Planar chiral alkenylferrocene phosphanes: Preparation, structural characterisation and catalytic use in asymmetric allylic alkylation

Article abstract of DOI:10.1016/j.jorganchem.2007.11.016

Planar chiral alkenylferrocene phosphanes, viz. (S_p)-[Fe(η⁵-C₅H₃-1-PPh₂-2-CH{double bond, long}CR₂)(η⁵-C₅H₅)] (R = H, (S_p)-2; Ph, (S_p)-5) and (S_p)-[Fe(η⁵-C₅H₃-1-PPh₂-2-(E)-CH{double bond, long}CHR)(η⁵-C₅H₅)] (R = Ph, (S_p)-3; C(O)CH₃, (S_p)-6; and CO₂CH₂CH₃, (S_p)-7) have been prepared by alkenylation of (S_p)-2-(diphenylphosphanyl)ferrocenecarboxaldehyde and tested as ligands for enantioselective palladium-catalysed allylic alkylation of 1,3-diphenyprop-2-en-1-yl acetate with dimethyl malonate. All phosphanylalkenes formed active catalysts. However, the induced enantioselectivity was only poor to moderate [12-43% ee after 20 h at room temperature], with the ee's and configuration of the preferred product strongly depending on the ligand structure. The catalytic results have been related to solution properties (NMR, ESI MS) and the solid-state structural data (X-ray diffraction) of [Pd(η³-1,3-Ph₂C₃H₃){(S_p)-2-η²:κP}]ClO₄ ((S_p)-12), which represent a model of the plausible reaction intermediate.

Full text of DOI:10.1016/j.jorganchem.2007.11.016

Available online at www.sciencedirect.com
Journal of Organometallic Chemistry 693 (2008) 446–456
www.elsevier.com/locate/jorganchem
Planar chiral alkenylferrocene phosphanes: Preparation,
structural characterisation and catalytic use in asymmetric
allylic alkylation
ˇ
*
´ ˇ
´
Petr Steˇpnicˇka , Martin Lamacˇ, Ivana Cısarova
Charles University in Prague, Faculty of Science, Department of Inorganic Chemistry, Hlavova 2030, 12840 Prague, Czech Republic
Received 20 August 2007; received in revised form 8 November 2007; accepted 9 November 2007
Available online 17 November 2007
Abstract
Planar chiral alkenylferrocene phosphanes, viz. (Sp)-[Fe(g5-C5H3-1-PPh2-2-CH@CR2)(g5-C5H5)] (R = H, (Sp)-2; Ph, (Sp)-5) and
(Sp)-[Fe(g5-C5H3-1-PPh2-2-(E)-CH@CHR)(g5-C5H5)] (R = Ph, (Sp)-3; C(O)CH3, (Sp)-6; and CO2CH2CH3, (Sp)-7) have been prepared
by alkenylation of (Sp)-2-(diphenylphosphanyl)ferrocenecarboxaldehyde and tested as ligands for enantioselective palladium-catalysed
allylic alkylation of 1,3-diphenyprop-2-en-1-yl acetate with dimethyl malonate. All phosphanylalkenes formed active catalysts. However,
the induced enantioselectivity was only poor to moderate [12–43% ee after 20 h at room temperature], with the ee’s and configuration of
the preferred product strongly depending on the ligand structure. The catalytic results have been related to solution properties (NMR,
ESI MS) and the solid-state structural data (X-ray diffraction) of [Pd(g3-1,3-Ph2C3H3){(Sp)-2-g2:jP}]ClO4 ((Sp)-12), which represent a
model of the plausible reaction intermediate.
Ó 2007 Elsevier B.V. All rights reserved.
Keywords: Ferrocene; Phosphanes; Alkenes; Alkenylphosphanes; Palladium; Enantioselective allylic alkylation
1. Introduction
[5,6] and, shortly afterwards, described also the prepara-
tion and coordination behaviour of its planar chiral coun-
terparts (Sp)-2 and (Sp)-3 (Scheme 1) [7]. Considering the
successful catalytic application of the chiral organic alke-
nylphosphanes [3,4], we decided to extend our studies on
chiral alkenylferrocene phosphanes further towards their
utilisation in enantioselective catalysis. In view of the coor-
dination ability of alkenylphosphanes (Sp)-2 and (Sp)-3
established earlier [7], we chose palladium-catalysed asym-
metric allylic alkylation as the testing reaction.
