Synthesis of ferrocenyl-substituted 1,3-dithiolanes via [3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones with thiocarbonyl S-methanides

Article abstract of DOI:10.3762/bjoc.12.136

Ferrocenyl hetaryl thioketones react smoothly with in situ generated thiocarbonyl S-methanides to give 1,3-dithiolanes. In the case of aromatic S-methanides, the sterically more crowded 4,4,5,5-tetrasubstituted 1,3-dithiolanes (2-CH₂ isomers) w

Full text of DOI:10.3762/bjoc.12.136

Synthesis of ferrocenyl-substituted 1,3-dithiolanes via
3 + 2]-cycloadditions of ferrocenyl hetaryl thioketones
[
with thiocarbonyl S-methanides
Grzegorz Mlostoń*1, Róża Hamera-Fałdyga1, Anthony Linden2 and Heinz Heimgartner2
Full Research Paper
Open Access
Address:
Beilstein J. Org. Chem. 2016, 12, 1421–1427.
1Department of Organic and Applied Chemistry, University of Łódź,
doi:10.3762/bjoc.12.136
Tamka 12, PL 91-403 Łódź, Poland and 2Department of Chemistry,
University of Zürich, Winterthurerstrasse 190, CH-8057 Zürich,
Switzerland
Received: 22 March 2016
Accepted: 23 June 2016
Published: 08 July 2016
Email:
Grzegorz Mlostoń* - gmloston@uni.lodz.pl
Associate Editor: J. A. Murphy
*
Corresponding author
© 2016 Mlostoń et al.; licensee Beilstein-Institut.
License and terms: see end of document.
Keywords:
3 + 2]-cycloadditions; 1,3-dithiolanes; ferrocene; thiocarbonyl
[
S-methanides; thioketones
Abstract
Ferrocenyl hetaryl thioketones react smoothly with in situ generated thiocarbonyl S-methanides to give 1,3-dithiolanes. In the case
of aromatic S-methanides, the sterically more crowded 4,4,5,5-tetrasubstituted 1,3-dithiolanes (2-CH2 isomers) were formed as sole
products. The reactions with cycloaliphatic S-methanides led to mixtures of 2-CH2 and 5-CH2 isomers with the major component
being the sterically more crowded 2-CH2 isomers. The preferred formation of the latter products is explained by the assumption that
the formal [3 + 2]-cycloadducts were formed via a stepwise reaction mechanism with a stabilized 1,5-diradical as a key intermedi-
ate. The complete change of the reaction mechanism toward the concerted [3 + 2]-cycloaddition was observed in the reaction of a
sterically crowded cycloaliphatic thiocarbonyl ylide with ferrocenyl methyl thioketone.
Introduction
In a recent publication, a straightforward method for the synthe- convenient access to thioketones 1 permitted their exploration
sis of hitherto little known ferrocenyl aryl/hetaryl thioketones of for the synthesis of diverse sulfur heterocycles based on the re-
type 1 via a standard procedure by treatment of the correspond- activity of compounds containing a C=S group, known as
ing ferrocenyl ketones with Lawesson reagent was described ‘superdipolarophiles’ [2] or ‘superdienophiles’ [3].
[
1]. The latter substrates were prepared efficiently via acylation
of ferrocene with in situ generated mixed anhydrides contain- The reactive thiocarbonyl S-methanides of type 2 can conve-
ing a trifluoroacetyl unit or, alternatively, by ferrocenylation of niently be generated by thermal elimination of N2 from 1,3,4-
furan, thiophene or selenophene with mixed trifluoroacetyl an- thiadiazoles 3 at ca. −45 °C in the case of 2,2-diaryl derivatives
hydride. The obtained ferrocenyl thioketones are remarkably 3a,b or upon gentle heating of cycloaliphatic precursors 3c,d in
stable in comparison with their aromatic analogues. Thus, the THF solution to ca. +45 °C [4,5]. The [3 + 2]-cycloaddition of
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dipoles 2 with thioketones is well known as an excellent method spectrum of the isolated sample 5a revealed the signal of the
for the construction of tetrasubstituted 1,3-dithiolanes [5]. A CH2 group at 30.8 ppm, typical for 4,4,5,5-tetrasubstituted 1,3-
remarkable feature of these reactions is the regioselectivity. dithiolanes (2-CH2 type [13]). Analogously, single 1,3-dithio-
Whereas aromatic S-methanides react to give the sterically lanes 5b–f were obtained, and the 13C NMR spectra showed the
crowded 4,4,5,5-tetrasubstituted 1,3-dithiolanes [6,7], CH2 absorption in the same region (27.3–33.0 ppm). Also in the
cycloaliphatic S-methanides tend to form mixtures of both case of 1,3-dithiolane 5g, bearing a phenyl group, the absorp-
regioisomeric cycloadducts with the major component being the tion of the CH2 group was found at 31.2 ppm.
