1,2-Disubstituted aryl-based ferrocenyl phosphines

Article abstract of DOI:10.1021/om400117n

Ferrocenylaryl-or ferrocenylheteroarylphosphines [Fe{1-PPh ₂(spacer)-2-NMe₂CH₂C₅H ₃}(C₅H₅)] (spacer = 1,4-phenylene (rac-6), 1,3-phenylene (rac-7), 4,4′-biphenylene (rac-8), 2,5-thienylene (rac-9)) were prepared in a facile two-step sequence starting with Negishi cross-coupling between N,N-dimethylaminomethylferrocene and aryl halide phosphine oxides, Br-spacer-P(O)Ph₂, followed by reduction with trichlorosilane. All products were characterized spectroscopically (¹H, ¹³C, and ³¹P NMR, MS, FTIR), and rac-6, the corresponding phosphine oxide rac-2, and rac-9 were also characterized by X-ray crystallography. Furthermore, the redox properties of rac-2-9 were studied by cyclic voltammetry.

Full text of DOI:10.1021/om400117n

Article
pubs.acs.org/Organometallics
1,2-Disubstituted Aryl-Based Ferrocenyl Phosphines
Martyna Madalska, Peter Lonnecke, and Evamarie Hey-Hawkins*
̈
Faculty of Chemistry and Mineralogy, Universitat Leipzig, Johannisallee 29, 04103 Leipzig, Germany
̈
S
* Supporting Information
ABSTRACT: Ferrocenylaryl- or ferrocenylheteroarylphos-
phines [Fe{1-PPh2(spacer)-2-NMe2CH2C5H3}(C5H5)]
(spacer = 1,4-phenylene (rac-6), 1,3-phenylene (rac-7), 4,4′-
biphenylene (rac-8), 2,5-thienylene (rac-9)) were prepared in a
facile two-step sequence starting with Negishi cross-coupling
between N,N-dimethylaminomethylferrocene and aryl halide
phosphine oxides, Br-spacer-P(O)Ph2, followed by reduction
with trichlorosilane. All products were characterized spec-
troscopically (1H, 13C, and 31P NMR, MS, FTIR), and rac-6,
the corresponding phosphine oxide rac-2, and rac-9 were also
characterized by X-ray crystallography. Furthermore, the redox properties of rac-2−9 were studied by cyclic voltammetry.
subsequent introduction of the diphenylphosphine substituent
by electrophilic substitution.7d,8a Our approach starts from
N,N-dimethylaminomethylferrocene (1)9 and aryl halide
phosphine oxides (Br-spacer-P(O)Ph2; spacer = 1,4-phenylene,
1,3-phenylene, 4,4′-biphenylene, 2,5-thienylene), which were
prepared according to known methodologies,10 and yields
ferrocenylaryl- (rac-6−8) and ferrocenylheteroarylphosphines
(rac-9) in a straightforward two-step sequence (Scheme 1).
The first step, formation of the new bond between two sp2-
hybridized carbon atoms, was achieved by palladium(0)-
catalyzed Negishi cross-coupling.11 None of the reagents are
sensitive toward the rather basic reaction conditions, and since
the Negishi reaction can be carried out with precursors
obtained in situ, the number of synthetic steps can be
lowered.12 Thus, ferrocenyl phosphine oxides rac-2−5 were
obtained as orange solids in moderate yields (35−49%);
unconverted N,N-dimethylaminomethylferrocene (1) can be
recovered from the reaction mixture. These results are in
agreement with related Negishi coupling reactions of various
ferrocenyl derivatives.13 Unfortunately, it is difficult to identify
which step of the reaction sequence is the limiting one. The
lithiation reaction can be excluded, since the lithioferrocene
derivative reacts with chlorodiphenylphosphine almost quanti-
tatively. This suggests that either the transmetalation reaction
or the C−C coupling process is inefficient.
INTRODUCTION
■
Since the first reports on ferrocene in 1951−1952 by Kealey
and Pauson,1 interest in ferrocene chemistry has remained
intense and has placed this compound among the most
important structural motifs in organometallic chemistry,
materials science, and especially catalysis.2 A significant feature
of ferrocene is its ability to undergo electrophilic substitution.
In lithiation reactions it behaves as an electron-rich compound,
leading to facile formation of lithioferrocene derivatives which
can efficiently react with a broad range of electrophiles.3 Ortho-
directing groups such as N,N-dimethylamino on the ferrocene
framework direct the lithium atom to the ortho position and
thus facilitate the preparation of 1,2-disubstituted ferrocenes.4
This opens the possibility to synthesize many novel compounds
and is the reason for the significant role of ferrocene as a
backbone or substituent in ancillary ligands: for example,
phosphine ligands.5 Most of these ligands are based on a direct
phosphorus−carbon (Cp) bond. There are only a few examples
of tertiary phosphines with alkylene spacers6 and even fewer
based on arylferrocene fragments,7 despite the fact that they
show promising results in rhodium-catalyzed reactions. For
example, a new family of chiral ligands with a phenyl-
ferrocenylethyl backbone, the so-called Walphos ligands
[Fe{1-PR2CHMe-2-(2-PPh2C6H4)C5H3}(C5H5)] (R = Cy,
3,5-(CF3)2-C6H3, Ph, 3,5-Me2-4-OMe-C6H2), was developed
by Weissensteiner et al.7d,8
Chemical shifts of rac-2−5 in the 31P{1H} NMR spectra are
typical for phosphine oxides. Signals of rac-2−4 are in the same
range as that of triphenylphosphine oxide (in CDCl3, δ 29.8
ppm);14 that is, the ferrocenyl moiety is too distant from the
phosphorus atom to influence its chemical shift. The 31P{1H}
NMR signal of rac-5 is observed at δ 21.8 ppm due to the
shielding effect of the thienylene spacer. As expected, the
Our research on new classes of ferrocenyl phosphines has
focused on aryl-based ferrocenyl derivatives with different
spacers between the ferrocene framework and the phosphorus
atom. Here, the synthesis and characterization of ferrocenyl
phosphines with phenylene, biphenylene, and thienylene
spacers are reported.
RESULTS AND DISCUSSION
The protocol developed by Weissensteiner et al. requires the
coupling reaction of ferrocenylamine and dibromobenzene and
■
Received: February 8, 2013
© XXXX American Chemical Society
A
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Scheme 1. Two-Step Synthesis of 1,2-Disubstituted Ferrocenyl Phosphines
Figure 1. Molecular structures of rac-2 (left) and rac-6 (right); only one independent molecule and only one enantiomer (R enantiomer) is shown.
