Anionic phospho-fries rearrangement at ferrocene: One-pot approach to P,O-substituted ferrocenes

Article abstract of DOI:10.1021/om5002827

For the first time the anionic phospho-Fries rearrangement has been successfully applied in ferrocene chemistry, giving access to 1,2-P,O-substituted ferrocenes. The 1,3 (O → C)-migration occurs at ferrocenyl phosphates, thiophosphates, phosphite-borane adducts, and phosphinates by treatment with a base such as lithium diisopropylamide at low temperature, whereas the highest yields were obtained starting from diethylferrocenyl phosphate. Complete reduction of the phosphonate to a primary phosphine and subsequent Stelzer P,C cross coupling allowed the synthesis of Fe(η⁵-C₅H₃-2-OMe-PPh₂) (η⁵-C₅H₅) (1). The qualification of 1 as a supporting ligand in palladium-catalyzed Suzuki-Miyaura C,C couplings has been proven by the synthesis of sterically congested tri-ortho-substituted biaryls under mild reaction conditions in good to excellent yields.

Full text of DOI:10.1021/om5002827

Article
pubs.acs.org/Organometallics
Anionic Phospho-Fries Rearrangement at Ferrocene: One-Pot
Approach to P,O-Substituted Ferrocenes
Marcus Korb, Dieter Schaarschmidt, and Heinrich Lang*
Fakultat fur Naturwissenschaften, Institut fur Chemie, Anorganische Chemie, Technische Universitat Chemnitz, Straße der Nationen
̈
̈
̈
̈
62, 09107 Chemnitz, Germany
S
* Supporting Information
ABSTRACT: For the first time the anionic phospho-Fries
rearrangement has been successfully applied in ferrocene
chemistry, giving access to 1,2-P,O-substituted ferrocenes. The
1,3 (O → C)-migration occurs at ferrocenyl phosphates,
thiophosphates, phosphite−borane adducts, and phosphinates
by treatment with a base such as lithium diisopropylamide at
low temperature, whereas the highest yields were obtained
starting from diethylferrocenyl phosphate. Complete reduction of the phosphonate to a primary phosphine and subsequent
Stelzer P,C cross coupling allowed the synthesis of Fe(η5-C5H3-2-OMe-PPh2)(η5-C5H5) (1). The qualification of 1 as a
supporting ligand in palladium-catalyzed Suzuki−Miyaura C,C couplings has been proven by the synthesis of sterically congested
tri-ortho-substituted biaryls under mild reaction conditions in good to excellent yields.
phosphine oxides6,7 as starting materials for this approach,
INTRODUCTION
■
which has therefore not been realized yet. In contrast,
intramolecular transformations, e.g. anionic hetero-Fries or
Fries-like rearrangements, would allow the straightforward
synthesis of such metallocenes; however, the scope of this
reaction has been scarcely explored, as there are only three
reports in ferrocene chemistry so far.5c,8 In principle, it should
be possible to access 1,2-P,O-substituted ferrocenes exerting an
anionic phospho-Fries rearrangement (Scheme 1, path iii),
circumventing difficulties in the synthesis of these molecules via
the ortho-directed metalation of ferrocenyl ethers.
Planar-chiral ferrocenes are undoubtedly of major importance
in asymmetric catalytic transformations in academia as well as
in industry.1 Most frequently their synthetic methodology relies
on the ortho-directed metalation of substituted ferrocenes
followed by the addition of an electrophile.2,3 Just a few of these
ortho-directing groups contain a heteroatom directly bonded to
ferrocene, thus limiting the diversity of accessible ferrocenes
carrying two heteroatoms in 1,2-positions. The synthesis of 1,2-
P,O-substituted ferrocenes can be realized by ortho-directed
metalation starting either from ferrocenyl ethers (Scheme 1,
Recently, we demonstrated that P,O-ferrocene ligands show
high activities in the synthesis of sterically congested biaryls via
Suzuki−Miyaura C,C couplings.3,4a We assume that the
ferrocene substitution pattern represents a promising structural
motif for this challenging catalytic transformation. Herein, we
report for the first time on an anionic phospho-Fries
rearrangement at ferrocene as the key step in the preparation
of 1,2-P,O-substituted ferrocenes and their successful applica-
tion as ligands in the synthesis of tri-ortho-substituted biaryls.
Scheme 1. Different Pathways for the Synthesis of 1,2-P,O-
Substituted Ferrocenes
RESULTS AND DISCUSSION
■
Accidentally discovered by Melvin in 1981,9 the anionic
phospho-Fries rearrangement is a well-established protocol
for access to phenyl-based phosphonates and related
compounds.10 It was used, for example, for the preparation of
chiral binol derivatives for asymmetric catalysis11 and is in
consideration for the synthesis of natural product analogues.12
The 1,3 (O → C)-migration is usually base-induced, requiring
deprotonation at the ortho position. Depending on the base as
path i) or ferrocenyl phosphine oxides (path ii). The first path
suffers from the formation of several byproducts due to di- and
polymetalation of ferrocenyl aryl ethers, requiring an elaborate
purification,4 while for the respective alkyl derivatives lithiation
occurs almost exclusively at the heretofore unsubstituted
cyclopentadienyl ring.4,5 The small number of oxygen electro-
philes not affecting the ferrocene backbone or the questionable
success of an Ullman-type coupling limits the use of ferrocenyl
Received: March 17, 2014
Published: April 8, 2014
© 2014 American Chemical Society
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Scheme 2. Possible Reactions of Phosphorous-Ferrocenolates Treated with a Base and Subsequently with an Electrophile
well as the substituents X and R at the phosphorus atom
(Scheme 2), ortho-directed metalation at ferrocene (B) or a
nucleophilic attack at the phosphorus atom (F) may occur.
Without doubt this process requires the use of a sterically
hindered, non-nucleophilic base. In contrast, no clear
conclusion regarding X and R can be drawn, as electron-
withdrawing substituents facilitate the deprotonation of the
ferrocene as well as a nucleophilic attack at phosphorus. The
different ring sizes of ferrocene and benzene as well as the
different C−C bond lengths,13 resulting in an increased
separation of two substituents at the 1,2-positions, should
decrease the rate of the Fries rearrangement at ferrocene-based
compounds and might therefore require a higher reaction
temperature. However, lithiated ferrocenes exhibit a lower
stability in comparison to corresponding benzene derivatives
regarding ether cleavage,14 which makes strict temperature
control necessary. Otherwise, ferrocene A will (seemingly) be
converted incompletely or undesired C may be formed to a
greater extent (Scheme 2).
Table 1. Reaction of Ferrocenol (3) with Different
Phosphorous Electrophiles to Afford 4−10
The ferrocenolato P(III) and P(V) compounds 4−10 were
synthesized starting from ferrocenol (3) (Table 1).15 The
organometallic analogue of phenol was reacted with the
respective chlorophosphorous derivatives (Table 1) in the
presence of triethylamine. The ferrocenolato P(III) compounds
were additionally either treated with [BH3·thf] (Table 1, entry
4) or oxidized using H2O2 (Table 1, entry 6) or elemental
sulfur (entry 7), respectively. Except for the less electrophilic
thio derivative 6 (entry 3), the products can typically be
isolated in good to excellent yields.
When a solution of phosphate 4 in tetrahydrofuran was
treated at temperatures below −40 °C for 4 h with 2 equiv of
freshly prepared LDA (lithium diisopropylamide) with
subsequent addition of excess dimethyl sulfate, almost all
starting material could be recovered, strongly indicating that no
ortho-directed lithiation took place. At −30 °C, however,
disubstituted ferrocene 12 could be isolated in 94% yield as the
only product (Scheme 3).
The absences of phosphate 4 and an ortho-methylated
ferrocene (Scheme 2, C) indicate that the rate of the anionic
phospho-Fries rearrangement is sufficiently high under these
conditions.10,17 Replacement of the PO oxygen atom by a
BH3 protecting group decreases the yield for ferrocene 14 to
37%. The recovery of only 31% of the starting material may be
due to partial decomposition during the reaction. Thiophos-
phate 6 gives under these conditions only recovered starting
material. If the stronger base sBuLi is used at −30 °C, however,
thiophosphonate 13 can be isolated in 50% yield. Running this
a
b
1,1′-Ferrocenediol 1115,16 was used instead of 3. [BH3·thf] was
c
d
added. H2O2 was added. Sulfur was added.
reaction at 0 °C decreases the yield to 11% (35% recovered
starting material).
Replacement of LDA by the Simpkins base (+)-bis[(R)-1-
phenylethyl]amine in the rearrangement of 4 resulted in a very
low enantioenrichment (<5% ee) of phosphonate 12, as
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(Scheme 4), from which desired phosphine oxide 16 was
isolated in 8% yield. However, for this transformation partial
nucleophilic attack of the base occurred at the phosphorus
atoms, which results in the formation of ferrocenyl methyl ether
(17; 16%).
Scheme 3. Anionic Phospho-Fries Rearrangement of
Ferrocenylphosphate 4, Ferrocenylhiophosphate 6, and
Borane Adduct 7
a
In the case of the corresponding thiophosphinate 10, LDA
turned out to be a too weak base, as the starting material could
s
be recovered completely. The stronger base BuLi exclusively
resulted in nucleophilic attack at the phosphorus atom, and
hence only ferrocenyl methyl ether (17) and sec-butyldiphe-
nylphosphane sulfide (18) were formed (Scheme 5). For
compounds 10 and 18 single-crystal structures could be
obtained (Figure SI1, Supporting Information).
a
Legend: (a) E = O, BH3, (1) LDA, thf, −30 °C, 4 h, (2) Me2SO4 or
s
MeI; (b) E = S, (1) BuLi, thf, −30 °C, 4 h, (2) MeI.
evinced by chiral HPLC. This is in accordance with other
ortho-directed lithiations at ferrocene, where a mere change of
the base without further adoptions of the reaction conditions
had only a small effect.8b,18
a
s
Scheme 5. Reaction of Thiophosphinate 10 with BuLi
The formation of the phospho-Fries rearrangement products
12−14 can be unambiguously proven using NMR spectrosco-
py. On the one hand, the resonance in the 31P{1H} NMR
spectra is shifted downfield from −5.4 (4), 63.8 (6), and 128.2
ppm (7) to 36.4 (12), 89.6 (13), and 135.4 ppm (14),
respectively. Additionally, a singlet for the methoxy group for
all three compounds was observed at 3.7 ppm (12,19 13, 14) in
1
the H NMR spectra (Supporting Information). Due to the
established planar chirality at ferrocene the two ethoxy moieties
become diastereotopic, resulting in a doubling of all their
resonances in 1H and 13C{1H} NMR spectra, respectively. The
C−P ipso-carbon atom gives a doublet in the 13C{1H} NMR
a
s
Legend: (a) (1) BuLi, −30 °C, 4 h, (2) MeI.