sterically more crowded isomer [7,8]. In a recent study, we pro-
posed a diradical mechanism for the [3 + 2]-cycloadditions of The structures of the ferrocenyl-substituted 1,3-dithiolanes 5b,
thiocarbonyl S-methanides with aromatic and heteroaromatic 5e, 5f, and 5g have been established unambiguously by X-ray
thioketones [7,9]. Furthermore, the analogous reaction mecha- crystallography (see Figure 1 for 5b and 5f). The space group of
nism was postulated to explain the results obtained with thiocar- 5b is non-centrosymmetric with a polar axis, but achiral.
bonyl S-ethanides, S-isopropanides, and S-(trimethyl- Refinement of the absolute structure parameter [14,15] yielded
silyl)methanides [10].
a value of 0.13(1), which indicates that the crystal is a partial
inversion twin with a major twin fraction of 0.87(1). In the
Ferrocenyl thioketones have never been exploited in reactions cases of 5e and 5f, the thiophene and selenophene rings are
with thiocarbonyl S-methanides. On the other hand, ferrocenyl- disordered over two orientations related by a 180° flip of the
substituted 1,3-dithiolanes can be of interest for materials chem- ring about its bonding axis, with the major conformation present
istry and for electrochemical studies [11]. The goal of the in 88% and 91% of the molecules, respectively.
present study was to examine reactions of selected ferrocenyl
hetaryl thioketones 1 with aromatic and cycloaliphatic thiocar- In similar experiments, 2,2,4,4-tetramethyl-3-thioxocyclo-
bonyl S-methanides 2. Preliminary results of this study have butanone S-methanide (2c) and adamantanethione S-methanide
been presented at the IRIS-14th conference as a poster commu- (2d), respectively, were generated in situ at 45 °C from the cor-
nication (see [12]).
responding precursors 3c,d. In the presence of an equimolar
amount of 1a–c, they were trapped to give mixtures of two
regioisomeric 1,3-dithiolanes 5 and 6 (Scheme 2). In all cases,
Results and Discussion
The precursors of aromatic S-methanides 2a,b, i.e., 1,3,4-thiadi- the 1H NMR analysis of the crude mixtures indicated that the
azolines 3a,b, were prepared from thiobenzophenone (4a) and major products obtained in these reactions were the sterically
thiofluorenone (4b), respectively, and diazomethane at –60 °C more crowded 1,3-dithiolanes 5. After separation of the prod-
in THF solution [6] (Scheme 1). After addition of an equimolar ucts, the 13C NMR spectra of the major isomers showed the
amount of a ferrocenyl hetaryl thioketone 1, the reaction mix- signal for H2C(2) in the typical region (25.7–28.9 ppm). The
ture was slowly warmed to room temperature. The crude mix- minor products were identified on the basis of the 13C NMR
ture was examined by 1H NMR spectroscopy, and in all cases spectra of the crude mixtures. In this series, the characteristic
only one single product 5 was detected (Table 1).
signals of H2C(5) appeared at 49.3–53.9 ppm, in agreement
with literature data [13].
For example, 1,3-dithiolane 5a showed a characteristic
AB-system for the CH2 group and only one singlet for five In an extension of the study with ferrocenyl hetaryl thioketones
equivalent CH groups of the unsubstituted cyclopentadiene unit 1, an experiment with ferrocenyl methyl thioketone (1e) and
of the ferrocenyl skeleton. On the other hand, the 13C NMR thiocabonyl S-methanide 2c was performed under typical condi-
Scheme 1: Reactions of aromatic thiocarbonyl S-methanides 2a,b with ferrocenyl thioketones 1 (Table 1).
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Table 1: Ferrocenyl-substituted 1,3-dithiolanes 5 and 6.