Thermal ellipsoids are drawn at the 50% probability level for rac-2 and the 30% probability level for rac-6. Hydrogen atoms (other than H15) are
omitted for clarity.
chemical shift is similar to that of (5-bromo-2-thienyl)-
diphenylphosphine oxide (δ 19.4 ppm).10d
Crystals of compound rac-2 were twinned and contain two
independent molecules with the same configuration that differ
slightly from each other in the asymmetric unit. In the
asymmetric unit of compound rac-6, two independent
molecules (both enantiomers) were found. The molecular
structure of rac-2 is remarkably similar to that of rac-6.
In both molecules, the planes of the cyclopentadienyl rings
are almost parallel to each other (tilt angles are 1.0(2) and
1.7(2)° for rac-2 and 3.7(2) (S) and 1.2(2)° (R) for the two
independent molecules of rac-6). The dihedral angles between
the plane of the substituted cyclopentadienyl ring and the plane
of the C6H4 spacer are 34.2(2) and 34.8(2)° in rac-2 and
32.1(2) (S) and 38.5(2)° (R) for the two independent
molecules of rac-6, and the phenylene spacer is turned toward
the amine substituent. The shortest distance between the
corresponding atoms H15 and N1 is 254.6 pm (or N2−H46 =
258.8 pm in the second independent molecule) (rac-2) and
236.6 (S) and 241.0 pm (R) (rac-6), which is smaller than the
sum of the van der Waals radii of these elements (264 pm).16
The molecular structure of rac-9 (Figure 2) exhibits a similar
tilt angle between the planes of the cyclopentadienyl rings
(1.9(2)°), but due to less steric hindrance the dihedral angle
between the plane of the substituted cyclopentadienyl ring and
the plane of the thienylene spacer (26.2(2)°) is smaller than the
angles observed in rac-2 and rac-6 and the distance between
H15 and N1 is 264.9 pm.
Reduction of phosphine oxides rac-2−5 with trichlorosilane
in the presence of triethylamine afforded phosphines rac-6−9
(Scheme 1) in almost quantitative yield.7e,15 Refluxing
overnight in toluene was sufficient to complete the reduction
process. As expected, reduction of rac-2−5 to phosphines rac-
6−9 was accompanied by an upfield shift in the 31P{1H} NMR
spectra (−5.1 to −6.0 ppm for rac-6 to rac-8 and to −19.3 ppm
for rac-9).
The molecular structures of compounds rac-2 and rac-6
(Figure 1) and rac-9 (Figure 2) were determined by single-
crystal X-ray crystallography (Table 1). The compounds
crystallize in the centrosymmetric space groups P1 (rac-2 and
̅
rac-6) and P21/c (rac-9) with four molecules in the unit cell.
Apparently, an energetically favored arrangement with a
conjugated π system is prevented due to steric hindrance also in
solution. Thus, the 13C{1H} NMR spectrum of rac-2 in C6D6
showed signals for nine nonequivalent carbon atoms (as
Figure 2. Molecular structure of rac-9 with thermal ellipsoids at the
30% probability level. Hydrogen atoms (other than H3 and H15) are
omitted for clarity. Only one enantiomer (S) is shown.
B
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
Table 1. Selected Bond Lengths (pm) and Angles (deg) for
rac-2, rac-6, and rac-9
Table 2. Oxidation (Epa (V)) and Reduction (Epc (V))
Potentials of rac-2−5 Measured in 0.1 M (Bu4N)BF4/
CH2Cl2 with a Scan Rate of dE/dt = 100 mV/s
a
rac-2
rac-6
rac-9
compd Epa(1) Epa(2) Epa(3) Epa(4) Epa(5) Epc(1) Epc(2)
Bond Lengths
molecule 1
rac-2
rac-3
rac-4
rac-5
0.716
0.982
0.602
0.746
1.281
1.471
0.734
0.896
0.485
0.540
0.566
0.495
C2−C14
P1−C17
P1−C26
P1−C20
P1−O1
147.1(5)
178.8(3)
180.2(4)
180.3(4)
148.7(2)
146.9(7)
182.2(5)
183.9(5)
183.2(5)
145.8(2)
180.8(2)
1.937
1.150
1.329
1.579
1.799
2.370
Table 3. Oxidation (Epa (V)) and Reduction (Epc (V))
Potentials of rac-6−9 Measured in 0.1 M (Bu4N)BF4/
CH2Cl2 with a Scan Rate of dE/dt = 100 mV/s
P1−C24
P1−C18
184.0(2)
183.9(2)
molecule 2
compd
Epa(1)
Epa(2)
Epa(3)
Epc(1)
Epc(2)
Epc(3)
C33−C45
P2−C48
P2−C51
P2−C57
P2−O2
147.4(5)
180.7(4)
181.4(4)
180.9(4)
148.5(2)
147.7(6)
182.9(5)
183.7(5)
183.6(5)
rac-6
rac-7
rac-8
rac-9
0.539
0.757
0.654
0.557
0.672
0.861
0.965
0.821
1.194
0.374
0.529
0.503
0.456
0.607a)
0.706
0.859
0.661
1.219
1.084
Bond Angles
molecule 1
The presence of electron-withdrawing substituents in the
ferrocenyl framework shifts the oxidation potential Epa(1)
corresponding to FeII/FeIII toward higher values in comparison
with unsubstituted ferrocene (Epa = 0.496 V). Moreover,
additional Epa processes could be observed.
C17−P1−C26
C17−P1−C20
C20−P1−C26
O1−P1−C20
O1−P1−C26
O1−P1−C17
C17−P1−C24
C17−P1−C18
C18−P1−C24
108.5(2)
107.9(2)
106.1(2)
111.7(2)
110.9(2)
111.5(2)
102.0(2)
100.7(2)
102.7(2)
The differences between the Epa(1) values of PIII and PV
ferrocene derivatives are caused by the less pronounced
electron-accepting properties of the −PPh2 group in compar-
ison to −P(O)Ph2.18
102.6(7)
98.8(7)
102.3(7)
Different redox mechanisms are expected to take place in the
redox reactions of ferrocenyl phosphine and phosphine oxide
derivatives. The oxidation and reduction processes observed for
rac-2−9 are in good agreement with those reported for 1,1′-
(diphenylphosphino)ferrocenecarboxylic acid and its PV
analogue, 1,1′-(diphenylphosphine oxide)ferrocenecarboxylic
acid.19 The first oxidation process is the oxidation of FeII. An
intramolecular electron transfer from the phosphorus(III) atom
via the cyclopentadienyl ligand to the generated FeIII ion results
in a FeII−PIV species, which is immediately stabilized by a
further one-electron oxidation of phosphorus, yielding
phosphine oxide. This process can occur either by an
electrochemical path or as chemical oxidation caused by traces
of oxygen or water.20
In the cyclic voltammogram of rac-6, Epa(1) = 0.539 V,
Epa(2) = 0.679 V, and Epa(3) = 1.194 V are observed. According
to the previously described mechanisms, the first value (Epa(1))
corresponds to the oxidation of FeII. Epa(2) can be assigned to
the oxidation of FeII in the in situ generated ferrocenyl
phosphine oxide. Podlaha et al. observed only two oxidation
steps.19 However, in that case, the phosphine group had no
neighboring group on the cyclopentadienyl ring. This suggests
that additional oxidation processes take place due to a
subsequent reaction in which the methylene(N,N-dimethyla-
mino) group is involved.
