Efficient synthesis of ferrocifens and other ferrocenyl-substituted ethylenes: Via a 'sulfur approach'

Article abstract of DOI:10.1039/c8ob01022f

Stable and non-odorous alkyl ferrocenyl thioketones react with bis(4-methoxyphenyl)diazomethane according to the 'two-fold extrusion' reaction principles, and tetrasubstituted ethylenes obtained thereby can be demethylated to give (Fc,2OH)-ferrocifens in good yields. The method offers an alternative approach to this class of medically relevant compounds. A similar protocol with alkyl ferrocenyl thioketones and selected diaryldiazomethanes leads to ferrocenyl-substituted ethylenes including dibenzofulvenes. These products are of potential interest for electrochemical and photophysical studies.

Full text of DOI:10.1039/c8ob01022f

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Efficient synthesis of ferrocifens and other ferrocenyl‐substituted
ethylenes via a ‘sulfur approach’
Received 00th January 20xx,
Accepted 00th January 20xx
Grzegorz Mlostoń*a Róża Hamera‐Fałdygaa, Małgorzata Celedaa and Heinz Heimgartnerb
,
DOI: 10.1039/x0xx00000x
Dedicated to Professor Jacek Gawroński (Poznań) on the occasion of the retierment and in recognition of his contributions
to the development of organic chemistry in Poland.
www.rsc.org/
Stable and non‐odorous alkyl ferrocenyl thioketones react with bis(4‐methoxyphenyl)diazomethane according to the ‘two‐
fold extrusion’ reaction principles, and tetrasubstituted ethylenes obtained thereby can be demethylated to give (Fc,2OH)‐
ferrocifens in good yields. The method offers an alternative approach to this class of medically relevant compounds. A
similar protocol with alkyl ferrocenyl thioketones and selected diaryldiazomethanes leads to ferrocenyl‐substituted
ethylenes including dibenzofulvenes. These products are of potential interest for electrochemical and photophysical
studies.
(Fc,2OH, 1 with R = Et) in 23% yield (over 3 steps).3a An alternative
Introduction
approach comprises
the
McMurray
coupling
of
1‐
ferrocenylpropanone and 4,4’‐dihydroxybenzophenone.3b In that
case, the target product was isolated in 53% yield. The disadvantage
of this method are the competitive coupling reactions leading to
symmetrical tetrasubstituted ethylenes.4
Tetrasubstituted ethylene derivatives bearing aryl,
hetaryl and ferrocenyl substituents form an important class of
organic compounds with interest in materials chemistry,
crystal engineering and medicinal chemistry.1 In the latter
case, aryl and ferrocenyl‐substituted representatives had been
studied extensively as ligands for estrogen receptors and
Except the McMurry coupling, reports on efficient preparations
of mono‐ferrocenylethylenes are rare. However, a recent report
describing
the
Rh(OAc)4/CeCl3‐catalyzed
reaction
of
anticancer agents.2 Ferrocifens with the general formula
1
ferrocenecarboxaldehyde with diazoacetates in the presence of
Ph3P in dichloroethane as a method for an efficient preparation of
3‐ferrocenylacrylates, is worth mentioning.5
One of the most efficient olefinations leading to sterically
hindered ethylenes is the Barton‐Kellogg reaction, also known as
‘two‐fold extrusion reaction’.6 In a recent study we used this
method for the preparation of diverse tetraaryl/hetarylethylenes
including dibenzofulvenes7 (Scheme 1).
containing both ferrocenyl and 4‐hydroxyphenyl substituents
are of special importance, and some of them are known as
organometallic drugs applied for treatment of breast
cancer.2c,d
Fig. 1 General structure of (Fc,2OH)‐ferrocifens 1.
Two methods for the preparation of ferrocifens 1 are known,
Scheme
1
‘Two‐fold extrusion reaction’ leading to
and the first one is based on a three‐step procedure starting with
tetraaryl/hetarylethylenes.
ethyl
2‐ferrocenylbutanoate.
Treatment
with
4‐
methoxyphenyllithium, and subsequent dehydration followed by
demethylation of the methoxy groups afforded ferrocifendiphenol
The key‐step of this reaction is the [3+2]‐cycloaddition of the
corresponding thioketone 2 with diazocompound 3 leading to an
unstable 2,5‐dihydro1,3,4‐thiadiazole 4, which spontaneously
eliminates N2 to give thiirane 5 via 1,3‐dipolar electrocyclization of
an intermediate thiocarbonyl ylide. In some cases, spontaneous
desulfurization leads to ethylene 6, whereas in the case of stable
a. Department of Organic and Applied Chemistry, University of Łódź, Tamka 12, PL‐
91‐403 Łódź, Poland. E‐mail: grzegorz.mloston@chemia.uni.lodz.pl
b. Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH‐8057
Zurich, Switzerland
Electronic Supplementary Information (ESI) available: [details of any
supplementary information available should be included here]. See
DOI: 10.1039/x0xx00000x
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thiiranes, removal of sulfur can be achieved by treatment with a Scheme 2 Synthesis of ferrocifenes via a ‘sulfur approach’ (Fc =
phosphine.6
ferrocenyl).
In contrast to aryl and hetaryl thioketones, ferrocenyl
derivatives are rarely used as building blocks for the synthesis of
more complex ferrocenyl functionalized compounds. On the other
During the attempted measurement of the NMR spectra of 1c
hand, in a series of recent publications, we demonstrated that in CDCl3 solution, slow decomposition of this product was observed
ferrocenyl thioketones containing aryl, hetaryl or even alkyl groups and only replacement of the solvent by D6‐acetone allowed the
are surprisingly stable compounds, which can be used as reactive correct measurement. Both 1H and 13C NMR data were in good
dipolarophiles in diverse [3+2]‐cycloaddition reactions, e.g. with agreement with the reported spectra.2e
diphenyldiazomethane,7a α‐diazoketones,7b silylated thiocarbonyl
ylides,7c and fluorinated nitrile imines.7d
The analogous three‐step procedure was also applied for the
conversion of thioketones 7a, b into ferrocifens 1a and 1b,
The successful preparation of ferrocenyl‐substituted thiiranes respectively. In all cases the final products were isolated in good
from aryl/hetaryl ferrocenyl thioketones and yields. In analogy to 1c, both products undergo decomposition
diphenyldiazomethane7a prompted us to study reactions of alkyl during longer storage in CDCl3 solution at room temperature. In our
ferrocenyl thioketones 7with bis(4‐methoxyphenyl)diazomethane hands, all three ferrocifenes 1a–c were obtained as orange‐red
(3a). To date, this readily available and relatively stable solids from ethereal solutions after careful evaporation of the
diazocompound has never been explored in reactions with solvent. All attempts to crystallize these materials were
thioketones. The initially formed ferrocenyl thiiranes 8 should be unsuccessful. Remarkably, the melting points determined for
used as precursors of tetrasubstituted ethylenes 9, which via products 1 differed significantly from the reported data (see
demethylation will be converted into the corresponding ferrocifens Experimental).