1
spectra at 59.2 ppm with a large JC,P coupling constant of 213
Hz (12), in agreement with the values for similar compounds.20
Replacing the ethoxy (4) by phenoxy substituents in
ferrocenyl phosphonate 8 opens two different reaction
pathways, as an anionic phospho-Fries rearrangement can
take place at ferrocene and at the benzene rings (Scheme 4).
Two subsequent anionic phospho-Fries rearrangements
could be performed when the intermediate of the reaction of
phosphate 4 and LDA was quenched with chlorodiethylphos-
phate to give ferrocene 19 (Scheme 6). Both transformations
Scheme 6. Anionic Phospho-Fries Rearrangement of
Ferrocenylphosphate 4 and Intermediately Formed
Phosphate 19
Scheme 4. Anionic Phospho-Fries Rearrangement of Phenyl-
Substituted Ferrocenylphosphate 8 and Phosphinate 9
a
a
a
Legend: (a) (1) LDA, thf, −20 °C, 4 h, (2) ClP(O)(OEt)2, 33%; (b)
a
Legend: (a) (1) LDA, thf, −40 °C, 4 h, (2) MeI, 8%; (b) (1) LDA,
(1) LDA, thf, −30 °C, 4 h, (2) MeI, 21%.
−30 °C, 4 h, (2) MeI, 8%.
When phosphate 8 was treated with LDA at −40 °C, double
phospho-Fries rearrangement was observed at the two benzene
moieties, and phosphinate 15 could be isolated in 8% yield.
Although further products were formed, as evinced by 31P{1H}
NMR spectroscopy, no additional compound could be either
isolated in pure form or identified.
This result discouraged us from investigating this trans-
formation further. Likewise, phosphinate 9 gave a complex
product mixture when similar reaction conditions were applied
proceeded as expected; no further ferrocene compounds could
be identified. The considerably lower yields in comparison to
that for the synthesis of 12 (Scheme 3) are due to the lower
stabilities of 19 and 20; partial decomposition has been
observed for both compounds even after purification. It is
interesting to note that the conversion of ferrocene 19 into
bisphosphonate 20 clearly simplified the NMR spectra, due to
the higher symmetry of the latter compound. For the
rearrangement of 1,1′-diphosphate 5 a complex mixture of
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a
Scheme 7. Possible Pathways for the Transformation of Phosphonate 12 into Phosphine 1
a
Legend: (a) (1) Li[AlH4] (4 equiv), Me3SiCl (4 equiv), thf, 25 °C, (2) 12, 40 °C, 12 h, 99%; (b) PhI (2 equiv), K3PO4 (2 equiv), [Pd(dppf)Cl2] (4
mol %), toluene, 110 °C, 12 h, 52%.
several phosphorus-containing molecules was obtained, from
which no product could be identified or isolated in pure form.
The transformation of phosphonate 12 into phosphine 1,
which has been considered as auxiliary ligand for palladium in
Suzuki C,C cross-couplings, was thoroughly investigated, as
outlined in Scheme 7. The attempted direct conversion of
phosphonate 12 into phosphine oxide 16 by treatment with
phenylmagnesium bromide or phenyllithium gave only
unreacted starting materials. Likewise, the conversion into the
dichlorophosphonate intermediate 2221−23 with subsequent
introduction of the phenyl moieties17e,24 in a “one-pot” reaction
turned out to be unsuccessful in the case of ferrocene 12. In
contrast, reduction of this phosphonate in the presence of an
excess of Li[AlH4] and trimethylsilyl chloride followed by acidic
Figure 1. ORTEP diagram (50% probability level) of the molecular
structure of rac-1 with the atom-numbering scheme. All hydrogen
workup under anaerobic conditions yielded phosphine 2
quantitatively.24−27 Successive palladium-catalyzed Stelzer P,C
cross-coupling28 was chosen for the conversion of the primary
phosphine into the title compound 1. As this transformation
has, to the best of our knowledge, never been applied in
ferrocene chemistry, the coupling of ferrocenylphosphine (25)
with phenyl iodide in presence of [Pd(PPh3)4] was selected as a
test reaction. Optimization of the reaction conditions furnished
diphenylphosphinoferrocene (26) in up to 72% yield (Table
SI1, Supporting Information). Application onto 1,2-disubsti-
tuted ferrocene 2, however, gave ferrocenyl methyl ether (17)
as the only product, which was formed due to a P,CCp bond
cleavage during the catalytic transformation.29 The utilization of
1,1′-bis(diphenylphosphino)ferrocene (dppf) as a sterically
demanding, chelating ligand for palladium and avoidance of
an excess of phenyl iodide circumvented this side reaction,
giving access to the desired ferrocene 1 in 52% yield.30
atoms have been omitted for clarity. Selected bond distances (Å),
angles (deg) and torsion angles (deg): C1−P1 1.8160(17), C12−P1
1.8388(18), C18−P1 1.8395(18), C2−O1 1.366(2), C11−O1
1.430(2), D1−Fe1 1.6443(2), D2−Fe1 1.6515(2); D1−Fe1−D2
179.10(2); P1−C1−C2−C3 −179.70(12), C5−C1−P1−C12
−90.73(17), C5−C1−P1−C18 11.54(17), C5−C1−C2−O1
176.16(15), C3−C2−O1−C11 −24.6(2), C1−D1−D2−C6
1.43(12), C2−D1−D2−C7 1.70(12). D1 denotes the centroid of
C5H3; D2 denotes the centroid of C5H5.
should allow for a chelating complexation of a suitable
transition metal, e.g. palladium.
P,O-ferrocenes show high activities in the synthesis of
sterically congested biaryls via Suzuki−Miyaura C,C couplings,
as demonstrated recently.3,4 This prompted us to investigate
the performance of phosphine 1 as a ligand in the palladium-
catalyzed synthesis of racemic tri-ortho-substituted biaryls,
starting from 1-bromonaphthalenes 23 and ortho-substituted
phenylboronic acids 24 (Figure 2).
At a catalyst concentration of 0.5 mol % and a reaction
temperature of 70 °C the respective biaryls 25 could typically
be isolated in good to excellent yields (Figure 2). A slightly
higher temperature was required to obtain biphenyl 25g
quantitatively. For the sterically more demanding 9-phenanthryl
derivative 25h only a moderate yield of 43% was achieved.31
These results demonstrate that P,O-substituted ferrocenes,
accessible through an anionic phospho-Fries rearrangement, are
catalytically active for the synthesis of axial-chiral biaryls via
Suzuki−Miyaura C,C couplings in the presence of palladium.
Enantioenriched phosphine 1, which enables the performance
of these biaryl couplings in an atropselective manner, may be
accessible by exerting a stereoselective ortho-directed metal-
Single crystals of ferrocene 1 suitable for X-ray diffraction
studies were obtained by crystallization from boiling n-hexane.
The molecular structure along with important bond distances
and bond and torsion angles is shown in Figure 1.
Phosphine 1 crystallizes in the monoclinic space group P21/c.
The solid-state structure unambiguously confirms the 1,2-
substitution pattern of the metallocene backbone, as already
deduced from NMR spectroscopy (vide supra). The ferrocenyl
substituent adopts an eclipsed conformation; as expected, the
phosphorus and oxygen atoms are both located in the plane of
the cyclopentadienyl ring (rms deviation 0.0008 Å, distance of
P1 −0.0010(3) Å and distance of O1 −0.079(3) Å). The
methyl and one phenyl group point in opposite directions;
consequently, the free electron pairs are directed into the
vacant space between the two substituents, which in principle
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EXPERIMENTAL SECTION
■
General Information. All reactions were carried out under an
argon or nitrogen atmosphere using standard Schlenk techniques.
Reaction vessels were heated at reduced pressure with a heat gun and
flushed with argon. This procedure was repeated three times. If
necessary, solvents were deoxygenated by standard procedures. For
column chromatography either silica with a particle size of 40−60 μm
(230−400 mesh (ASTM), Fa. Macherey-Nagel) or alumina with a
particle size of 90 μm was used.
Instruments. FT IR spectra were recorded between NaCl crystals
1
or as KBr pellets. NMR spectra (500.3 MHz for H, 125.7 MHz for
13C{1H}, 160.5 MHz for 11B{1H} and 202.5 MHz for 31P{1H} spectra)
are reported with chemical shifts in δ (ppm) downfield from
tetramethylsilane with the solvent as reference signal (1H NMR,
CHCl3 δ 7.26, C6HD5 δ 7.16; 13C{1H} NMR, CDCl3 δ 77.00, C6D6 δ
128.06; 31P{1H} NMR, standard external relative to 85% H3PO4 δ 0.0,
P(OMe)3 δ 139.0).
Single-Crystal X-ray Diffraction Analysis. Single crystals of 1,
10, and 18 suitable for X-ray diffraction analysis were obtained by
recrystallization from n-hexane at ambient temperature. Data were
collected at 100 K with graphite-monochromated Mo Kα radiation (λ
= 0.71073 Å). The structures were solved by direct methods and
refined by full-matrix least-squares procedures on F2.32 All non-
hydrogen atoms were refined anisotropically, and a riding model was
employed in the treatment of the hydrogen atom positions.
The HPLC measurements were performed with an UV detector
operating at 245 nm equipped with a Chiralcel OD-H column (4.6 ×
250 mm) using a 9/1 (v/v) hexane/2-propanol mixture (0.5 mL/min)
as the solvent. Retention times t are reported in minutes.
Reagents. Tetrahydrofuran was purified by distillation from
sodium/benzophenone ketyl and dichloromethane from calcium
hydride.
All starting materials were obtained from commercial suppliers and
used without further purification. Acetoxyferrocene,15 ferrocenol,8,15,33
1,1-bis(acetoxy)ferrocene,15 and 1,1′-ferrocenediol15 were prepared
according to published procedures.