molecule 2
C48−P2−C57
C48−P2−C51
C51−P2−C57
C57−P2−O2
C51−P2−O2
C48−P2−O2
108.8(2)
108.1(2)
105.8(2)
110.9(2)
111.9(2)
111.2(2)
103.6(2)
99.9(2)
105.3(2)
a
Given for both independent molecules in the asymmetric unit for rac-
2 and rac-6.
doublets due to P−C coupling), while in the case of free
rotation around the C2−C14 bond (Figure 1, left), only eight
signals (four for the phenylene spacer and four for the phenyl
substituents) should be observed in the range between 120 and
150 ppm. As can be concluded from the values of the coupling
constants, three of them are carbon atoms bonded directly to
1
the phosphorus atom (131.2 (d, JCP = 104.9 Hz), 134.4 (d,
1JCP = 102.6 Hz), 134.5 ppm (d, 1JCP = 102.6 Hz)); that is, the
two phenyl rings (C20−C25 and C26−C31) are non-
equivalent. When rac-2 was dissolved in CDCl3, even 12
separate signals were observed in the 13C{1H} NMR spectrum
in the aromatic region. In this case, five signals, one of which
consists of two overlapping signals, can be assigned to carbon
1
atoms directly bonded to phosphorus (129.3 (d, JCP = 105.9
1
1
Hz), 129.4 (d, JCP = 105.9 Hz), 132.9 (d, JCP = 112.8 Hz),
132.8 (2 overlapping signals, d, 1JCP = 95.0 Hz), 132.7 ppm (d,
1JCP = 112.8 Hz)). As rac-2 is a planar-chiral compound,
hindered rotation of the phenylene−diphenylphosphine oxide
unit (C17−P1 bond) leads to axial chirality, and thus two
diastereoisomers of rac-2 are observed.
The redox properties of rac-2−9 were studied by cyclic
voltammetry, and the oxidation (Epa) and reduction potentials
(Epc) are given in Tables 2 and 3.17
CONCLUSION
■
Aryl- or heteroaryl-based ferrocene derivatives rac-6−9 were
prepared by a facile two-step synthetic route. We have shown
that a palladium-catalyzed Negishi cross-coupling reaction can
be employed for the first step, formation of a C−C bond
between the ferrocenyl framework and the aryl phosphine
oxide. The resulting phosphine oxides were successfully
reduced with a mixture of trichlorosilane and triethylamine.
C
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
3
(s), 72.6 (s), 82.1 (s), 86.3 (s), 128.2 (d, JCP = 11.9 Hz), 129.0 (d,
This synthetic approach should also be applicable for other
derivatives as well as for diastereomerically pure ligands starting
from Ugi’s amine, (S)- or (R)-[Fe(NMe2CHMeC5H3)-
(C5H5)].21 Compounds rac-6−9 combine the advantages of
aryl-based phosphines with the properties of the ferrocenyl
moiety and should therefore be suitable ligands in catalytic
processes. These studies are now under way.
2JCP = 12.2 Hz), 131.2 (d, JCP = 2.2 Hz), 131.2 (d, JCP = 104.9 Hz),
131.9 (d, JCP = 9.8 Hz), 132.2 (d, JCP = 9.6 Hz), 134.4 (d, JCP
4
1
2
3
1
=
1
4
102.6 Hz), 134.5 (d, JCP = 102.6 Hz), 143.6 (d, JCP = 3.1 Hz) ppm.
13C{1H} NMR (CDCl3, 100 MHz): δ 45.0 (s), 58.2 (s), 68.2 (s), 70.6
3
(s), 71.0 (s), 72.9 (s), 82.5 (s), 86.2 (s), 128.5 (d, JCP = 12.2 Hz),
128.9 (d, 3JCP = 12.2 Hz), 129.3 (d, 1JCP = 105.9 Hz), 129.4 (d, 1JCP
=
105.9 Hz), 131.8 (d, 2JCP = 9.7 Hz), 131.8 (d, 4JCP = 2.2 Hz), 132.1 (d,
3JCP = 9.9 Hz), 132.7 (d, 1JCP = 112.8 Hz), 132.8 (2 overlapped signals
d, 1JCP = 95.0 Hz), 132.9 (d, 1JCP = 112.8 Hz), 143.9 (d, 4JCP = 2.7 Hz)
ppm. EI MS: m/z (relative intensity, %) 519 (100) [M]+, 504 (14),
475 (90), 462 (7), 438 (12), 409 (20), 355 (28), 257 (9), 238 (27),
229 (21), 201 (23), 183 (20), 152 (40), 133 (13), 121 (72), 77 (28),
58 (64). Anal. Calcd for C31H30FeNOP: C, 71.69; H, 5.82; N, 2.70.
Found: C, 72.03; H, 6.21; N, 2.66.
EXPERIMENTAL SECTION
■
General Considerations. All manipulations were carried out by
standard Schlenk techniques under an atmosphere of dry, high-purity
nitrogen. Toluene, THF, and dichloromethane were dried with an MB
SPS-800 Solvent Purification System and stored over activated 4 Å
molecular sieves. Et3N was distilled from MgSO4. Deuterated solvents
for NMR spectroscopy were purchased from Eurisotop and Chemo-
trade GmbH. CDCl3 was distilled from P2O5 and stored over activated
4 Å molecular sieves. C6D6 was dried with sodium, filtered, and stored
over potassium mirror.
(3-Diphenylphosphine oxide)phenyl-2-N,N-dimethylamino-
methylferrocene (rac-3). rac-3 was obtained by a Negishi coupling
reaction starting from N,N-dimethylaminomethylferrocene (1) and (3-
bromophenyl)diphenylphosphine oxide. The same procedure as in the
synthesis of rac-2 was used. rac-3 was obtained as an orange-red
The compounds N,N-dimethylaminomethylferrocene (1),9
[PdCl2(PPh3)2],22 (4-bromophenyl)diphenylphosphine oxide,10a (3-
bromophenyl)diphenylphosphine oxide,10b (4′-bromobiphenyl-4-yl)-
diphenylphosphine oxide,10c and (5-bromo-2-thienyl)-
diphenylphosphine oxide10d were synthesized according to literature
procedures. Other chemicals were obtained from commercial sources
and used as supplied.
viscous oil (almost solid) in 49% yield.