Apart from serving as a benchmark test reaction for chi-
ral ligands, the asymmetric allylic alkylation represents a
powerful method for stereoselective construction of new
carbon–carbon bonds. With a proper catalyst, it usually
proceeds with good yields and enantioselectivity, under
mild conditions and, above all, tolerates many reactive
functional groups, thus opening an access to stereodefined
functional allylic products that themselves are valuable
synthons [8].
Chiral bidentate ferrocene ligands are frequently used as
efficient chirality sources to various asymmetric metal-
mediated reactions. The most commonly applied ligand
families are ferrocene diphosphanes and their monophos-
phane analogues bearing an additional standard donor
moiety, i.e. ligands of the P,P-, P,N-, P,O- and P,S-types
[1]. Chiral ferrocene donors that combine a phosphane
group with potentially p-coordinating substituent(s) (e.g.,
C–C double bond) are still very uncommon [2], which con-
trasts with the current interest in catalytic and coordination
chemistry of C-chiral organic phosphanylalkene donors
[3,4].
Recently, we have reported about the coordination
properties of the achiral ferrocene phosphanylalkene 1
*
Corresponding author. Fax: +420 221 951 253.
ˇ
E-mail address: stepnic@natur.cuni.cz (P. Steˇpnicˇka).
0022-328X/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2007.11.016

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P. Steˇpnicˇka et al. / Journal of Organometallic Chemistry 693 (2008) 446–456
447
Ph
Et
TsNHNH2/AcONa
PPh
PPh
2
PPh
2
2
Fe
Fe
THF/H2O, reflux
PPh
PPh
2
2
Fe
Fe
Fe
(S )-2
p
(S )-8
p
1
(S
p
)-2
(S )-3
p
Scheme 3.
Scheme 1.
reducing agent being generated in situ from tosyl hydrazine
in the presence of sodium acetate in biphasic THF–water
mixture at reflux temperature [12].
In this contribution we report about the preparation and
catalytic use in palladium-catalysed asymmetric allylic
alkylation of a series of planar chiral alkenylferrocene
phosphanes formally derived from the archetypal com-
pound (Sp)-2. We also present the solution NMR and
solid-state X-ray structural study of complex [Pd(g3-1,3-
Ph2C3H3){(Sp)-2-g2:jP}]ClO4 ((Sp)-12), which comprises
the [Pd(g3-1,3-Ph2C3H3){(Sp)-2-g2:jP}]+ cation as the
likely reaction intermediate in the alkylation reaction.
All newly prepared compounds have been characterised
by the conventional spectral methods and their composi-
tion confirmed by combustion analysis or high-resolution
1
mass spectra. In H and 13C NMR spectra, phosphanes
5–8 show typical sets of signals due to the 1,2-disubstituted
ferrocene unit bearing the diphenylphosphanyl group. The
presence of a,b-disubstituted alkenyl moieties in (Sp)-6 and
(Sp)-7 is reflected by a pair of doublets in 1H NMR spectra
that are further split with the phosphorus. As indicated by
the 3JHH coupling constants (ca. 16 Hz), the CH@CH dou-
ble bonds in (Sp)-6 and (Sp)-7 possess the expected (E)-
geometry; signals due to the corresponding (Z)-isomers
were not detected in the spectra. On the other hand, the
spectrum of (Sp)-8 shows a binomial triplet for the terminal
methyl group while the diastereotopic methylene protons
give rise to a pair of double quartets (ABM3 spin system)
with one component showing an additional coupling with
2. Results and discussion
2.1. Synthesis and characterisation of the phosphanylalkene
ligands
The preparation of (Sp)-2 and (Sp)-3 has been reported
elsewhere [7]. Alkenylphosphanes 5–7 were synthesised
similarly by Horner–Wadsworth–Emmons alkenylation
[9] of enantiomerically pure aldehyde (Sp)-4 [10] with the
appropriate phosphonates (Scheme 2). In all cases, the olef-
ination reactions proceeded with excellent yields and gave
exclusively the (E)-configured alkenes. The products were
conveniently purified by column chromatography and iso-
lated as air stable, intensely coloured solids.
For a comparison, a monodentate, planar-only chiral
phosphane with a saturated hydrocarbyl substituent, (Sp)-
8, was also prepared. This compound was obtained by
diimide reduction [11] of alkene (Sp)-2 (Scheme 3), the
4
the phosphorus (ddq with JPH = 1.6 Hz).
