065

The 2,3-bis(spiro-2-indanyl-1,3-dione)-indeno[1,2-b]furan-4-one has been synthesized by cathodic reduction of 2,2-dibromo-1,3-indandione in dichloromethane-Bu₄NBF₄. In contrast, tris-indanedione was the main product when acetonitrile

Full text of DOI:10.1016/j.tetlet.2007.07.065

Tetrahedron Letters 48 (2007) 6437–6441
One-pot electrosynthesis of 2,3-bis(spiro-2-indanyl-1,3-dione)-
indeno[1,2-b]furan-4-one
a
a
a,
b
*
Roberto Horcajada, Belen Batanero, Fructuoso Barba and Avelino Mart ´ı n
a
Department of Organic Chemistry, University of Alcal a´ , 28871 Alcal a´ de Henares, Madrid, Spain
Department of Inorganic Chemistry, University of Alcal a´ , 28871 Alcal a´ de Henares, Madrid, Spain
b
Received 15 June 2007; revised 4 July 2007; accepted 10 July 2007
Available online 14 July 2007
Abstract—The 2,3-bis(spiro-2-indanyl-1,3-dione)-indeno[1,2-b]furan-4-one has been synthesized by cathodic reduction of 2,2-di-
bromo-1,3-indandione in dichloromethane-Bu NBF . In contrast, tris-indanedione was the main product when acetonitrile was
4
4
used as a solvent. Sunlight exposition of the dispiro compound afforded the tris-indandione in quantitative yield.
2007 Elsevier Ltd. All rights reserved.
ꢀ
OH
O
O
O
O
Since 1,3-indandione (1) was synthesized a hundred
years ago, chemists have paid a lot of attention to this
O
O
1
compound with dyeing properties due to its easy self-
2
condensation, under both acid and basic conditions.
O
Oxidation of 1,3-indandione afforded a red compound,
OH
O
2
3
1
O
3
named by Kaufmann as ‘indenigo’ due to its similarity
O
to indigo. This compound turned out later to be 6,11-
dihydroxy-5,12-naphthacenedione (2). The structure of
O
O
0 0 0
,2 -biindanylidene-1,3,1 ,3 -tetraone (3) was unequivo-
2
O
O
O
4
cally determined by X-ray diffraction, and possesses
strong electron acceptor properties, close to those of
O
O
O
5
chloranil. As well, the structure of 1-(indan-1,3-dione-
6
4
5
2
-ylidene)indan-3-one (4) was determined by X-ray dif-
fraction. However, 1,3-[bis(1,3-indandione-2-ylidene)]-
indane (5) and tribenzo[a,f,k]trindenone (6) were char-
6
7
O
acterized by NMR.
O
O
O
O
OO
O
O
O
Derivatives of 1,3-indandione are important intermedi-
ates in the synthesis of ninhydrins. The biologically
O
O
8
O
active tris-indanedione (7) was synthesized from
O
O
O
9
10
ninhydrin and later its X-ray study was performed.
10
8
0
0
0
7
Also, 6- or 7-substituted 2 ,4-spiro(1 ,3 -indanedion)-
indeno-[3,2-b]chromenes (8) have been prepared from
1
0
ninhydrin.
diketones in the presence of olefins with copper pow-
1
1
12
der or by electrochemistry, as it is summarized in
Schemes 1 and 2, respectively.
On the other hand, Yoshida et al. published a regioselec-
tive synthesis of dihydrofurans from 2,2-dibromo-1,3-
However, the cathodic reduction of 2,2-dibromo-1,3-
indandione (9) in the presence of an olefin led to the
formation of a cyclopropane derivative, rather than a
dihydrofuran (see Scheme 3). No explanation was
given to this reaction.
Keywords: Cathodic reduction; 2,2-Dibromo-1,3-indandione; Dispiro
compound.
1
2
*
Corresponding author. Tel.: +34 91 8854617; fax: +34 91 8854686;
e-mail: fructuoso.barba@uah.es
0040-4039/$ - see front matter ꢀ 2007 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2007.07.065