Figure 2. Application of phosphine 1 to the palladium-catalyzed
synthesis of tri-ortho-substituted biaryls via Suzuki−Miyaura C,C
couplings. Legend: (a) 50 °C; (b) K3PO4·3H2O; (c) 100 °C. Yields
are based on isolated material; reaction times were not minimized.
Synthesis of (2-Methoxyferrocenyl)diphenylphosphane (1).
(2-Methoxyferrocenyl)phosphine (2; 480 mg, 1.94 mmol), iodoben-
zene (0.43 mL, 3.90 mmol), K3PO4 (825 mg, 3.90 mmol), and
[(dppf)PdCl2] (55 mg, 4 mol %) were dissolved in 6 mL of toluene.
The reaction mixture was degassed and stirred for 18 h at 110 °C.
After the mixture was cooled to ambient temperature, water (30 mL)
was added in a single portion and the mixture was extracted with
diethyl ether (3 × 20 mL). The organic layer was dried over MgSO4,
and the solvent was removed under reduced pressure. The residue was
purified by column chromatography (column size 2 × 6 cm, silica)
using a 7/3 (v/v) hexane/CH2Cl2 mixture to give 1 (Rf = 0.14) as an
orange solid. Yield: 410 mg (1.01 mmol, 52% based on 2). Anal. Calcd
for C23H21FeOP (400.23): C, 69.02; H, 5.29. Found: C, 68.48; H,
ation of ferrocenyl phosphates; this will be investigated in due
course.
The anionic phospho-Fries rearrangement was successfully
applied in ferrocene chemistry for the first time, giving
straightforward access to planar-chiral 1,2-P,O-disubstituted
derivatives. Treatment of diethylferrocenylphosphate (4) with
LDA and subsequent O-methylation yielded diethyl(2-
methoxyferrocenyl)phosphonate (12) as the only product. 1,3
(O → C)-Migrations proceeded at structurally related
ferrocenes as well; however, for the corresponding phos-
phite−borane adduct (7) a lower yield was observed and
diethylferrocenylthiophosphate (6) required the use of the
stronger base sBuLi. In contrast, the related diphenylphosphate
8, phosphinate 9, and thiophosphinate 10 are essentially
unsuited for an anionic phospho-Fries rearrangement, as side
reactions occur, including but not limited to a nucleophilic
attack of the base at the phosphorus atom.
Planar-chiral diethyl(2-methoxyferrocenyl)phosphonate (12)
was further converted into Fe(η5-C5H3-2-OMe-PPh2)(η5-
C5H5) (1) by complete reduction of the phosphonate moiety
and subsequent P,C cross-coupling (Stelzer coupling). The
qualification of phosphine 1 as a supporting ligand in
palladium-catalyzed Suzuki−Miyaura C,C couplings has been
proven by the synthesis of sterically congested tri-ortho-
substituted biaryls under mild reaction conditions in good to
excellent yields.
1
3
5.28. Mp: 147 °C. H NMR (CDCl3, δ): 3.50 (ddd, JH,H = 2.5 Hz,
4JH,H = 1.4 Hz, 3JH,P = 1.3 Hz, 1H, o-PPh2), 3.67 (s, 3H, OCH3), 3.98
(dpt, 4JH,P = 0.5 Hz, 3JH,H = 2.5 Hz, 1H, m-OCH3), 4.11 (s, 5H, C5H5),
4.26 (ddd, 4JH,P = 1.5 Hz, 4JH,H = 1.4 Hz, 3JH,H = 2.5 Hz, 1H, o-OCH3),
7.24−7.29 (m, 5H, o,m-Ph), 7.36−7.39 (m, 3H, o,m-Ph), 7.53−7.58
3
(m, 2H, p-Ph). 13C{1H} NMR (CDCl3, δ): 54.7 (d, JC,P = 2.6 Hz, o-
1
OCH3), 58.0 (s, OCH3), 63.1 (s, m-OCH3), 65.0 (d, JC,P = 7.6 Hz,
C−PPh2), 65.7 (d, 2JC,P = 2.0 Hz, o-PPh2), 69.3 (s, C5H5), 127.8 (s, p-
Ph), 128.05 (d, 3JC,P = 6.0 Hz, m-Ph), 128.10 (d, 3JC,P = 7.7 Hz, m-Ph),
129.0 (s, p-Ph), 131.1 (d, 2JC,P = 18.0 Hz, C−OCH3), 132.3 (d, JC,P
=
1
18.4 Hz, o-Ph), 134.9 (d, JC,P = 21.1 Hz, o-Ph), 137.3 (d, JC,P = 8.7
1
Hz, Ci-Ph), 139.6 (d, JC,P = 11.1 Hz, Ci-Ph). 31P{1H} NMR (CDCl3,
δ): −23.97 (s). HRMS (ESI-TOF, m/z): calcd for C23H21FeOP
400.0674, found 400.0754 [M]+.
Crystal Data for 1: C23H21FeOP, M = 400.22, monoclinic, P21/c, λ
= 0.71073 Å, a = 8.1036(2) Å, b = 19.4551(4) Å, c = 12.1025(3) Å, β
= 100.958(2)°, V = 1873.25(8) Å3, Z = 4, ρcalcd =1.419 Mg m−3, μ =
0.899 mm−1, T = 107.1(2) K, θ range 2.99−25.99°, 8695 reflections
collected, 3655 independent reflections (Rint = 0.0240), R1 = 0.0275,
wR2 = 0.0633 (I > 2σ(I)).
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1
3
4
Synthesis of (2-Methoxyferrocenyl)phosphine (2). In tetrahy-
drofuran (20 mL) an excess of Li[AlH4] (0.6 g, 16 mmol) was treated
with trimethylchlorosilane (1.65 mL, 12.9 mmol) at −30 °C. After the
suspension was stirred for 5 min, phosphonate 12 (645 mg, 1.83
mmol) was added dropwise. The mixture was slowly heated to 45 °C
until gas evaporation was no longer detectable. Afterward, the oil bath
was replaced by an ice bath. Acidification was realized by dropwise
addition of oxygen-free H2SO4 (3 mL, ω = 30%). Caution! During the
addition an immense gas emission occurs. The mixture was extracted
three times with oxygen-free diethyl ether (3 × 20 mL) under an argon
atmosphere. The organic layer was dried over MgSO4, and all volatiles
were removed under reduced pressure. Phosphine 2 was obtained as
an orange oil and subsequently used in further reactions (see above).
11). H NMR (CDCl3, δ): 1.36 (td, JH,H = 7.1 Hz, JH,P = 1.0 Hz,
12H, CH3), 3.99 (pt, 3+4JH,H = 1.9 Hz, 4H, C5H4), 4.14−4.21 (m, 8H,
3+4
CH2), 4.46 (pt,
J
= 1.9 Hz, 4H, C5H4). 13C{1H} NMR (CDCl3,
H,H
δ): 16.1 (d, 3JC,P = 6.7 Hz, CH3), 61.1 (d, 3JC,P = 3.8 Hz, o-C5H4), 64.4
2
2
(d, JC,P = 5.6 Hz, CH2), 64.6 (s, m-C5H4), 118.0 (d, JC,P = 4.6 Hz,
C5H4−O). 31P{1H} NMR (CDCl3, δ): −5.4. HRMS (ESI-TOF, m/z):
calcd for C18H28FeO8P2 490.0604, found 490.0633 [M]+.
Synthesis of O,O-Diethyl-O-ferrocenylthiophosphate (6).
Ferrocenol (3; 1.00 g, 4.1 mmol) was dissolved in CH2Cl2 (30 mL),
cooled to −30 °C, and treated with NEt3 (0.63 mL, 4.5 mmol) in a
single portion. After 5 min, O,O-diethylchlorothiophosphate (0.71 mL,
4.5 mmol) was added with a syringe and the solution was stirred
overnight at ambient temperature. After removal of all volatiles the
residue was collected in CH2Cl2 (30 mL) and washed with water (100
mL). The organic layer was dried over MgSO4, and all volatiles were
removed under reduced pressure. Column chromatography (column
size 3.5 × 14.5 cm, silica) using toluene as the eluent afforded 6 as an
orange oil. Yield: 450 mg (1.27 mmol, 31% based on 3). IR data
(NaCl, ν/cm−1): 3095 m, 2982 s, 2931 w, 2904 w, 2867 w, 1629 w,
1452 s, 1390 m, 1371 m, 1352 w, 1236 s, 1162 m, 1105 m, 1025 s, 945
1
Yield: 450 mg (1.82 mmol, 99% based on 12). H NMR (CDCl3, δ):
1
2
3.62 (dd, JH,P = 202.6 Hz, JH,H = 12.6 Hz, 1H, PH), 3.70 (s, 3H,
1
2
OCH3), 3.81 (dd, JH,P = 207.8 Hz, JH,H = 12.6 Hz, 1H, PH), 3.94
3+4
(ptd,
J
= 2.6 Hz, JH,P = 0.84 Hz, 1H, o-OCH3), 4.01 (ddd, JH,H =
H,H
2.6 Hz, JH,P = 1.4 Hz, JH,H = 1.4 Hz, 1H, o-PH2), 4.15 (dd, JH,H = 2.6
Hz, JH,H = 1.4 Hz, 1H, m-OCH3), 4.16 (s, 5H, C5H5).13C{1H} NMR
(CDCl3, δ, HMBC): 54.0 (d, 3JC,P = 0.86, m-OCH3), 57.9 (s, OCH3),
62.9 (d, 3JC,P = 5.0 Hz, o-OCH3), 69.5 (s, C5H5), 70.0 (d, 2JC,P = 19.9
Hz, o-PH2), 129.8 (C−OCH3).34 31P NMR (CDCl3, δ): −159.9 (dd,
1
3
4
s, 885 s, 818 s. H NMR (CDCl3, δ): 1.35 (td, JH,H = 7.0 Hz, JH,P
=
0.4 Hz, 6H, CH3), 3.89 (pt, 3+4JH,H = 1.9 Hz, 2H, m-C5H4), 4.13−4.22
1
1JH,P = 202.6 Hz, JH,P = 207.8 Hz).