The 13C NMR resonances of the double bond carbons in
(Sp)-6 and (Sp)-7 are observed as phosphorus-coupled dou-
blets with characteristic shifts [3JPC = 11–12 Hz (Ca),
4JPC = ca. 2–3 Hz (Cb)]; the 13C NMR resonance due to
CH@ in the trisubstituted alkene (Sp)-5 occurs at dC
3
124.31 with JPC = 15 Hz. By contrast, the 31P NMR sig-
nals of 5–8 are rather insensitive to changes within the
adjacent alkenyl group, occurring in a narrow range at
around dP –22.
Ph
Ph
Phosphanes 5–8 are thermally robust, showing molecu-
lar ions in EI mass spectra. Their IR spectra are rather
complicated, displaying characteristic bands due to the
functional substituents. For instance, the C@O and C@C
stretching bands in (Sp)-6 are observed at 1683 and
1599 cmꢀ1, respectively. Whereas the position of the
high-energy band corresponds well with that in methyl
vinyl ketone, the band due to C@C stretching is shifted
to lower energies (by 19 cmꢀ1) because of conjugation with
the ferrocene unit [13]. Likewise, the IR bands of (Sp)-7 at
1705 and 1626 cmꢀ1 are shifted to lower frequencies than
the corresponding bands in ethyl (E)-cinnamate (by ca.
10 and 17 cmꢀ1, respectively) [14].
(EtO) P(O)CPh /LiBu
2
2
PPh
2
Fe
º
THF, 25 C
(
S
)-5
p
O
CHO
Me
(EtO) P(O)CH C(O)Me/NaH
2
2
PPh
PPh
2
2
Fe
Fe
toluene, 60 ºC
(
S
)-4
p
(S
)-6
p
The phosphanylalkenes are intensely coloured solids,
the colour of which changes with the nature of the alkenyl
substituent. The vinyl derivative (Sp)-2 and its phenylated
analogues (Sp)-3 and (Sp)-5 are rusty brown while
compounds (Sp)-6 and (Sp)-7 bearing the conjugated
CH@CHC(O) moiety are deep burgundy red. The extent
CO
Et
2
(EtO) P(O)CH CO Et/NaH
2
2
2
PPh
2
Fe
toluene, 60 ºC
(S
)-7
p
Scheme 2.

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P. Steˇpnicˇka et al. / Journal of Organometallic Chemistry 693 (2008) 446–456
448
is shown in Fig. 2 and the selected geometric data are given
in Table 1. The ferrocene unit in (Sp)-6 shows a negligible
tilt and practically identical Fe-ring centroid distances.
Although the ferrocene substituents do not cause any
notable torsion to their parent cyclopentadienyl ring as
evidenced by the torsion angle s(C(23)–C(1)–C(2)–
P) = 1.8(3)°, they bind somewhat asymmetrically: Whereas
the C(2/5)–C(1)–C(23) angles differ by only 2.2°, the differ-
ence between the C(1/3)–C(2)–P angles is 5.4°. The phos-
phanyl group is oriented so that one of its phenyl rings is
directed above the ferrocene unit while the other extends
away from the alkenyl substituent.
Interatomic distances within the oxobutenyl group com-
pare favourably with those in (E)-4-phenylbut-3-en-2-one
[15]. The unsaturated moiety has the expected trans-geom-
etry at the double [torsion angle s(C(1)–C(23)–C(24)–
C(25)) = ꢀ 179.7(2)°] and extends away from the phosphanyl
Fig. 1. UV–Vis (top) and CD spectra (bottom) of (Sp)-2 (solid line), (Sp)-6
(dashed line), and (Sp)-7 (dotted line) as recorded on methanol solutions
(0.45 mg/mL; optical path 0.5 mm). The inset shows the expansion of the
low-energy region of the UV–Vis spectra.
Fig. 2. View of the molecular structure of (Sp)-6. Displacement ellipsoids
are shown with 30% probability.
of the p-conjugated chromophore is nicely reflected in UV–
Vis spectra (Fig. 1, top). In the visible region, (Sp)-2 has
only a relatively weak, broad band at ca. 460 nm [log(e/
1 Mꢀ1 cmꢀ1) ꢁ 2.4]. Compounds (Sp)-6 and (Sp)-7 display
similar bands at practically identical positions but with a
slightly higher intensities. In addition, however, the car-
bonyl compounds possess additional stronger bands at
378 and 374 nm [log(e/1 Mꢀ1 cmꢀ1) = 3.31 and 3.40],
respectively, that account for their deep red colour. Further
bands occur at higher energies at the slope of much stron-
ger bands extending from the UV region. Their position
again varies with the type of the p-system [kmax: (Sp)-2
ca. 270 nm, (Sp)-6 and (Sp)-7 ca. 300 nm].