1 (Scheme 2). Along with 3a, other diaryldiazomethanes such as
diphenyldiazomethane (3b), 9‐diazofluorene (3c), and 5‐diazo‐ were reacted with diphenyldiazomethane (3b), 9‐diazofluorene (3c)
10,11‐dihydro‐5H‐dibenzo[a,d]cyloheptene (3d) will also be tested and 5‐diazo‐10,11‐dihydro‐5H‐dibenzo[a,d]cycloheptene (3d)
in reactions with alkyl ferrocenyl thioketones aimed at the (Scheme 3) and a similar procedure has been applied. The reaction
In the next part of the study, alkyl ferrocenyl thioketones 7a–d
preparation of corresponding ferrocifen analogues.
mixtures of equimolar amounts of reagents in THF were prepared
at –75 ºC and then slowly warmed to room temperature, whereby
N2‐evolution was observed and the blue colour of the starting
thioketones changed to orange‐red. The initially formed thiiranes
were isolated in some cases (8d–g) or directly converted into
ethylenes (9d–m). The alternative procedure was applied in the
cases in which partial elimination of sulfur from thiiranes was
observed during workup. Complete desulfurizations were achieved
by treatment with (Et2N)3P. All these two‐step reactions and the
products obtained there from are outlined in Scheme 3.
Results and discussion
The surprisingly stable and non‐odorous ferrocenyl
thioketones 7 are easily available from the corresponding ketones
by treatment with Lawesson′s reagent.7a To date they have
practically not been applied as useful building blocks for the
preparation of more complex molecules. A test experiment was
performed with the propyl derivative 7c and 3a in THF solution at
room temperature. Immediate evolution of N2 was observed and
the blue colour of 7c disappeared. The solvent of the red‐coloured
reaction mixture was evaporated and the residue was identified as
Scheme 3 Reactions of alkyl ferrocenyl thioketones 7a‐d with
diaryldiazomethanes 3b‐d.
1
the expected thiirane 8c by H NMR spectroscopy. Two singlets of
MeO groups were found at 3.69 and 3.74 ppm along with the
characteristic set of signals for the ferrocenyl moiety. The n‐propyl
substituent appeared as a triplet for the Me group at 0.78 ppm and
two pairs of multiplets for two CH2 groups located at 1.46/1.80 and
1.95/2.17 ppm, respectively. Without further purification, this
product was treated with an equimolar amount of
tris(diethylamino)phosphine in boiling THF. After 30 min, the TLC
control evidenced completion of the reaction, and after column
chromatography; desired ethylene 9c was obtained in 79% yield.
The latter product was converted into ferrocifen 1c by treatment
with BBr3 as demethylation agent in CH2Cl2 according to a known
procedure.2b Pure product was isolated after column
chromatography in 67% yield.
The ethylenes 9i–m obtained in the reactions with 3c form a new
group of hitherto unknown ferrocenyl‐substituted dibenzofulvenes.
Conclusions
The presented study shows that easily available alkyl
ferrocenyl thioketones, which are stable at ambient conditions, can
be explored for an alternative synthesis of ferrocifens based on the
Barton‐Kellogg reaction. These products are of current interest due
to their unique biological activities, and their application as anti‐
cancer drugs has extensively been discussed.8 In comparison with
generally applied, traditional methods, e.g. McMurry coupling, the
elaborated ‘sulfur approach’ offers
a simple procedure and
2 | J. Name., 2012, 00, 1‐3
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comparable yields of the target products. Moreover, a long series of
To a solution of the corresponding carboxylic acid (1 mmol) in
alkyl ferrocenyl ketones, which can be converted into the required dry CH2Cl2 (10 mL) was added trifluoroacetic anhydride (TFAA, 1
thioketones, is accessible via an efficient acylation of ferrocene mmol, 0.15 mL). After stirring the solution for ca. 2 min at room
under mild conditions with the in situ generated mixed temperature, triflic acid (TfOH, 1 mmol, 0.07 mL) and ferrocene (1
anhydrides.7a In contrast to alkyl aryl thioketones, the alkyl mmol, 0.19g) were added. The progress of the reaction was
ferrocenyl representatives are remarkably stable compounds but monitored by thin layer chromatography (TLC). After completion of
they have been studied only very scarcely yet.9 The key the reaction, water (15 mL) was added. The organic layer was
intermediates in the three‐step procedure are 2‐alkyl‐2‐ferrocenyl‐ separated and the aqueous layer was extracted with CH2Cl2. The
substituted thiiranes formed via [3+2]‐cycloaddition of the combined organic extracts were dried (MgSO4) and the solvent
superdipolarophilic
methoxyphenyl)diazomethane
thioketones
followed
with
by
bis(4‐ evaporated. Crude products were purified by flash chromatography
spontaneous (CH2Cl2/CH3OH 99:1).
elimination of N2. Subsequent desulfurization and demethylation
can be performed with commercial reagents in good to high yields.
The replacement of bis(4‐methoxyphenyl)diazomethane by
other diaryldiazomethanes opens an convenient access to a variety
of tetrasubstituted ferrocenyl‐functionalized ethenes. Due to the
known electrochemical and optical properties of ferrocene
derivatives, these products are of potential interest for materials
chemistry and optoelectronic applications.10
1.1. Ferrocenyl methyl ketone. Orange solid; yield: 203 mg (89%);
o
m.p. 84.8–86.5 oC (ref.12 85–86 C). 1H NMR (600 MHz, CDCl3): δ
2.40 (bs, 3H, CH3), 4.21 (bs, 5H, 5 Fc‐CH), 4.51 (bs, 2H, 2 Fc‐CH), 4.78
(bs, 2H, 2 Fc‐CH) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 27.4 (CH3),
69.6, 72.3 (4 CH‐Fc), 69.8 (5 CH‐Fc), 79.3 (C‐Fc), 202.0 (C=O) ppm.