6438
R. Horcajada et al. / Tetrahedron Letters 48 (2007) 6437–6441
O
Control potential electrolysis (E = ꢀ 0.25 vs SCE) of 9
in CH Cl /Bu NBF at platinum mesh cathode did not
show any substrate conversion, due to a passivation pro-
cess. The current measured during the experiment
dropped dramatically to zero after a few seconds.
O
2
2
4
4
Br
Br
Cu
+
R
R
O
O
Scheme 1.
The cyclic voltammetry of 9 in CH Cl /Bu NBF (as
2
2
4
4
SSE) on glassy carbon electrode showed an irreversible
O
peak with a reduction potential value of ꢀ0.4 V (vs
O
+
Ag/Ag ) (see Fig. 2).
Br
Br
e- (Pt cathode)
+
+
R
Different behavior was observed when dried dichloro-
DMF/Et NOTs
4
O
13
R
methane was used as the solvent. The electrolysis of
O
+
9
at ꢀ0.3 V (vs Ag/Ag ) on a graphite cathode showed
Scheme 2.
an initial current of 200 mA, dropping to residual
current (i.e., 20 mA) after the charge corresponding to
a 2 F/mol process was consumed. After the work-up, a
yellow solid-insoluble in chloroform was obtained in
good yield. This compound did not contain any bromine
atom, as shown in the MS spectrum, and it had a mole-
O
O
+
e- (Pt)
DMF/Et NOTs
Br
Br
+
4
+
1
Ph
cular ion of M = 432. The H NMR spectrum in
Ph
O
O
DMSO-d , the only suitable solvent for this purpose,
6
9
87%
1
4
did show two multiplets in the aromatic region and
ꢀ
1
Scheme 3.
one carbonyl group (m = 1761 cm ) was present by
FTIR spectroscopy. The compound was crystallized in
DMF and an X-ray diffraction study was performed
(see Fig. 3) to conclude that the main product of this
reaction was the 2,3-bis(spiro-2-indanyl-1,3-dione)-inde-
no[1,2-b]furan-4-one (10). Calculated bond lengths and
angles support the structural proposal for compound
10 shown in Scheme 4 (see Supplementary data).
In this Letter, we present the achieved results in the elec-
trochemical reduction of 2,2-dibromo-1,3-indandione
9) in the absence of olefin. In this case, a new and
interesting product, 2,3-bis(spiro-2-indanyl-1,3-dione)-
indeno[1,2-b]furan-4-one (10), with two spiro carbons
in the molecule is afforded.
(
The cyclic voltammetry of 9 in CH Cl /Bu NBF (as
The electrochemical formation of 10 can be rationalized
2
2
4
4
SSE: solvent-supporting-electrolyte system) on Pt
showed an irreversible peak with a reduction potential
through an ionic pathway, as it is indicated in Scheme 4.
+
value of ꢀ0.18 V (vs Ag/Ag ). Furthermore, as it is
However this pathway proposal has two objections: (a)
the dibrominated intermediate h has experimentally
never been detected, and (b) the cathodic reduction peak
observed in Figure 1, this compound begins to accept
electrons at positive potentials.
+
Figure 1. Cyclic voltammetry of 2,2-dibromo-1,3-indandione (9) (5 mM) on Pt electrode (/ = 0.2 mm). CH
2
Cl
2
/Bu
4
NBF
4
(0.1 M), E versus Ag/Ag .

R. Horcajada et al. / Tetrahedron Letters 48 (2007) 6437–6441
6439
+
2 2 4 4
Figure 2. Cyclic voltammetry of 2,2-dibromo-1,3-indandione (9) on glassy carbon cathode. CH Cl /Bu NBF (0.1 M), E versus Ag/Ag .
Figure 3. Perspective view of compound 10. Thermal ellipsoids correspond to 50% probability.
potential of h, although close to 9, should be more neg-
CH Cl were employed as the solvent) and it is in agree-
2 2
ative than it is. To avoid the further electroreduction of
ment with the experimental consumption of charge, cor-
responding to a 2e /substrate molecule process.
ꢀ
h, electrolysis of 9 at a constant potential value of
+
ꢀ
0.2 V (vs Ag/Ag ) (the voltammogram of 9 shows
some reduction current at this potential value) was car-
ried out. Under these conditions compound 10 was
again formed, and h was not detected.
When acetonitrile is used, radicals are able to abstract
.
H from the solvent, however with dichloromethane it
does not happen. The results obtained in acetonitrile
suggest that the bromide evolution from i (to get the car-
bene species) is quicker than the substitution reaction.
Besides, electrochemical processes where carbene inter-
mediates are involved have demonstrated that trimeriza-
In contrast, the electrolysis of 9 using a graphite cathode
and acetonitrile as the solvent allowed the formation of
1
5
compound 7 according to the MS and NMR spectra.
1
6
tion is favored to dimerization, and in our case no
traces of dimer were observed.
Another mechanism pathway was proposed to explain
the formation of 10. As it is shown in Scheme 5, the
implication of a diketocarbene justifies the generation
The trispirocyclopropane was not formed because both
the inherent ring tension and also the hindered effect
of 7 and 10 (respectively obtained when CH CN or
3