Table 1
a
˚
Selected distances and angles [in A and °] for (Sp)-6
Distances
Fe–Cg(1)
Fe–Cg(2)
P–C(2)
P–C(11)
P–C(17)
C(1)–C(23)
C(23)–C(24)
C(24)–C(25)
C(25)-O
1.645(1)
1.659(1)
1.818(2)
1.833(2)
1.841(2)
1.448(3)
1.330(3)
1.467(3)
1.219(3)
1.490(3)
C(25)–C(26)
CD spectra (Fig. 1, bottom) confirm identical configura-
tions at the chirality plane. All compounds show a weak
positive Cotton effect at around 460 nm. The CD spectra
of the carbonyl derivatives exhibit an additional, positive
Cotton band at around 290 nm.
Angles
\Cp(1), Cp(2)
0.9(2)
100.2(1)–102.3(1)
126.4(2)
122.2(2)
121.7(2)
C–P–Cb
C(1)–C(23)–C(24)
C(23)–C(24)–C(25)
C(24)–C(25)-O
C(24)–C(25)–C(26)
a
117.0(2)
2.2. The crystal structure of (Sp)-6
The ring planes are defined as follows: Cp(1) = C(1–5), Cp(2) = C(6–
10). Cg(1,2) are the respective ring centroids.
The structure of (Sp)-6 has been determined by single-
crystal X-ray diffraction. View of the molecular structure
b
The range of C(2)–P–C(11,C17) and C(11)–P–C(17) angles.

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P. Steˇpnicˇka et al. / Journal of Organometallic Chemistry 693 (2008) 446–456
449
Ph
Ph
Ph
Ph
group. Because of conjugation, the C(23)@C(24) double
bond is practically coplanar with the Cp(1) ring. The car-
bonyl carbon atom of the acetyl moiety, C(25), does not
deviate from Cp(1) plane either. However, the acetyl group
is rotated from the Cp(1) plane by 12.9(3)° along the
C(24)–C(25) bond with the C(26) atom being more distant
from both the iron centre and the phosphane group [16].
In crystal, the individual molecules of (Sp)-6 associate
via C(3)–H(3)ꢂ ꢂ ꢂO hydrogen bonds to form infinite helical
chains along the 21 screw axes parallel to the crystallo-
graphic c-axis (space group P212121; Fig. 3). This interac-
tion appears to be the chief force towards intermolecular
aggregation, leading to an antiparallel orientation of the
molecular dipoles.
NOESY spectra suggest that the conformation of (Sp)-6
encountered in the solid-state is retained also in solution.
The spectrum recorded at 25 °C in CDCl3 shows NOE cor-
relation for the terminal methyl group at dH 2.24 and the
CH@ group attached to the ferrocene unit (CHa at dH
7.71) and correlation between the @CHb (dH 6.38) and
the adjacent CH hydrogen of the ferrocene unit (dH
4.85). Apparently, the transoid-configuration of the C@O
and C@C bonds and coplanar disposition of the unsatu-
rated chain and the Cp(1) ring is energetically favoured
owing to extensive conjugation of the p-systems.
*
[PdL ]
O
Me
H2C(CO2Me)2/base
CO2Me
MeO2C
O
9
10
Scheme 4.
rather random influence on the enantioselectivity. This
becomes evident even from a comparison of the perfor-
mance of the simplest ligand (Sp)-2 and its phenylated
derivatives (Sp)-3 and (Sp)-5 (entries 1–3). Whereas the
catalytic systems based on (Sp)-2 produces predominantly
(R)-10, those involving (Sp)-3 and (Sp)-5 give mainly the
(S)-configured product, with the ee increasing with bulki-
ness of the ligand. Similar situation is observed for the
ligands bearing the carbonyl substituents (entries 4 and 5).
The catalyst resulting from (Sp)-8 afforded 10 enriched with
the (R)-enantiomer, similarly to (Sp)-2 albeit with a lower
stereodiscrimination. The use two equivalents of (Sp)-8
per palladium did not change the result (entries 6 and 7).