1H NMR (CDCl3, 400 MHz): δ 2.06 (s, 6H), 3.02 (d, 1H, JHH
12.8 Hz), 3.48 (d, 1H, JHH = 12.8 Hz), 3.87 (s, 5H), 4.20 (s, 1H),
=
2
2
2
4.26 (s, 1H), 4.40 (s, 1H), 7.18−7.05 (m. 7H), 7.36 (t, 1H, JHH
=
2
15.9 Hz), 7.54−7.46 (m, 4H), 7.94 (d, 1H, JHH = 7.7 Hz), 8.01 (d,
1H, JHH = 7.6 Hz) ppm. 31P{1H} NMR (CDCl3, 161 MHz): δ 29.3
2
ppm. 13C{1H} NMR (C6D6, 100 MHz): δ 44.7 (s), 58.1 (s), 67.2 (s),
Spectra were recorded on a Bruker AVANCE DRX 400 NMR
spectrometer at 400.13 (1H NMR), 161.98 (31P NMR), or 100.61
70.2 (s), 70.9 (s), 72.2 (s), 82.3 (s), 87.0 (s), 128.1 (d, overlapped
signals, JCP not determined), 128.3 (d, 2JCP = 11.8 Hz), 129.7 (d, 3JCP
=
1
MHz (13C NMR). TMS was used as an internal standard for the H
4
4
9.9 Hz), 131.3 (d, JCP = 2.5 Hz), 131.3 (d, JCP = 2.8 Hz), 132.2 (d,
NMR spectra, and spectra of other nuclei were referenced to TMS on
the δ scale.23 The signals of the 13C NMR spectra were assigned by
13C{31P} experiments. EI mass spectra were recorded on a ZAB-HSQ-
VG12-520 Analytical Manchester spectrometer or a MASPEC II
spectrometer; ESI mass spectra were recorded on a Bruker-Daltonics
FT-ICR-MS APEX II. FTIR spectra were recorded on a Perkin-Elmer
Spectrum 2000 spectrometer. C, H, N analyses were performed with a
Heraeus VARIO EL Analyzer. Air-sensitive samples were prepared in a
glovebox. Melting points were determined in sealed glass capillaries
under nitrogen and are uncorrected.
3JCP = 9.6 Hz), 133.3 (d, JCP = 10.8 Hz), 133.3 and 134.0 (d, JCP
=103.3 Hz), 134.2 and 134.3 (d, 1JCP = 103.3 Hz), 134.3 and 134.4 (d,
1JCP = 102.6 Hz), 140.0 (d, 2JCP = 12.3 Hz), 140.0 (d, 3JCP = 12.3 Hz)
2
1
ppm. EI MS: m/z (relative intensity, %) 519 (100) [M]+, 504 (23),
476 (73), 409 (20), 355 (14), 243 (19), 238 (38), 199 (38), 152 (20),
133 (9), 121 (38), 77 (10), 58 (34), 43 (11).
(4-Diphenylphosphine oxide)biphenyl-2-N,N-dimethylami-
nomethylferrocene (rac-4). rac-4 was obtained by a Negishi
coupling reaction starting from N,N-dimethylaminomethylferrocene
(1) and (4′-bromobiphenyl-4-yl)diphenylphosphine oxide. The same
procedure as for the synthesis of rac-2 was used. rac-4 was obtained as
an orange-red powder in 43% yield. Mp: 169−172 °C. 1H NMR
(CDCl3, 400 MHz): δ 2.21 (s, 6H), 3.13 (d, 1H, 2JHH = 12.8 Hz), 3.69
(d, 1H, 2JHH = 12.4 Hz), 4.06 (s, 5H), 4.26 (t br, 1H, 3JHH = 2.5 Hz),
4.33 (t br, 1H, 3JHH = 1.6 Hz), 4.53 (t br, 1H, 3JHH = 1.85 Hz), 7.51−
7.47 (m, 4H), 7.58−7.55 (m, 4H), 7.75−7.69 (m, 8H), 7.84−7.82 (m,
2H) ppm. 31P{1H} NMR (CDCl3, 161 MHz): δ 28.9 ppm. 13C{1H}
NMR (CDCl3, 100 MHz): δ 45.1 (s), 58.1 (s), 67.6 (s), 70.1 (s), 72.0
(4-Diphenylphosphine oxide)phenyl-2-N,N-dimethylamino-
n
methylferrocene (rac-2). At −78 °C, 4.9 mL of BuLi in n-hexane
(1.66 M, 8.23 mmol, 1 equiv) was added dropwise to a solution of 2.0
g (8.23 mmol) of N,N-dimethylaminomethylferrocene (1) in 20 mL of
THF. The reaction mixture was stirred overnight at room temperature.
In the next step, 1.94 g of dry ZnCl2 (8.64 mmol, 1.05 equiv) was
added at 0 °C. The obtained orange suspension was then stirred at
room temperature for 4 h.
One equivalent of nBuLi in n-hexane (4.9 mL, 1.66 M, 8.23 mmol)
was added to a suspension of 0.29 g (0.41 mmol, 5 mol %) of
[PdCl2(PPh3)2] in THF. The obtained dark purple solution was added
to the suspension of the ferrocenyl zinc derivative followed by addition
of 2.8 g (8.23 mmol, 1 equiv) of (4-bromophenyl)diphenylphosphine
oxide in 20 mL of THF. The reaction mixture was heated to reflux for
20 h under an inert atmosphere. THF was removed under reduced
pressure. The remaining solid was dissolved in CH2Cl2, water was
added, and the mixture was extracted with CH2Cl2. The organic phase
was dried with MgSO4. The solvent was evaporated under reduced
pressure, and the dark brown crude product was purified by column
chromatography (silica gel, eluent acetone/Et3N 1000/1) to give a
brown oil consisting of rac-2 and N,N-dimethylaminomethylferrocene
(1). Compound 1 was distilled off under reduced pressure (6 × 10−3
mbar) at 140 °C. The remaining brown powder was dissolved in Et2O,
the solution was filtered, and the solvent was evaporated under
reduced pressure to give rac-2 as an orange powder in 47% yield.
Crystals suitable for X-ray diffraction were obtained by recrystallization
from acetone. Mp: 160−163 °C. 1H NMR (CDCl3, 400 MHz): δ 2.16
2
(s), 77.2 (s), 82.3 (s), 87.1 (s), 126.8 (s), 126.8 (d, JCP = 13.1 Hz),
128.5 (d, 2JCP = 12.1 Hz), 129.7 (s), 130.8 and 130.9 (d, JCP = 105.6
1
Hz), 131.9 (d, 4JCP = 2.5 Hz), 132.1 (d, 3JCP = 9.6 Hz), 132.6 (d, 3JCP
=
1
10.4 Hz), 132.8 (d, JCP = 104.7 Hz), 137.2 (s), 139.4 (s), 144.5 (d,
4JCP = 2.7 Hz) ppm. EI MS: m/z (relative intensity, %) 595 (100)