5/6
R, R
Hetar, Ph
Ratio of 5/6a
Yield of 5 + 6 [%]b
a
b
c
Ph, Ph
Ph, Ph
Ph, Ph
furan-2-yl
thiophen-2-yl
selenophen-2-yl
100:0
100:0
100:0
49
57
62
d
e
f
furan-2-yl
thiophen-2-yl
selenophen-2-yl
Ph
100:0
100:0
100:0
100:0
33
32
32
40
g
h
i
furan-2-yl
thiophen-2-yl
selenophen-2-yl
76:24
93:7
62c
79c
53c
j
78:22
k
l
thiophen-2-yl
75:25
67:33
57c
73c
selenophen-2-yl
aDetermined by 1H NMR spectroscopy in the crude mixture. bYields of isolated product after chromatography and crystallization. cYields of isolated
mixtures of products.
Figure 1: ORTEP Plot [16] of the molecular structures of the ferrocenyl-substituted 1,3-dithiolanes 5b and 5f (with 50% probability ellipsoids; arbitrary
numbering of the atoms; only the major disorder conformation of the selenophene ring is shown).
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Scheme 2: Reactions of cycloaliphatic thiocarbonyl S-methanides with ferrocenyl hetaryl thioketones 1 (Table 1).
tions (THF, 45 °C). Unexpectedly, in this case, the 1H NMR mechanism, controlled by frontier-orbital (FMO) interactions, is
spectrum of the crude product revealed the presence of only one strongly influenced by steric effects in the case of C=S dipo-
1
1
,3-dithiolane, i.e., only one set of five methyl signals at 1.36, larophiles [8,17].
.38, 1.41, 1.42, and 1.97 ppm was present. The AB-system of
the CH2 group appeared at 2.97 and 3.25 ppm with J = 12.0 Hz.
After chromatographic purification, the 13C NMR spectrum
confirmed the 5-CH2-type of the 1,3-dithiolane 6m, as the cor-
responding CH2 absorption was found at 52.5 ppm (Scheme 3).
Scheme 4: Mesomeric stabilization of the 1,5-diradical intermediate in
the reaction of aromatic thiocarbonyl S-methanides with ferrocenyl
hetaryl thioketones.
Conclusion
Scheme 3: Reaction of 3c with ferrocenyl methyl thioketone 1e.
The presented study indicated that ferrocenyl thioketones show
an enhanced stability in comparison with aromatic thioketones.
Based on our earlier interpretation of the reaction mechanism Therefore, they are considered as promising substrates for the
leading to 1,3-dithiolanes via [3 + 2]-cycloaddition of thiocar- synthesis of more complex sulfur-containing compounds. The
bonyl S-methanides with aryl and hetaryl thioketones, we reactions with electron-rich thiocarbonyl S-methanides occur
propose that the reactions with ferrocenyl thioketones 1 occur smoothly to give 1,3-dithiolanes as products of formal
predominantly via an intermediate 1,5-diradical. The formation [3 + 2]-cycloadditions. The high reactivity of ferrocenyl thioke-
of the sterically more crowded 1,3-dithiolanes 5a–g confirms tones is demonstrated by the fact that no products of competi-
that the stabilized 1,5-diradicals of type 7 (Scheme 4) are key- tive reactions, such as dimerization of the intermediate 1,3-
intermediates in the reaction. On the other hand, the formation dipole or 1,3-dipolar electrocyclizations, were observed. Based
of 1,3-dithiolanes of type 5 in reactions with cycloaliphatic on these observations one can expect that ferrocenyl thioke-
thiocarbonyl S-methanides competes with the concerted tones may also be used as prone dipolarophiles in reactions with
[
3 + 2]-cycloaddition leading to the sterically less crowded 1,3- other dipoles. Similarly, they are expected to display a high
dithiolanes 6 (Scheme 2). These results demonstrate that the dienophilicity.
ferrocenyl moiety shows a comparable effect to that found for
aryl and hetaryl groups. This interpretation of the reaction The results obtained with thiocarbonyl S-methanides, i.e., the
mechanism got additional support from the reaction of 1e with preferred formation of the sterically more crowded 4,4,5,5-tetra-
3
c. Apparently, the replacement of a radical-stabilizing aryl or substituted 1,3-dithiolanes, supports the proposed stepwise
hetaryl group by a methyl substituent results in the preferred radical reaction mechanism via a stabilized 1,5-diradical as an
concerted [3 + 2]-cycloaddition. It is well known that this intermediate. Finally, in the case of ferrocenyl methyl thioke-
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Beilstein J. Org. Chem. 2016, 12, 1421–1427.