3+4
(m, 4H, CH2), 4.25 (s, 5H, C5H5), 4.40 (pt,
J
= 1.9 Hz, 2H, o-
H,H
Synthesis of Ferrocenol (3).8,15,33 Ferrocenylacetate15 (1.00 g,
4.10 mmol) was dissolved in ethanol (30 mL), and 2 M oxygen-free
aqueous KOH (2.5 mL, 5.00 mmol) was added with a syringe in a
single portion. The reaction solution was heated to 70 °C and stirred
for 15 min. After addition of 2 M oxygen-free aqueous HCl (2.5 mL,
5.00 mmol) in a single portion, all volatiles were removed under
reduced pressure. The precipitate was dissolved in diethyl ether (30
mL) and filtered through a layer of Celite (5 cm). Subsequent removal
of the solvent under reduced pressure gave 3 as an orange solid. Yield:
805 mg (4.00 mmol, 97% based on ferrocenylacetate).
C5H4).13C{1H} NMR (CDCl3, δ): 15.9 (d, 3JC,P = 7.4 Hz, CH3), 60.4
3
2
(d, JC,P = 3.5 Hz, o-C5H4), 62.8 (s, m-C5H4), 64.9 (d, JC,P = 5.7 Hz,
CH2), 69.5 (s, C5H5), 117.5 (d, JC,P = 4.7 Hz, C5H4−O).31P{1H}
2
NMR (CDCl3, δ): 63.8. HRMS (ESI-TOF, m/z): calcd for
C14H19FePSO3 354.0136, found 354.0170 [M]+.
Synthesis of O,O-Diethyl-O-ferrocenylphosphite−Borane
(7). Ferrocenol (3; 728 mg, 3.60 mmol) was dissolved in CH2Cl2
(30 mL), cooled to −30 °C, and treated with NEt3 (0.55 mL, 3.96
mmol) in a single portion. After 5 min, chlorodiethylphosphite (0.57
mL, 4.5 mmol) was added with a syringe and the solution was stirred
for 12 h. Borane−tetrahydrofuran (4.00 mL, 3.95 mmol) was added,
and stirring was continued for 12 h. After removal of all volatiles, the
residue was collected in CH2Cl2 (30 mL) and washed with water (100
mL). The organic layer was dried over MgSO4, and all volatiles were
removed under reduced pressure. Purification was realized by column
chromatography (column size 3 × 16 cm, silica) using a 1/1 (v/v)
hexane/toluene mixture as the eluent. Product 7 (Rf = 0.39) was
obtained as an orange oil. Yield: 910 mg (2.70 mmol, 76% based on
Synthesis of O,O-Diethyl-O-ferrocenylphosphate (4). Ferro-
cenol (3; 1.00 g, 4.1 mmol) was dissolved in CH2Cl2 (30 mL). This
solution was cooled to −30 °C, and NEt3 (0.63 mL, 4.5 mmol) was
added. After 5 min, O,O-diethylchlorophosphate (0.65 mL, 4.5 mmol)
was added in a single portion with a syringe and the reaction solution
was stirred overnight at ambient temperature. After removal of all
volatiles, the residue was collected in CH2Cl2 (30 mL) and washed
with water (100 mL). The organic layer was dried over MgSO4, and all
volatiles were removed under reduced pressure. Column chromatog-
raphy (column size 3.5 × 14.5 cm, alumina) using CH2Cl2 as the
eluent afforded 4 as an orange oil. Yield: 1.032 g (3.05 mmol, 90%
based on 3). Anal. Calcd for C14H19FeO4P (338.12): C, 49.73; H,
5.66. Found: C, 49.86; H, 5.79. IR data (NaCl, ν/cm−1): 3098 w, 2986
m, 2932 w, 2909 w, 2871 w, 1793 w, 1711 w, 1647 w, 1460 s, 1412 w,
1394 m, 1373 m, 1278 s, 1241 m, 1166 m, 1106 m, 1065 w, 1033 s,
959 s, 887 s, 820 s, 757 m, 640 m. 1H NMR (CDCl3, δ): 1.36 (td, 3JH,H
3). 1H NMR (C6D6, δ): 1.06 (t, 3JH,H = 7.1 Hz, 6H, CH3), 3.92−4.03
3+4
(m, 4H, CH2), 3.72 (pt,
J
= 2.0 Hz, 2H, m-C5H4), 4.22 (s, 5H,
H,H
C5H5), 4.46 (pt, 3+4JH,H = 2.0, 2H, o-C5H4). 13C{1H} NMR (C6D6, δ):
16.1 (d, 3JC,P = 5.5 Hz, CH3), 60.8 (d, 3JC,P = 2.8 Hz, o-C5H4), 63.1 (s,
m-C5H4), 63.4 (d, 2JC,P = 3.1 Hz, CH2), 70.0 (s, C5H5), 117.7 (d, 2JC,P
= 4.3 Hz, C5H4−O). 11B{1H} NMR (C6D6, δ): −42.7 (d, JB,P = 92
1
Hz). 31P{1H} NMR (C6D6, δ): 128.2 (q, 1JP,B = 92 Hz). HRMS (ESI-
TOF, m/z): calcd for C14H22BFeO3P − BH3 322.0416, found
322.0403 [M − BH3]+.
4
3+4
= 7.0 Hz, JH,P = 0.9 Hz, 6H, CH3), 3.88 (pt,
J
= 1.9 Hz, 2H,
H,H
C5H4), 4.13−4.21 (m, 4H, CH2), 4.25 (s, 5H, C5H5), 4.39 (pt, 3+4JH,H
Synthesis of O-Ferrocenyl-O,O-diphenylphosphate (8). Fer-
rocenol (3; 1.080 g, 5.3 mmol) was dissolved in CH2Cl2 (30 mL),
cooled to −30 °C, and treated with NEt3 (0.81 mL, 5.8 mmol) in a
single portion. After 5 min, O,O-diphenylchlorophosphate (1.2 mL,
5.9 mmol) was added with a syringe and the solution was stirred
overnight at ambient temperature. After removal of all volatiles the
residue was collected in CH2Cl2 (30 mL) and washed with water (100
mL). The organic layer was dried over MgSO4, and all volatiles were
removed under reduced pressure. Column chromatography (column
size 4 × 18 cm, alumina) using CH2Cl2 as the eluent afforded 8 as an
orange solid. Yield: 1.45 g (3.3 mmol, 62% based on 3). Anal. Calcd
for C22H19FeO4P (434.04): C, 60.86; H, 4.41. Found: C, 60.86; H,
4.29. Mp: 67 °C. 1H NMR (CDCl3, δ): 3.91 (pt, 3+4JH,H = 2.0 Hz, 2H,
m-C5H4), 4.22 (s, 5H, C5H5), 4.44 (pt, 3+4JH,H = 1.9 Hz, 2H, o-C5H4),
= 1.9 Hz, 2H, C5H4).13C{1H} NMR (CDCl3, δ): 16.1 (d, JC,P = 6.9
3
Hz, CH3), 59.6 (d, JC,P = 4.1 Hz, C5H4), 62.7 (s, C5H4), 64.3 (d, 2JC,P
2
= 6.2 Hz, 2C, CH2), 69.5 (s, C5H5), 117.7 (d, JC,P = 4.8 Hz,
C5H4−O). 31P{1H} NMR (CDCl3, δ): −5.4. HRMS (ESI-TOF, m/z):
calcd for C14H19FeO4P 338.0365, found 338.0367 [M]+.
Synthesis of 1,1′-Bis(O,O-diethylphosphato)ferrocene (5).
1,1′-Ferrocenediol 11 was prepared in accordance with the method for
ferrocenol8,15,33 using 1,1′-diacetoxyferrocene15 (655 mg, 2.2 mmol)
and KOH (2.5 mL, 4.8 mmol) followed by HCl (2.5 mL, 4.8 mmol)
addition. The resulting orange solid was subsequently treated with
NEt3 (0.60 mL, 4.8 mmol) and chlorodiethylphosphate (0.73 mL, 4.8
mmol) in CH2Cl2 at −30 °C. The reaction mixture was warmed to
room temperature and stirred for 12 h. After removal of all volatiles
the residue was collected in CH2Cl2 (30 mL) and washed with water
(100 mL). The organic layer was dried over MgSO4, and all volatiles
were removed under reduced pressure. Purification was realized by
column chromatography (column size 3 × 10 cm, silica) using a 3/1
(v/v) CH2Cl2/ethyl acetate mixture as the eluent. Product 5 was
obtained as an orange oil. Yield: 635 mg (1.30 mmol, 60% based on
3
7.18−7.27 (m, 6H, o,p-Ph), 7.36 (t, JH,H = 7.9 Hz, 4H, m-Ph).
13C{1H} NMR (CDCl3, δ): 59.8 (d, JC,P = 3.8 Hz, o-C5H4), 62.9 (s,
3
m-C5H4), 69.6 (s, C5H5), 117.9 (d, 2JC,P = 5.4 Hz, C5H4−O), 120.1 (d,
3JC,P = 5.3 Hz, 2 Hz, o-Ph), 125.5 (s, p-Ph), 129.8 (s, m-Ph), 150.5 (d,
2JC,P = 7.4 Hz, Ph−O). 31P{1H} NMR (CDCl3, δ): −16.9. HRMS
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(ESI-TOF, m/z): calcd for C22H19FeO4P 434.0365, found 434.0362
[M]+.
753 m. 1H NMR (C6D6, δ): 1.11 (t, 3JH,H = 7.1 Hz, 3H, CH3), 1.17 (t,
3
3JH,H = 7.1 Hz, 3H, CH3), 3.25 (s, 3H, OCH3), 3.71 (dd, JH,H = 2.7
Synthesis of O-Ferrocenyldiphenylphosphinate (9). Ferroce-
nol (3; 830 mg, 4.1 mmol) was dissolved in CH2Cl2 (30 mL), cooled
to −30 °C, and treated with NEt3 (0.63 mL, 4.5 mmol) in a single
portion. After 5 min, chlorodiphenylphosphane (0.83 mL, 4.5 mmol)
was added in a single portion with a syringe and the solution was
stirred overnight at ambient temperature. Oxidation was realized by
adding a H2O2 solution (0.40 mL, ω = 35%, 4.5 mmol), whereupon
the reaction mixture turned slightly darker. After removal of all
volatiles, the residue was collected in CH2Cl2 (30 mL) and washed
with water (100 mL). The organic layer was dried over MgSO4, and all
volatiles were removed under reduced pressure. Column chromatog-
raphy (column size 4 × 18 cm, silica) using a 4/1 (v/v) CH2Cl2/ethyl
acetate mixture as the eluent afforded 9 as a yellow solid. Yield: 1.41 g
Hz, 1H, m-OCH3), 3.76 (m, 1H, o-OCH3), 4.07 (m, 2H, CH2), 4.15
(m, 2H, CH2), 4.30 (s, 5H, C5H5), 4.36 (m, 1H, o-P(O)). 13C{1H}
NMR (C6D6, δ): 16.6 (m, CH3), 55.4 (d, 3JC,P = 11 Hz, o-OCH3), 57.8
1
(s, OCH3), 59.2 (d, JC,P = 213.7 Hz, C−P), 61.6 (m, CH2), 63.8 (d,
2
3JC,P = 13.7 Hz, m-OCH3), 67.7 (d, JC,P = 12.8 Hz, o-P(O)), 70.4 (s,
2
C5H5), 129.0 (d, JC,P = 10.3 Hz, C−OCH3). 31P{1H} NMR (C6D6,
δ): 36.4. HRMS (ESI-TOF, m/z): calcd for C15H21FeO4P 352.0521,
found 352.0602 [M]+. HPLC (t): 19.6, 20.6.