[M]+, 580 (20), 551 (72), 538 (36), 485 (25), 428 (8), 351 (8), 297
(23), 275 (39), 228 (19), 201 (20), 183 (23), 149 (20), 121 (34), 77
(23), 58 (64). Anal. Calcd for C37H34FeNOP: C, 74.63; H, 5.75; N,
2.35. Found: C, 75.13; H, 5.98; N, 2.30.
(5-Diphenylphosphine oxide)thienyl-2-N,N-dimethylamino-
methylferrocene (rac-5). rac-5 was obtained by a Negishi coupling
reaction starting from N,N-dimethylaminomethylferrocene (1) and (5-
bromothienyl)-2-diphenylphosphine oxide. The same procedure as for
the synthesis of rac-2 was used. rac-5 was obtained as an orange-red
powder in 35% yield. Mp: 82−84 °C. 1H NMR (CDCl3, 400 MHz): δ
2.16 (s, 6H), 3.08 (d, 1H, JHH = 12.8 Hz), 3.76 (d, 1H, JHH = 12.4
Hz), 4.04 (s, 5H), 4.26 (t, 1H, 3JHH = 4.9 Hz), 4.32 (s br, 1H), 4.55 (s
br, 1H), 7.21−7.18 (m, 1H), 7.34−7.33 (m, 1H), 7.50−7.47 (m, 4H),
7.56−7.55 (m, 2H), 7.81−7.74 (m, 4H) ppm. 31P{1H} NMR (CDCl3,
161 MHz): δ 21.8 ppm. 13C{1H} NMR (CDCl3, 100 MHz): δ 45.0
(s), 58.0 (s), 67.8 (s), 70.21 (s), 70.7 (s), 72.4 (s), 78.9 (s), 82.8 (s),
2
2
2
2
(s, 6H), 3.07 (d, 1H, JHH = 12.8 Hz), 3.64 (d, 1H, JHH = 12.8 Hz),
4.02 (s, 5H), 4.27 (s, 1H), 4.32 (s, 1H), 4.53 (s, 1H), 7.47−7.85 (m,
14H) ppm. 31P{1H} NMR (CDCl3, 161 MHz): δ 29.4 ppm. 13C{1H}
NMR (C6D6, 100 MHz): δ 44.6 (s), 58.2 (s), 67.5 (s), 70.3 (s), 71.3
2
3
1
126.2 (d, JCP = 12.2 Hz), 128.4 (d, JCP = 11.1 Hz), 130.9 (d, JCP
=
D
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
2
4
113.8 Hz), 131.9 (d, JCP = 10.2 Hz), 132.1 (d, JCP = 2.5 Hz), 133.1
(5-Diphenylphosphino)thienyl-2-N,N-dimethylaminome-
thylferrocene (rac-9). rac-9 was synthesized by using the same
procedure as for the synthesis of rac-6. rac-9 was obtained as an orange
powder in 93% yield. Crystals suitable for X-ray diffraction were
1
3
4
(d, JCP = 109.5 Hz), 137.3 (d, JCP = 10.4 Hz), 152.7 (d, JCP = 5.1
Hz) ppm. EI MS: m/z (relative intensity, %) 525 (100) [M]+, 481
(96), 468 (6), 415 (15), 361 (6), 324 (9), 241 (20), 202 (15), 133 (6),
121 (15), 77 (6), 58 (22). Anal. Calcd for C29H28FeNOPS: C, 66.29;
H, 5.37; N, 2.67. Found: C, 66.54; H, 5.48; N, 2.60.
1
obtained by recrystallization from Et2O. Mp: 39−41 °C. H NMR
(C6D6, 400 MHz): δ 2.10 (s, 6H), 2.84 (d, 1H, 2JHH = 12.4 Hz), 3.77
(d, 1H, 2JHH = 12.4 Hz), 3.86 (s 5H), 3.93 (t, 1H, 3JHH = 4.9 Hz), 4.04
(s, 1H), 4.36 (s, 1H), 7.10−7.04 (m, 6H), 7.26−7.23 (m, 1H), 7.58−
7.52 (m, 5H) ppm. 31P{1H} NMR (C6D6, 161 MHz): δ −19.3 ppm.
13C{1H} NMR (C6D6, 100 MHz): δ 44.6 (s), 58.2 (s), 67.2 (s), 70.1
(4-Diphenylphosphino)phenyl-2-N,N-dimethylaminome-
thylferrocene (rac-6). A 5.3 mL portion (38.5 mmol, 20 equiv) of
Et3N and 3.8 mL (38.5 mmol, 20 equiv) of SiHCl3 were added to a
toluene solution of 1 g (1.92 mmol) of rac-2. The suspension was
heated to reflux overnight under an inert atmosphere. After the
mixture was cooled to room temperature, 10 mL of a NaOH solution
in degassed water (30%) was added and the mixture was stirred at 60
°C for 2 h. The two phases were separated under an inert atmosphere,
and the water phase was extracted twice with dry Et2O. The organic
phase was dried with MgSO4 and filtered, and the solvent was
evaporated under vacuum. The obtained orange wax was purified by
flash column chromatography (eluent acetone with 1 mL of Et3N per
liter) to give rac-6 as an orange solid in 96% yield. Crystals suitable for
X-ray diffraction were obtained by recrystallization from Et2O. Mp:
3
(s), 70.6 (s), 72.0 (s), 80.7 (s), 82.8 (s), 126.7 (d, JCP = 7.1 Hz),
3
128.4 (d, JCP = 6.7 Hz), 128.6 (s), 133.3 (two overlapping doublets,
1JCP = 19.6 Hz and 1JCP =19.7 Hz), 136.2 (d, 2JCP = 27.9 Hz), 136.9 (d,
2
3
1JCP = 25.6 Hz), 138.6 (d, JCP = 9.6 Hz), 138.7 (d, JCP = 9.9 Hz),
150.1 (s) ppm. EI MS: m/z (relative intensity, %) 509 (52) [M]+, 465
(17), 324 (17), 280 (19), 183 (8), 121 (26), 91 (100), 58 (29). Anal.
Calcd for C29H28FeNPS: C, 68.37; H, 5.54; N, 2.75. Found: C, 68.83;
H, 5.90; N, 2.80.
Cyclic Voltammetry Studies. Cyclic voltammetry measurements
were performed with a standard three-electrode cell (volume 10 mL)
on a single-channel SP-50 potentiostat which was coupled with EC-
Lab Software designed by BioLogic Science Instruments. The working
electrode (WE) was a platinum disk (diameter 2 mm) sealed in
Teflon, a platinum wire was used as the reference electrode (RE), and
a platinum plate was used as the counterelectrode (CE). The
voltammograms were recorded in dry CH2Cl2 with (Bu4N)BF4 as
supporting electrolyte. Potentials were calibrated by using ferrocene as
an external standard.
