New cyclopentadienylethylphosphane chelate complexes with unsymmetrical phosphane substitution

Article abstract of DOI:10.1039/c1nj20292h

The syntheses, characterization, and some reactions of (phosphanylethyl) cyclopentadienyl chelate complexes of cobalt, rhodium, iridium, nickel, and chromium with unsymmetrical substitution at the phosphorus atom are described. The ligand systems were prepared by nucleophilic ring opening of spiro[2.4]hepta-4,6-diene with lithium tert-butylphenylphosphide or lithium tert-butylcyclohexylphosphide. The anionic ligands give the respective chelate complexes by treatment with metal halide reagents. In three cases it was possible to obtain X-ray crystal structure analyses. The cobalt chelate complex undergoes oxidative addition with a dihydrosilane, the reaction results in the formation of products with three stereogenic centers at phosphorus, cobalt, and silicon, which show dynamic behavior as indicated by VTNMR. The rhodium chelate complex undergoes oxidative addition of iodomethane with diastereoselective formation of the respective Rh(iii) chelate. While diastereoselectivity caused by a planar chiral indenyl ligand or by a stereogenic carbon center in the chelate backbone has earlier been observed, this is the first case of a stereoinduction by the stereogenic phosphorus ligand. Activation energies for the rotation of cobalt and rhodium chelates have also been determined by VTNMR.

Full text of DOI:10.1039/c1nj20292h

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PAPER
New cyclopentadienylethylphosphane chelate complexes with
unsymmetrical phosphane substitutionwz
´ ¨
Karin Janssen (nee Kirleis) and Holger Butenschon*
Received (in Victoria, Australia) 3rd April 2011, Accepted 13th June 2011
DOI: 10.1039/c1nj20292h
The syntheses, characterization, and some reactions of (phosphanylethyl)cyclopentadienyl
chelate complexes of cobalt, rhodium, iridium, nickel, and chromium with unsymmetrical
substitution at the phosphorus atom are described. The ligand systems were prepared by
nucleophilic ring opening of spiro[2.4]hepta-4,6-diene with lithium tert-butylphenylphosphide
or lithium tert-butylcyclohexylphosphide. The anionic ligands give the respective chelate
complexes by treatment with metal halide reagents. In three cases it was possible to obtain X-ray
crystal structure analyses. The cobalt chelate complex undergoes oxidative addition with a
dihydrosilane, the reaction results in the formation of products with three stereogenic centers at
phosphorus, cobalt, and silicon, which show dynamic behavior as indicated by VTNMR.
The rhodium chelate complex undergoes oxidative addition of iodomethane with
diastereoselective formation of the respective Rh(III) chelate. While diastereoselectivity caused by
a planar chiral indenyl ligand or by a stereogenic carbon center in the chelate backbone has
earlier been observed, this is the first case of a stereoinduction by the stereogenic phosphorus
ligand. Activation energies for the rotation of cobalt and rhodium chelates have also been
determined by VTNMR.
Introduction
Cyclopentadienyl (Cp) complexes are among the most
common ones in organometallic chemistry and have found
various applications in fields such as catalysis,1 synthesis,2
materials sciences,3,4 medicinal chemistry3–6 and many
more.7–11 One characteristic feature of cyclopentadienyl
Complexes with two different substituents at phosphorus
ligands is their facile rotation around the axis between the
center of the Cp ligand and the metal atom.12 Such a rotation
is impossible in Cp chelate complexes, in which the Cp ligand
is connected to other coordinated moieties. The chemistry
of Cp complexes with heteroatomic tethers, e.g. phosphane
complexes such as 1 has been reviewed some time ago,
and complexes with an ethylene tether (n = 1) are the
most prominent representatives of this class of chelates.13,14
Most complexes of this kind have two identical substituents
at the phosphorus atom. This includes a number of cobalt
and nickel complexes reported by our group, which have
a di-tert-butyl substitution pattern, such as complexes 2
and 3.13,15–30
are comparatively rare. The few, in some cases rather special
examples of such complexes, have been reported by Nakazawa
and Miyoshi et al. (Zr, Hf),31–33 Hey-Hawkins et al. (Ti, Zr),34
Ganter et al. (Mn, Ru),35–37 and Saunders et al. (Rh).38–41
Different substituents at phosphorus render the complexes less
symmetric and are expected to affect the chemical and spectro-
scopic properties of the complexes as well as the energy of
activation of an ethene rotation, which has earlier been
reported for 2.27 In order to get a deeper insight into these
aspects we prepared the first cyclopentadienylethylphosphane
chelates of cobalt, rhodium, iridium, nickel, and chromium
with tert-butyl and phenyl or with tert-butyl and cyclohexyl
substituents at phosphorus. Three of these complexes were
characterized by crystal structure analyses.
Institut fur Organische Chemie, Leibniz Universitat Hannover,
¨
¨
Schneiderberg 1B, D-30167 Hannover, Germany.
E-mail: holger.butenschoen@mbox.oci.uni-hannover.de
Results and discussion
As first shown by Kauffmann et al., spiro[2.4]hepta-4,6-diene
(4) is the superior starting material for the synthesis of
cyclopentadienylethylphosphane ligands.42 The ligands, which
w Dedicated to Didier Astruc on the occasion of his 65th birthday.
z CCDC reference numbers 820401–820403. For crystallographic data
in CIF or other electronic format see DOI: 10.1039/c1nj20292h
c
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are obtained by treatment of 4 with the respective phosphide,
are treated with metal halides to form the respective cyclo-
pentadienyl complexes.
Reaction of
4 with lithium tert-butylphenylphosphide
followed by addition of CoCl2, chromatographic product
isolation and recrystallization from tert-butyl methyl ether
(TBME)/petroleum ether (PE) at ꢀ25 1C gave paramagnetic
chloro chelate rac-5 as purple crystals in 65% yield. rac-5
was characterized spectroscopically by the IR and MS data
obtained in addition to an elemental analysis. The data
obtained resemble those of the closely related di-tert-butyl
substituted complex.28,29 Subsequent treatment of rac-5 with
sodium amalgam (1%) and ethene in THF at ꢀ78 1C followed
by warming to 25 1C gave ethene chelate complex rac-6 in 40%
yield.
Fig. 1 Structure of rac-6 in the crystal.45 Displacement ellipsoids
correspond to the 50% probability level. Selected bond lengths [pm]
and angles [1]: Co1–P1 215.76(9), Co1–C1 205.2(3), Co1–C2 208.3(3),
Co1–C3 207.4(3), Co1–C4 209.1(3), Co1–C5 208.8(3), Co1–C19
200.8(3), Co1–C20 200.8(3), C1–C6 150.8(4), C6–C7 152.7(4);
C1–C6–C7 109.9(2), C6–C7–P1 105.43(19), Co1–P1–C7 103.08(10).
As a consequence of the asymmetric substitution pattern at
phosphorus the 1H NMR spectrum of rac-6 is more complicated
than that of 2. The cyclopentadienyl protons give rise to a
ABCD line system, and the diastereotopic methylene protons
6-H give rise to two signals, which appear as multiplets. The
However, the diastereomeric excess was only 23% in the
reported case. In contrast to 2 chelate rac-6 has an additional
stereocenter at the phosphorus atom. Consequently, the respective
reaction of rac-6 with methylphenylsilane was expected to give
four diastereomers. The experiment showed that this was
indeed the case, addition of methylphenylsilane to rac-6 afforded
complex rac-7 in 71% yield as a mixture of diastereomers in
the ratio 1.00 : 0.95 : 0.56 : 0.48 as determined by deconvolution
1
ethene ligand shows three clearly separated H NMR signals
at d = 2.05 (m, 2H), 2.44 (m, 1H), and 2.73 (m, 1H) ppm,
whereas the corresponding signals of 2 are observed at
d = 1.87 (2H) and 2.27 (m, 2H) ppm. This clearly attests for
the asymmetry of the compound and for the profound difference
of the electronic environment of the ethene protons as a result
of the magnetic anisotropy of the phenyl substituent. Remarkably,
a corresponding difference is not observed for the 13C NMR
signal assigned to the ethene carbon atoms, which give rise to
only one signal at d = 22.9 ppm, a value very close to the
corresponding one observed for 2 (d = 22.4 ppm).27 Dynamic
1H NMR measurements allowed for the determination of the
activation energy of the hindered rotation of the ethene ligand
around the ethene-cobalt axis in 2, which was found to be
1
calculations from the 500 MHz H NMR spectrum at 280 K.
The ratio clearly shows that two out of four diastereomers
are predominantly formed. Although attempts to obtain
crystals suitable for structure analyses failed, we speculate
that diastereomers with the cobalt hydride ligand being
located closely to the tert-butyl group are favored for obvious
steric reasons.
62 kJ molꢀ1 29
at 350 K (400 MHz) corresponding to an estimated activation
energy of 68.7 kJ mol
ꢀ1 43 This value is somewhat higher than
.
For 6 the respective coalescence was observed
.
that obtained for 2, CpNi(C2H4)CH3, and CpRh(C2H4)2, but
significantly lower than that for CpCo(C2H4)2.43,44
Crystallization from hexane at ꢀ25 1C afforded crystals,
which were suitable for an X-ray crystal structure analysis
(Fig. 1). The structure shows a torsion of the ethylene bridge,
which is typical for this class of complexes and allows a
minimization of H–H interactions in the bridge. Remarkably,
the cyclopentadienyl ring and the phenyl substituent adopt
an almost coplanar orientation. In contrast to the NMR
investigation the asymmetry of the phosphane substitution is
not structurally reflected in the ethene ligand, both carbon
atoms show almost identical distances to the cobalt atom.
Chelate 2 has been shown to undergo oxidative addition
reactions with hydrosilanes resulting in hydridosilylcobalt(III)
chelates.18 When a dihydrosilane was used the process generates
a new stereogenic center at silicon as well as at cobalt.
The diastereomeric mixture was fully characterized by IR
and NMR spectroscopy including DEPT, HMQC, H–H-COSY
and NOE experiments allowing assignments of all observed
signals. The Co–H absorptions are observed at 2043 cmꢀ1 in
contrast to 2052 cmꢀ1 for the corresponding di-tert-butyl-
phosphanyl complex.18 The 31P NMR signals for the two
dominant diastereomers appear at d = 93.7 and 95.5 ppm.