Synthesis of O,O-Diethyl(2-methoxyferrocenyl)-
thiaphosphonate (13). An O,O-diethyl-O-ferrocenylthiophosphate
solution (6; 250 mg, 0.71 mmol) in 10 mL of tetrahydrofuran was
treated with sBuLi (0.65 mL, 0.85 mmol) at −60 °C. The mixture was
stirred for 4 h between −30 and −20 °C, and iodomethane (0.1 mL,
1.6 mmol) was added in a single portion. Additional stirring for 18 h
and removal of all volatiles afforded a residue, which was chromato-
graphed (column size 3.5 × 6 cm, silica). First, unreacted 6 (46%) was
eluted with a 3/1 (v/v) toluene/hexane mixture. Afterward, the eluent
was changed to pure toluene and the product 13 (Rf = 0.35) was
obtained as an orange oil. Yield: 130 mg (0.35 mmol, 49% based on
1
(3.5 mmol, 85% based on 3). H NMR (CDCl3, δ): 3.80 (s, 2H, m-
C5H4), 4.18 (s, 5H, C5H5), 4.30 (s, 2H, o-C5H4), 7.46 (td, 3JH,H = 7.4
Hz, 3JH,P = 3.6 Hz, 4H, m-Ph), 7.54 (t, 3JH,H = 6.9 Hz, 2H, p-Ph), 7.85
2
3
(dd, JH,P = 12.4 Hz, JH,H = 7.3 Hz, 4H, o-Ph). 13C{1H} NMR
(CDCl3, δ): 60.3 (d, 3JC,P = 3.7 Hz, o-C5H4), 62.7 (s, m-C5H4), 69.5 (s,
2
3
C5H5), 117.5 (d, JC,P = 6.7 Hz, C5H4−O), 128.5 (d, JC,P = 13.1 Hz,
1
1
3
m-Ph), 130.7 (s, Ph−P (HMBC); 132.8 (C6D6) (d, JC,P = 130.0 Hz,
6). H NMR (CDCl3, δ): 1.30 (t, JH,H = 7.1 Hz, 3H, CH3), 1.39 (t,
3JH,H = 7.1 Hz, 3H, CH3), 3.70 (s, 3H, OCH3), 4.03 (m, 1H, C5H3),
4.09−4.37 (m, 11H, CH2, C5H5, C5H3). 13C{1H} NMR (CDCl3, δ):
Ph−P)),35 131.8 (d, 2JC,P = 10.2 Hz, o-Ph), 132.3 (d, 4JC,P = 2.7 Hz, p-
Ph). 31P{1H} NMR (CDCl3, δ): 30.1. HRMS (ESI-TOF, m/z): calcd
for C22H19FeO2P 402.0467, found 402.0465 [M]+.
3
3
16.1 (d, JC,P = 7.9 Hz, CH3), 16.2 (d, JC,P = 7.9 Hz, CH3), 55.3 (d,
2
Synthesis of O-Ferrocenyldiphenylthiaphosphinate (10).
Ferrocenol (3; 828 mg, 4.1 mmol) was dissolved in CH2Cl2 (30
mL), cooled to −30 °C, and treated with NEt3 (0.63 mL, 4.5 mmol) in
a single portion. After 5 min, chlorodiphenylphosphane (0.83 mL, 4.5
mmol) was added with a syringe and the solution was stirred overnight
at ambient temperature. Sulfur (160 mg, 4.9 mmol) was added, and
the mixture was stirred for an additional 10 min. After removal of all
volatiles, the residue was collected in CH2Cl2 (30 mL) and washed
with water (100 mL). The organic layer was dried over MgSO4, and all
volatiles were removed under reduced pressure. Purification was
realized by column chromatography (column size 3 × 10 cm, alumina)
using first hexane to elute the excess sulfur and then changing to
CH2Cl2 to elute the title compound as a yellow solid. Yield: 1.65 g (3.9
mmol, 95% based on 10). Anal. Calcd for C22H19FeOPS (418.27): C,
JC,P = 10.1 Hz, C5H3), 58.2 (s, OCH3), 62.1 (d, JC,P = 6.4 Hz, CH2),
62.6 (d, 2JC,P = 5.7 Hz, CH2), 63.4 (d, JC,P = 14.1 Hz, C5H3), 64.6 (d,
1JC,P = 174.6 Hz, C5H3−P), 67.7 (d, JC,P = 15.7 Hz, C5H3), 70.2 (s,
C5H5), 127.7 (d, JC,P = 9.0 Hz, C−OCH3). 31P{1H} NMR (CDCl3,
2
δ): 89.6. HRMS (ESI-TOF, m/z): calcd for C15H21FeO3PS 368.0293,
found 368.0310 [M]+.
Synthesis of O,O-Diethyl(2-methoxyferrocenyl)-
phosphonite−Borane (14). LDA was prepared by treating
n
diisopropylamine (0.42 mL, 2.98 mmol) with BuLi (1.20 mL, 3.0
mmol) in tetrahydrofuran (10 mL) at −60 °C. After the mixture was
stirred for 10 min, 7 (500 mg, 1.49 mmol) in tetrahydrofuran (2 mL)
was added with a syringe in a single portion. Stirring was continued for
4 h between −30 and −20 °C, while the solution turned dark. The
reaction was stopped by adding iodomethane (0.30 mL, 4.8 mmol) in
a single portion. The reaction mixture was warmed to room
temperature. After removal of all volatiles the residue was collected
in CH2Cl2 (30 mL) and washed with water (100 mL). The organic
layer was dried over MgSO4, and all volatiles were removed under
reduced pressure. Purification by column chromatography (column
size 2 × 16 cm, silica) using a 2/1 (v/v) hexane/toluene mixture as the
eluent afforded first unreacted 7 (31%) and second 14 as an orange oil.
1
63.17; H, 4.58. Found: C, 63.03; H, 4.71. H NMR (CDCl3, δ): 3.82
3+4
(pt,
J
J
= 2.0 Hz, 2H, m-C5H4), 4.20 (s, 5H, C5H5), 4.24 (pt,
H,H
3+4
= 1.8 Hz, 2H, o-C5H4), 7.44−7.50 (m, 4H, o-Ph), 7.50−7.56
H,H
(m, 2H, p-Ph), 7.88−7.96 (m, 4H, m-Ph). 13C{1H} NMR (CDCl3, δ):
3
61.1 (d, JC,P = 3.9 Hz, o-C5H4), 62.8 (s, m-C5H4), 69.5 (s, C5H5),
117.4 (d, 2JC,P = 5.6 Hz, C5H4−O), 128.4 (d, JC,P = 13.4 Hz, Ph), 131.4
(d, JC,P = 11.2 Hz, Ph), 132.0 (d, 4JC,P = 2.8 Hz, p-Ph), 134.2 (d, 1JC,P
=
110.3 Hz, Ph−P). 31P{1H} NMR (CDCl3, δ): 81.5. Mp: 147−149 °C.
Crystal Data for 10: C22H19FeOPS, M = 418.25, monoclinic, P21/c,
λ = 0.71073 Å, a = 10.6166(6) Å, b = 30.5540(17) Å, c = 11.5573(7)
Å, β = 97.308(6)°, V = 3718.5(4) Å3, Z = 8, ρcalcd =1.494 Mg m−3, μ =
1.017 mm−1, T = 110 K, θ range 2.87−26.00°, 17774 reflections
collected, 7148 independent reflections (Rint =0.0389), R1 = 0.0436,
wR2 = 0.1031 (I > 2σ(I)).
1
Yield: 190 mg (0.55 mmol, 37% based on 7). H NMR (CDCl3, δ):
3
3
1.29 (t, JH,H = 7.1 Hz, 3H, CH3), 1.33 (t, JH,H = 7.1 Hz, 3H, CH3),
3.69 (s, 3H, OCH3), 3.99−4.07 (m, 2H, CH2), 4.08−4.10 (m, 1H,
C5H3), 4.11−4.16 (m, 2H, CH2), 4.23−4.24 (m, 1H, C5H3), 4.26−
4.27 (m, 1H, C5H3), 4.32 (s, 5H, C5H5). 13C{1H} NMR (CDCl3, δ):
3
16.5 (d, JC,P = 5.8 Hz, CH3), 55.3 (d, JC,P = 6.5 Hz, C5H3), 58.2 (s,
OCH3), 60.1 (d, 1JC,P = 90.1 Hz, C−P), 62.6 (d, 2JC,P = 5.5 Hz, CH2),
2
Synthesis of Diethyl(2-methoxyferrocenyl)phosphonate
(12). LDA was prepared by treating diisopropylamine (1.25 mL, 8.9
mmol) with nBuLi (3.6 mL, 9.0 mmol) in tetrahydrofuran (20 mL) at
−60 °C. After the mixture was stirred for 10 min at −60 °C, phosphate
4 (1.5 g, 4.4 mmol) was added dropwise. The yellow solution was
stirred for 4 h between −30 and −15 °C and the color changed from
orange to red. The reaction was stopped by adding Me2SO4 (1.3 mL,
13.7 mmol) in a single portion. The mixture was warmed to room
temperature and subsequently heated to 50 °C for 1 h to complete the
methylation. After removal of all volatiles, the residue was collected in
CH2Cl2 (30 mL) and washed with water (100 mL). The organic layer
was dried over MgSO4, and all volatiles were removed under reduced
pressure. Purification by column chromatography (column size 2 × 8
cm, alumina) using ethyl acetate as the eluent afforded 12 as an orange
oil. Yield: 1.46 g (4.14 mmol, 94% based on 4). IR data (NaCl, ν/
cm−1): 3095 m, 2980 s, 2931 w, 2905 w, 2865 w, 1639 m, 1482 s, 1412
s, 1388 w, 1340 m, 1254 s, 1168 m, 1106 s, 1051 s, 1029 s, 964 s, 801 s,
62.8 (d, JC,P = 4.9 Hz, CH2), 64.2 (d, JC,P = 10.0 Hz, C5H3), 70.2 (s,
C5H5), 128.7 (d, 2JC,P = 6.2 Hz, C−OCH3). 11B{1H} NMR (C6D6, δ):
−40.8 (d, 1JB,P = 89 Hz). 31P{1H} NMR (CDCl3, δ): 135.4 (q, 1JP,B
=
89 Hz). HRMS (ESI-TOF, m/z): calcd for C15H24BFeO3P+H
350.0903, found 350.0856 [M + H]+.