1
69−73 °C. H NMR (C6D6, 400 MHz): δ 2.09 (s, 6H), 2.83 (d, 1H,
2JHH = 12.4 Hz) 3.64 (d, 1H, JHH = 12.8 Hz), 3.85 (s, 5H), 4.03 (t,
2
3
3
1H, JHH = 5.0 Hz), 4.10 (t, 1H, JHH = 3.4 Hz), 4.38 (s, 1H), 7.08−
2
7.05 (m, 6H), 7.52−7.45 (m, 6H), 7.93 (d, 2H, JHH = 7.1 Hz) ppm.
31P{1H} NMR (C6D6, 161 MHz): δ −5.8 ppm. 13C{1H} NMR (C6D6,
100 MHz): δ 44.7 (s), 58.2 (s), 67.2 (s), 70.2 (s), 70.8 (s), 72.3 (s),
4
3
82.1 (s), 87.2 (s), 128.5 (d, JCP = 5.3 Hz), 128.5 (d, JCP = 6.8 Hz),
129.4 (d, JCP = 6.9 Hz), 133.7 (d, JCP = 18.7 Hz), 133.9 (d, JCP
3
2
2
=
2
1
19.7 Hz), 133.9 (d, JCP = 19.7 Hz), 134.8 (d, JCP = 11.5 Hz), 137.9
(d, 1JCP = 12.2 Hz), 138.0 (d, 1JCP = 12.2 Hz), 140.3 (s) ppm. EI MS:
m/z (relative intensity, %) 503 (100) [M]+, 460 (23), 274 (41), 183
(33), 163 (12), 152 (18), 121 (41), 91 (36), 58 (52). Anal. Calcd for
C31H30FeNP: C, 73.96; H, 6.01; N, 2.78. Found: C, 74.25; H, 6.32; N,
3.02.
(3-Diphenylphosphino)phenyl-2-N,N-dimethylaminome-
thylferrocene (rac-7). rac-7 was synthesized by using the same
procedure as for the synthesis of rac-6. rac-7 was obtained as an orange
Table 4. Crystal Data and Structure Refinement Details for
Compounds rac-2, rac-6, and rac-9
rac-2
rac-6
rac-9
formula
fw
C31H30FeNOP
519.38
C31H30FeNP
503.38
C29H28FeNPS
509.40
1
powder in 96% yield. Mp: 59−61 °C. H NMR (C6D6, 400 MHz): δ
T (K)
130(2)
130(2)
130(2)
2
2
2.09 (s, 6H), 2.87 (d, 1H, JHH = 12.8 Hz), 3.61 (d, 1H, JHH = 12.4
Hz), 3.78 (s, 5H), 3.97 (t, 1H, 3JHH = 4.9 Hz), 4.09 (t, 1H, 3JHH = 3.4
Hz), 4.28 (t, 1H, 3JHH = 3.5 Hz), 7.18−7.04 (m, 7H), 7.37 (t, 1H, 2JHH
= 15.5 Hz), 7.54−7.46 (m, 4H), 7.94 (d, 1H, 2JHH = 7.7 Hz), 8.02 (d,
cryst syst
space group
a (pm)
b (pm)
c (pm)
α (deg)
β (deg)
γ (deg)
V (nm3)
Z
triclinic
triclinic
monoclinic
P21/c
P1
̅
P1
̅
1006.63(6)
1494.6(1)
1678.9(1)
96.048(6)
90.550(5)
99.252(5)
2.4783(3)
4
948.42(9)
1285.1(1)
2265.4(2)
81.326(7)
82.564(8)
71.866(9)
2.5840(4)
4
1539.27(2)
1289.96(2)
1288.58(2)
90
1H, JHH = 7.6 Hz) ppm. 31P{1H} NMR (C6D6, 161 MHz): δ −5.1
2
ppm. 13C{1H} NMR (C6D6, 100 MHz): δ 44.7 (s), 58.1 (s), 67.0 (s),
70.1 (s) 70.5 (s), 71.8 (s), 82.4 (s), 87.8 (s), 128.2 (d, 3JCP = 8.0 Hz),
128.5 (d, 3JCP = 7.2 Hz), 128.6 (d, 3JCP = 6.6 Hz), 129.6 (s), 131.7 (d,
102.034(2)
90
2JCP = 22.8 Hz), 133.9 (d, JCP = 19.5 Hz), 134.0 (d, JCP = 19.5 Hz),
2
2
135.00 (d, 1JCP = 16.8 Hz), 137.2 (d, 1JCP = 11.8 Hz), 137.9 (d, 1JCP
=
2.50237(6)
4
12.3 Hz), 138.1 (d, 1JCP = 12.5 Hz), 139.8 (d, 3JCP = 6.2 Hz) ppm. EI
MS: m/z (relative intensity, %) 503 (100) [M]+, 459 (33), 339 (11),
274 (37), 257 (11), 230 (20), 183 (27), 152 (16), 121 (35), 58 (29).
Anal. Calcd for C31H30FeNP: C, 73.96; H, 6.01; N, 2.78. Found: C,
74.21; H, 6.35; N, 2.98.
Dc (Mg m−3
)
1.392
1.294
1.352
μ (mm−1
)
0.698
0.665
0.768
F(000)
cryst size (mm3)
1088
1056
1064
0.23 × 0.15 ×
0.04
0.3 × 0.1 ×
0.05
0.2 × 0.15 × 0.1
(4-Diphenylphosphino)biphenyl-2-N,N-dimethylaminome-
thylferrocene (rac-8). rac-8 was synthesized by using the same
procedure as for the synthesis of rac-6. rac-8 was obtained as an orange
powder in 96% yield. Mp: 123−127 °C. 1H NMR (C6D6, 400 MHz):
δ 2.19 (s, 6H), 2.91 (d, 1H, 2JHH = 12.4 Hz), 3.77 (d, 1H, 2JHH = 12.4
θ range (deg)
ranges of h,k,l
2.78−26.37
3.03−25.03
3.13−30.51
−12 ≤ h ≤ 12
−18 ≤ k ≤ 18
−20 ≤ l ≤ 20
−10 ≤ h ≤ 11 −20 ≤ h ≤ 21
−15 ≤ k ≤ 14 −18 ≤ k ≤ 16
−26 ≤ l ≤ 26 −18 ≤ l ≤ 18
2
Hz), 3.91 (s, 5H), 7.38−7.34 (m, 12H), 7.55 (d, 2H, JHH = 8.4 Hz),
7.60 (d, 2H, 2JHH = 7.5 Hz), 7.79 (d, 2H, 2JHH = 8.4 Hz) ppm. 31P{1H}
NMR (C6D6, 161 MHz): δ −6.0 ppm. 13C{1H} NMR (C6D6, 100
MHz): δ 45.1 (s), 58.1 (s), 67.3 (s), 70.0 (s), 70.1 (s), 71.9 (s), 82.1
(s), 87.4 (s), 126.5 (s), 126.86 (d, 3JCP = 6.9 Hz), 128.5 (d, 3JCP = 7.0
no. of indep rflns
17123 (R(int) = 9116 (R(int) = 7629 (R(int) =
a
0)
0.0629)
0.989
R1 = 0.0684
wR2 = 0.1295 wR2 = 0.0743
R1 = 0.1318 R1 = 0.0530
wR2 = 0.1582 wR2 = 0.0809
0.0326)
1.027
R1 = 0.0365
GOF (F2)
0.935
final R1 (all data)
R1 = 0.0598
wR2 = 0.1132
R1 = 0.1227
wR2 = 0.1259
2
2
Hz), 128.7 (s), 129.6 (s), 133.8 (d, JCP = 19.4 Hz), 134.2 (d, JCP
=
1
1
wR2 (all data)
19.4 Hz), 135.8 (d, JCP = 10.8 Hz), 137.2 (d, JCP = 10.8 Hz), 137.9
(s), 138.6 (s), 141.2 (s) ppm. EI MS: m/z (relative intensity, %) 580
(60) [M]+, 535 (100), 523 (19), 470 (18), 334 (20), 289 (19), 267
(30), 183 (63), 163 (40), 121 (96), 58 (98). Anal. Calcd for
C37H34FeNP: C, 76.69; H, 5.91: N, 2.42. Found: C, 76.38; H, 6.10; N,
2.29.