tone used as a dipolarophile, the concerted [3 + 2]-cycloaddi- 4-Ferrocenyl-5,5-diphenyl-4-(selenophen-2-yl)-1,3-di-
tion dominated due to the reduced stabilizing effect of the thiolane (5c): Yield: 354 mg (62%). Orange crystals;
methyl group compared with that of a hetaryl substituent.
mp >162 °C (decomposition); IR (KBr) ν: 3094 (m), 3030 (w),
967 (w), 2911 (m), 1595 (w), 1577 (w), 1488 (m), 1440 (s),
1409 (m), 1391 (m), 1233 (s), 1216 (m), 1188 (m), 1105 (s),
2
Experimental
General information: All solvents were dried over appropriate 1084 (m), 1061 (m), 1044 (m), 1030 (s), 1001 (m), 950 (m),
drying agents and distilled before use. Melting points were de- 816 (s), 745 (s), 717 (vs), 697 (vs), 677 (vs), 641 (m), 603 (m),
termined in a capillary using a Stewart® SMP30 apparatus. The 502 (vs), 490 (s) cm–1; 1H NMR (600 MHz, CDCl3) δ 7.91 (d,
IR spectra (KBr pellets) were recorded on a Nexus FTIR spec- JH,H = 6.0 Hz, 1H, Harom.), 7.55–7.54 (m, 3H, Harom.),
trometer. The 1H and 13C NMR spectra were measured on a 7.23–7.21 (m, 2H, Harom.), 7.18–7.07 (m, 7H, Harom.), 4.12 (bs,
Bruker Avance III (600 and 150 MHz, respectively) instrument 1H, H-Fc), 4.09 (bs, 6H, H-Fc), 4.04 (bs, 1H, H-Fc), 3.94 (bs,
in CDCl3, using the solvent signal as reference. ESIMS were re- 1H, H-Fc), 3.91, 3.87 (AB system, JH,H = 9.0 Hz, 2H, CH2)
corded on a Varian 500-MS IT Mass Spectrometer. The ppm; 13C NMR (150 MHz, CDCl3) δ 154.7, 143.1 (3 Carom.),
elemental analyses were performed on a Vario Micro Cube 132.2, 131.0, 130.7, 130.0, 128.1, 127.1, 126.8, 126.5, 126.1
apparatus. Flash chromatography was carried out using Silica (13 CHarom.), 90.5, 78.8, 74.8 (C-Fc, 2 Cq), 72.2, 72.1 (2
gel 60 (Sigma-Aldrich, 230–400 mesh). The notation Fc in this CH-Fc), 69.8 (5 CH-Fc), 67.7, 67.1 (2 CH-Fc), 30.8 (CH2)
study represents ferrocenyl. Applied reagents such as ferro- ppm; ESIMS m/z (%): 572 (100, [M + H]+), 571 (60, [M+]);
cenyl-substituted thioketones (1) [1], thiobenzophenone (4a) anal. calcd for C29H24FeS2Se (571.44): C, 60.95; H, 4.23; S,
[
18], and thiofluorenone (4b) [19] were prepared using known 11.22; found: C, 61.04; H, 4.33; S, 11.01.
procedures. 1,1,3,3-Tetramethyl-8-thia-5,6-diazaspiro[3.4]oct-
-en-2-one (3c) [20] and spiro[1,3,4-thiadiazole-2(5H),2’- 5-Ferrocenyl-5-phenylspiro[1,3-dithiolane-4,9’-[9H]fluo-
5
tricyclo[3.3.1.13,7]decane] (3d) [21] were obtained by known rene] (5g): Yield: 206 mg (40%). Orange crystals; mp >185 °C
methods according to the literature protocols. Diazomethane (decomposition); IR (KBr) ν: 3057 (m), 2918 (m), 1636 (m),
was prepared in a 5 mmol scale either from N-nitroso-N- 1597 (m), 1492 (m), 1474 (m), 1445 (vs), 1414 (m), 1390 (m),
methylurea or from N-nitrosotoluene-4-sulfonylmethylamide by 1286 (m), 1225 (m), 1157 (m), 1108 (m), 1051 (m), 1035 (m),
treatment with aqueous KOH solution in a two-phase system 1000 (m), 863 (m), 816 (s), 746 (vs), 730 (vs), 710 (s), 698 (m),
with diethyl ether at room temperature. After separation of the 521 (m), 503 (m), 484 (m) cm–1; 1H NMR (600 MHz, CDCl3) δ
ethereal phase it was dried over KOH pellets and used for 7.67 (dd, JH,H = 7.8, 10.8 Hz, 2H, Harom.), 7.59 (d, JH,H = 7.8
further experiments with no distillation. Other reagents used in Hz, 1H, Harom.), 7.36 (t, JH,H= 7.8 Hz, 1H, Harom.), 7.15 (t, JH,H
the present study were commercially available.