Synthesis of Bis(2-hydroxyphenyl)-O-ferrocenylphosphi-
nate (15). LDA was prepared by treating diisopropylamine (0.98
mL, 7.07 mmol) with nBuLi (2.75 mL, 6.90 mmol) in tetrahydrofuran
(10 mL) at −60 °C. After the mixture was stirred for 10 min, 8 (500
mg, 1.15 mmol) was added in a single portion. The solution was
stirred for 5 h between −60 and −40 °C, while the solution turned
dark. The reaction was stopped by adding iodomethane (0.43 mL, 1.6
mmol) in a single portion. The reaction mixture was allowed to warm
to room temperature. After removal of all volatiles the residue was
collected in CH2Cl2 (30 mL) and washed with water (100 mL). The
organic layer was dried over MgSO4, and all volatiles were removed
under reduced pressure. Purification by column chromatography
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(column size 3 × 18 cm, silica) using a 3/1 (v/v) CH2Cl2/ethyl
acetate mixture as the eluent afforded 15 as an orange oil. Yield: 40 mg
(0.5 mL, 3.6 mmol) with nBuLi (1.45 mL, 3.6 mmol) in
tetrahydrofuran (20 mL) at −60 °C. After the mixture was stirred
for 10 min at this temperature, phosphate 4 (600 mg, 1.8 mmol) was
added dropwise. The solution was stirred for 4 h between −30 and
−15 °C, during which the color changed from orange to red. The
reaction was stopped by adding O,O-diethylchlorophosphate (0.75
mL, 5.2 mmol) in a single portion. The reaction mixture was warmed
to room temperature. After removal of all volatiles the residue was
collected in CH2Cl2 (30 mL) and washed with water (100 mL). The
organic layer was dried over MgSO4, and all volatiles were removed
under reduced pressure. Purification by column chromatography
(column size 3 × 8 cm, silica) using a 9/1 (v/v) ethyl acetate/
methanol mixture as the eluent afforded 19 as an orange oil. Yield: 290
mg (0.6 mmol, 33% based on 4). 1H NMR (CDCl3, δ): 1.33 (td, 3JH,H
= 7.1 Hz, 4JH,P = 0.9 Hz, 3H, CH3), 1.34 (t, 3JH,H = 7.0 Hz, 3H, CH3),
1.38 (t, 3JH,H = 7.1 Hz, 3H, CH3), 1.43 (td, 3JH,H = 7.1 Hz, 4JH,P = 1.1
Hz, 3H, CH3), 4.09−4.33 (m, 10H, CH2, C5H3), 4.39 (s, 5H, C5H5),
4.79 (ddd, JH,P = 2.3 Hz, JH,H = 2.3 Hz, JH,H = 1.5 Hz, 2H C5H3).
13C{1H} NMR (CDCl3, δ): 15.8−16.0 (m, CH3), 16.2−16.3 (m,
(0.10 mmol, 8% based on 8). 1H NMR (CDCl3, δ): 3.85 (pt, 3+4JH,H
=
1.9 Hz, 2H, C5H4), 4.22 (s, 5H, C5H5), 4.29 (pt, 3+4JH,H = 1.9 Hz, 2H,
C5H4), 6.92−6.98 (m, 4H, Ph), 7.42−7.47 (m, 3H, Ph), 7.48 (dd, JH,H
= 7.8 Hz, JH,H = 1.6 Hz, 1H, Ph), 9.86 (s, 2H, OH). 13C{1H} NMR
(CDCl3, δ): 60.0 (d, JC,P = 3.9 Hz, C5H4), 63.1 (s, C5H4), 69.7
1
2
(C5H5), 111.1 (d, JC,P = 139.9 Hz, Ph−P), 117.1 (d, JC,P = 6.9 Hz,
C5H4−O), 118.6 (d, JC,P = 9.4 Hz), 119.9 (d, JC,P = 12.8 Hz), 131.6 (d,
2
JC,P = 8.0 Hz), 135.6 (d, JC,P = 1.8 Hz), 162.1 (d, JC,P = 5.9 Hz, C−
OH). 31P{1H} NMR (CDCl3, δ): 42.3. HRMS (ESI-TOF, m/z): calcd
for C22H19FeO4P 434.0365, found 434.0364 [M]+.
Synthesis of (2-Methoxyferrocenyl)diphenylphosphane
Oxide (16). LDA was prepared by treating diisopropylamine (0.33
mL, 2.35 mmol) with nBuLi (0.92 mL, 2.30 mmol) in tetrahydrofuran
(10 mL) at −60 °C. After the mixture was stirred for 10 min,
compound 9 (500 mg, 1.24 mmol) was added in a single portion. The
solution was stirred for 4 h between −30 and −20 °C, while the
reaction solution turned dark. The reaction was stopped by adding
iodomethane (0.30 mL, 4.8 mmol) in a single portion. The reaction
mixture was warmed to room temperature. After removal of all
volatiles the residue was collected in CH2Cl2 (30 mL) and washed
with water (100 mL). The organic layer was dried over MgSO4, and all
volatiles were removed under reduced pressure. Purification by column
chromatography (column size 3 × 14 cm, silica) using a 2/1 (v/v)
CH2Cl2/ethyl acetate mixture as the eluent afforded 16 as an orange
CH3), 58.1 (dd, 1JC,P = 208.7 Hz, 3JC,P = 7.1 Hz, C−P), 61.6 (d, 2JC,P
=
2
5.7 Hz, CH2), 61.8 (d, JC,P = 5.7 Hz, CH2), 62.3 (d, JC,P = 10.2 Hz,
2
2
C5H3), 64.4 (d, JC,P = 6.4 Hz, CH2), 64.5 (d, JC,P = 6.4 Hz, CH2),
65.0 (d, JC,P = 13.7 Hz, C5H3), 67.2 (d, JC,P = C5H3), 71.1 (s, C5H5),
2
2
118.3 (dd, JC,P = 9.1 Hz, JC,P = 4.5 Hz, C−O).31P{1H} NMR
(CDCl3, δ): −6.1 (s, O−P(O)(OEt)2), 22.2 (C−P(O)(OEt)2).
HRMS (ESI-TOF, m/z): calcd for C18H28FeO7P2 497.0552, found
497.0635 [M]+.
1
oil. Yield: 45 mg (0.10 mmol, 8% based on 9). H NMR (CDCl3, δ):
3.58 (s, 3H, OCH3), 4.03−4.05 (m, 1H, C5H3), 4.08 (dd, JH,P = 4.6
Hz, JH,H = 2.4 Hz, 1H, C5H3), 4.20 (s, 5H, C5H5), 4.28 (dd, JH,P = 3.6
Hz, JH,H = 1.9 Hz, 1H, C5H3), 7.40 (td, JH,H = 7.4 Hz, J = 2.7 Hz, 2H,
Ph), 7.42−7.53 (m, 4H, Ph), 7.63−7.68 (m, 2H, Ph), 7.84−7.90 (m,
Synthesis of 1,3-Bis(O,O-diethylphosphonato)-2-methoxy-
ferrocene (20). LDA was prepared by treating diisopropylamine
(0.11 mL, 0.78 mmol) with nBuLi (0.31 mL, 0.75 mmol) in
tetrahydrofuran (10 mL) at −60 °C. After the mixture was stirred
for 10 min at this temperature, 19 (183 mg, 0.39 mmol) was added in
a single portion. The solution was stirred for 4 h between −30 and
−20 °C, while the solution turned dark. The reaction was stopped by
adding iodomethane (0.1 mL, 1.6 mmol) in a single portion. The
reaction mixture was warmed to room temperature. After removal of
all volatiles the residue was collected in CH2Cl2 (30 mL) and purified
by column chromatography (column size 2 × 15 cm, silica) using a 9/
1 (v/v) ethyl acetate/methanol mixture as the eluent, which afforded
2H, Ph). 13C{1H} NMR (CDCl3, δ): 55.5 (d, JC,P = 8.0 Hz, C5H3),
1
58.1 (s, OCH3), 62.4 (d, JC,P = 116.1 Hz, C5H3−P), 63.9 (d, JC,P
=
10.8 Hz, C5H3), 68.3 (d, JC,P = 11.0 Hz, C5H3), 69.8 (s, C5H5), 127.9−
128.1 (m, Ph), 128.4−128.6 (m, C−OCH3), 131.3−131.4 (m, Ph),
131.9 (d, JC,P = 10.0 Hz, Ph), 133.6−135.0 (m, P−Ph). 31P{1H} NMR
(CDCl3, δ): 28.3. HRMS (ESI-TOF, m/z): calcd for C23H21FePO2
416.0623, found 416.0658 [M]+.
Synthesis of sec-Butyldiphenylphosphine Sulfide (18). O-
Ferrocenyldiphenylthiaphosphinate (10; 620 mg, 1.48 mmol) was
dissolved in tetrahydrofuran (10 mL) and cooled to −60 °C. After
dropwise addition of sBuLi (1.80 mL, 2.37 mmol) the reaction mixture
was stirred for 4 h at −40 °C and the reaction subsequently stopped by
adding iodomethane (0.15 mL, 2.37 mmol) in a single portion. All
volatiles were removed under reduced pressure, and the residue was
taken up in CH2Cl2 (30 mL) and washed with water (100 mL). After
the organic layer was dried over MgSO4, all volatiles were removed
under reduced pressure and purified by column chromatography
(column size 3.5 × 11 cm, silica). Ferrocenyl methyl ether (86%) was
eluted using a 1/1 (v/v) hexane/toluene mixture, followed by 18 using
pure toluene as eluent. Yield: 280 mg (1.01 mmol, 68% based on 10).