Subsequently, the reaction conditions were optimised
for the catalytic system based on (Sp)-2 by surveying alkali
metal acetates as the base additive and the reaction temper-
ature (entries 1 and 8–14). The reaction performed with
LiOAc afforded the alkylation product with complete con-
version but with the lowest enantioselectivity. On the other
hand, the reactions carried out in the presence of the hea-
vier alkali metal acetates gave the product with similar
ee’s but in varying conversions, the reaction rate decreasing
with increasing size of the cation. Notably, the reaction
performed without the base additive proceeded as well –
with very similar ee but only 50% conversion over 20 h
(entry 8). Lowering of the reaction temperature had no sig-
nificant beneficiary effect. Cooling to 0 and ꢀ25 °C dramat-
ically reduced the reaction rate while the ee increased only
slightly.
2.3. Catalytic study
Catalytic ability of 2–8 was probed in palladium-cataly-
sed asymmetric allylic alkylation of racemic 1,3-diphenyl-
prop-2-en-1-yl acetate (9) [8], using dimethyl malonate
and N,O-bis(trimethylsilyl)acetamide (BSA)/potassium
acetate as the nucleophile source [17] and pre-catalysts
formed in situ by mixing [{Pd(l-Cl)(g3-C3H5)}2] with a
slight excess of the appropriate ligand (Scheme 4). All reac-
tions were carried out in dichloromethane at room temper-
ature unless noted otherwise. The results are presented in
Table 2.
The alkylation reactions proceeded with complete con-
versions but with only poor to moderate enantioselectivity
(entries 1–7 in Table 2). A closer inspection of the data
indicates that the ligand structure has a pronounced but
2.4. Preparation and structural characterisation of [Pd(g3-
1,3-Ph2C3H3){(Sp)-2}]+
In order to determine factors controlling the sterochem-
ical course of the alkylation reaction, we studied the cation
[Pd(g3-1,3-Ph2C3H3){(Sp)-2}]+ as the putative reaction
intermediate.
Complex
[Pd(g3-1,3-Ph2C3H3){(Sp)-2-
g2:jP}]ClO4 ((Sp)-12) was synthesised by cleavage of dimer
11 with the stoichiometric amount of (Sp)-2 followed by
treatment with silver(I) perchlorate as a halide scavenger
(Scheme 5). Subsequent crystallisation from dichlorometh-
ane/acetone–diethyl ether mixture gave CH2Cl2-solvated
(Sp)-12 as a dark red, microcrystalline solid.
b
d
c
a
The structure of the complex has been established by
single-crystal X-ray diffraction analysis for the solvate
(Sp)-12 ꢂ CH2Cl2. View of the molecular structure is shown
in Fig. 4a and the selected geometric data are given in
Table 3.
Fig. 3. Section of the hydrogen bonded chains in the structure of (Sp)-6.
˚
Selected data: C(3)ꢂ ꢂ ꢂO = 3.142(3) A, angle at H(3) = 124°. Symmetry
operations: a, 1/2 ꢀ x, 1 ꢀ y, ꢀ1/2 + z; b, x, y, z; c, 1/2 ꢀ x, 1 ꢀ y, 1/2 + z;
and d, x, y, 1 + z.

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P. Steˇpnicˇka et al. / Journal of Organometallic Chemistry 693 (2008) 446–456
450
Table 2
Application of the chiral ligands to palladium-catalysed enantioselective allylic alkylationa
Entry
Ligand
T (°C)
Additive
Conversion (%)b
ee (%) [config.]c
1
2
3
4
5
6
7
8
(Sp)-2
(Sp)-3
(Sp)-5
(Sp)-6
(R)-7
(Sp)-8
(Sp)-8d
(Sp)-2
(Sp)-2
(Sp)-2
(Sp)-2
(Sp)-2
(Sp)-2
(Sp)-2
22
22
22
22
22
22
22
22
22
22
22
22
0
KOAc
KOAc
KOAc
KOAc
KOAc
KOAc
KOAc
None
LiOAc
NaOAc
RbOAc
CsOAc
KOAc
KOAc
100 (93)
100 (92)
100
100
100
100
100
50
100
100
90
74
58
32 [R]
22 [S]
43 [S]
26 [S]
12 [R]
18 [R]
18 [R]
33 [R]
18 [R]
29 [R]
33 [R]
33 [R]
37 [R]
44 [R]
9
10
11
12
13
14
a
–25
16
Common details: reaction time 20 h, 5 mol% of Pd-catalyst generated in situ. The results are an average of two runs. For detailed conditions, see
Section 2.
b
Conversion determined by 1H NMR spectroscopy. The isolated yields are given in parentheses.
Absolute configuration has been assigned via comparison of the sign of the optical rotation with the literature data [29].