6440
R. Horcajada et al. / Tetrahedron Letters 48 (2007) 6437–6441
O
O
Br
Br
O
O
+4e-
-2Br-
Br
Br
Br
O
2
_
2
SN
O
9
O
O
O
O
Br Br
O
O
O
O O
O
O
(
h)
+
2e-
O
-
2Br-
1
0
Scheme 4.
O
O
O
O
O
Br
Br
6e-
-3Br-
3Br-
+
Br
-
:
3
_
3
3
(
i)
O
9
trimerization
O
O
O
O
O
O
O
O
.
.
CH CN
3
H
H
abstraction of 2H .
O
O
O
O
7
CH Cl2
2
O
O
O
O
O
O O
O
radical coupling
.
O
. O
O
O
1
0, 52%
Scheme 5.
caused by the three indandione groups joined to
cyclopropane through spiro carbons. The dihydrofuran
formation minimizes the instability.
Crystallography data: Complex 10 crystallized with one
molecule of DMF. Data were collected on a Bruker
Nonius KappaCCD diffractometer at 200 K, Ka
˚
(
Mo) = 0.71073 A. The structure was solved, using the
1
7
Finally, it has been observed that 10 in methanol solu-
tion can be transformed by sunlight irradiation into 7,
as it was confirmed by MS spectrometry of 10 before
and after being exposed to the sunlight.
WINGX
package, by direct methods (SHELXS-97) and
refined by least-squares against F (SHELXL-97). X-
ray data for C H NO : 0.21 · 0.16 · 0.09 mm , mono-
clinic, Cc, a = 12.487(2) A, b = 16.180(2) A, c =
2
18
3
3
0
19
7
˚
˚