2. Typical procedure for the synthesis of alkyl ferrocenyl
thioketones (7).7a
The solution of the corresponding ketone (1 mmol) in THF (15
mL) and Lawesson’s reagent (LR, 0.6 mmol, 0.24g) was heated to
reflux. The progress of the reaction was monitored by TLC. After
completion of the reaction, the mixture was concentrated and the
crude product was purified by flash chromatography
(hexane/CH2Cl2 7:3).
Experimental
General experimental method
All solvents were dried over appropriate drying agents and
distilled before use. The H‐ and 13C‐NMR spectra were measured
1
on a Bruker Avance III instrument (600 and 150 MHz, respectively),
using the solvent (CDCl3, residual CHCl3) signal as reference. The
following abbreviations are used to describe peak patterns where
appropriate: b = broad, s = singlet, d = doublet, t = triplet, q =
quartet, sept = septet, m = multiplet, dd = doublet  doublet, and td
= triplet  doublet. Coupling constants (J) are reported in Hertz (Hz).
The IR spectra (KBr pellets) were recorded on a Nexus FT‐IR
spectrophotometer. The elemental analyses were determined on a
Vario Micro Cube. Flash column chromatography (FCC) was carried
out using Silica gel 60 (Sigma‐Aldrich, 230–400 mesh). Melting
points were determined in a capillary using a Stewart® SMP30
apparatus. The notation Fc in this study represents ferrocenyl.
Applied ferrocenyl alkyl ketones and thioketones 7 were obtained
by known methods according to the literature protocols.7 Bis(4‐
methoxyphenyl)diazomethane (3a),2a diphenyldiazomethane (3b),11
2.1. Ferrocenyl methyl thioketone (7a). Dark violet solid; yield: 200
mg (82%); m.p. 38.0–40.0 oC (ref.9 39.0–40.0 oC). 1H NMR (600 MHz,
CDCl3): δ 2.88 (bs, 3H, CH3), 4.19 (bs, 5H, 5 Fc‐CH), 4.74 (t, 2H, JH,H
=
1.8 Hz, 2 Fc‐CH), 5.03 (t, 2H, JH,H = 1.8 Hz, 2 Fc‐CH) ppm. 13C{1H}
NMR (150 MHz, CDCl3): δ 37.9 (CH3), 70.2, 74.3 (4 CH‐Fc), 71.5 (5
CH‐Fc), 89.2 (C‐Fc), 241.2 (C=S) ppm.IR (KBr): υ 3104w, 3085m,
2924m, 2854w, 1443m, 1376m, 1350m, 1288s, 1226m, 1158m,
1105m, 999m, 820s, 658w, 512m, 474m cm–1.Anal. calcd. for
C12H12FeS (244.13): C 59.04, H 4.95, S 13.13; found: C 59.29, H 5.23,
S 13.09.
3. Reaction of alkyl ferrocenyl thioketones
diaryldiazomethanes 3; Synthesis of thiiranes
7
with
A solution of the ferrocenyl substituted thioketone 7 (1 mmol)
9‐diazofluorene
(3c),11
and
5‐diazo‐10,11‐dihydro‐5H‐
o
in dry THF (5 mL) was cooled to –75 C (dry ice/acetone). Then, a
dibenzo[a,d]cycloheptene (3d)11 were prepared from the
corresponding hydrazones by oxidation with activated manganium
dioxide (MnO2)2a or with yellow mercury oxide (HgO).11 Hydrazones
of bis(4‐methoxyphenyl)ketone, 9H‐fluorenone, and 10,11‐dihydro‐
5H‐dibenzo[a,d]cycloheptenone were efficiently prepared from the
corresponding thioketones by treatment with hydrazine hydrate in
ethanolic solutions; all reactions were completed after 10–30 min
at room temperature and the required hydrazones were obtained
in 80–90% yield. Other reagents used were commercially available
substances.
solution of an appropriate diaryldiazomethane 3 (1 mmol) in dry
THF (4 mL) was added and the mixture was allowed to warm slowly
to r.t. After that, the reaction was completed (TLC). The solvent was
evaporated and the product was purified by flash chromatography
(petroleum ether/CH2Cl2, 7:3). Some of the obtained thiiranes
underwent spontaneous, partial desulfurization during purification.
3.1. 3‐Ferrocenyl‐3‐methyl‐2,2‐bis(4‐methoxyphenyl)thiirane (8a).
Yellow solid; yield: 324 mg (69%); m.p. 162.0–164.0 oC. 1H NMR
(600 MHz, CDCl3): δ 1.85 (bs, 3H, CH3), 3.60 (bs, 1H, Fc‐CH), 3.69 (bs,
3H, OCH3), 3.77 (bs, 3H, OCH3), 3.89 (bs, 1H, Fc‐CH), 4.13 (bs, 1H, Fc‐
1. Typical procedure for the synthesis of alkyl ferrocenyl ketones.7a
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CH), 4.19 (bs, 5H, 5 Fc‐CH), 4.39 (bs, 1H, Fc‐CH), 6.54–6.61 (m, 2H, 2 calcd. for C26H24FeS (424.38): C 73.58, H 5.70, S 7.56; found: C
CHarom.), 6.7–6.82 (m, 2H, 2 CHarom.), 6.99–7.04 (m, 2H, 2 CHarom.), 73.47, H 5.69, S 7.50.