This reaction was performed with two molar equivalents of (Sp)-8 per palladium.
c
d
phorus lone pair with the ferrocene cyclopentadienyl. Fur-
ClO4
thermore, the conformation of the ligand changes so as to
allow for an efficient chelation. First, the double bond in
the complex is rotated above the ferrocene unit, intersect-
ing the least-squares Cp(1) plane at an angle of 40.8(2)°
(cf. 7.4(2)° for (Sp)-2). Second, the phosphane group
becomes inclined towards the vinyl group. Whereas the
C(1/3)–C(2)–P diverge by as much as 12.8°, the vinyl moi-
ety binds to the Cp(1) ring more symmetrically, with the
C(2/5)–C(1)–C(23) angles differing only by 3.6°.
Ph
Ph
Ph
Ph
Cl
Cl
Ph
Ph
Pd
1. (
S )-2
p
1
2
P
Pd
Pd
Fe
Ph
2. AgClO4
– AgCl
Ph
(
S
p
)-12
11
Scheme 5.
The geometry of the Pd((Sp)-2) part is quite regular: the
Upon going from free (Sp)-2 [7] to the complexed form,
there is noted a slight lengthening of the double bond (ca.
0.02 A). The C(2)–P bond is elongated as well (0.03 A),
presumably due to a diminished conjugation of the phos-
˚
Pd–P and Pd–Cg(3) distances differ by less than 0.08 A and
˚
˚
the P–Pd–Cg(3) angle is by only 3° more acute than the
ideal value of 90° (N.B. Cg(3) denotes the geometric centre
a
b
O(1)
Fe
O(3)
Cl
C(18)
C(2)
C(12)
C(6)
O(2)
C(17)
C(1)
C(7)
C(23)
O(4)
P
C(11)
C(24)
c
Pd
C(29)
C(28)
C(34)
C(35)
C(27)
C(25)
C(26)
Fig. 4. (a) View of the molecular structure of the complex in the crystals of solvate (Sp)-12 ꢂ CH2Cl2 showing the atom-labelling scheme. Displacement
ellipsoids are drawn with 30% probability. (b,c) Space filling models of the cation in (Sp)-12 as viewed (b) along the C(25)–C(27) line and (c) perpendicular
to the plane of the g3-allyl moiety.

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P. Steˇpnicˇka et al. / Journal of Organometallic Chemistry 693 (2008) 446–456
451
Table 3
a
˚
Selected distances and angles [in A and °] for (Sp)-12 ꢂ CH2Cl2
Distances
Angles
Pd–P
2.3215(9)
2.245(4)
2.403(3)
2.284(4)
2.221(3)
2.188(3)
2.199(3)
1.640(2)
1.659(2)
1.786(3)–1.824(3)
1.351(4)
1.464(4)
1.394(5)
1.410(5)
P–Pd–Cg(3)
87.04(9)
84.47(8)/90.01(9)
98.0(1)
Pd–Cg(3)
Pd–C(23)
Pd–C(24)
Pd–C(25)
Pd–C(26)
Pd–C(27)
Fe–Cg(1)
Fe–Cg(2)
P–Cb
C(23)–C(24)
C(1)–C(23)
C(25)–C(26)
C(26)–C(27)
a
P–Pd–C(23/24)
Cg(3)–Pd–C(25)
Cg(3)–Pd–C(27)
P–Pd–C(25)
163.4(1)
171.18(7)
109.15(9)
66.4(1)
4.6(2)
102.9(2)–108.1(2)
123.1(3)
119.5(2)
132.3(3)
124.6(3)
128.2(3)
P–Pd–C(27)
C(25)–Pd–C(27)
\Cp(1), Cp(2)
C–P–Cc
C(1)–C(23)–C(24)
C(1)–C(2)–P
C(3)–C(2)–P
C(2)–C(1)–C(23)
C(5)–C(1)–C(23)
The ring planes are defined as follows: Cp(1) = plane C(1–5), Cp(2) = plane C(6–10). Cg(1,2) denote the centroids of the cyclopentadienyl ring Cp(1,2)
while Cg(3) stands for the midpoint of the C(23)@C(24) double bond.
b
The range of the P–C(2,11,17) distances.
The range of the C(2)–P–C(11,17) and C(11)–P–C(17) angles.
c
of the C(23)–C(24) double bond). By contrast, the (g3-
allyl)Pd moiety is considerably twisted. The allyl plane
C(25–27) and the plane comprising Pd, P, and Cg(3) inter-
a
b
C(27)
C(11)
˚
sect each other at an angle of 68.8(3) A so that the meso
carbon atom is the most distant from the ferrocene moiety.