The 1H NMR spectrum, which was obtained at 294 K, shows
the four Co–H doublet signals at ꢀ16.89, ꢀ16.85, ꢀ16.58
2
and ꢀ16.50 ppm with JH,P coupling constants in the range
of 45.1–53.8 Hz. Variable temperature measurements in
5 K steps up to 350 K show coalescence resulting in two
doublets (approx. ratio 1 : 1.5) with a coalescence temperature
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Fig. 2 Coalescence of the Co–H signals in the 1H NMR spectrum of rac-7. Left: variable temperature measurements. Right: signal at 350 K with
P decoupling (A) and with P coupling (B).
of Tc = 325 K, which corresponds to an estimated free
enthalpy of activation of 64.9 kJ molꢀ1, which is well in the
range observed for related cases.18 Fig. 2 shows the coalescence
as well as the signals observed at 350 K.
The diastereoisomerization process causing the coalescence
is presumably closely related to the configurational instability
of the cobalt stereogenic center in cyclopentadienylcobalt
systems, which has been the subject of theoretical investigations
recently published by Gandon and Aubert et al.46 According
to these calculations a reductive elimination of the hydrosilane
with formation of an intermediate Z2 Si–H system has to be
invoked, which undergoes a change in conformation followed
by oxidative re-addition. Alternatively, one might discuss
(4) by treatment with lithium tert-butylcyclohexylphosphide
followed by CoCl2 and subsequent reduction with sodium
amalgam in the presence of ethene. The complexes were
characterized spectroscopically. According to HMQC
measurements 1H NMR signals at d = 2.34 (m, 1H) and
2.64 (m, 1H) ppm are assigned to the ethene ligand. In
addition, resonances of two other ethene protons are unresolved
in a broad signal at d = 1.87 ppm overlapping with signals
derived from the cyclohexyl substituent. The 31P NMR signal
at d = 93.2 ppm is in accord with a completely aliphatic
substitution pattern at phosphorus and resembles that of 2
(d = 96.4 ppm).
a
temporary decomplexation of the phosphane tether
with formation of a vacant coordination site facilitating the
diastereoisomerization process. The activation energies of
both processes are in the same order of magnitude.46,47
The carbonylcobalt complex rac-8 corresponding to rac-6
was obtained in 65% yield by the procedure of Pa
treatment of spiro[2.4]hepta-4,6-diene (4) with lithium tert-
butylphenylphosphide followed by THF solution of
´
lyi by
a
Co(CO)4I.48 rac-8 complements a series of complexes with
phenyl, isopropyl and tert-butyl substituents at the phosphorus
atom28,30 and is the first representative with two different
substituents at this position. The carbonyl absorption of
rac-8 is observed at 1894 cmꢀ1, a value similar to that
for the diphenyl (1897 cmꢀ1) and the di-tert-butyl derivative
(1898 cmꢀ1).49
The syntheses as well as reactions of cyclopentadienyl or
indenyl rhodium chelate complexes bearing a phosphane
tether have been reported by Poilblanc et al.,50 Tani
et al.,51–56 Nelson et al.,57,58 Saunders et al.,38–40,59–61 Hidai
et al.,62 Jones et al.,63 Green et al.,64 Salzer et al.,65–68
Cole-Hamilton et al.,69 Lalinde et al.,70 and Whitby et al.71
In most cases the phosphane tether bears phenyl substituents,
however, there are also some in which alkyl, pentafluorophenyl
Similar to the formation of rac-5 and rac-6 the corresponding
tert-butyl(cyclohexyl) substituted complexes rac-9 and rac-10
are obtained in moderate yields from spiro[2.4]hepta-4,6-diene
c
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or more complicated substituents are present. To our knowl-
edge there are no examples with tert-butyl substituents, which,
according to our experience with cobalt complexes, increase
the stability of the complexes and improve their crystallization
properties. Therefore, and for the possibility of comparison,
the di-tert-butyl substituted rhodium(I) chelate 11 was prepared
by treatment of spiro[2.4]hepta-4,6-diene (4) with lithium
di-tert-butylphosphide followed by [Rh2(C2H4)4Cl2]. 11 was
obtained in 72% yield as a brown oil, which is less air sensitive
than the corresponding cobalt chelate 2. The unsymmetric
chelates rac-12 and rac-13 with tert-butylphenyl and tert-
butylcyclohexyl substitution at phosphorus were prepared
accordingly in 85% and 55% yield, respectively, and are also
brown oils.
in d8-toluene, corresponding to energies of activation Ea of
63.0 kJ molꢀ1 and 62.5 kJ molꢀ1, respectively.43 These values are
rather similar to those observed for the di-tert-butyl substituted
cobalt complex 2 but significantly smaller than those observed
for the tert-butylphenyl substituted cobalt analog rac-7 of rac-12.
Treatment of rac-13 with iodomethane resulted in an
oxidative addition with formation of a diastereomeric mixture
of rac-14 and rac-15 in 72% yield. The diastereomeric excess
(de) was 81% (1H NMR) and could be improved to de of 95%
by recrystallization from dichloromethane/hexane. Diastereo-
selective oxidative additions to (cyclopentadienylethyl)phosphane
rhodium chelates have been investigated by the group
of Kataoka and Tani, as well as by the group of Salzer.
Kataoka and Tani prepared planar chiral carbonyl[1-(diphenyl-
Chelates 11–rac-13 were characterized spectroscopically. The
symmetric complex 11 shows two 1H NMR signals for the ethene
ligand, which appear at d = 2.40 (m, 2H) ppm and at d = 2.78
(m, 2H) ppm [2:29 1.87 (m, 2H), 2.27 (m, 2H) ppm]. The
less symmetric complex rac-12 with a phenyl group at the
phosphorus atom shows four signals for the ethene ligand, which
appear at d = 2.31 (m, 1H), 2.50 (m, 1H), 2.93 (m, 1H), 3.11
(m, 1H) ppm. The cyclohexyl substituted chelate rac-13 shows a
1H NMR signal at d = 2.86 (m, 2H) for the ethene ligand. The
resonances for the other two ethene protons overlap with a large
multiplet caused by the cyclohexyl protons as well as by the
ethylene bridge between the cyclopentadienyl group and the
phosphorus atom. The data show that the phenyl substituent
has a significantly larger influence on the magnetic behavior of
the ethene protons than that of the aliphatic tert-butyl or cyclo-
hexyl substituents, an effect, which we attribute to the magnetic
anisotropy of the phenyl group. The clear separation of the
signals in rac-12 made it possible to determine the energy of
activation of the ethene rotation by temperature dependent
1H NMR spectroscopy (Fig. 3). At 400 MHz the coalescence
was observed at Tc = 330 K in d6-benzene and at Tc = 325 K
phosphanylethyl)indenyl]rhodium chelates and methylated
these with formation of the respective acetyliodo chelates
possessing metal centered chirality in addition to the planar
chirality caused by the indenyl ligand. These reactions
proceeded with high diastereoselectivity.54–56,72,73 The Salzer
group prepared a [(diphenylphosphanyl)ethylcyclopentadienyl]-
ethenerhodium(I) chelate with a methyl substituent at the carbon
atom next to phosphorus in enantiomerically pure form. In
addition, the corresponding indenyl and fluorenyl complexes
were reported. Reaction with iodomethane resulted in highly
diastereoselective oxidative additions with formation of the
respective iodomethyl chelate complexes.65,67,74 While Kataoka
and Tani reported a stereoinduction from the planar chiral
indenyl ligand to the metal center, the results of Salzer include
a stereoinduction from an asymmetric carbon atom in the
chelate backbone to rhodium. To our knowledge, the formation
of rac-14 and rac-15 is the first case in the chemistry of
cyclopentadienylalkylphosphane chelate complexes involving
a stereoinduction from the asymmetric phosphorus atom to
rhodium. The assignment of rac-14 as the major diastereomer
is the result of NOE measurements and is in accord with an
X-ray crystal structure analysis (Fig. 4).
Although the quality of the analysis is limited, the data
clearly show that cyclopentadienyl carbon atoms C1 and C2 are
bound significantly closer to the rhodium atom as compared to
the other three cyclopentadienyl carbon atoms. This observation
presumably reflects the asymmetric ligand environment
around the rhodium atom and is detectable clearly, because
the usual rotation around the cyclopentadienyl-rhodium axis
is impossible in rac-14.
We recently reported that the nucleophilic ring opening of
[4,5]benzospiro[2.4]heptadiene (16) proceeds rather slowly with
LiPtBu2 (reflux in THF for 12 h or microwave heating at 150 1C
for 40 min) as compared to less bulky nucleophiles LiPR2
(R = Ph, Cy, iBu, Et).15 In the context of the present work 16
was treated with LiPtBuPh in THF at reflux for 3 d resulting in
Fig. 3 1H NMR coalescence of rac-12 (400 MHz, C6D6).
c
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Nickel chelate complexes with cyclopentadienylalkyl-
phosphane ligands have been unknown until we recently
reported on the synthesis and reactivity of a number of
examples with the di-tert-butyl substitution pattern at the
phosphorus atom.15,16 With the new tert-butylphenyl substituted
ligand in hand, we prepared the respective nickel chelate
rac-20 in 70% yield. rac-20 was characterized spectroscopically,
all data are in accord with related complexes.15,16
Jolly et al. reported the synthesis of cyclopentadienyl-
chromium dichloride chelates with a phosphane tether and
their application as catalysts in alkene oligo- and polymerization
reactions.76 The complexes reported bear identical substituents at
phosphorus, crystal structure analyses of the diphenyl and the
dicyclohexyl complexes were included. We succeeded in the
synthesis of the tert-butylphenyl substituted derivative,
which was obtained in 48% yield by treatment of the anionic
ligand with CrCl3ꢁ3THF as blue needles from toluene. The
paramagnetic complex was characterized by IR spectroscopy,
mass spectrometry (including HRMS), and by an elemental
analysis. These data are in accord with those obtained by Jolly
for related complexes. In addition, it was possible to obtain an
X-ray crystal structure analysis (Fig. 5).