7.36–7.38 (m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ
3.5.3’‐Ethyl‐3'‐ferrocenyl‐10,11‐dihydro‐
26.1 (CH3), 55.1, 55.2 (2 OCH3), 55.7 (Cq), 67.6, 67.8, 68.9, 70.2 (4
CH‐Fc), 69.0 (5 CH‐Fc), 69.3 (Cq), 91.2 (C‐Fc), 112.6, 113.3, 129.8,
131.0 (8 CHarom.), 135.3, 157.8, 158.3 (3 signals for 4 Carom.) ppm. IR
(KBr): υ 2965w, 2917w, 2860w, 2832w, 1730w, 1605m, 1461m,
1441m, 1281m, 1244vs, 1173s,1105m,1028m, 824m, 566m, 494m
cm–1. Anal. calcd. for C27H26FeO2S (470.40): C 68.94, H 5.57, S 6.82;
found: C 68.89, H 5.58, S 6.71
5Hspiro[dibenzo[a,d][7]annulene‐5,2'‐thiirane] (8g). Yellow solid;
yield: 338 mg (75%); m.p. 180.0–182.0 oC. 1H NMR (600 MHz,
CDCl3): δ 1.39 (t, 3H, JH,H = 7.2 Hz, CH3), 1.47–1.57, 2.28–2.35 (2m,
2H, CH2), 2.36–2.43, 2.83–2.92, 2.94–3.00, 3.26–3.33 (4m, 4H, 2
CH2), 3.40 (bs, 1H, Fc‐CH), 3.75 (bs, 1H, Fc‐CH), 4.01 (bs, 1H, Fc‐CH),
4.14 (bs, 5H, 5 Fc‐CH), 4.40 (bs, 1H, Fc‐CH), 6.82–6.87 (m, 1H,
CHarom.), 6.94–7.00 (m, 1H, CHarom.), 7.04–7.16 (m, 4H, 4 CHarom.),
3.2. 3‐Ethyl‐3‐ferrocenyl‐2,2‐bis(4‐methoxyphenyl)thiirane (8b). 7.58–7.64 (m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ
Orange solid; yield: 368 mg (76%); m.p. 145.5–148.0 oC. H NMR 14.2 (CH3), 29.9 (CH2), 30.3 (CH2), 32.5 (CH2), 62.3 (Cq), 67.0, 67.8,
1
(600 MHz, CDCl3): δ 1.15 (t, 3H, JH,H = 7.2 Hz, CH3), 1.92–2.00, 2.23– 70.2 (4 CH‐Fc), 69.5 (5 CH‐Fc), 72.7 (Cq), 89.7 (C‐Fc), 125.6, 125.9,
2.32 (2m, 2H, CH2), 3.47 (bs, 1H, Fc‐CH), 3.71 (bs, 3H, OCH3), 3.75 127.4, 127.5, 127.7, 130.3, 130.4 (8 CHarom.), 137.1, 138.2, 138.7,
(bs, 3H, OCH3), 3.84 (bs, 1H, Fc‐CH), 4.13 (bs, 1H, Fc‐CH), 4.15 (bs, 142.1 (6 Carom.) ppm. IR (KBr): υ 2987w, 2960w, 2933w, 2892w,
5H, 5 Fc‐CH), 4.41 (bs, 1H, Fc‐CH), 6.57–6.61 (m, 2H, 2 CHarom.), 2843w, 1479m, 1453m, 1106m, 1030m, 994m, 817s, 772s, 749vs,
6.73–6.77 (m, 2H, 2 CHarom.), 6.97–7.00 (m, 2H, 2 CHarom.), 7.33–7.37 645m, 482s cm–1. Anal. calcd. for C28H26FeS (450.42): C 74.66, H
(m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 13.9 (CH3), 5.82, S 7.12; found: C 74.60, H 5.80, S 7.14.
30.6 (CH2), 55.1, 55.2 (2 OCH3), 60.9 (Cq), 66.9, 67.4, 69.5, 70.2 (4
4. Desulfurization of thiiranes 8 to give ethylenes 9
CH‐Fc), 69.1 (5 CH‐Fc), 70.0 (Cq), 91.0 (C‐Fc), 112.6, 113.2, 130.2,
131.4 (8 CHarom.), 134.9, 135.7, 157.8, 158.2 (4 Carom.) ppm. IR (KBr):
υ 2955m, 2933m, 2832m, 1606m, 1511vs, 1464m, 1448m, 1378w,
1293s, 1245vs, 1185s, 995m, 821vs, 596m, 561m, 492m cm–1. Anal.
calcd. for C28H28FeO2S (484.43): C 69.42, H 5.83, S 6.62; found: C
69.26, H 6.11, S 6.52
To a solution of the corresponding thiirane (pure compound
or crude material; 1 mmol) in THF (4 mL), hexaethyl phosphorous
triamide ([(C2H5)2N]3P, 1.2 mmol, 296 mg, 0.32 mL) was added.
Then, the mixture was heated to reflux, and the progress of the
reaction was monitored by TLC. After the completion of the
reaction, the solvent was evaporated and the crude product was
purified by FCC (petroleum ether/CH2Cl2, 7:3).
3.3. 3‐Ferrocenyl‐3‐propyl‐2,2‐bis(4‐methoxyphenyl)thiirane (8c).
Yellow solid; yield: 354 mg (71%); m.p. 107.0–109.5 oC. 1H NMR
(600 MHz, CDCl3): δ 0.78 (t, 3H, JH,H = 7.2 Hz, CH3), 1.42–1.51, 1.76–
1.85 (2m, 2H, CH2), 1.91–1.98, 2.14–2.21 (2m, 2H, CH2), 3.48 (bs,
1H, Fc‐CH), 3.71 (bs, 3H, OCH3), 3.76 (bs, 3H, OCH3), 3.84 (bs, 1H,
Fc‐CH), 4.12 (bs, 1H, Fc‐CH), 4.15 (bs, 5H, 5 Fc‐CH), 4.38 (bs, 1H, Fc‐
CH), 6.58–6.60 (m, 2H, 2 CHarom.), 6.74–6.77 (m, 2H, 2 CHarom.), 6.97–
7.01 (m, 2H, 2 CHarom.), 7.33–7.37 (m, 2H, 2 CHarom.) ppm. 13C{1H}
NMR (150 MHz, CDCl3): δ 14.7 (CH3), 22.6 (CH2), 40.1 (CH2), 55.1,
55.2 (2 OCH3), 60.1 (Cq), 66.8, 67.4, 69.4, 70.4 (4 CH‐Fc), 69.1 (5 CH‐
Fc), 69.6 (Cq), 91.4 (C‐Fc), 112.6, 113.1, 130.2, 131.4 (8 CHarom.),
134.7, 135.6, 157.8, 158.2 (4 Carom.) ppm. IR (KBr): υ 3088w, 2996w,
2965m, 2930m, 2866m, 1606s, 1511vs, 1464m, 1222vs, 1179s,
1027s, 995m, 827s, 568m, 508m cm–1. Anal. calcd. for C29H30FeO2S
(498.46): C 69.88, H 6.07, S 6.43; found: C 69.85, H 6.24, S 6.49.