In accordance with (thermodynamic) trans-influence [18],
the Pd–C(25) bond trans to phosphorus is longer that the
Pd–C(27) bond located trans to the g2-coordinated double
Pd
H(27)
P
C(17)
O(4B)
C(4)
H(4)
O(1A)
˚
Fe
bond (by 0.022 A); the shortest, however, being the bond to
the meso carbon atom C(26). As a consequence of steric
demands of the bulky phosphanyl group, the P–Pd–C(26)
angle (142.6(1)°) is less acute that the complementary angle
Cg(3)–Pd–C(26) (126.0(1)°).
Each complex cation in the crystal interacts with two
neighbouring perchlorate ions by means of hydrogen
bonds between the H(4) and H(27) and perchlorate oxy-
gens (Fig. 5a). The anions thus act as bridges between cat-
ions related by translation along the b-axis, which in turn
gives rise to infinite alternating chains running parallel to
the crystallographic b-axis (Fig. 5b).
b direction
In solution, complex (Sp)-12 dissociates producing
intact cations [Pd(g3-1,3-Ph2C3H3)(2)]+, that are observed
as intense peaks at m/z 695 in the ESI+ mass spectra. How-
ever, solution NMR spectra revealed the cation in (Sp)-12
to exist as a mixture of isomers differing presumably by
conformation of the allyl moiety [19]. The 31P{1H} NMR
spectrum recorded at 25 °C displays only very broad,
asymmetric signal (Fig. 6). Upon cooling to 0 and
ꢀ25 °C (Fig. 6), four distinct signals separate that can be
tentatively assigned to species involving the isomeric forms
of the g3-allyl moiety (N.B. Only four of the eight possible
conformers resulting by exhaustive permutations in the
exo/endo–syn/anti–syn/anti set were detected) [20]. Unfor-
tunately, a more detailed structural analysis by means of
1H NMR, COSY, and NOESY spectra was not feasible
due to extensive overlaps of the signals.
Fig. 5. (a) Hydrogen bonding interactions between the complex cation
and the neighbouring perchlorate counter ions in the crystal of (Sp)-
12 ꢂ CH2Cl2. Geometric data: C(27)–H(27)ꢂ ꢂ ꢂO(1A), C(27)ꢂ ꢂ ꢂO(1A) =
˚
3.291(4) A, angle at H(4) = 137°; C(4)–H(4)ꢂ ꢂ ꢂO(4B), C(4)ꢂ ꢂ ꢂO(4B) =
˚
3.194(4) A, angle at H(4) = 124°; symmetry operations (A) = 3/2 ꢀ x, ꢀ1/
2 + y, 2 ꢀ z; (B) = 3/2 ꢀ x, 1/2 + y, 2 ꢀ z. Note that the Cꢂ ꢂ ꢂO distances
˚
are nearly equal to the sum of the van der Waals radii (about 3.2 A).
(b) Section of the infinite hydrogen chains in the crystal of (Sp)-12 ꢂ
CH2Cl2. The solvent molecules are omitted.
Nonetheless, the collected structural information pro-
vides a good base for rationalisation of the catalytic results.
The solid-state structure revealed the exo–syn–syn geome-
try for (Sp)-12 which is the obvious precursor to the major
product (R)-10 provided that the nucleophilic attack occurs
at the site opposite to the donor with relatively stronger
trans influence (i.e., trans to phosphorus; this assumption

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452
steric requirements of the Pd(g3-allyl)+ unit and, above
all, provide a much better access for the nucleophile.
a
b
3. Summary
A range of planar-only chiral, ferrocene-based alkenyl-
phosphanes can be conveniently accessed via alkenylation
of aldehyde (Sp)-4. These phosphanylalkene donors readily
coordinate to palladium as g2:jP-chelating donors, form-
ing complexes that are capable of promoting asymmetric
allylic alkylation of racemic diphenylallyl acetate (9) with
dimethyl malonate. The alkylation reactions proceed with
complete conversions but only modest enantioselectivity
that does not match that of other planar-only chiral biden-
tate ferrocene ligands [1,8,23]. Based on the solid-state
structural data and solution dynamics of complex (Sp)-
12, which may serve as a model of the anticipated reaction
intermediate [(L–L0)Pd(g3-PhC3H3Ph)]+, the limited ste-
reodiscrimination can be accounted for by a structural mis-
match within the g3-allyl intermediate that, in turn, results
in its stereochemical non-rigidity and lowers the preference
among the reaction intermediates.