Fig. 4 Structure of rac-14 in the crystal.45 There are two similar
molecules of rac-14 in the asymmetric unit, only one molecule is
shown. Displacement ellipsoids correspond to the 50% probability
level. Selected bond lengths [pm] and angles [1]: Rh1–I1 268.59(9),
Rh1–P1 227.39(14), Rh1–C1 216.7(6), Rh1–C2 214.8(5), Rh1–C3
222.8(6), Rh1–C4 226.1(7), Rh1–C5 225.0(6), Rh1–C18 217.4(5),
P1–C7 185.7(5), P1–C8 181.4(5), P1–C14 188.9(5), C1–C2 142.7(9),
C1–C5 143.8(10), C1–C6 149.5(9), C2–C3 139.0(10), C3–C4 133.1(11),
C4–C5 138.4(11), C6–C7 150.3(9); I1–Rh1–P1 101.52(4), I1–Rh1–C18
84.26(19), P1–Rh1–C18 97.7(2), Rh1–P1–C7 100.53(19), Rh1–P1–C8
119.14(16), C7–P1–C14 105.7(2), C8–P1–C14 104.7(2).
The difference in Cr–Cl bond lengths reflects the asymmetry
of the complex. In this context a comparison with the closely
related structures of the dicyclohexyl and the diphenyl
substituted complexes is instructive. Those Cr–Cl bond lengths
are 227.53(8) and 227.86(8) pm for the dicyclohexyl but
228.37(12) and 228.44(11) pm for the diphenyl substituted
complex, and the Cr–P bond lengths also differ considerably
[PCy2: 245.9(1), PPh2: 244.7(1) pm].76 In rac-21 both features
are present, and consequently differences in the Cr–Cl bond
the formation of rac-17. Subsequent addition of [Rh2(C2H4)4Cl2]
gave the indenyl chelate rac-18 as a diastereomeric mixture
(10 : 1) in 71% yield. rac-18 is more air-sensitive as compared
to the cyclopentadienyl chelate rac-12, so that attempts to
remove a minor amount of the uncoordinated ligand were only
partly successful. rac-18 was characterized spectroscopically, the
NMR data reflect the asymmetry of the compound.
As early as 1994 Poilblanc et al. reported the first synthesis of
an iridium chelate with the [2-(diphenylphosphanyl)ethyl]cyclo-
pentadienyl ligand.50 The ethene complex decomposed readily,
but corresponding carbonyl or cyclooctene (coe) complexes have
been isolated.75 Therefore, the iridium chelate rac-19 was
prepared by reaction of the anionic ligand system with
[IrCl(coe)]2. rac-19 was obtained in only 21% yield in addition
to the residual uncoordinated ligand and was characterized
spectroscopically.
lengths are observed. The shorter bond is next to the tert-butyl
group [Cr1–Cl1, 227.4(1) pm] and the longer one next to the
phenyl substituent [Cr1–Cl2, 228.7(1) pm]. The Cr–P bond
length in rac-21 [246.1(1) pm] resembles more that of
the dicyclohexyl [245.9(1) pm] than that of the diphenyl
compound [244.7(1) pm]. It seems reasonable that these data
reflect the steric bulk of the tert-butyl substituent as compared
to that of the phenyl group.
In conclusion, we have reported the first chelate complexes
with the [2-(tert-butylphenylphosphanyl)ethyl]cyclopentadienyl
ligand system, in which the phosphorus atom is a center of
chirality. This asymmetry is reflected in the structures of the
complexes, three of which have been determined, as well as
in the diastereoselectivity of the reaction of rhodium chelate
rac-12 with iodomethane. While stereoinduction from an
c
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Chloro-{g5:g1[2-(tert-butylphenylphosphanyl)ethyl]-
cyclopentadienyl}cobalt(II) (rac-5)
At ꢀ78 1C butyllithium in hexane (19.4 mL, 31.2 mmol,
1.6 M) was added dropwise to tert-butylphenylphosphane
(4.314 g, 25.9 mmol) in THF (100 mL). After stirring for 2 h
at 20 1C spiro[2.4]hepta-4,6-diene (4, 2.484 g, 27.0 mmol) was
added, and after stirring for 4 h at 65 1C the mixture was
cooled to ꢀ78 1C, and CoCl2 (4.050 g, 31.2 mmol) was added.
The mixture was slowly warmed to 20 1C and stirred for
another 1 h. After solvent removal at reduced pressure the
residue was taken up with diethyl ether (25 mL) and filtered
through a 3 cm thick layer of Celite. After solvent removal the
product was isolated by column chromatography (3 ꢂ 20 cm,
TBME) to give 5 (5.960 g, 16.9 mmol, 65%) as a purple solid,
mp 106.1 1C.
IR: v˜ = 3406 (w), 3078 (m), 2940 (s, C-H), 2863 (w, C-H),
2360 (w), 1630 (m), 1473 (w), 1461 (m), 1437 (w, P-Ph), 1365
(w, t-Bu), 1183 (m), 1163 (w), 1101 (w), 1035 (m), 1023 (s,
Fig. 5 Structure of rac-21 in the crystal.45 There are two similar
molecules of rac-21 in the asymmetric unit, only one molecule is
shown. Displacement ellipsoids correspond to the 50% probability
level. Selected bond lengths [pm] and angles [1]: Cr1–Cl1 227.39(10),
Cr1–Cl2 228.71(11), Cr1–P1 246.13(11), Cr1–C1 224.5(3), Cr1–C2
222.3(4), Cr1–C3 222.6(4), Cr1–C4 222.3(3), Cr1–C5 222.4(3),
P1–C6 182.9(3), P1–C9 181.5(3), P1–C15 186.1(3), C1–C2 138.8(4),
C1–C5 141.9(4), C1–C14 150.2(4), C2–C3 138.7(5), C3–C4 137.4(5),
C4–C5 141.0(4), C6–C14 152.6(5); Cl1–Cr1–Cl2 98.27(4), Cl1–Cr1–P1
98.91(4), Cl2–Cr 101.18(4).
t-Bu), 934 (m), 848 (w), 806 (s, Cp), 755 (m), 700 (s), 621 (m) cmꢀ1
.
MS: m/z (%) = 351 (20) [M+], 259 (54) [M+ ꢀ CoCl],
182 (17), 160 (40), 126 (65), 110 (62), 79 (76), 57 (19) [t-Bu+].
HRMS (M+
= C17H22ClCoP) calcd 351.0482, found
351.0479. Anal. (C17H22ClCoP) calcd C 50.01; H 7.27, found
C 50.14; H 7.19.
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]cyclopentadienyl}-
(g2-ethen)-cobalt(I) (rac-6)
indenyl ligand or an asymmetric carbon atom in the chelate
backbone has earlier been reported, this is the first case that
the asymmetric phosphorus atom causes this diastereoselectivity.
At ꢀ78 1C sodium amalgam (1%, 3.2 mL, 2.1 mmol) was
added to chlorocobalt complex rac-5 (0.765 g, 4.3 mmol) in
THF (15 mL), and ethene was purged through the mixture.
After 1 h the mixture was slowly warmed to 20 1C and stirred
for another 4 h. After separation of the organic layer from the
amalgam the solvent was removed at reduced pressure, and the
residue was taken up with hexane (15 mL) and filtered through
a frit covered with a 3 cm thick layer of Celite. After
concentration at reduced pressure the filtrate was cooled to
ꢀ25 1C affording complex rac-6 (1.19 g, 3.5 mmol, 40%) as
brown-black crystals (mp 73.0 1C), purity (1H NMR) Z 95%.
IR: v˜ = 3052 (m, C2H4), 2959 (s, C-H), 2862 (m, C-H), 2364
(w), 1474 (m, C-H), 1461 (m), 1434 (m, P-Ph), 1362 (m, t-Bu),
1261 (m, C2H4), 1164 (m), 1095 (m), 1027 (m, t-Bu), 895 (w),
Experimental section
General: All manipulations involving air sensitive material
were performed in flame-dried reaction vessels in an argon
or nitrogen atmosphere using vacuum line and standard Schlenk
techniques. Spiro[2.4]hepta-4,6-diene (4) and [4,5]benzospiro[2.4]-
hepta-4,6-diene (16) were prepared according to published
procedures.53,77 Diethyl ether (EE), and THF were distilled
from sodium benzophenone ketyl. Hexane, pentane and
dichloromethane were dried with calcium hydride and freshly
distilled before use. Petroleum ether (PE) was dried with
calcium chloride. All the solvents were purged with nitrogen
before use. Column chromatography was carried out by flash
chromatography.78 Silica gel (J. T. Baker, 40 mm) was
degassed three times by heating it with a flame at reduced
pressure followed by setting it at normal pressure with nitrogen.
IR-Spectra: Bruker FT-IR spectrometer Vektor 22 (ATR).
Mass spectra: Finnegan MAT 112 and MAT 312. HRMS
(ESI): Micromass LCT with a lock spray ion source combined
with a Water Alliances 2695 HPLC unit; VG autospec (peak-
800 (s, Cp-R), 745 (m), 699 (s) cmꢀ1 1H-NMR (400 MHz,
.
C6D6): d = 0.76 (d, 3JH,P = 12.7 Hz, 9H, CH3), 1.46 (m, 1H,
PCH2CH2), 1.79–1.96 (m, 1H, PCH2CH2), 2.03 (m, 2H,
PCH2), 2.05 (m, 2H, CH2QCH2), 2.44 (m, 1H, CH2QCH2),
2.73 (m, 1H, CH2QCH2), 3.54 (s, 1H, PCH2CH2CCHCH),
3.81 (s, 1H, PCH2CH2CCH), 5.05 (s, 1H, PCH2CH2CCH),
2
5.55 (s, 1H, PCH2CH2CCHCHCH), 7.15 (d, JH,P = 6.0 Hz,
3
3H, o-, p-CH), 7.98 (t, JH,P = 7.5 Hz, 2H, m-CH) ppm.