4.1.
2‐Ferrocenyl‐1,1‐bis(4‐methoxyphenyl)prop‐1‐ene
(9a).
Orange solid; yield: 456 mg (97%); m.p. 126.0–128.0 oC;
1
desulfurization of thiirane. H NMR (600 MHz, CDCl3): δ 2.12 (bs,
3H, CH3), 3.78 (bs, 3H, OCH3), 3.82 (bs, 3H, OCH3), 3.96 (bs, 2H, 2 Fc‐
CH), 4.11 (bs, 2H, 2 Fc‐CH), 4.16 (bs, 5H, 5 Fc‐CH), 6.72–6.75 (m, 2H,
2 CHarom.), 6.84–6.89 (m, 2H, 2 CHarom.), 6.91–6.95 (m, 2H, 2 CHarom.),
7.08–7.10 (m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ
22.0 (CH3), 55.1, 55.2 (2 OCH3), 67.9, 69.2 (4 CH‐Fc), 69.0 (5 CH‐Fc),
88.1 (C‐Fc), 113.3, 113.4, 131.0, 131.5 (8 CHarom.), 129.7, 137.1,
137.2, 137.4, 157.9, 158.0 (C=C, 4 Carom.) ppm.IR (KBr): υ 2984w,
2949w, 2825w, 1604m, 1505s, 1461m,1432m, 1290m, 1280m,
1242vs, 1171m, 1106m, 1038m, 992m, 910w, 835m, 817m, 485m
cm–1. Anal. calcd. for C27H26FeO2 (438.34): C 73.98, H 5.98; found: C
73.82, H 5.85.
3.4. 3‐Ethyl‐3‐ferrocenyl‐2,2‐diphenylthiirane (8e). Orange solid;
yield: 229 mg (54%); m.p. 142.6–144.8 oC. 1H NMR (600 MHz,
CDCl3): δ 1.91 (t, 3H, JH,H = 7.2 Hz, CH3), 1.91–2.00, 2.33–2.44 (2m,
2H, CH2), 3.47 (bs, 1H, Fc‐CH), 3.85 (bs, 1H, Fc‐CH), 4.18 (bs, 6H, 6
Fc‐CH), 4.46 (bs, 1H, Fc‐CH), 7.03–7.11 (m, 3H, 3 CHarom.), 7.12–7.20
(m, 3H, 3 CHarom.), 7.23–7.28 (m, 2H, 2 CHarom.), 7.49–7.53 (m, 2H, 2
CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 13.8 (CH3), 30.6
(CH2), 60.3 (Cq), 66.7, 67.5, 69.5, 69.9 (4 CH‐Fc), 69.1 (5 CH‐Fc), 71.1
(Cq), 90.8 (C‐Fc), 126.2, 126.7, 127.2, 127.8, 129.2, 130.4 (10
CHarom.), 142.3, 143.0 (2 Carom.) ppm. IR (KBr): υ 3070w, 3018w,
3053w, 2965m, 2930m, 2873w, 1597w, 1489m, 1445m, 1372m,
1103m, 1030m, 998m, 812s, 742m, 698vs, 511m, 482s cm–1. Anal.
4.2. 2‐Ferrocenyl‐1,1‐bis(4‐methoxyphenyl)but‐1‐ene (9b).13 Thick
orange oil; yield: 431 mg (95%); desulfurization of thiirane. 1H NMR
(600 MHz, CDCl3): δ 1.02 (t, 3H, JH,H = 7.2 Hz, CH3), 2.51 (q, 2H, JH,H
7.2 Hz, CH2), 3.79 (bs, 3H, OCH3), 3.82 (bs, 3H, OCH3), 4.02 (bs, 2H, 2
Fc‐CH), 4.12–4.21 (m, 7H, 7 Fc‐CH), 6.76–6.80 (m, 2H, 2 CHarom.),
6.85–6.89 (m, 2H, 2 CHarom.), 6.97–7.00 (m, 2H, 2 CHarom.), 7.09–7.12
(m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 15.4 (CH3),
27.9 (CH2), 55.1, 55.2 (2 OCH3), 68.0, 69.3 (4 CH‐Fc), 69.2 (5 CH‐Fc),
87.3 (C‐Fc), 113.5, 113.6, 130.4, 131.0 (8 CHarom.), 136.6, 137.3,
137.5, 157.8, 157.9 (C=C, 4 Carom.) ppm.
=
4 | J. Name., 2012, 00, 1‐3
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4.3. 2‐Ferrocenyl‐1,1‐bis(4‐methoxyphenyl)pent‐1‐ene (9c). Yellow Fc), 69.5 (5 CH‐Fc), 91.8 (C‐Fc), 118.8, 119.4, 124.8, 125.5, 125.8,
o
solid; yield: 457 mg (98%); m.p. 103.0–106.0 C; desulfurization of 126.4, 126.7, 126.9 (8 CHarom.), 133.9, 138.6, 138.9, 139.5, 139.9,
thiirane. 1H NMR (600 MHz, CDCl3): δ 0.83 (t, 3H, JH,H = 7.2 Hz, CH3), 146.9 (C=C, 4 Carom.) ppm. IR (KBr): υ 3094w, 2984w, 2958w, 2927w,
1.45–1.51 (m, 2H, CH2), 2.50–2.57 (m, 2H, CH2), 3.79 (bs, 3H, OCH3), 2870w, 1613m, 1591m, 1473m, 1448s, 1337w, 1277w, 1109m,
3.83 (bs, 3H, OCH3), 3.96 (bs, 2H, 2 Fc‐CH), 4.12 (bs, 2H, 2 Fc‐CH), 1024m, 1002m, 941w, 821s, 768m, 694w, 732vs, 694w, 485s cm–1.
4.15 (bs, 5H, 5 Fc‐CH), 6.75–6.78 (m, 2H, 2 CHarom.), 6.85–6.88 (m, Anal. calcd. for C26H22Fe (390.30): C 80.01, H 5.68; found: C 80.06, H
2H, 2 CHarom.), 6.96–6.99 (m, 2H, 2 CHarom.), 7.09–7.12 (m, 2H, 2 5.70.
CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 14.4 (CH3), 23.9
4.7.
5‐(1‐Ferrocenylethylidene)‐10,11‐dihydro‐5H‐
(CH2), 37.1 (CH2), 55.1, 55.2 (2 OCH3), 68.4, 69.5 (4 CH‐Fc), 69.6 (5
CH‐Fc), 88.6 (C‐Fc), 113.4, 113.5, 130.6, 131.2 (8 CHarom.), 135.0,
137.3, 137.6, 138.0, 157.9, 158.0 (C=C, 4 Carom.) ppm. IR (KBr): υ
3031w, 3006w, 2955w, 2873w, 2832w, 1603m, 1507m, 1458m,
1439m, 124vs, 1181m, 1169m, 1103m, 1035m, 838m, 755m, 584m
cm–1. Anal. calcd. for C29H30FeO2 (466.39): C 74.68, H 6.48; found: C
74.56, H 6.50.
dibenzo[a,d][7]annulene (9l). Orange solid; yield: 392 mg (97%);
m.p. 143.0–145.0 oC; desulfurization of thiirane. 1H NMR (600 MHz,
CDCl3): δ 2.14 (bs, 3H, CH3), 2.83–2.98 (m, 2H, CH2), 3.43–3.57 (m,
3H, Fc‐CH, CH2), 4.02 (bs, 1H, Fc‐CH), 4.14 (bs, 5H, 5 Fc‐CH), 4.25
(bs, 1H, Fc‐CH), 4.40 (bs, 1H, Fc‐CH), 6.94–6.98 (m, 1H, CHarom.),
6.99–7.03 (m, 1H, CHarom.), 7.12–7.20 (m, 6H, 6 CHarom.) ppm. 13C{1H}
NMR (150 MHz, CDCl3): δ 20.3 (CH3), 32.3 (2 CH2), 68.2, 68.5, 69.2,
4.4. 2‐Ferrocenyl‐1,1‐diphenylbut‐1‐ene (9e). Orange solid; yield: 69.5 (4 CH‐Fc), 69.3 (5 CH‐Fc), 87.1 (C‐Fc), 125.3, 126.0, 126.7,
o
1
384 mg (98%); m.p. 114.7–116.5 C; desulfurization of thiirane. H 126.8, 128.6, 129.0, 129.1, 129.2 (8 CHarom.), 136.2, 137.3, 137.5,
NMR (600 MHz, CDCl3): δ 1.07 (t, 3H, JH,H = 7.2 Hz, CH3), 2.61 (q, 2H, 142.6, 142.8 (C=C, 4 Carom.) ppm. IR (KBr): υ 3063w, 3006w, 2939w,
JH,H = 7.2 Hz, CH2), 3.91 (t, 2H, JH,H = 1.8 Hz, 2 Fc‐CH), 4.09 (t, 2H, JH,H 2909m, 2828w, 1594w, 1481m, 1440m, 1396m, 1255m, 1104m,
= 1.8 Hz, 2 Fc‐CH), 4.14 (bs, 5H, 5 Fc‐CH), 7.10–7.13 (m, 2H, 2 1006m, 907m, 821vs, 775s, 756vs, 745m, 622m, 509m cm–1. Anal.
CHarom.), 7.16–7.19 (m, 1H, CHarom.), 7.22–7.26 (m, 5H, 5 CHarom.), calcd. for C27H24Fe (404.32): C 80.21, H 5.98; found: C 80.24, H 5.91.
7.32–7.36 (m, 2H, 2 CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ
5. Typical procedure for the demethylation of compounds 9a–c.
15.5 (CH3), 27.8 (CH2), 68.1, 69.3 (4 CH‐Fc), 69.2 (5 CH‐Fc), 86.5 (C‐
Fc), 126.2, 128.1, 128.2, 129.3, 129.8 (10 CHarom.), 137.4, 138.0,
144.6, 144.7 (C=C, 2 Carom.) ppm. IR (KBr): υ 3079w, 3044w, 2974m,
2961m, 2933w, 2870w, 1597m, 1489m, 1442m, 1109m, 1074m,
1049m, 1024m, 1005m, 821m, 805m, 774m, 704vs, 523m, 489s cm–
1. Anal. calcd. for C26H24Fe (392.31): C 79.60, H 6.17; found: C 79.64,
H 6.20.
The solution of the corresponding ethylene 9a–c (1 mmol) in
dichloromethane (4 mL) was cooled to –78 oC (acetone/dry ice) and
then 2 mL (2 mmol) of a solution of BBr3 (1M in CH2Cl2) was added
in one portion. The cooling bath was removed and the solution was
stirred for 1.5 h. Then, the mixture was again cooled to 0 oC in ice
bath, 3 mL of methanol were added, and the solvent was
evaporated. The crude product was purified by CC (SiO2, petroleum
ether/ethyl acetate 8:2). In all cases, viscous materials were
obtained, which after dissolution in diethylether and careful
evaporation of the solvent converted into foam‐like solids.
4.5. 9‐(1‐Ferrocenylethylidene)‐9H‐fluorene (9h). Orange solid;
yield: 301 mg (80%); m.p. >215 oC (decomposition); spontaneous
desulfurization. 1H NMR (600 MHz, CDCl3): δ 2.91 (bs, 3H, CH3), 4.27
(bs, 5H, 5 Fc‐CH), 4.47 (t, 2H, JH,H = 1.8 Hz, 2 Fc‐CH), 4.54 (t, 2H, JH,H
=
1.8 Hz, 2 Fc‐CH), 6.97–7.01 (m, 1H, CHarom.), 7.18–7.23 (m, 1H,
CHarom.), 7.31–7.34 (m, 1H, CHarom.), 7.35–7.38 (m, 2H, 2 CHarom.),
7.69–7.71 (m, 1H, CHarom.), 7.78–7.81 (m, 1H, CHarom.), 7.98–8.01 (m,
1H, CHarom.) ppm. 13C{1H} NMR (150 MHz, CDCl3): δ 26.5 (CH3), 68.9,
71.0 (4 CH‐Fc), 69.5 (5 CH‐Fc), 90.0 (C‐Fc), 119.0, 119.5, 124.8,
125.0, 125.9, 126.4, 126.6, 126.7 (8 CHarom.), 134.4, 138.5, 139.4,
139.5, 139.7, 140.5 (C=C, 4 Carom.) ppm. IR (KBr): υ 3098w, 3060w,
3047w, 2961w, 1613m, 1591s, 1445s, 1432m, 1340m, 1106m,
1005m, 995m, 780s, 736vs, 644m, 482m cm–1. Anal. calcd. for
C25H20Fe (376.27): C 79.80, H 5.36; found: C 79.87, H 5.45.