= 7.8 Hz, 1H, Harom.), 7.02–6.98 (m, 5H, Harom.), 6.24 (d,
JH,H= 4.2 Hz, 1H, Harom.), 5.06 (bs, 1H, H-Fc), 4.50–4.49 (m,
Preparation of diaryl-substituted 1,3-dithiolanes (5a–g) – 1H, H-Fc), 4.28, 4.20 (AB system, JH,H= 9.6 Hz, 2H, CH2),
General procedure: A solution of thioketone 4a or 4b 4.08–4.07 (m, 1H, H-Fc), 4.04 (s, 5H, H-Fc), 3.53 (bs, 1H,
(
1 mmol) in THF (3 mL) was cooled to –75 °C (acetone/dry H-Fc) ppm; 13C NMR (150 MHz, CDCl3) δ 149.5, 142.3,
ice). Then, the mixture was treated with small portions of 141.0, 140.9, 138.1 (5 Carom.), 128.7, 127.9, 127.5, 127.3,
ethereal diazomethane solution, until the disappearance of the 126.6, 126.5, 124.8, 119.8, 119.7 (13 CHarom.), 98.2, 74.8, 74.5
characteristic color of the thioketone (4a,b). Excess of diazo- (C-Fc, 2 Cq), 73.5, 71.6 (2 CH-Fc), 69.1 (for 5 CH-Fc), 69.0,
methane was removed under reduced pressure at −75 °C. Then, 67.6 (2 CH-Fc), 31.2 (CH2) ppm; ESIMS m/z (%): 517 (43, [M
a solution of ferrocenyl hetaryl thioketone 1 (1 mmol) in THF + H]+), 516 (100, [M]+); anal. calcd for C31H24FeS2 (516.50):
(
4 mL) was added to the mixture, which was allowed to warm C, 72.09; H, 4.68; S, 12.42; found: C, 71.97; H, 4.70; S, 12.26.
slowly to rt. Next, the solvent was evaporated, and the crude
products were purified by crystallization (hexane/CH2Cl2).
8-Ferrocenyl-1,1,3,3-tetramethyl-8-(thiophen-2-yl)-5,7-di-
thiaspiro[3.4]octan-2-one (5i): Isolated as the major product.
Preparation of cycloaliphatic-substituted 1,3-dithiolanes Yield: 381 mg (79%; crude product ratio 93:7). Orange solid;
5h–l, 6h–m) – General procedure: To a solution of the corre- mp 190.2–192.0 °C; IR (KBr) ν: 3137 (w), 3112 (w), 3066 (m),
sponding ferrocenyl-substituted thioketone 1 (1 mmol) in THF 3042 (w), 3021 (m), 2965 (m), 2929 (s), 2866 (m), 1776 (vs,
4 mL), 1,3,4-thiadiazoline 3c or 3d (1 mmol) was added. The C=O), 1469 (m), 1455 (m), 1382 (m), 1362 (m), 1231 (m), 1165
(
(
mixture was heated at 45 °C until the evolution of N2 ceased. (m), 1131 (m), 1106 (m), 1056 (m), 1022 (m), 1003 (m), 905
Then, the solvent was evaporated and the crude products were (m), 825 (s), 815 (s), 779 (m), 694 (vs), 486 (vs) cm–1;
purified by CC (SiO2, hexane/ethyl acetate 95:5). The major 1H NMR (600 MHz, CDCl3) δ 7.32 (dd, JH,H = 3.6, 1.2 Hz, 1H,
product was isolated using diethyl ether (precipitation).