R. Horcajada et al. / Tetrahedron Letters 48 (2007) 6437–6441
6441
3
1
˚
˚
1
1
1.816(1) A, b = 94.74(1), V = 2379.3(5) A , q
=
on a Perkin–Elmer Model 583 spectrophotometer.
H
calcd
3
NMR (300 MHz) spectra were recorded on a Varian
Unity 300 apparatus. The chemical shifts are given in
ppm. Melting points were determined on a Reichert
Thermovar microhot stage apparatus, and are uncor-
rected. Cyclic voltammetry were recorded on a VoltaLab
PGZ100 using a 0.1 M solution of Bu NBF (Fluka)/
.411 Mg/m . / and x scans were performed to obtain
intensity measurements in the range 6ꢁ < 2h < 55ꢁ, of
the 24395 measured reflections, 2740 were independent;
R = 0.050 and wR = 0.098 (for 1799 reflections with
F > 4r(F)). Largest difference peak and hole 0.445 and
0.304 e A . Hydrogen atoms were geometrically posi-
1
2
ꢀ
3
4
4
˚
ꢀ
+
2 2
CH Cl as SSE and a Ag/Ag reference electrode.
tioned and all non-hydrogen atoms were anisotropically
refined.
Synthesis of 2,2-dibromo-1,3-indandione (9): 1,3-Indandi-
one (1) (Fluka, 4.37 mg, 30 mmol) was dissolved in glacial
acetic acid (Panreac, 50 ml). Bromine (Fluka, 3.2 ml,
6
2.5 mmol) was dissolved also in acetic acid (20 ml). The
Acknowledgments
bromine solution was added on the 1,3-indandione solu-
tion for 30 min with stirring of the mixture. After that
time, a pale yellow solid is filtrated and recrystallized with
methanol (6.52 mg, 72%). Mp 177–178 ꢁC. H NMR
3
(CDCl ): d = 7.96–8.02 (2H, m, Ar); 8.0–8.1 (2H, m, Ar);
This study was financed by the Spanish Ministry of Sci-
ence and Education CTQ2004-05394/BQU and Factor ı´ a
de Cristalizaci o´ n (CONSOLIDER-INGENIO 2010
CSD2006-00015). B.B. thanks the Spanish Ministry of
Science and Technology for the ‘Ramon y Cajal’ con-
tract and the CAM-UAH for financial support
1
[lit. (Kosmrlj, J.; Kocevar, M.; Polancs, S. Synth. Com-
1
mun. 1996, 26, 3583): H NMR (CDCl
m, Ar); 8.0–8.1 (2H, m, Ar)]. MS (EI): m/z (%) = 306
3
): d = 7.9–8.0 (2H,
+
+
+
(M +4, 50), 304 (M +2, 100), 302 (M , 49), 226 (21), 224
(20), 197 (30), 195 (29), 169 (56), 167 (57), 104 (21), 76
(25).
(
CCG06-UAH/PPQ-0447).
Cathodic reduction of 9: The electrolysis of 2,2-dibromo-
,3-indandione (2 mmol, 0.05 M) was carried out under
Supplementary data
1
controlled potential conditions using as a solvent-support-
ing-electrolyte system Bu NBF (0.1 M)/CH Cl2 (40 ml)
in a divided cell equipped with a magnetic stirrer
containing a piece of glass tubing with a glass frit at one
end (anodic compartment). Sodium thiosulfate (2.1 g,
Supplementary data (Cif file for compound 10) associ-
ated with this article can be found, in the online version,
at doi:10.1016/j.tetlet. 2007.07.065.
4
4
2
0
.14 mmol) was added in the anodic compartment to
References and notes
avoid the evolution of the generated chlorine and bromine.
As electrode system, a graphite cathode, platinum anode
and Ag/Ag reference were chosen. The electrolysis was
+
1
2
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Lett. 1994, 35, 2955.
+
1
carried at ꢀ0.3 V versus Ag/Ag until the initial current of
200 mA dropped to a residual current of 20 mA. After
electrolysis the solvent was evaporated 1/5 under reduced
pressure and passed through a filtrating column contain-
ing silica gel and eluted with ether to remove the
electrolyte. After evaporation of the solvent, chloroform
was added. The mixture was introduced in a sonic bath for
2 min and the insoluble yellow solid filtrated. This process
was repeated five times and the several filtrated solids were
collected to obtain 149 mg (52%) of 2,3-bis(spiro-2-indan-
yl-1,3-dione)-indeno[1,2-b]furan-4-one (10), which was
3
4
5
6
7
8
9
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976, 5, 5.
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1
. Joullie, M. M.; Tompson, T. R.; Nemeroff, N. H.
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crystallography. Mp 248 ꢁC (decomp.),
H
NMR
(DMSO): d = 7.30–7.36 (1H, m, Ar), 7.48–7.58 (6H, m,
Ar); 7.72–7.80 (1H, m, Ar), 7.90–8.0 (4H, m, Ar). IR
(KBr): m = 1716, 1603, 1583, 1465, 1405, 1240, 1099, 915,
. Vanags, G.; Duburs, G. Zh. Obshch. Khim. 1957, 27, 2729;
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Kovalenko, V. N.; Kotoushchikova, M. A. Farmakol.
Toksikol. 1956, 19, 23.
+
+
768. MS (EI): m/z (%) = 434 (M +2, 6), 433 (M +1, 18),
+
432 (M , 62), 348 (35), 263 (20), 187 (21), 104 (71), 76
(100).
1
3
1
1
1
1
0. Das, S.; Pramanik, A.; Fr o¨ hlich, R.; Patra, A. Tetrahedron
14. C NMR was not possible to record because DMSO
2
004, 60, 10196.
decomposes compound 10 in the time scale of the
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3. Experimental procedure: The solvents were distilled before
use unless state otherwise. Dichloromethane was dried by
refluxing over calcium hydride over 2 h and distilled. The
electrolyses were carried out using an Amel potentiostat
Model 552 with an electronic integrator Amel Model 721.
MS spectra (EI, ionizing voltage 70 eV) were determined
using a Hewlett–Packard Model 5988A mass-selective
detector equipped with a Hewlett–Packard MS Chem
Station. IR spectra were obtained, as dispersions in KBr,
experiment.
1
15. H NMR of 7 (CDCl
3
) d = 5.45 (2H, s, CH), 7.86–8.03
+
(12H, m, Ar). MS of 7 (EI): m/z (%) = 436 (M +2, 1), 435
+
+
(M +1, 6), 434 (M , 20), 390 (15), 389 (53), 290 (29), 289
(11), 189 (14), 146 (12), 105 (28), 104 (100), 77 (33), 76
(83).
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