5.1.
2‐Ferrocenyl‐1,1‐bis(4‐hydroxyphenyl)prop‐1‐ene
(1a).14
Purified chromatographically, orange‐red solid; yield: 316 mg (77%);
m.p. 59−63oC (ref.14 94.0–95.0 oC (from pentane/diethylether)). 1H
NMR (600 MHz, acetone‐d6): δ 2.15 (bs, 3H, CH3), 3.94 (bs, 2H, 2 Fc‐
CH), 4.06 (bs, 2H, 2 Fc‐CH), 4.14 (bs, 5H, 5 Fc‐CH), 6.67–6.70 (m, 2H,
2 CHarom.), 6.79–6.84 (m, 4H, 4 CHarom.), 7.01–7.04 (m, 2H, 2 CHarom.),
8.13 (bs, 1H, OH), 8.20 (bs, 1H, OH) ppm. 13C{1H} NMR (150 MHz,
acetone‐d6): δ 22.3 (CH3), 68.6, 69.9 (4 CH‐Fc), 69.8 (5 CH‐Fc), 89.1
(C‐Fc), 115.6, 115.7, 131.9, 132.3 (8 CHarom.), 129.9, 137.0, 137.1,
138.8, 156.6, 156.7 (C=C, 4 Carom.) ppm.
4.6. 9‐(1‐Ferrocenylpropylidene)‐9H‐fluorene (9i). Yellow solid;
5.2.
2‐Ferrocenyl‐1,1‐bis(4‐hydroxyphenyl)but‐1‐ene
(1b).3b
yield: 355 mg (91%); m.p. >166 oC (decomposition); spontaneous
Purified chromatographically, orange‐red solid; yield: 316 mg (90%);
m.p. 81−83 °C (ref.3b m.p. 219 oC (no solvent used for crystallization
reported)). H NMR (600 MHz, acetone‐d6): δ 1.03 (t, 3H, JH,H = 7.2
Hz, CH3), 2.62 (q, 2H, JH,H = 7.2 Hz, CH2), 3.92 (bs, 2H, 2 Fc‐CH), 4.06
(bs, 2H, 2 Fc‐CH), 4.11 (bs, 5H, 5 Fc‐CH), 6.69–6.72 (m, 2H, 2
CHarom.), 6.80–6.83 (m, 2H, 2 CHarom.), 6.86–6.89 (m, 2H, 2 CHarom.),
7.05–7.08 (m, 2H, 2 CHarom.), 8.16 (bs, 2H, 2 OH) ppm. 13C{1H} NMR
1
desulfurization. H NMR (600 MHz, CDCl3): δ 1.45 (t, 3H, JH,H = 7.2
Hz, CH3), 3.44 (q, 2H, JH,H = 7.2 Hz, CH2), 4.24 (bs, 5H, 5 Fc‐CH), 4.45
(t, 2H, JH,H = 1.8 Hz, 2 Fc‐CH), 4.50 (t, 2H, JH,H = 1.8 Hz, 2 Fc‐CH),
6.94–6.98 (m, 1H, CHarom.), 7.11–7.16 (m, 1H, CHarom.), 7.17–7.20 (m,
1H, CHarom.), 7.34–7.38 (m, 2H, 2 CHarom.), 7.66–7.70 (m, 1H, CHarom.),
7.76–7.80 (m, 1H, CHarom.), 7.92–7.96 (m, 1H, CHarom.) ppm. 13C{1H}
NMR (150 MHz, CDCl3): δ 15.1 (CH3), 32.4 (CH2), 68.6, 70.8 (4 CH‐
1
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ARTICLE
Journal Name
5
6
S. Chen, L. Zhang, Y. Du and B. Li, Synlett 2012, 23, 943.
(150 MHz, acetone‐d6): δ 15.0 (CH3), 27.6 (CH2), 67.7, 69.1 (4 CH‐
Fc), 69.0 (5 CH‐Fc), 87.1 (C‐Fc), 114.9, 115.0, 130.3, 130.8 (8
CHarom.), 136.0, 136.3, 136.6, 137.9, 155.7, 155.8 (C=C, 4 Carom.) ppm.
(a) In: Barton‐Kellogg Olefination. Comprehensive organic
name reactions and reagents. Vol. 56: pp. 249–253, Wiley;
2010; (b) F. S. Guziec Jr. and L. J. Sanfilippo, Tetrahedron,
1988, 44, 6241.
5.3.
2‐Ferrocenyl‐1,1‐bis(4‐hydroxyphenyl)pent‐1‐ene
(1c).2e
7
(a) G. Mlostoń, R. Hamera and H. Heimgartner, Phosphorus
Sulfur, and Silicon, 2015, 190, 2125; (b) G. Mlostoń, R.
Hamera‐Fałdyga, M. Jeske, M. Godziszewska, K. Urbaniak
and H. Heimgartner, J. Sulfur Chem., 2018, 39, 47; (c) G.