Harom.), 7.29 (dd, JH,H = 1.2, 5.4 Hz, 1H, Harom.), 7.11 (dd, JH,H
1425

Beilstein J. Org. Chem. 2016, 12, 1421–1427.
=
3.6, 4.8 Hz, 1H, Harom.), 4.91–4.90 (m, 1H, H-Fc), 4.54–4.53 (100, [M + H]+); anal. calcd for C26H28FeS2Se (539.44): C,
(
m, 1H, H-Fc), 4.25–4.24 (m, 1H, H-Fc), 4.15–4.14 (m, 1H, 57.89; H, 5.23; S, 11.89; found: C, 57.96; H, 5.31; S, 11.92.
H-Fc), 3.94 (s, 5H, H-Fc), 3.78, 3.74 (AB system, JH,H = 8.4
Hz, 2H, CH2), 1.72, 1.64, 1.19, 1.17 (4s, 12H, CH3) ppm; 6-Ferrocenyl-1,1,3,3,6-pentamethyl-5,8-dithiaspiro[3.4]oct-
1
3C NMR (150 MHz, CDCl3) δ 153.2 (C=O), 126.6, 123.3, an-2-one (6m): Yield: 302 mg (73%). Yellow crystals; mp
1
6
4
23.2 (3 CHarom.), 72.2, 73.0 (2 CH-Fc), 70.1 (5 CH-Fc), 66.3, 140.0–142.0 °C; IR (KBr) ν: 3094 (w), 3079 (w), 2968 (m),
8.6 (2 CH-Fc), 84.9, 76.5, 71.0, 70.7, 69.4, 62.7 (Carom., C-Fc, 2923 (m), 1777 (vs, C=O), 1752 (m), 1635 (m), 1458 (m), 1446
Cq), 26.1, 24.9, 24.1, 23.3 (4 CH3), 28.3 (CH2) ppm; ESIMS (m), 1378 (m), 1363 (m), 1277 (m), 1239 (m), 1169 (m), 1106
m/z (%): 583 (53, [M + H]+), 482 (100, [M]+); anal. calcd for (m), 1055 (m), 1030 (m), 998 (m), 935 (m), 837 (m), 819 (m),
C24H26FeOS3 (482.50): C, 59.74; H, 5.43; S, 19.94; found: C, 482 (m) cm–1; 1H NMR (600 MHz, CDCl3) δ 4.44 (bs, 1H,
5
9.99; H, 5.40; S, 19.62.
H-Fc), 4.23–4.21 (m, 7H, H-Fc), 4.17 (bs, 1H, H-Fc), 3.25, 2.97
AB system, JH,H = 12.0 Hz, 2H, CH2), 1.97, 1.42, 1.41, 1.38,
-Ferrocenyl-1,1,3,3-tetramethyl-6-(selenophen-2-yl)-5,8- 1.36 (5bs, 5H, CH3) ppm; 13C NMR (150 MHz, CDCl3) δ
(
6
dithiaspiro[3.4]octan-2-one (6i) (from the spectra of a mixture 220.6 (C=O), 93.1, 75.4 (C-Fc, 1 Cq), 68.9 (5 CH-Fc), 68.2,
of 6i with the major product 5i): 1H NMR (600 MHz, CDCl3) δ 68.0, 67.3, 66.3 (4 CH-Fc), 67.0, 66.0, 63.9 (3 Cq), 52.5 (CH2),
7
3
4
.26 (dd, JH,H = 5.4, 1.2 Hz, 1H, Harom.), 7.14 (dd, JH,H = 1.2, 29.3, 25.0, 24.4, 22.8, 22.3 (5 CH3) ppm; ESIMS m/z (%): 416
.6 Hz, 1H, Harom.), 7.03 (dd, JH,H = 3.6, 5.4 Hz, 1H, Harom.), (63, [M + 2H]+), 415 (100, [M + H]+); anal. calcd for
.37–4.36 (m, 1H, H-Fc), 4.23–4.22 (m, 1H, H-Fc), 4.22 (s, 5H, C21H26FeOS2 (414.41): C, 60.86; H, 6.32; S, 15.48; found: C,
H-Fc), 4.14–4.13 (m, 1H, H-Fc), 4.02–4.01 (m, 1H, H-Fc), 60.87; H, 6.38; S, 15.47.