2
13C-NMR (100.6 MHz, C6D6): d = 22.1 (d, JC,P = 5.5 Hz,
1
matching method, PFK). H NMR: Bruker AVS 200 (200.1
PCH2CH2), 22.9 (QCH2), 26.5 (d, 2JC,P = 3.7 Hz, CH3), 31.2
MHz), AVS 400 (400.1 MHz) and DRX 500 (500.1 MHz).
13C NMR: Bruker AVS 200 (50.3 MHz) and AVS 400
(100.6 MHz). Signal multiplicities were determined with
ATP and DEPT techniques. 31P NMR: Bruker AVS 400
(161.9 MHz). Melting points: Electrothermal IA9000 Series
Digital Melting Point Apparatus. Elemental analyses: Elementar
Vario EL.
(d, 1JC,P = 14.1 Hz, PCCH3), 38.8 (d, 1JC,P = 24.9 Hz, PCH2),
4
77.7 (PCH2CH2CCHCH), 79.1 (d, JC,P
= 5.1 Hz,
4
PCH2CH2CCH), 82.4 (PCH2CH2CCHCH), 83.0 (d, JC,P
=
3
5.3 Hz, PCH2CH2CCH), 108.8 (d, JC,P
=
6.3 Hz,
2
PCH2CH2C), 127.6 (d, JC,P = 8.3 Hz, o-CH), 129 (p-CH),
3
1
134.0 (d, JC,P = 9.1 Hz, m-CH), 135.4 (d, JC,P = 20.3 Hz,
PCCH) ppm. 31P-NMR (162 MHz, C6D6): d = 79.9 ppm.
c
2292 New J. Chem., 2011, 35, 2287–2298
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View Article Online
MS: m/z (%) = 344 [M+] (11), 316 [M+ ꢀ CH2QCH2] (100),
addition at ꢀ78 1C of butyllithium in hexane (3.2 mL, 5.1 mmol,
1.6 M) to tert-butylphenylphosphane (0.719 g, 4.3 mmol) in THF
(15 mL), followed by stirring for 2 h at 20 1C and addition of
spiro[2.4]hepta-4,6-diene (4, 0.45 mL, 4.5 mmol). This solution
was added to the ICo(CO)4 solution at ꢀ78 1C, and the mixture
was stirred for 1 h at ꢀ78 1C and then for 4 h at 20 1C. After
solvent removal at reduced pressure the residue was taken up with
hexane (15 mL) and filtered through a frit covered with a 3 cm
thick layer of Celite. Solvent removal from the filtrate afforded
complex rac-8 (0.667 g, 1.9 mmol, 45%) as a brown-black oil
(purity Z 90%, 1H NMR).
IR: v˜ = 2961 (m, C-H), 2077 (w), 2015 (s, impur.), 1946 (s,
impur.), 1894 (CO, s), 1620 (w), 1474 (w, C-H), 1435 (w, P-Ph),
1166 (w), 1099 (w), 1015 (w, t-Bu), 815 (w, Cp), 746 (w), 697 (m)
cmꢀ1. 1H-NMR (400 MHz, C6D6): d = 0.9 (d, 3JH,P = 14.3 Hz,
CH3), 1.37 (m, 1H, PCH2CH2), 1.72 (m, 1H, PCH2CH2), 2.30 (m,
2H, PCH2), 4.62 (s, 1H, PCH2CH2CCHCH), 4.89 (s, 1H,
259 (86), 180 (43), 136 (61), 91 (24), 57 (41). HRMS (M+
=
C19H26CoP) calcd 344.1104, found 344.1102. Tc = 350 K
(d8-toluene, 400 MHz), DGz E 68.7 kJ molꢀ1
.
Crystal structure analysis of rac-6:45 empirical formula
C19H26CoP, molecular weight 344.30, crystal system mono-
clinic, space group P21/n, a = 11.070(5), b = 11.504(4),
c = 14.202(6) A, a = 90.001, b = 104.47(5)1, g = 90.001,
V = 1751.3(12) A3, Z = 4, dcalcd = 1.306 g cmꢀ1, F(000) =
728, m = 1.063 mmꢀ1, Stoe IPDS diffractometer, T = 294 K,
MoKa (l = 0.71073 A), ymin = 2.101, ymax = 26.231, 24 177
measured reflections (ꢀ13 r h r 13, ꢀ14 r k r 14, ꢀ17 r
l r 17), 3479 independent, 2070 observed reflections, Rint
=
0.089, R = 0.0301, wR = 0.0534, residual electron density
0.244 and ꢀ0.286 e Aꢀ3, Gof = 0.803, refinement program
SHELXL-97, Nref = 3479, Npar = 202.
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]cyclopentadienyl}-
(hydrido)(methylphenylsilyl)cobalt(III) (rac-7)
PCH2CH2CCHCH), 4.97 (s, 1H, PCH2CH2CCH), 5.81 (s, 1H,
3
PCH2CH2CCH), 7.08 (m, 3H, o-CH, p-CH), 7.79 (t, JH,P
=
9.5 Hz, 2H, m-CH) ppm. 13C-NMR (100.6 MHz, C6D6): d = 23.2
Methylphenylsilane (0.5 mL, 4.0 mmol) was added to ethene-
cobalt chelate rac-6 (465 mg, 1.4 mmol) in toluene (14 mL).
After stirring for 11 h at 60 1C the solvent was removed at
reduced pressure, and the residue was taken up with hexane
(5 mL) and filtered through a frit covered with a 3 cm thick
layer of Celite. The solvent was removed at reduced pressure
to give rac-7 (420 mg, 1.35 mmol, 71%) as a yellow oil as a
mixture of four diastereomers [1.00 : 0.95 : 0.56 : 0.48, purity
Z 95% (1H NMR)].
2
2
(d, JC,P = 6.5 Hz, PCH2CH2), 26.7 (d, JC,P = 4.7 Hz, CH3),
32.1 (d, 1JC,P = 25.1 Hz, CCH3), 39.5 (d, 1JC,P = 24.7 Hz, PCH2),
78.6 (d, 4JC,P = 3.6 Hz, PCH2CH2CCH), 80.5 (d, 5JC,P = 1.1 Hz,
4
PCH2CH2CCHCH), 81.1 (d, JC,P = 3.6 Hz, PCH2CH2CCH),
5
83.8 (d, JC,P = 1.1 Hz, PCH2CH2CCHCH), 108.7 (d, JC,P
3
=
6.5 Hz, PCH2CH2C), 127.8 (d, 2JC,P = 5.1 Hz, o-CH), 129.7 (d,
4JC,P = 2.3 Hz, p-CH), 133.7 (d, 3JC,P = 10.1 Hz, m-CH), 134.2
1
(d, JC,P = 31.2 Hz, PCCH), 207.1 (CO) ppm. 31P-NMR (162
MHz, C6D6): d = 108.7 ppm. MS: m/z (%) = 344 (34) [M+], 316
(96) [M+ ꢀ CO], 260 (100), 259 (65), 180 (28), 136 (44), 58 (24).
HRMS (M+ = C18H22CoOP) calcd 344.0740, found 344.0741.
IR: v˜ = 3060 (w), 2956 (m, C-H), 2043 (m, Co-H), 1946 (w,
Si-H), 1461 (w, C-H), 1426 (m, P-Ph), 1392 (w), 1363 (w, t-Bu),
1310 (w), 1260 (m), 1232 (w), 1181 (w), 1123 (w), 1095 (m, C-H),
1014 (s), 996 (m), 878 (m), 816 (s, Si-H), 730 (m), 696 (s) cmꢀ1
.
Chloro-{g5:g1[2-(tert-butylcyclohexylphosphanyl)ethyl]-
cyclopentadienyl}cobalt(II) (rac-9)
1H-NMR (400 MHz, C6D6): d = ꢀ16.89 (d, 2JH,P = 53.8 Hz,
1/4H, 14-H), ꢀ16.85 (d, 2JH,P = 45.1 Hz, 1/4H, 14-H), ꢀ16.58
(d, 2JH,P = 53.1 Hz, 1/4H, 14-H), ꢀ16.50 (d, 2JH,P = 46.1 Hz,
1/4H, 14-H), 0.37 (s, 3H, SiCH3), 0.87 (m, 9H, CCH3),
1.66–2.07 (m, 2H, PCH2CH2), 1.42–2.58 (m, 2H, PCH2),
4.26–5.15 (m, 4H, Cp-H), 5.59 (s, 1H, Si-H), 7.07–7.58
(m, 10H, Ph-H) ppm. 13C-NMR (100.6 MHz, C6D6, main
At ꢀ78 1C butyllithium in hexane (6.4 mL, 10.2 mmol, 1.6 M)
was added dropwise to tert-butylphenylphosphane (1.489 g,
8.7 mmol) in THF (30 mL). After stirring for 2 h at 20 1C
spiro[2.4]hepta-4,6-diene (4, 0.9 mL, 9.0 mmol) was added,
and after stirring for 2 h at 65 1C the mixture was cooled to
ꢀ78 1C, and CoCl2 (1.350 g, 10.4 mmol) was added. The
mixture was slowly warmed to 20 1C and stirred for another
2 h. After solvent removal at reduced pressure the residue was
taken up with diethyl ether (15 mL) and filtered through a frit
covered with a 3 cm thick layer of Celite. The filtrate was
concentrated and cooled at ꢀ25 1C affording complex rac-9
(1.717 g, 4.8 mmol, 55%) as a purple solid (mp 113 1C).
IR: v˜ = 2922 (s, C-H), 2851 (m, C-H), 2357 (w), 1693 (w),
1446 (m), 1394 (w), 1365 (m, t-Bu), 1262 (w), 1103 (m), 1031 (m),
1016 (m, t-Bu), 936 (w), 888 (w), 851 (w), 828 (m), 796 (s, Cp),
735 (w) cmꢀ1. MS: m/z (%) = 357 (100) [M+], 263 (82)
[M+ ꢀ CoCl], 258 (49), 182 (90), 163 (44), 57 (34). HRMS
(M+ = C17H28ClCoP) calcd 357.0949, found 357.0949.