Anal. Calcd for C16H19PS (274.36): C, 70.04; H, 6.98. Found: C,
1
20 as an orange oil. Yield: 40 mg (0.08 mmol, 21% based on 19). H
3
3
NMR (CDCl3, δ): 1.35 (t, JH,H = 7.0 Hz, 3H, CH3), 1.38 (t, JH,H
=
7.0 Hz, 3H, CH3), 3.89 (s, 3H, OCH3), 4.13−4.26 (m, 8H, CH2), 4.43
3
(t, JH,P = 2.55 Hz, 2H, C5H2), 4.49 (s, 5H, C5H5). 13C{1H} NMR
2
(CDCl3, δ): 16.4−16.5 (m, CH3), 62.1 (t, JC,P = 5.5 Hz, CH2), 63.1
(dd, 1JC,P = 211.9 Hz, 3JC,P = 10.7 Hz, C−P), 64.0 (s, OCH3), 69.4 (t,
2
2JC,P = 13.6 Hz, C5H2), 128.7 (t, JC,P = 63.2 Hz, C−OCH3).31P{1H}
NMR (CDCl3, δ): 22.1. HRMS (ESI-TOF, m/z): calcd for
C19H30P2O7 + Na 511.0709, found 511.0747 [M + Na]+.
General Procedure for Suzuki−Miyaura Cross-Coupling
Reactions. A glass vessel (4 mL size) was charged with
[Pd2(dba)3] (0.25 mol %), compound 1 (Pd/P ratio 1/2 (n/n)),
boronic acid (1.5 mmol), powdered K3PO4·xH2O (690 mg, 3.0
mmol), the appropriate aryl halide (1.0 mmol), and dry toluene (3
mL). The vessel was purged with argon and closed. The reaction
mixture was heated at 70 °C, except as otherwise noted, with vigorous
stirring for 24 h. After it was cooled to room temperature, the reaction
mixture was diluted with water (25 mL) and extracted with diethyl
ether (3 × 25 mL). The combined organic extracts were filtered
through alumina and concentrated under reduced pressure. The
obtained crude material was purified by flash chromatography on silica
(hexane/diethyl ether mixtures).
1
3
70.15; H, 6.93. Mp: 93 °C. H NMR (CDCl3, δ): 0.97 (t, JH,H = 7.4
2
3
Hz, 3H, CH2CH3), 1.15 (dq, JH,P = 19.4 Hz, JH,H = 6.8 Hz, 3H,
CHCH3), 1.43−1.67 (m, 2H, CH2), 2.56−2.66 (m, 1H, CH), 7.41−
7.51 (m, 6H, m,p-Ph), 7.89−7.97 (m, 4H, o-Ph). 13C{1H} NMR
(CDCl3, δ): 12.0 (s, CHCH3), 12.1 (d, 3JC,P = 15.2 Hz, CH2CH3), 22.6
1
(s, CH2), 34.8 (d, JC,P = 55.7 Hz, CH), 128.4−128.6 (m, m-Ph),
1
131.18−131.25 (m, p-Ph), 131.3−131.4 (m, o-Ph), 131.9 (d, JC,P
=
1
76.4 Hz, Ph−P), 132.1 (d, JC,P = 76.3 Hz, Ph−P). 31P{1H} NMR
(CDCl3, δ): 52.8. HRMS (ESI-TOF, m/z): calcd for C16H19PS+H
275.1018, found 275.1005 [M+H]+.
Further spectroscopic details for 25a−h are given in the Supporting
Information.
Crystal Data for 18: C H PS, M = 274.34, triclinic, P1, λ =
̅
16 19
0.71073 Å, a = 9.1715(7) Å, b = 11.9513(8) Å, c = 13.8640(10) Å, α =
86.089(6)°, β = 88.870(6)°, γ = 76.849(6) °, V = 1476.34(18) Å3, Z =
4, ρcalcd = 1.234 Mg m−3, μ = 0.308 mm−1, T = 110.00(10) K, θ range
3.00−25.00°, 9738 reflections collected, 5158 independent reflections
(Rint =0.0700), R1 = 0.0907, wR2 = 0.2353 (I > 2σ(I)).
ASSOCIATED CONTENT
■
S
* Supporting Information
Text and figures giving full experimental and spectroscopic
details for all compounds and X-ray crystallographic data for 1,
10, and 18. This material is available free of charge via the
Synthesis of (2-(Diethoxyphosphoryl)ferrocenyl)-O,O-dieth-
ylphosphate (19). LDA was prepared by treating diisopropylamine
2106
dx.doi.org/10.1021/om5002827 | Organometallics 2014, 33, 2099−2108

Organometallics
Article
G.; Lehmann, C. W.; Butenschon, H. Adv. Synth. Catal. 2010, 352,
1345−1355.
(9) Melvin, L. S. Tetrahedron Lett. 1981, 22, 3375−3376.
(10) Taylor, C. M.; Watson, A. J. Curr. Org. Chem. 2004, 8, 623−626.
(11) (a) Hatano, M.; Miyamoto, T.; Ishihara, K. J. Org. Chem. 2006,
71, 6474−6484. (b) Hatano, M.; Ishihara, K. Chem. Rec. 2008, 8, 143−
155.
̈
Internet at http://pubs.acs.org. Crystallographic data are also
available from the Cambridge Crystallographic Database as file
numbers CCDC 978226 (1), 978248 (10), and 978227 (18).
AUTHOR INFORMATION
■
Corresponding Author
(12) Jayasundera, K. P.; Watson, A. J.; Taylor, C. M. Tetrahedron Lett.
*H.L.: e-mail, heinrich.lang@chemie.tu-chemnitz.de; phone,
+49 (0)371-531-21210; fax, +49 (0)371-531-21219.
2005, 46, 4311−4313.
(13) (a) Coriani, S.; Haaland, A.; Helgaker, T.; Jørgensen, P.
ChemPhysChem 2006, 7, 245−249. (b) Tamagawa, K.; Ilijima, T.;
Kimura, M. J. Mol. Struct. 1976, 30, 243−253.
Notes
The authors declare no competing financial interest.
(14) In similarity to other organolithium compounds, lithiated
ferrocenes underwent a faster ether cleavage than the less electron rich
phenyl derivatives. For details, see: (a) Stanetty, P.; Koller, H.;
Mihovilovic, M. J. Org. Chem. 1992, 57, 6833−6837. (b) Schlosser, M.
Organometallics in Organic Synthesis; Wiley: New York, 1994; p 172.
(c) Elschenbroich, C. Organometallchemie, 6th ed.; Teubner:
Wiesbaden, Germany, 2008, p 46.
ACKNOWLEDGMENTS
■
This work was supported by the Fonds der Chemischen
Industrie. M.K. and D.S. thank the Fonds der Chemischen
Industrie for Chemiefonds fellowships. The authors thank Dr.
Alexander Hildebrandt for his help in the preparation of this
paper.
(15) Nesmayanov, A. N.; Ssasonowa, W. A.; Drosd, V. N. Chem. Ber.
1960, 96, 2717−2729.
REFERENCES
(16) Herberhold, M.; Brendel, H.-D. J. Organomet. Chem. 1993, 458,
205−209.
■
(1) See, for example: (a) Togni, A., Hayashi, T., Eds. Ferrocenes:
homogeneous catalysis, organic synthesis, material science; VCH:
Weinheim, Germany, 1995. (b) Kagan, H. B.; Diter, P.; Gref, A.;
(17) (a) Legrand, O.; Brunel, J. M.; Constantieux, T.; Buono, G.
Chem. Eur. J. 1998, 4, 1061−1067. (b) Dhawan, N.; Redmore, D.
Tetrahedron Lett. 1984, 49, 4018−4021. (c) Ngono, C. J.;
Constantieux, T.; Buono, G. Eur. J. Org. Chem. 2006, 1499−1507.
̀
Guillaneux, D.; Masson-Szymczak, A.; Rebiere, F.; Riant, O.; Samuel,
O.; Taudien, S. Pure Appl. Chem. 1996, 68, 29−36. (c) Richards, C. J.;
Locke, A. J. Tetrahedron: Asymmetry 1998, 9, 2377−2407.
(d) Atkinson, R. C. J.; Gibson, V. C.; Long, N. J. Chem. Soc. Rev.
2004, 33, 313−328. (e) Stepnicka, P., Ed. Ferrocenes: ligands, materials
and biomolecules; Wiley: Chichester, 2008. (f) Togni, A.; Bieler, N.;
(d) Berchel, M.; Salaun, J.-Y.; Couthion-Gourves
̀
, H.; Haelters, J.-P.;
̈
Jaffres
̀
, P.-A. Dalton Trans. 2010, 39, 11314−11316. (e) Li, S.; Wang,
G. Phosphorus, Sulfur Silicon Relat. Elem. 1991, 61, 119−129.
(18) (a) Price, D.; Simpkins, N. S. Tetrahedron Lett. 1995, 36, 6135−
6136. (b) Nishibayashi, Y.; Arikawa, Y.; Ohe, K.; Uemura, S. J. Org.
Chem. 1996, 61, 1172−1174. (c) Dayaker, G.; Tilly, D.; Chevallier, F.;
Hilmersson, G.; Gros, P. C.; Monging, F. Eur. J. Org. Chem. 2012,
6051−6057.
Burckhardt, U.; Kollner, C.; Pioda, G.; Schneider, R.; Schnyder, A.
̈
Pure Appl. Chem. 1999, 71, 1531−1537. (g) Dai, L.-X.; Hou, X.-L.;
Deng, W.-P.; You, S.-L.; Zhou, Y.-G. Pure Appl. Chem. 1999, 71,
1401−1405. (h) Dai, L.-X.; Tu, T.; You, S.-L.; Deng, W.-P.; Hou, X.-L.
Acc. Chem. Res. 2003, 36, 659−667. (i) Colacot, T. J. Chem. Rev. 2003,
103, 3101−3118. (j) Barbaro, P.; Bianchini, C.; Giambastiani, G.;
Parisel, S. L. Coord. Chem. Rev. 2004, 248, 2131−2150. (k) Hou, X. L.;
You, S. L.; Tu, T.; Deng, W. P.; Wu, X. W.; Li, M.; Yuan, K.; Zhang, T.