residual electron
1.036 and
−0.434
0.635 and
−0.407
0.397 and
−0.277
density (e Å−3
)
a
Twinned crystal.
E
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
X-ray Structure Determinations. Suitable crystals were mounted
on a glass needle with perfluoro polyalkyl ether and cooled under a
nitrogen stream. Crystallographic measurements were made with a
Gemini diffractometer (Agilent Technologies). Data were collected by
using monochromated Mo Kα radiation (λ = 71.073 pm). Structure
solution was carried out with SIR92 (for rac-2 and rac-6) and
SHELXS-97 (rac-9).24 Anisotropic refinement of all non-hydrogen
atoms used SHELXL-97.24 All hydrogen atoms of rac-2 and rac-6 were
calculated on idealized positions; for rac-9, all H atoms were located in
difference Fourier maps calculated at the final stage of the structure
refinement. The crystal of rac-2 was found to be twinned (twin law by
rows: −1.00,0.00,0.00; 0.48,1.00,0.19; 0.00,0.00,−1.00). In rac-6, one
cyclopentadienyl ring (C6−C10) was found to be disordered over two
positions (ratio 0.51(1):0.49(1)). ORTEP25 was used for visualization.
Crystal data and details of data collection and refinement are given in
Table 4.
2006, 45, 7674. (c) Colacot, T. J. Chem. Rev. 2003, 103, 3101.
(d) Hayashi, T.; Kumada, M. Acc. Chem. Res. 1982, 15, 395.
(e) Mateus, N.; Routaboul, L.; Daran, J.-C.; Manoury, E. Organomet.
Chem. 2006, 691, 2297. (f) Malacea, R.; Manoury, E.; Routaboul, L.;
Daran, J.-C.; Poli, R.; Dunne, J. P.; Withwood, A. C.; Godard, C.;
Duckett, S. B. Eur. J. Inorg. Chem. 2006, 1803. (g) Routaboul, L.;
Vincendeau, S.; Daran, J.-C.; Manoury, E. Tetrahedron: Asymmetry
2005, 16, 2685. (h) Smaliy, R. V.; Beauperin, M.; Cattey, H.; Meunier,
́
P.; Hierso, J.-C.; Roger, J.; Doucet, H.; Coppel, Y. Organometallics
2009, 28, 3152. (i) Lohan, M.; Milde, B.; Heider, S.; Speck, J. M.;
Krauße, S.; Schaarschmidt, D.; Ruffer, T.; Lang, H. Organometallics
̈
́
2012, 31, 2310. (j) Roy, D.; Mom, S.; Beauperin, M.; Doucet, H.;
Hierso, J.-C. Angew. Chem., Int. Ed. 2010, 49, 6650. (k) Roy, D.; Mom,
S.; Lucas, D.; Cattey, H.; Hierso, J.-C.; Doucet, H. Chem. Eur. J. 2011,
17, 6453. (l) Schaarschmidt, D.; Lang, H. ACS Catal. 2011, 1, 411.
(6) (a) Hoppe, S.; Welchmann, H.; Jurkschat, K.; Neumann, K. J.
Organomet. Chem. 1995, 505, 63. (b) Yamamoto, Y.; Tanase, T.; Mori,
I.; Nakamura, Y. Dalton Trans. 1994, 3191. (c) Hayashi, T.;
Matsumoto, Y.; Morikawa, I.; Ito, Y. Tetrahedron: Asymmetry 1990,
1, 151. (d) Sawamura, M.; Hamashima, H.; Ito, Y. Tetrahedron:
Asymmetry 1991, 2, 593.
ASSOCIATED CONTENT
* Supporting Information
■
S
Text, figures, and CIF files giving detailed assignments of NMR
and MS data and IR spectroscopic data for compounds rac-2−9
and crystallographic data for rac-2, rac-6, and rac-9. This
material is available free of charge via the Internet at http://
pubs.acs.org. CCDC 922458 (rac-2), 922459 (rac-6) and
922460 (rac-9) contain supplementary crystallographic data for
this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.
uk/data_request/cif.
(7) (a) Lemenovskii, D. A.; Makarov, M. V.; Dyadchenko, V. P.;
Bruce, A. E.; Bruce, M. R. M.; Larkin, S. A.; Averkiev, B. B.; Starikova,
Z. A.; Antipin, M. Yu. Russ. Chem. Bull., Int. Ed. 2003, 25, 607.
(b) Tappe, K.; Knochel, P. Tetrahedron: Asymmetry 2004, 15, 91.
(c) Fukuzawa, S.-I.; Yamamoto, M.; Hosaka, M.; Kikuchi, S. Eur. J.
Org. Chem. 2007, 5540. (d) Sturm, T.; Weissensteiner, W.; Spindler, F.
Adv. Synth. Catal. 2003, 345, 160. (e) Stead, R.; Xiao, J. Lett. Org.
Chem. 2004, 1, 148.
(8) (a) Sturm, T.; Xiao, L.; Weissensteiner, W. Chimia 2001, 55, 688.
(b) Nishibayashi, Y.; Segawa, K.; Takada, H.; Ohe, K.; Uemura, S.
Chem. Commun. 1996, 847. (c) Xiao, L.; Mereiter, K.; Weissensteiner,
W.; Widhalm, W. Synthesis 1999, 1354. (d) Nishibayashi, Y.; Takei, I.;
AUTHOR INFORMATION
Notes
The authors declare no competing financial interest.
■
́
Uemura, S.; Hidai, M. Organometallics 1998, 17, 3420. (e) Gerard, S.;
Pressel, Y.; Riant, O. Tetrahedron: Asymmetry 2005, 16, 1889.