2
product): d = 1.4 (SiCH3), 22.5 (d, JC,P = 5.2 Hz,
PCH2CH2), 26.5 (d, JC,P = 3.6 Hz, CCH3), 31.9 (d,
2
1
1JC,P = 9.5 Hz, CCH3), 40.5 (d, JC,P = 24.7 Hz, PCH2),
80.2 (CCpCH), 80.8 (CCpCH), 80.9 (CCpCH), 84.2 (CCpCH),
3
2
116.0 (d, JC,P = 6.7 Hz, CCpCH2), 127.6 (d, JC,P = 5.3 Hz,
P-o-CPhH), 127.9 (Si-CPhH), 129.4 (P-p-CPhH), 132.7
3
(Si-CPhH), 133.5 (d, JC,P = 9.1 Hz, P-m-CPhH), 134.7
(Si-CPhH), 135.0 (PCPhC), 148.6 (SiCPhC) ppm. 31P-NMR
(162 MHz, C6D6): d = 93.7, 95.5 ppm. MS: m/z (%) = 437
(32) [M+ ꢀ H], 436 (100) [M+ ꢀ 2H], 358 (31), 258 (42), 121
(58), 105 (39), 78 (70), 57 (78) [t-Bu+]. HRMS (M+ ꢀ 2H =
C24H30CoPSi) calcd 436.1186, found 436.1182.
Carbonyl{g5:g1[2-(tert-butylphenylphosphanyl)ethyl]-
cyclopentadienyl}cobalt(I) (rac-8)
{g5:g1[2-(tert-Butylcyclohexylphosphanyl)ethyl]-
cyclopentadienyl}-(g2-ethen)-cobalt(I) (rac-10)
A solution of ICo(CO)4 was prepared by addition of Co2(CO)8
(1.000 g, 2.9 mmol) in THF (15 mL) to I2 (0.740 g, 2.9 mmol)
in THF (25 mL) at ꢀ78 1C and subsequent stirring for 1 h at
ꢀ78 1C.48 A solution of the anionic ligand was prepared by
At ꢀ78 1C sodium amalgam (1%, 6.3 mL, 3.7 mmol) was
added to chlorocobalt complex rac-9 (1.171 g, 4.8 mmol) in
THF (80 mL), and ethene was purged through the mixture.
c
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New J. Chem., 2011, 35, 2287–2298 2293

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After 1 h the mixture was slowly warmed to 20 1C and stirred
for another 6 h. After separation of the organic layer from the
amalgam the solvent was removed at reduced pressure, and the
residue was taken up with hexane (30 mL) and filtered through
a frit covered with a 3 cm thick layer of alumina. After solvent
removal at reduced pressure complex rac-10 [0.637 g, 1.8 mmol,
38%, purity (1H NMR) Z 95%] was obtained as a red oil.
IR: v˜ = 2921 (s, C-H), 2850 (s, C-H), 1447 (m, C-H), 1364
(w, t-Bu), 1266 (w, C2H4), 1161 (m), 1013 (w, t-Bu), 890 (w),
C6D6): d = 99.3 (d, 1JP,Rh = 211.7 Hz) ppm. MS: m/z (%) =
368 (18) [M+], 340 (60) [M+ ꢀ CH2QCH2], 284 (100),
227 (45), 224 (56), 180 (30), 57 (76) [t-Bu+]. HRMS
(M+ = C17H30RhP) calcd 368.1137, found 368.1140.
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]cyclopentadienyl}-
(g2-ethen)-rhodium(I) (rac-12)
At ꢀ78 1C butyllithium in hexane (6.4 mL, 10.2 mmol, 1.6 M) was
added dropwise to di-tert-butylphosphane (1.438 g, 8.7 mmol) in
THF (30 mL). After stirring for 2 h at 21 1C spiro[2.4]hepta-4,6-
diene (4, 0.9 mL, 9.0 mmol) was added, and after stirring for 2 h at
65 1C the mixture was cooled to ꢀ78 1C, and [Rh2(C2H4)4Cl2]
(2.020 g, 5.2 mmol) was added. The mixture was slowly warmed to
20 1C and stirred for another 2 h. After solvent removal at reduced
pressure the residue was taken up with pentane (15 mL) and
filtered through a frit covered with a 3 cm thick layer of Celite.
The solvent was removed at reduced pressure and the residue was
taken up with 3 mL of toluene. As attempts to crystallize the
product at ꢀ25 1C failed, the solvent was removed at reduced
pressure affording rac-12 (2.850 g, 7.7 mmol, 85%) as a brown oil,
purity Z 95% (1H NMR).
816 (m), 793 (m, Cp), 681 (m) cmꢀ1 1H-NMR (400 MHz,
.
C6D6): d = 1.02 (d, 3JH,P = 12.1 Hz, 9H, CH3), 1.87 (m, 17H,
7 CH2, QCH2, PCH), 2.34 (m, 1H, QCH2), 2.64 (m, 1H,
QCH2), 3.36 (s, 1H, PCH2CH2CCHCH), 4.29 (s, 1H,
PCH2CH2CCH), 5.47 (s, 1H, PCH2CH2CCHCH), 5.54 (s, 1H,
PCH2CH2CCH) ppm. 13C-NMR (100.6 MHz, C6D6): d =
4
22.5 (QCH2), 23.5 (d, JC,P = 4.6 Hz, PCHCH2CH2CH2),
25.1 (d, JC,P = 6.9 Hz, PCH2CH2), 27.5 (d, JC,P = 6.3 Hz,
2
3
PCHCH2CH2), 28.7 (d, 4JC,P = 3.4 Hz, CH3), 29.4 (d, 2JC,P
=
4
5.9 Hz, PCHCH2), 31.0 (d, JC,P = 12.4 Hz, PCCH3), 34.8
4
(d, JC,P = 10.5 Hz, PCH), 36.2 (d, JC,P = 21.2 Hz,
4
4
PCH2), 77.2 (d, JC,P = 6.5 Hz, PCH2CH2CCH), 79.2
(PCH2CH2CCHCH), 80.9 (PCH2CH2CCHCH), 83.5 (d,
3
IR: v˜ = 3045 (w, C2H4), 2941 (m, C-H), 2861 (w, C-H), 1474
(w, C-H), 1433 (m, P-Ph), 1416 (w), 1390 (w), 1362 (m, t-Bu),
1308 (m), 1266 (w, kompl. C2H4), 1167 (w), 1095 (s), 1028 (m,
t-Bu), 1013 (w), 929 (w), 841 (m, Cp), 809 (s, Cp), 772 (m), 744
4JC,P = 4.6 Hz, PCH2CH2CCH), 109.3 (d, JC,P = 6.7 Hz,
PCH2CH2CCH) ppm. 31P-NMR (162 MHz, C6D6): d =
93.2 ppm. MS: m/z (%) = 350 (10) [M+], 322 (59)
[M+ ꢀ CH2 = CH2], 263 (73) [M+ ꢀ CH2QCH2-Co], 240
(30), 183 (69), 136 (55), 83 (61), 57 (100) [t-Bu+], 55 (73).
HRMS (M+ = C19H32CoP) calcd 350.1573, found 350.1571.
(m), 697 (s), 668 (m), 620 (s) cmꢀ1 1H-NMR (400 MHz,
.
C6D6): d = 0.87 (d, 3JH,P = 13.6 Hz, 9H, CH3), 1.59 (m, 1H,
PCH2CH2), 2.03 (dddd, JH,P = 45.6, JH,H = 13.5, 6.6,
2
2.4 Hz, 1H, PCH2CH2), 2.24 (m, 1H, PCH2), 2.31 (m, 1H,
{g5:g1[2-(Di-tert-butylphosphanyl)ethyl]cyclopentadienyl}-
(g2-ethen)-rhodium(I) (rac-11)
QCH2), 2.50 (m, 1H, QCH2), 2.54 (m, 1H, PCH2), 2.93
4
(m, 1H, QCH2), 3.11 (m, 1H, QCH2), 4.70 (d, JH,P
=
3
2.7 Hz, 1H, PCH2CH2CCH), 4.99 (d, JH,P = 2.0 Hz,
1H, PCH2CH2CCH), 5.23 (d, 5JH,P = 1.0 Hz, 1H, PCH2CH2-
5
CCHCH), 5.60 (d, JH,P = 1.3 Hz, 1H, PCH2CH2CCHCH),
At ꢀ78 1C butyllithium in hexane (2.9 mL, 4.6 mmol, 1.6 M) was
added dropwise to di-tert-butylphosphane (0.610 g, 4.2 mmol) in
THF (15 mL). After stirring for 2 h at 21 1C spiro[2.4]hepta-4,6-
diene (4, 0.5 mL, 5.0 mmol) was added, and after stirring for 2 h at
65 1C the mixture was cooled to ꢀ78 1C, and [Rh2(C2H4)4Cl2]
(0.982 g, 2.5 mmol) was added. The mixture was slowly warmed to
20 1C and stirred for another 2 h. After solvent removal at reduced
pressure the residue was taken up with pentane (15 mL) and
filtered through a frit covered with a 3 cm thick layer of Celite.
The solvent was removed at reduced pressure affording rac-11
7.17 (m, 3H, o-CH, p-CH), 7.89 (m, 2H, m-CH) ppm. 13C-NMR
(100.6 MHz, C6D6): d = 22.7 (d, 2JC,P = 2.6 Hz, PCH2CH2),
2
1
25.9 (dd, JC,P = 15.1 Hz, JC,Rh = 2.4 Hz, QCH2), 26.5
(d, JC,P = 4.7 Hz, CH3), 32.0 (d, JC,P = 16.7 Hz, JC,Rh =
2
1
2
1
2.7 Hz, PCCH3), 42.2 (d, JC,P = 24.5 Hz, PCH2), 80.8 (dd,
1
5JC,P = 4.2 Hz, JC,Rh = 2.6 Hz, PCH2CH2CCHCH), 84.8
5
(dd, JC,P = 3.8 Hz, JC,Rh = 3.0 Hz, PCH2CH2CCHCH),
1
4
85.3 (dd, JC,P = 8.8 Hz, JC,Rh = 2.8 Hz, PCH2CH2CCH),
1
[1.120 g, 3.0 mmol, 72%, purity
as a brown oil.