3
1
1
6
4
.63, 3.60 (AB system, JH,H = 12.0 Hz, 2H, CH2), 1.48, 1.44,
.41, 1.13 (s, 12H, CH3) ppm; 13C NMR (150 MHz, CDCl3) δ
50.7 (C=O), 126.4, 125.2, 124.3 (3 CHarom.), 69.4, 68.3, 68.2,
8.0, 67.4 (9 CH-Fc), 92.8, 75.3, 69.0, 67.1, 66.2 (Carom., C-Fc,
Cq), 53.3 (CH2), 25.1, 24.4, 22.8, 22.0 (4 CH3) ppm.
Supporting Information
CCDC-1469435–1469438 contain the supplementary
crystallographic data for this paper. These data can be
obtained free of charge from The Cambridge
Crystallographic Data Centre via
5
-Ferrocenyl-5-(selenophen-2-yl)spiro[1,3-dithiolane-4,2’-
tricyclo[3.3.1.13,7]decane] (5l); 4-Ferrocenyl-4-(selenophen-
-yl)spiro[1,3-dithiolane-2,2’-tricyclo[3.3.1.13,7]decane] (6l):
http://www.ccdc.cam.ac.uk/getstructures.
2
Isolated as a mixture of regioisomers. Yield: 393 mg (73%;
Supporting Information File 1
crude product ratio 67:33). Yellow solid; IR (KBr) ν: 3085 (w),
Experimental data for selected compounds 5 and 6, details
of the crystal structure determination, and the original 1H
and 13C NMR spectra for all products.
3
1
1
7
072 (w), 3012 (w), 2974 (w), 2901 (vs), 2854 (s), 1473 (w),
442 (m), 1385 (w), 1347 (w), 1255 (w), 1233 (m), 1103 (m),
036 (m), 998 (m), 970 (w), 929 (w), 824 (s), 808 (s), 755 (w),
20 (w), 701 (vs), 495 (s), 479 (s) cm–1; 1H NMR (600 MHz,
[http://www.beilstein-journals.org/bjoc/content/
supplementary/1860-5397-12-136-S1.pdf]
CDCl3) δ 7.99 (d, JH,H = 6.0 Hz, 1H, Harom.), 7.90 (dd, JH,H =
.6, 5.4 Hz, 1H, Harom.), 7.41 (dd, JH,H = 6.0, 3.6 Hz, 1H,
Harom.), 7.24 (dd, JH,H = 6.0, 3.6 Hz, 1H, Harom.), 7.19 (dd, JH,H Acknowledgements
1.2, 3.6 Hz, 1H, Harom.), 7.14 (d, JH,H = 3.6 Hz, 1H, Harom.), The authors thank the National Science Center (Cracow,
0
=
4
1
4
.93–4.92 (m, 1H, H-Fc), 4.41 (bs, 1H, H-Fc), 4.30–4.29 (m, Poland) for generous financial support (Grant Maestro–3
H, H-Fc), 4.24 (bs, 5H, H-Fc), 4.23–4.22 (m, 1H, H-Fc), (Dec–2012/06/A/ST5/00219)). Skillful performance of micro-
.21–4.20 (m, 1H, H-Fc), 4.19–4.18 (m, 1H, H-Fc), 4.13–4.12 analyses by Ms Hanna Jatczak and Ms Agnieszka Cieślińska
(
m, 1H, H-Fc), 4.04 (s, 5H, H-Fc), 3.95, 3.64 (AB system, JH,H (University of Łódź) is gratefully acknowledged.
8.4 Hz, 2H, CH2 (major)), 3.89, 3.58 (AB system, JH,H = 12.6
Hz, 2H, CH2 (minor)), 2.96 (d, JH,H = 12.6 Hz, 1H), 2.47–1.27 This work is part of the planned Ph.D. thesis of Róża Hamera-
m, 27H) ppm; 13C NMR (150 MHz, CDCl3) δ 161.3, 160.6 (2 Fałdyga, University of Łódź.
Carom.) 130.1, 129.9, 129.8, 129.3, 126.6, 125.1 (6 CHarom.),
=
(
9
7
3
3
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doi:10.1080/10426507.2015.1071817
ESIMS m/z (%): 563 (60, [M + Na]+), 541 (40, [M + 2H]+), 540
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