(f) Takei, I.; Nishibayashi, Y.; Arikawa, Y.; Uemura, S.; Hidai, M.
Organometallics 1999, 18, 2271.
ACKNOWLEDGMENTS
This work was funded by the European Union and the Free
■
(9) Lindsay, J. K.; Hauser, C. R. J. Org. Chem. 1957, 22, 355.
(10) (a) Dreissig, W.; Pleith, K. Acta Crystallogr. 1967, B27, 1140.
(b) Baldwin, R. A.; Cheng, M. T. J. Org. Chem. 1967, 32, 1572.
(c) Braddock-Wilking, J.; Gao, L.-B.; Rath, N. P. Organometallics 2010,
29, 1612. (d) Leriche, P.; Aillerie, D.; Roquet, S.; Allain, M.; Cravino,
A.; Frere, P.; Roncali, J. Org. Biomol. Chem. 2008, 6, 3202.
̀
(11) King, A. O.; Okukado, N.; Negishi, E.-I. J. Chem. Soc., Chem.
Commun. 1977, 683.
State of Saxony (Europaischer Sozialfonds (ESF) Nachwuchs-
̈
forschergruppe “Katalyse”, doctoral grant for M.M., project
number 080937615). Support from the Graduate School
BuildMoNa (funded by the Deutsche Forschungsgemeinschaft
and the EU COST Action CM0802 PhoSciNet) is gratefully
acknowledged. We thank Chemetall GmbH and BASF SE for
generous donations of chemicals.
́
(12) Kurti, L.; Czako, B. Strategic Applications of Named Reactions in
̈
REFERENCES
organic Synthesis. Background and Detailed Mechanisms; Elsevier:
Amsterdam, 2005.
■
(1) (a) Kealey, T. J.; Pauson, P. L. Nature 1951, 168, 1039.
(b) Fisher, E. O. Z. Naturforsch. 1952, 7b, 377. (c) Wilkinson, G.;
Rosenbaum, M.; Whiting, M. C.; Woodward, R. B. J. Am. Chem. Soc.
1952, 74, 2125. (d) Miller, S. A.; Tebboth, J. A.; Tremaine, J. F. J.
(13) Sturm, T.; Xiao, L.; Weissensteiner, W. Chimia 2001, 55, 688.
(14) Hu, F.-H.; Wang, L.-S.; Cai, S.-F. J. Chem. Eng. Data 2009, 54,
1382.
(15) Tian, F.; Yao, D.; Zhang, Y. J.; Zhang, W. Tetrahedron 2009, 65,
9609.
Chem. Soc. 1952, 632.
̌
(2) (a) Step
̌
nick
̌
a, P. Ferrocene. Ligands, Materials and Biomolecules;
(16) Bondi, A. J. Phys. Chem. 1964, 68, 441.
Wiley: Chichester, U.K., 2008. (b) Hayashi, T.; Kumada, M. Acc.
Chem. Res. 1982, 15, 395. (c) Atkinson, R. C. J.; Gibson, V. C.; Long,
N. J. Chem. Soc. Rev. 2004, 33, 313.
(17) (a) Wang, J. Analytical Electrochemistry, 3rd ed.; Wiley-VCH:
Weinheim, Germany, 2006. (b) Grizner, G.; Kuta, J. Pure Appl. Chem.
1984, 56, 461. (c) Karpinski, Z. J.; Nanjundiah, C.; Osteryoung, R. A.
Inorg. Chem. 1984, 23, 3358. (d) Zanello, P.; Cinquantini, A.; Mangani,
S.; Opromolla, G.; Pardi, L.; Janiak, C.; Rausch, M. D. J. Organomet.
Chem. 1994, 471, 171.
(3) Togni, A.; Hayashi, T. Ferrocenes: Homogeneous Catalysis, Organic
Synthesis, Material Science; Wiley-VCH: Weinheim, Germany, 1995.
(4) (a) Gokel, G.; Marquarding, D.; Ugi, J. I. J. Org. Chem. 1972, 37,
̀
3052. (b) Whitesell, J. K. Chem. Rev. 1989, 89, 1581. (c) Rebiere, F.;
(18) Silva, M. E. N. P. R. A.; Pombeiro, A. J. L.; de Silva, J. J. R. F.;
Herrnamm, R.; Deus, N.; Castilho, T. J; Silva, M. F. C. G. J.
Organomet. Chem. 1991, 421, 75.
Riant, O.; Ricard, L.; Kagan, H. B. Angew. Chem., Int. Ed. 1993, 32,
568. (d) Riant, O.; Samuel, O.; Kagan, H. B. J. Am. Chem. Soc. 1993,
115, 5835. (e) Richards, C. J.; Damalidis, T.; Hibbis, D. E.; Hurstouse,
M. B. Synlett 1995, 74. (f) Wildhalm, M.; Mereiter, K.; Bourghida, M.
Tetrahedron: Asymmetry 1998, 9, 2983. (g) Farrell, Y.; Goddard, R.;
Guiry, P. J. J. Org. Chem. 2002, 67, 4209.
̌
̌ ̌ ̌ ́
(19) Podlaha, J.; Stepnicka, P.; Ludvík, J.; Císarova, I. Organometallics
1996, 15, 543.
(20) Burfield, D. R.; Lee, K. H.; Smithers, R. H. J. Org. Chem. 1997,
(5) (a) Dai, L.-X.; Hou, X.-L. Chiral Ferrocene In Asymetric Catalysis:
Synthesis and Applications; Wiley-VCH: Weinheim, Germany, 2010.
(b) Gomez Arrayas, R.; Adrio, J.; Carretero, J. C. Angew. Chem., Int. Ed.
́ ́
42, 3060.
(21) Marquarding, D.; Klusacek, H.; Gokel, G.; Hoffmann, P.; Ugi, I.
J. Am. Chem. Soc. 1970, 92, 5389.
F
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
(22) Oskooie, H. A.; Herami, M. M.; Behbahani, F. K. Molecules
2007, 12, 1438.
(23) (a) Harris, R. H.; Becker, E. D.; Cabral de Menezes, S. M.;
Goodfellow, R.; Granger, P. Concepts Magn. Reson 2002, 14, 326. (b)
NMR Nomenclature. Nuclear Spin-Properties and Conventions for
Chemical Shifts, IUPAC Recommendations 2001.
(24) SHELX97 (inclusive SHELXS97, SHELXL97, SHELXH97):
Sheldrick, G. M. Acta Crystallogr., Sect. A 2008, 64, 112. SIR92:
Altomare, A.; Cascarano, G.; Giacovazzo, C.; Guagliardi, A. J. Appl.
Crystallogr. 1993, 26, 343.
(25) Farrugia, L. J. J. Appl. Crystallogr. 1997, 30, 565.
G
dx.doi.org/10.1021/om400117n | Organometallics XXXX, XXX, XXX−XXX