Z
95% (1H NMR)]
4
88.9 (dd, JC,P = 8.4 Hz, JC,Rh = 2.7 Hz, PCH2CH2CCH),
1
3
1
112.0 (dd, JC,P = 5.5 Hz, JC,Rh = 4.2 Hz, PCH2CH2C),
IR: v˜ = 2958 (m, C-H), 2896 (m, C-H), 1471 (m, C-H), 1386
(w), 1366 (m, t-Bu), 1167 (s), 1019 (m, t-Bu), 928 (w), 809 (m),
772 (m), 661 (w) cmꢀ1. 1H-NMR (400 MHz, C6D6): d = 1.06
(d, 18H, 3JH,P = 12.2 Hz, CH3), 1.88 (m, 2H, PCH2CH2), 2.02
(m, 2H, PCH2), 2.40 (m, 2H, CH2QCH2), 2.78 (m, 2H,
CH2QCH2), 4.72 (m, 2H, PCH2CH2CCHCH), 5.51 (m, 2H,
PCH2CH2CCH) ppm. 13C-NMR (100.6 MHz, C6D6): d =
2
127.5 (d, JC,P = 8.8. Hz, o-CH), 129.4 (d, JC,P = 2.3 Hz,
4
3
p-CH), 134.1 (d, JC,P = 10.5 Hz, m-CH), 136.3 (dd, JC,P
1
=
25.1 Hz, 2JC,Rh = 1.5 Hz, PCCH) ppm. 31P-NMR (162 MHz,
1
C6D6): d = 79.7 (d, JP,Rh = 215 Hz) ppm. MS: m/z (%) =
388 (47) [M+], 360 (99) [M+ ꢀ CH2QCH2], 304 (100)
[M+ ꢀ C4H8], 223 (34), 180 (50), 57 (39) [t-Bu+]. HRMS
(M+
Tc
= C19H26RhP) calcd 388.0827, found 388.0828.
2
3
25.5 (dd, JC,P = 15.1 Hz, JC,Rh = 2.4 Hz, PCH2CH2), 30.1
2
=
=
330 K = .
(d6-benzene). DGz 62.98 kJ molꢀ1
2
(d, JC,P = 4.9 Hz, CH3), 35.5 (dd, 1JC,P = 9.5 Hz, JC,Rh
Tc = 325 K (d8-toluene), DGz = 62.5 kJ molꢀ1
.
2.4 Hz, PCCH3), 37.9 (dd, 2JC,P = 13.4 Hz, 1JC,Rh = 2.1 Hz,
1
H2CQCH2), 42.4 (d, JC,P = 19.5 Hz, PCH2), 82.9 (dd,
JC,P = 4.0 Hz, JC,Rh = 3.0 Hz, PCH2CH2CCHCH or
{g5:g1[2-(tert-Butylcyclohexylphosphanyl)ethyl]-
cyclopentadienyl}-(g2-ethen)rhodium(I) (rac-13)
1
1
PCH2CH2CCH), 86.2 (dd, JC,P = 8.4 Hz, JC,Rh = 2.8 Hz,
PCH2CH2CCHCH or PCH2CH2CCH), 113.6 (dd, JC,P = 6.4 Hz,
1JC,Rh = 4.2 Hz, PCH2CH2C) ppm. 31P-NMR (162 MHz,
At ꢀ78 1C butyllithium in hexane (2.9 mL, 4.6 mmol,
1.6 M) was added dropwise to tert-butylcyclohexylphosphane
c
2294 New J. Chem., 2011, 35, 2287–2298
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011

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3
3
(0.726 g, 4.2 mmol) in THF (15 mL). After stirring for 2 h at
20 1C spiro[2.4]hepta-4,6-diene (4, 0.9 mL, 9.0 mmol) was
added, and after stirring for 2 h at 65 1C the mixture was
cooled to ꢀ78 1C, and [Rh2(C2H4)4Cl2] (0.982 g, 2.5 mmol)
was added. The mixture was slowly warmed to 20 1C and
stirred for another 2 h. After solvent removal at reduced
pressure the residue was taken up with pentane (15 mL) and
filtered through a frit covered with a 3 cm thick layer of Celite.
The solvent was removed at reduced pressure affording rac-13
(0.910 g, 2.3 mmol, 55%) as a brown oil.
9.8 Hz, JH,H = ꢀ14.2 Hz, JH,Rh = 0.6 Hz, 1H, PCH2),
3 3 2
3.23 (d, JH,H = 6.0 Hz, JH,H = 6.0 Hz, JH,P = 9.0 Hz,
3JH,H = ꢀ14.2 Hz, 3JH,Rh = 1.2 Hz, 1H, PCH2), 4.50 (m, 1H,
PCH2CH2CCH), 5.15 (m, 1H, PCH2CH2CCHCH), 5.40 (m,
1H, PCH2CH2CCH), 5.89 (m, 1H, PCH2CH2CCHCH),
7.28 (m, 5H, Ph-H) ppm. 13C-NMR (100.6 MHz, CDCl3):
d = ꢀ13.5 (dd, 2JC,P = 20.9 Hz, 1JC,Rh = 10.4 Hz, RhCH3),
2
2
23.3 (d, JC,P = 1.3 Hz, PCH2CH2), 27.9 (d, JC,P = 3.4 Hz,
1
2
CCH3), 35.0 (d, JC,P = 19.1 Hz, JC,Rh = 0.5 Hz, CCH3),
42.5 (d, 1JC,P = 24.9 Hz, PCH2), 81.7 (dd, JC,P = 6.9 Hz, 1JC,Rh
3.1 Hz, PCH2CH2CCH), 84.9 (dd, JC,P 3.2 Hz,
=
IR: v˜ = 2920 (s, C-H), 2849 (s, C-H), 1944 (m), 1782 (w),
1447 (m, C-H), 1415 (w), 1391 (w), 1363 (m, t-Bu), 1268 (w,
C2H4), 1184 (m), 1168 (s), 1026 (m), 1012 (m, t-Bu), 930 (m),
887 (w), 850 (w), 810 (m), 769 (s, Cp), 730 (m) cmꢀ1. 1H-NMR
=
PCH2CH2CCH), 87.2 (dd, JC,P = 11.3 Hz, JC,Rh = 3.6 Hz,
PCH2CH2CCHCH), 102.7 (dd, JC,P = 5.7 Hz, JC,Rh = 2.3 Hz,
3
PCH2CH2CCHCH), 118.3 (dd, JC,P = 7.7 Hz, JC,Rh
=
2
5.0 Hz, PCH2CH2C), 127.8 (d, JC,P = 9.0 Hz, o-CH), 130.0
3
(400 MHz, C6D6): d = 0.94 (d, JH,P = 12.1 Hz, 9H, CH3),
4
3
1.81 (m, 17H, 7 CH2, QCH2), 2.86 (m, 2H, QCH2), 4.71
(d, JH,P = 2.4 Hz, 1H, PCH2CH2CCHCH), 5.00 (s, 1H,
(d, JC,P = 2.4 Hz, p-CH), 132.9 (d, JC,P = 7.2 Hz, m-CH),
133.9 (dd, 1JC,P = 8.4 Hz, PCCH) ppm. 31P-NMR (162 MHz,
4
5
PCH2CH2CCH), 5.54 (d, JH,P = 1.0 Hz, 1H, PCH2CH2CCH),
1
C6D6): d = 75.7 (d, JP,Rh = 167 Hz) ppm. MS (95% de):
m/z (%) = 501 (14) [M+], 486 (61) [M+ ꢀ CH3], 360 (61)
[M+ ꢀ CH3 ꢀ I], 302 (100), 180 (40), 68 (24), 57 (40) [t-Bu+].
HRMS (M+ = C18H25PRhI) calcd 501.9793, found 501.9791.
Crystal structure analysis of rac-14:45 empirical formula
C18H25IPRh, molecular weight 502.16, crystal system
5
5.60 (d, JH,P = 1.4 Hz, 1H, PCH2CH2CCHCH) ppm.
2
13C-NMR (100.6 MHz, C6D6): d = 25.3 (d, JC,P = 2.8 Hz,
PCH2CH2), 26.6 (d, 4JC,P = 1.3 Hz, PCHCH2CH2CH2), 27.6
3
(d, JC,P = 8.0 Hz, PCHCH2CH2), 28.0 (d, JC,P = 13.2 Hz,
2
2
2
QCH2), 28.4 (d, JC,P = 4.2 Hz, CH3), 29.3 (d, JC,P = 3.2
Hz, PCHCH2), 32.1 (dd, JC,P = 15.5 Hz, JC,Rh = 2.3 Hz,
1
2
orthorhombic, space group Pbca,
b = 16.109(5) A, c = 21.823(6) A, a = 90.001, b = 90.001,
g = 90.001, V = 7415(4) A3, Z = 16, dcalcd = 1.799 g cmꢀ1
F(000) = 3936.0, m = 2.665 mmꢀ1, Stoe IPDS diffractometer,
T = 297 K, MoKa (l = 0.71073 A), ymin = 1.931, ymax
26.151, 1 02 298 measured reflections (ꢀ26 r h r 25, ꢀ19 r k
r 19, ꢀ26 r l r 26), 7303 independent, 4923 observed
reflections, Rint = 0.0967, R = 0.0361, wR = 0.0881, residual
electron density 1.195 and ꢀ1.055 e Aꢀ3, Gof = 0.950,
refinement program SHELXL-97, Nref = 7303, Npar = 376.
a = 21.093(9) A,
1
PCCH3), 35.8 (dd, JC,P = 13.3 Hz, JC,Rh = 2.0 Hz, PCH),
2
1
41.1 (d, JC,P = 21.0 Hz, PCH2), 81.7 (dd, JC,P = 4.1 Hz,
5
,
5
1JC,Rh = 2.5 Hz, PCH2CH2CCHCH), 82.6 (dd, JC,P = 4.0
1
Hz, JC,Rh = 3.0 Hz, PCH2CH2CCHCH), 85.2 (dd, JC,P
4
=
=
=
1
9.2 Hz, JC,Rh = 2.6 Hz, PCH2CH2CCH), 88.1 (dd, JC,P
4
1
7.4 Hz, JC,Rh = 2.8 Hz, PCH2CH2CCHCH), 113.1 (dd,
1
3JC,P = 6.3 Hz, JC,Rh = 4.2 Hz, PCH2CH2C) ppm.