(19) Please note that this value refers to a NMR measurement of
compound 12 dissolved in CDCl3. The spectroscopic data given in the
Supporting Information refer to a measurement of a C6D6 solution.
(20) Oms, O.; Maurel, F.; Carre, F.; Le Bideau, J.; Vioux, A.;
́
Leclercq, D. J. Organomet. Chem. 2004, 689, 2654−2661.
́ ́
Z.; Dai, L. X. Top. Catal. 2005, 35, 87−103. (l) Gomez Arrayas, R.;
Adrio, J.; Carretero, J. C. Angew. Chem., Int. Ed. 2006, 45, 7674−7715.
(m) Dai, L.-X., Hou, X.-L., Eds. Chiral Ferrocenes in Asymmetric
Catalysis; Wiley-VCH: Weinheim, Germany, 2010. (n) Peters, R.;
Fischer, D. F.; Jautze, S. Top. Organomet. Chem. 2011, 33, 139−175.
(2) For an introduction to ferrocene chemistry, see: Astruc, D.
Metallocenes and Sandwich Complexes in Organometallic Chemistry and
Catalysis; Springer-Verlag: Berlin, 2007; pp 251−288.
(21) (a) McKenna, C. E.; Higa, M. T.; Cheung, N. H.; McKenna, M.-
C. Tetrahedron Lett. 1977, 18, 155−158. (b) McKenna, C.;
Schmidhauser, J. J. Chem. Soc., Chem. Commun. 1979, 739. (c) Gloede,
J.; Weigt, E.; Gros, H. J. Prakt. Chem. 1980, 322, 327−328.
(d) Hanessian, S.; Cantin, L.-D.; Roy, S.; Andreotti, D.; Gomtsyan,
A. Tetrahedron Lett. 1997, 38, 1103−1106. (e) Blackburn, G. M.;
Ingleson, D. J. Chem. Soc., Perkin Trans. 1 1980, 1150−1153. (f) Goff,
J. D.; Huffstetler, P. P.; Miles, W. C.; Pothayee, N.; Reinholz, C. M.;
Ball, S.; Davis, R. M.; Riffle, J. S. Chem. Mater. 2009, 21, 4784−4795.
(3) For a recent review, see: Schaarschmidt, D.; Lang, H.
Organometallics 2013, 32, 5668−5704.
(4) (a) Schaarschmidt, D.; Lang, H. Eur. J. Inorg. Chem. 2010, 4811−
4821. (b) Schaarschmidt, D.; Lang, H. DE Patent 10 2010 001 364,
2010. (c) Schaarschmidt, D.; Lang, H. ACS Catal. 2011, 1, 411−416.
(5) For other examples of the ortho-directed lithiation of ferrocenyl
ethers, see: (a) Epton, R.; Marr, G.; Rogers, G. K. J. Organomet. Chem.
1976, 110, C42−C44. (b) Epton, R.; Marr, G.; Rogers, G. K. J.
́
(g) Oms, O.; Maurel, F.; Carre, F.; Bideau, J.; Vioux, A.; Leclercq, D. J.
Organomet. Chem. 2004, 689, 2654−2661. (h) Harnden, M. R.;
Serafinowska, H. T. Bioorg. Med. Chem. Lett. 1996, 6, 2215−2218.
(22) Bhongle, N. N.; Notter, R. H.; Turcotte, J. G. Synth. Commun.
1987, 17, 1071−1076. Sørensen, M. D.; Blæhr, L. K. A.; Christensen,
M. K.; Høyer, T.; Latini, S.; Hjarnaac, P.-J. V.; Bjorkling, F. Bioorg.
̈
Organomet. Chem. 1978, 150, 93−100. (c) Werner, G.; Butenschon, H.
Organometallics 2013, 32, 5798−5809.
̈
Med. Chem. 2003, 11, 5461−5484.
(23) Maier, L. Phosphorus, Sulfur Silicon Relat. Elem. 1990, 47, 465−
470.
(24) Kazul’kin, D. N.; Ryabov, A. N.; Izmer, V. V.; Churakov, A. V.;
Beletskaya, I. P.; Burns, C. J.; Voskoboynikov, A. Z. Organometallics
2005, 24, 3024−3035.
(25) Andrieu, J.; Azouri, M. Inorg. Chim. Acta 2007, 360, 131−135.
(26) Sasamori, T.; Hori, A.; Kaneko, Y.; Tokitoh, N. New J. Chem.
(6) For examples of the ortho-directed metalation of ferrocenyl-
phosphine oxides, see: (a) Sawamura, M.; Yamauchi, A.; Takegawa, T.;
Ito, Y. J. Chem. Soc., Chem. Commun. 1991, 874−875. (b) Baillie, C.;
Zhang, L.; Xiao, J. J. Org. Chem. 2004, 69, 7779−7782.
(7) Bolm and co-workers observed for the copper(I)-mediated
coupling of an ortho-substituted iodoferrocene with pyrazole or
methyl phenyl sulfoximine solely the deiodinated product, which was
2010, 34, 1560−1564. Hiney, R. M.; Higham, L. J.; Muller-Bunz, H.;
̈
attributed to steric crowding and further coordination of copper. For
̈
Gilheany, D. G. Angew. Chem., Int. Ed. 2006, 45, 7248−7251; Angew.
Chem. 2006, 118, 7406−7409.
details, see: Ozcu
̧
bukcu
̧
, S.; Schmitt, E.; Leifert, A.; Bolm, C. Synthesis
2007, 389−392.
(27) Denis, J. M.; Forintos, H.; Szelkeb, H.; Keglevich, G.
Tetrahedron Lett. 2002, 43, 5569−5571.
(8) (a) Bonini, B. F.; Femoni, C.; Fochi, M.; Gulea, M.; Massonc, S.;
Riccia, A. Tetrahedron: Asymmetry 2005, 16, 3003−3010. (b) Werner,
2107
dx.doi.org/10.1021/om5002827 | Organometallics 2014, 33, 2099−2108

Organometallics
Article
(28) (a) Herd, O.; Hessler, A.; Hingst, M.; Tepper, M.; Stelzer, O. J.
Organomet. Chem. 1996, 522, 69−76. (b) Herd, O.; Hessler, A.;
Hingst, M.; Machnitzki, P.; Tepper, M.; Stelzer, O. Catal. Today 1998,
42, 413−420. (c) Machnitzki, P.; Nickel, T.; Stelzer, O.; Landgrafe, C.
Eur. J. Inorg. Chem. 1998, 1029−1034. (d) Brauer, D. J.; Hingst, M.;
Kottsieper, K. W.; Liek, Ch.; Nickel, T.; Tepper, M.; Stelzer, O.;
Sheldrick, W. S. J. Organomet. Chem. 2002, 645, 14−26. (e) Hesser, A.;
Stelzer, O. J. Org. Chem. 1997, 62, 2362−2369. (f) Kumobayashi, H.;
Miura, T.; Sayo, N.; Saito, T.; Zhang, X. Synlett 2001, 1055−1064.
(g) Birdsall, D. J.; Hope, E. G.; Suart, A. M.; Chen, N.; Hu, Y.; Xiao, J.
Tetrahedron Lett. 2001, 42, 8551−8553. (h) Kraatz, H.-B.; Pletsch, A.
Tetrahydron: Asymmetry 2000, 11, 1617−1621.
̈
(29) (a) Herrmann, W. A.; Broßmer, C.; Ofele, K.; Beller, M.;
Fischer, H. J. Organomet. Chem. 1995, 491, C1−C4. (b) Herrmann, W.
̈
A.; Broßmer, C.; Ofele, K.; Beller, M.; Fischer, H. J. Mol. Catal. A
1995, 103, 133−146. (c) Kong, K.-C.; Cheng, C.-H. J. Am. Chem. Soc.
1991, 113, 6313−6315. (d) Goodson, F. E.; Wallow, T. I.; Novak, B.
M. J. Am. Chem. Soc. 1997, 119, 12441−12453. (e) Grushin, V. V.
Organometallics 2000, 19, 1888−1900. (f) Macgregor, S. A. Chem. Soc.
Rev. 2007, 36, 67−76.
(30) The P,CCp bond cleavage proceeds through a P-aryl/aryl
exchange at a metal complex of the type [Pd(I)(Ph)(Fc′PPh2)2] (Fc′
= Fe(η5-C5H3-2-OMe)(η5-C5H5)). Its formation can be prevented by
the use of a chelating ligand suppressing ligand scrambling as well as
the absence of phenyl iodide after complete conversion of the primary
and intermediately formed secondary phosphines.
(31) These results are comparable with those of P,O-substituted
ferrocenes described before4 and exceed the performance of other
(ferrocene-based) phosphines regarding reaction temperature and
palladium concentration. See, for example: (a) Terao, Y.; Wakui, H.;
Nomoto, M.; Satoh, T.; Miura, M.; Nomura, M. J. Org. Chem. 2003,
68, 5236−5243. (b) Su, W.; Urgaonkar, S.; McLaughlin, P. A.;
Verkade, J. G. J. Am. Chem. Soc. 2004, 126, 16433−16439. (c) Vinci,
D.; Martins, N.; Saidi, O.; Basca, J.; Brigas, A.; Xiao, J. Can. J. Chem.
2009, 87, 171−175. (d) Tu, T.; Sun, Z.; Fang, W.; Xu, M.; Zhou, Y.
Org. Lett. 2012, 14, 4250−4253.
(32) Sheldrick, G. M. Acta Crystallogr., Sect. A 1990, 46, 467.
Sheldrick, G. M. SHELXL-97: Program for Crystal Structure Refinement;
Universitat Gottingen, Gottingen, Germany, 1997
̈
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(33) Schaarschmidt, D.; Lang, H. Organometallics 2010, 29, 4196−
4198.
(34) The C−PH2 carbon was not detected in the 13C or in the
1H,13C-HMBC spectra.
(35) In the 13C{1H} NMR spectrum of a concentrated sample
solution in CDCl3 the signal of this carbon atom could not be
1
observed. However, the corresponding H,13C-HMBC spectrum was
measured, from which the resonance was received. The spectrum of an
additional measurement in C6D6 exhibited the resonance of this
carbon atom as well as the C,P-coupling constant.
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dx.doi.org/10.1021/om5002827 | Organometallics 2014, 33, 2099−2108