Mlostoń, R. Hamera‐Fałdyga and H. Heimgartner J. Sulfur
Chem., 2018, 39, 267; (d) G. Mlostoń, K. Urbaniak, G. Utecht,
D. Lentz and M. Jasiński, J. Fluorine Chem., 2016, 192, 147.
Purified chromatographically, orange‐red solid; yield: 425 mg (97%);
m.p. 59−62 °C (ref.2e m.p. 186.0 oC (no solvent used for
crystallization reported)). 1H NMR (600 MHz, acetone‐d6): δ 0.82 (t,
3H, JH,H = 7.2 Hz, CH3), 1.46–1.63 (m, 2H, CH2), 2.57–2.64 (m, 2H,
CH2), 3.92 (bs, 2H, 2 Fc‐CH), 4.05 (bs, 2H, 2 Fc‐CH), 4.12 (bs, 5H, 5
Fc‐CH), 6.69–6.72 (m, 2H, 2 CHarom.), 6.79–6.83 (m, 2H, 2 CHarom.),
6.85–6.88 (m, 2H, 2 CHarom.), 7.03–7.07 (m, 2H, 2 CHarom.), 8.15 (bs,
2H, 2 OH) ppm. 13C{1H} NMR (150 MHz, acetone‐d6): δ 14.7 (CH3),
24.7 (CH2), 37.7 (CH2), 68.7, 70.1 (4 CH‐Fc), 69.9 (5 CH‐Fc), 88.7 (C‐
Fc), 115.8, 115.9, 131.4, 131.8 (8 CHarom.), 135.3, 137.4, 137.6,
139.3, 156.6, 156.7 (C=C, 4 Carom.) ppm.
8
9
M. Patra and G. Gasser, Nat. Rev. Chem. 2017, 1, 0066.
(a) D. N. Kursanow, V. N. Setkina and S. P. Dolgova, Russ.
Chem. Bull., 1979, 28, 814; (b) D. N. Kursanov, V. N. Setkina,
S. P. Dolgova and M. N. Nefedova, Russ. Chem. Bull., 1981,
30, 1360.
10 (a) D. Astruc, Eur. J. Inorg. Chem., 2017, 6; (b) K. Heinze and
H. Lang (guest eds), Organometallics, 2013, 32, 5623.
11 (a) W. Chew, R. C. Hynes and D. N. Harpp, J. Org. Chem.,
1993, 58, 4398; (b) B. B. Wright and M. S. Platz, J. Am. Chem.
Soc. 1984, 106, 4175.
12 Ch. R. Hauser and J. K. Lindsay, J. Org. Chem. 1957, 22, 482.
13 J. B. Heilmann, E. A. Hillard, M.‐A. Plamont, P. Pigeon, M.
Bolte, G. Jaouen and A. Vessières, J. Organometal. Chem.
2008, 693, 1716.
Conflicts of interest
There are no conflicts to declare.
14 P. Pigeon, M. Görmen, K. Kowalski, H. Müller‐Bunz, M. J.
McGlinchey, S. Top and G. Jaouen, Molecules 2014, 19
,
Acknowledgements
10350.
Funding for this research was provided by grants Maestro‐3 (grant
No. Dec‐2012/06/A/ST5/00219, National Science Center, Cracow)
and Institutspartnerschaft (Jena‐Lodz) (Alexander von Humboldt
Foundation Bonn) to R. H.‐F. and G. M. Stimulating discussions with
Prof. Wolfgang Weigand (Jena) on the chemistry of ferrocene
thioketones are gratefully acknowledged.
Notes and references
1
(a) G.‐F. Zhang, H. Wang, M. P. Aldred, T. Chen, Z.‐Q. Chen, X.
Meng and M.‐Q. Zhu, Chem.Mater., 2014, 26, 4433; (b) T.
Suzuki, H. Shiohara, M. Monobe, T. Sakimura, S. Tanaka, Y.
Yamashita and T. Miyashi, Angew. Chem., 1992, 104, 454; (c)
A. Bolzoni, L. Viglianti, A. Bossi, P. R. Mussini, S. Canteruccio,
C. Baldoli and E. Licandro, Eur. J. Org. Chem., 2013, 7489; (d)
F.‐Y. Cao, Y. Long, S.‐B. Wang, B. Li, J.‐X. Fan, X. Zeng and X.‐
Z. Zhang, J. Mater. Chem. B., 2016, 4, 4534; (e) Y. Yuan, S. Xu,
X. Cheng and B. Liu, Angew. Chem. Int. Ed., 2016, 55, 6457.
(a) R. S. Muthyala, S. Sheng, K. E. Carlson, B. S.
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2003, 46, 1589; (b) V. Lubczyk, H. Bachmann and R. Gust, J.
Med. Chem., 2002, 45, 5358; (c) G. Jaouen, A. Vessières and
S. Top, Chem. Soc. Rev., 2015, 44, 8802; (d) H. Z. S. Lee, O.
Buriez, F. Chau, E. Labbé, R. Ganguly, C. Amatore, G. Jaouen,
A. Vessières, W. K. Leong and S. Top, Eur. J. Inorg. Chem.,
2015, 4217; (e) P. Pigeon, Y. Wang, S. Top, F. Najlaoui, M. C.
G. Alvarez, J. Bignon, M. J. McGlinchey and G. Jaouen, J.
Med. Chem., 2017, 60, 8358; (f) J. Skiba, Q. Yuan, A.
Hildebrandt, H. Lang, D. Trzybinski, K. Wozniak, R. Balogh, B.
Gyurcsik, V. Vrcek and K. Kowalski, ChemPlusChem, 2018,
83, 77.
(a) S. Top, J. Tang, A. Vessiéres, D. Carrez, C. Provot and G.
Jaouen, Chem. Commun., 1996, 955; (b) G. Jaouen, S. Top, A.
Vessiéres, G. Leclercq, J. Quivy, L. Jin and A. Croisy, CR Acad.
Sci. Paris, Serie IIc, 2000, 3, 89.
X.‐F. Duan, J. Zeng, J.‐W. Lü and Z.‐B. Zhang, J. Org. Chem.,
2006, 71, 9873.
2
3
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DOI: 10.1039/C8OB01022F
Scheme 1
N
N
N
N
Ar3
Ar4
Ar1
Ar2
Ar1
Ar2
THf or Et2O
-30 °C
+
S
S
Ar3
Ar4
2
3
4
-N2
(Et2N)3P
THF, r.t.
Ar1
Ar2
Ar3
Ar4
Ar1
Ar2
Ar3
Ar4
-S
S
6
5

Organic & Biomolecular Chemistry
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DOI: 10.1039/C8OB01022F
OH
R
Fe
OH
1 (R = alkyl)
Figure 1

Page 9 of 9
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Graphical abstract:
View Article Online
DOI: 10.1039/C8OB01022F
R
n
Alk
Alk
Fc
S
Fe
Alk
R
Fc = ferrocenyl
Fe
Alk = Me, Et or iPr
R = H, OMe, OH
n = 0 or 1