1
31P-NMR (162 MHz, C6D6): d = 91.5 (d, JP,Rh
=
209.6 Hz) ppm. MS: m/z (%) = 394 (12) [M+], 366 (41)
[M+ ꢀ CH2QCH2], 284 (34), 224 (33), 166 (24), 82 (100)
[C6H10+], 57 (57) [t-Bu+]. HRMS (M+ = C19H32RhP) calcd
394.1296, found 394.1298.
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]indenyl}-
(g2-ethen)rhodium(I) (rac-18)
At ꢀ78 1C butyllithium in hexane (2.3 mL, 3.7 mmol, 1.6 M)
was added dropwise to tert-butylphenylphosphane (0.159 g,
3.1 mmol) in THF (15 mL). After stirring for 2 h at 20 1C
[4.5]benzospiro[2.4]hepta-4,6-diene (16, 0.440 g, 3.1 mmol)
was added. After stirring for 3 d at 65 1C the mixture was
cooled to ꢀ78 1C, and [Rh2(C2H4)Cl2] (0.720 g, 1.9 mmol) was
added, and the solution was warmed to 20 1C. After 2 h the
solvent was removed at reduced pressure, and the residue was
taken up with diethyl ether (5 mL). After filtration through a
frit covered with a 3 cm thick layer of Celite the solvent was
removed at reduced pressure, and the residue was taken up
with pentane (5 mL). Another filtration through a frit covered
with a 3 cm thick layer of Celite afforded after solvent removal
rhodium(I) chelate rac-18 [0.963 g, 2.2 mmol, 71%, diastereo-
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]-
cyclopentadienyl}iodomethyl-rhodium(II) (rac-14 and rac-15)
At 22 1C iodomethane (0.6 mL, 9.0 mmol) was added to
rhodium(I) complex rac-11 (767 mg, 1.9 mmol) in THF
(120 mL). After stirring at 22 1C for 24 h the solvent was
removed at reduced pressure, and the residue was taken up
with dichloromethane (20 mL). The mixture was filtered
through a frit covered with a 3 cm thick layer of Celite. The
filtrate was concentrated and the product was crystallized
from dichloromethane/hexane at ꢀ25 1C. The product was
obtained as a diastereomeric mixture of rac-14 and rac-15
1
(100 : 0.7, H NMR) as a red solid (593 mg, 1.2 mmol, 60%).
IR (95% de): v˜ = 2958 (m, C-H), 2893 (m, C-H), 1460 (m,
1
C-H), 1432 (m, P-Ph), 1260 (m), 1168 (w), 1125 (m), 1096 (s),
1015 (s, t-Bu), 840 (m, Cp), 797 (s, Cp), 746 (m), 698 (s) cmꢀ1
meric mixture (10 : 1, H NMR), purity Z 95% (1H NMR)]
.
as a brown oil.
1
rac-14: H-NMR (500 MHz, CDCl3): d = 1.06 (dd, J = 5.4,
2.3 Hz, 3H, RhCH3), 1.15 (d, JH,P = 14.8 Hz, 9H, CCH3),
IR (de 82%): v˜ = 3050 (w, C2H4), 2961 (m, C-H), 2356 (w),
2130 (w), 1948 (w), 1592 (w), 1430 (w, P-Ph), 1327 (w), 1260 (s,
C2H4), 1124 (m), 1091 (s), 1017 (s, t-Bu), 922 (w), 842 (m, Cp),
3
3
2.17 (d, JH,H = 6.9 Hz, JH,H = 6.0 Hz, JH,P = 34.7 Hz,
3
3
2JH,H = ꢀ14.1 Hz, 1H, PCH2CH2), 2.32 (d, 1H, JH,H = 6.0
797 (s, Cp), 731 (m), 697 (s) cmꢀ1
.
1H-NMR (400 MHz,
3
3
3
2
3
Hz, JH,H = 9.8 Hz, JH,P = 20.6 Hz, JH,H = ꢀ14.1 Hz,
CDCl3, major diastereomer): d = 0.74 (d, JH,P = 13.3 Hz,
9H, CH3), 2.11 (m, 2H, PCH2CH2), 2.47 (d, JH,H = 6.1 Hz,
3
PCH2CH2), 2.84 (d, 3JH,H = 9.8 Hz, 3JH,H = 6.9 Hz, 2JH,P
=
c
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New J. Chem., 2011, 35, 2287–2298 2295

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3
2H, QCH2), 2.75 (m, 2H, PCH2), 3.02 (dt, JH,H = 7.9,
CCHCH), 76.8 (d, JC,P = 2.4 Hz, PCH2CH2CCHCH), 83.7
(d, JC,P = 9.5 Hz, PCH2CH2CCH), 89.8 (d, JC,P = 8.2 Hz,
PCH2CH2CCH), 105.1 (d, 3JC,P = 5.9 Hz, PCH2CH2C), 127.4
3
2.0 Hz, 2H, QCH2), 5.36 (d, JH,H = 2.9 Hz, 1H, PCH2CH2-
CCHCH), 6.13 (d, 3JH,H = 2.6 Hz, 1H, PCH2CH2CCH), 6.41 (d,
3JH,H = 8.2 Hz, 1H, PCH2CH2CCCH or PCH2CH2CCH), 6.77
2
4
(d, JC,P = 9.0 Hz, o-CH), 129.3 (d, JC,P = 2.3 Hz, p-CH),
3
(t, JH,H = 7.9 Hz, 1H, PCH2CH2CCCHCH or PCH2CH2-
3
1
134.4 (d, JC,P = 9.7 Hz, m-CH), 136.5 (d, JC,P = 34.1 Hz,
PCCH) ppm. 31P NMR (162 MHz, C6D6): d = 35.3 ppm. MS:
m/z (%) = 560 (12) [M+], 450 (12) [M+ ꢀ coe], 392 (47), 366
(100), 257 (19) [M+ ꢀ Ir ꢀ coe]. HRMS (M+ = C25H36IrP)
calcd 560.2184, found 560.2180.
3
CCHCH), 6.93 (d, JH,H = 8.2 Hz, 1H, PCH2CH2CCCH or
3
PCH2CH2CCH), 7.03 (t, JH,H = 7.2 Hz, 1H, PCH2CH2-
CCCHCH or PCH2CH2CCHCH), 7.19 (m, 3H, o-, p-CH), 7.52
(m, 2H, m-H) ppm. 13C-NMR (100.6 MHz, CDCl3): d = 19.3 (d,
2JC,P = 2.4 Hz, PCH2CH2), 26.3 (d, JC,P = 4.7 Hz, CH3),
2
1
2
32.0 (d, JC,P = 16.7 Hz, JC,Rh = 3.7 Hz, CCH3), 35.2 (dd,
Chloro-{g5:g1[2-(tert-butylphenylphosphanyl)ethyl]-
cyclopentadienyl}-nickel(II) (rac-20)
2JC,P = 13.9 Hz, JC,Rh = 1.3 Hz, QCH2), 42.5 (d, JC,P
23.7 Hz, PCH2), 77.0 (dd, JC,P = 13.2 Hz, JC,Rh = 2.6 Hz,
=
1
1
5
1
At ꢀ78 1C butyllithium in hexane (6.4 mL, 10.2 mmol, 1.6 M)
was added dropwise to tert-butylphenylphosphane (1.438 g,
8.7 mmol) in THF (30 mL). After stirring at 20 1C for 2 h
spiro[2.4]hepta-4,6-diene (4, 0.9 mL, 9.0 mmol) was added,
and the solution was stirred at 65 1C for 2 h. Then the mixture
was cooled to ꢀ78 1C, and NiCl2 (1.350 g, 10.3 mmol) was
added, and the mixture was slowly warmed to 20 1C. After
stirring for 1 h the solvent was removed at reduced pressure,
and the residue was taken up with diethyl ether (5 mL). After
filtration through a frit covered with a 3 cm thick layer of
Celite, solvent removal at reduced pressure, and purification of
the residue by column chromatography (3 ꢂ 20 cm, SiO2,
TBME) rac-20 [2.122 g, 6.1 mmol, 70%, purity Z 95%
(1H-NMR)] was isolated as a purple solid, mp 105.5 1C.
IR: v˜ = 3077 (w), 2945 (m, C-H), 2916 (m), 2862 (m, C-H),
1610 (w), 1460 (m, C-H), 1437 (m, P-Ph), 1394 (w), 1361 (m,
t-Bu), 1183 (m), 1162 (m), 1102 (m), 1022 (m, t-Bu), 847 (m,
5
1
PCH2CH2CCHCH), 90.2 (dd, JC,P = 5.7 Hz, JC,Rh = 3.2 Hz,
4
PCH2CH2CCH), 102.6 (dd, JC,P = 6.3 Hz, JC,Rh
1
=
=
3
4.7 Hz, PCH2CH2CC or PCH2CH2CCC), 109.2 (d, JC,P
2.5 Hz, PCH2CH2C), 113.6 (d, 4JC,P = 2.1 Hz, PCH2CH2CC
or PCH2CH2CCC), 115.9 (PCH2CH2CCCH or PCH2CH2-
CCCCH), 118.0 (PCH2CH2CCCH or PCH2CH2CCCCH),
119.3 (PCH2CH2CCCHCH or PCH2CH2CCCCHCH), 123.4
(PCH2CH2CCCHCH or PCH2CH2CCCCHCH), 127.7 (d,
2JC,P = 9.2 Hz, o-CH), 129.5 (d, JC,P = 2.1 Hz, p-CH),
4
133.9 (dd, 1JC,P = 22.2 Hz, PCCH), 134.1 (d, 3JC,P = 11.3 Hz,
m-CH) ppm. 31P-NMR (162 MHz, C6D6): d = 84.0 (d, 1JP,Rh
= 227.7 Hz) ppm. MS (de 82%): m/z (%) = 438 (16) [M+],
410 (100) [M+ ꢀ CH2QCH2], 354 (62), 231 (18), 197 (25), 135
(30), 57 (12) [t-Bu+]. HRMS (M+ = C23H28PRh) calcd
438.0984, found 438.0987.
Cp), 785 (s, Cp), 755 (s), 688 (s), 617 (m) cmꢀ1
.
1H-NMR
{g5:g1[2-(tert-Butylphenylphosphanyl)ethyl]cyclopentadienyl}-
(g2-cycloocten)iridium(I) (rac-19)
3
(400 MHz, CDCl3): d = 1.43 (d, JH,P = 15.1 Hz, 9H, CH3),
1.39 (m, 1H, PCH2CH2), 1.45 (m, 2H, PCH2CH2), 2.44 (m,
At ꢀ78 1C butyllithium in hexane (1.1 mL, 1.7 mmol, 1.6 M)
was added dropwise to tert-butylphenylphosphane (0.269 g,
1.6 mmol) in THF (15 mL). After stirring at 22 1C for 2 h
spiro[2.4]hepta-4,6-diene (4, 0.15 mL, 1.6 mmol) was added,
and the solution was stirred at 65 1C for 2 h. Then the mixture
was cooled to ꢀ78 1C, and [Ir(coe)2Cl]2 (0.871 g, 1.0 mmol, coe
= cyclooctene) was added, and the mixture was slowly
warmed to 20 1C. After stirring for 12 h the solvent was
removed at reduced pressure, and the residue was taken up
with diethyl ether (5 mL). After filtration through a frit
covered with a 3 cm thick layer of Celite rac-19 (0.187 g,
0.3 mmol, 21%) was isolated as a yellow oil. Residual
cyclooctene could not be removed.
3
1H, PCH2), 2.69 (m, 1H, PCH2), 5.55 (dd, JH,P = 1.3,
3
2.2 Hz, 1H, PCH2CH2CCH), 5.76 (d, JH,P = 2.1 Hz, 1H,
PCH2CH2CCH), 5.82 (dt, 3JH,P = 1.5, 3.3 Hz, 1H, PCH2CH2-
3
CCHCH), 5.96 (t, JH,P = 1.7 Hz, 1H, PCH2CH2CCHCH),
2
3
7.62 (t, JH,P = 2.6 Hz, 3H, o-, p-H), 8.30 (ddd, JH,P = 1.6,
7.9, 10.1 Hz, 2H, m-H) ppm. 13C-NMR (100.6 MHz, CDCl3):
d = 22.2 (d, 2JC,P = 4.4 Hz, PCH2CH2), 25.5 (d, 2JC,P = 3.8,
CH3), 30.7 (d, 1JC,P = 21.2 Hz, PCCH3), 33.4 (d, 1JC,P = 27.0,
3
PCH2), 93.7 (PCH2CH2CCHCH), 94.6 (d, JC,P = 7.0 Hz,
4
PCH2CH2C), 96.6 (d, JC,P = 6.3 Hz, PCH2CH2CCH),
4
98.1 (PCH2CH2CCHCH), 99.6 (d, JC,P
= 5.5 Hz,
2
PCH2CH2CCH), 127.4 (d, JC,P = 9.3 Hz, o-CH), 127.8 (d,
4
1JC,P = 32.5, PCCH), 130.0 (d, JC,P = 2.3 Hz, p-CH), 132.6
IR: v˜ = 3055 (w), 2918 (s, C-H), 2855 (m, C-H), 2321 (w),
2104 (w), 1947 (w), 1623 (m), 1463 (m, C-H), 1435 (s, P-Ph),
1392 (w), 1361 (w, t-Bu), 1261 (m), 1156 (w), 1100 (s), 1015 (s,
t-Bu), 920 (w), 805 (s, Cp), 745 (s, Cp), 687 (s) cmꢀ1. 1H-NMR
3
(d, JC,P = 10.1 Hz, m-CH) ppm. 31P-NMR (162 MHz,
CDCl3): d = 99.3 ppm. MS: m/z (%) = 350 (76) [M+], 358
(100) [M+ ꢀ NiCl], 182 (50), 126 (59), 91 (11), 79 (10), 57 (13)
[t-Bu+]. HRMS (M+ = C17H22NiPCl) calcd 350.0501, found
350.0499.
2
(400 MHz, C6D6): d = 0.93 (d, JH,P = 13.0 Hz, 9H, CH3),
1.23–2.07 (m, 14H, coe-H), 2.64 (m, 2H, PCH2CH2), 2.86 (m,
2H, PCH2), 4.70 (d, JH,P = 2.4 Hz, 1H, PCH2CH2CCHCH),
4.86 (s, 1H, PCH2CH2CCH), 5.02 (s, 1H, PCH2CH2CCHCH),
5.28 (s, 1H, PCH2CH2CCH), 7.14 (m, 3H, o-, p-H), 7.93 (t,
3JH,P = 8.2 Hz, 2H, m-H) ppm. 13C-NMR (100.6 MHz,
Dichloro{g5:g1[2-(tert-butylphenylphosphanyl)ethyl]-
cyclopentadienyl}-chromium(III) (rac-21)
At ꢀ78 1C butyllithium in hexane (2.9 mL, 3.7 mmol, 1.6 M)
was added dropwise to tert-butylphenylphosphane (0.518 g,
3,1 mmol) in THF (15 mL). After stirring at 20 1C for 2 h
spiro[2.4]hepta-4,6-diene (4, 0.3 mL, 3.3 mmol) was added,
and the solution was stirred at 65 1C for 2 h. Then the mixture
2
C6D6): d = 21.6 (d, JC,P = 0.7 Hz, PCH2CH2), 27.0 (d,
2JC,P = 4.0 Hz, CH3), 31.6 (d, JC,P = 23.9 Hz, CCH3), 33.2
1
(coe-C), 34.8 (coe-C), 36.6 (coe-C), 36.8 (coe-C), 46.4 (d,
1JC,P = 46.5 Hz, PCH2), 72.0 (d, JC,P = 1.9 Hz, PCH2CH2-
c
2296 New J. Chem., 2011, 35, 2287–2298
This journal is The Royal Society of Chemistry and the Centre National de la Recherche Scientifique 2011

View Article Online
was cooled to ꢀ78 1C, and Cr(THF)3Cl3 (1.16 g, 3.1 mmol)
was added, and the mixture was slowly warmed to 20 1C. After
stirring for 12 h the solvent was removed at reduced pressure,
and the residue was washed with pentane and then taken up
with boiling toluene (10 mL). After filtration through a frit
covered with a 3 cm thick layer of Celite, the solution was
concentrated and cooled to ꢀ25 1C. rac-21 (0.570 g, 1.5 mmol,
48%) was obtained as a blue solid, mp 239.9 1C.
18 L. Yong, E. Hofer, R. Wartchow and H. Butenschon, Organo-
¨
metallics, 2003, 22, 5463–5467.
19 A. Kakoschke, L. Yong, R. Wartchow and H. Butenschon,
¨
J. Organomet. Chem., 2003, 674, 86–95.
20 L. Yong and H. Butenschon, Chem. Commun., 2002, 2852–2853.
¨
21 J. Foerstner, A. Kakoschke, R. Goddard, J. Rust, R. Wartchow
and H. Butenschon, J. Organomet. Chem., 2001, 617/618,
¨
412–422.
22 J. Foerstner, A. Kakoschke, R. Wartchow and H. Butenschon,
¨
Organometallics, 2000, 19, 2108–2113.
23 J. Foerstner, R. Wartchow and H. Butenschon, New J. Chem.,
¨
IR: v˜ = 3092 (w), 3055 (w), 2959 (w, C-H), 2361 (w), 1474
1998, 22, 1155–1157.
24 J. Foerstner, S. Kozhushkov, P. Binger, P. Wedemann,
(m, C-H), 1435 (m, P-Ph), 1366 (m, t-Bu), 1172 (m), 1100 (m),
1053 (w), 892 (w), 819 (m), 810 (s, Cp), 747 (s, Cp), 699 (s) cmꢀ1
.
M. Noltemeyer, A. de Meijere and H. Butenschon, Chem. Com-
mun., 1998, 239–240.
¨
MS: m/z (%) = 379 (30) [M+], 288 (54), 286 (100), 202 (44),
124 (26), 109 (37), 91 (36), 57 (76) [t-Bu+]. HRMS (M+
25 J. Foerstner, A. Kakoschke, D. Stellfeldt, H. Butenschon and
¨
R. Wartchow, Organometallics, 1998, 17, 893–896.
=
C17H22Cl2CrP) calcd 379.0241, found 379.0242. Anal.
(C17H22Cl2CrP) calcd C 52.86; H 7.30, found C 52.90; H 7.03.
Crystal structure analysis:45 empirical formula C17H22Cl2CrP,
molecular weight 380.22, crystal system monoclinic, space
group P21/c, a = 15.428(3) A, b = 16.376(5) A, c =
15.847(3) A, a = 90.001, b = 115.182(19)1, g = 90.001,
26 J. Foerstner, F. Olbrich and H. Butenschon, Angew. Chem., 1996,
¨
108, 1323–1325 (Angew. Chem., Int. Ed. Engl., 1996, 35, 1234–1237).
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104, 1052–1054 (Angew. Chem., Int. Ed. Engl., 1992, 31, 1066–1068).
¨
V = 3623.3(14) A3, Z = 8, dcalcd = 1.394 g cmꢀ1
F(000)=1576.0, m = 1.006 mmꢀ1, Stoe IPDS diffractometer,
T = 297 K, MoKa (l = 0.71073 A), ymin = 1.921, ymax
,
30 R. T. Kettenbach and H. Butenschon, New J. Chem., 1990, 14,
599–601.
¨
=
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26.141, 50 517 measured reflections (ꢀ18 r h r 18, ꢀ20 r
k r 20, ꢀ19 r l r 19), 7080 independent, 3591 observed
reflections, Rint = 0.1203, R = 0.0343, wR = 0.0558, residual
electron density 0.366 and ꢀ0.237 e Aꢀ3, Gof = 0.841,
refinement program SHELXL-97, Nref = 3591, Npar = 379.
Acknowledgements
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