36
32
28
24
20
16
ppm
Fig. 6. 31P{1H} NMR spectra (161.9 MHz) of (Sp)-12 recorded in CD2Cl2
at (a) 25 and (b) ꢀ25 °C. The spectra have been recorded on the same
solution but with 24000 (a) and 280 (b) transitions (exponential weighting
was applied to both FIDs; line broadening = 3 Hz).
is supported by Pd–C(25) > Pd–C(27)) [21]. Although any
relation between the solution and solid-state data might
be considered far reaching, in the present case it is justified
by mechanistic studies that indicate the more populated
intermediate (i.e., a species thermodynamically preferred
in solution and perhaps also in the solid state) to afford
the more abundant product enantiomer [22].
4. Experimental
4.1. Materials and methods
Besides, the solid-state structure of (Sp)-12 accounts for
the presence of different reaction intermediates and, hence,
only modest enantioselectivity. A plausible explanation can
be sought in structural mismatch between the phos-
phanylalkene ligand and the Pd(g3-1,3-Ph2C3H3) moiety.
Since the double bond is directly connected to the ferrocene
moiety, formation of chelate complexes from 2–8 is only
possible after rotation of the alkenyl side arm, preferably
above the ferrocene unit. The formed donor pocket accom-
modates the Pd(g3-1,3-Ph2C3H3)+ moiety at the side of the
ferrocene group so that it sterically interacts with it (see
the space filling model in Fig. 4b and c). Consequently,
there is no pronounced steric preference for a particular
conformation and orientation of the allyl moiety, which
in turn results in the observed fluxional behaviour. Since
the enantioselectivity is determined by reactivity of the
individual allylic species and their exchange rate, the cata-
lysts produce both (S)-10 and (R)-10 with only low enan-
tiodiscrimination and varying preference for a single
enantiomer. This unfavourable situation can only partly
be improved by changing the double bond substituents.
When compared with the analogous catalytic system
featuring (1S,4R,7S)-7-(diphenylphosphanyl)-2-phenylnor-
bornene as the g2:jP-donor [3a], the ferrocene donors
induce lower ee’s under similar reaction conditions. The
observed difference may be again attributed to steric prop-
erties. First, the organic ligand is much less sterically
encumbered, which is reflected in the conformer equilib-
rium (only two isomers in the 56:44 ratio were detected
in CDCl3). Second, the spatial arrangement of the donor
groups in the organic ligand may better comply with the
All syntheses were performed under an argon
atmosphere and with exclusion of the direct daylight. Tet-
rahydrofuran (THF) was distilled from potassium-benzo-
phenone ketyl. Toluene was dried over sodium or
potassium metals and distilled. Dichloromethane was dried
over anhydrous potassium carbonate. Compounds (Sp)-2
and (Sp)-3 [7], (Sp)-4 [10], Ph2CHP(O)(OEt)2 [24], racemic
1,3-diphenylallyl acetate (9) [25], and di-l-chloridobis(g3-
1,3-diphenylallyl)dipalladium(II) (11) [26] were synthesised
by the literature procedures. Other chemicals and solvents
were used as received from commercial sources (Fluka,
Aldrich; solvents from Penta).
NMR spectra were measured on a Varian UNITY Inova
400 spectrometer at 25 °C unless noted otherwise. Chemical
shifts (d/ppm) are given relative to internal tetramethylsilane
(1H and 13C) or to an external 85% aqueous H3PO4 (31P).
The assignment of the NMR signals is based on COSY,
NOESY, 13C gHSQC, and 13C gHMBC two-dimensional
spectra. IR spectra were recorded on an FT IR Nicolet
Magna 760 instrument in the range of 400–4000 cmꢀ1. Mass
spectra were obtained on a ZAB-SEQ VG Analytical spec-
trometer. Electrospray (ESI) mass spectra were recorded
with a Bruker Esquire 3000 spectrometer on methanol solu-
tions. CD spectra were obtained with a Jobin Yvon-Spex
CD6 spectrometer at room temperature (methanol solutions
0.9 mg/2 mL: c = 1.14 mM for (Sp)-2, 1.03 mM for (Sp)-6,
and 0.96 mM for (Sp)-7; optical path 0.5 mm). Optical rota-
tions were determined with an automatic polarimeter Auto-
pol III (Rudolph Research) at room temperature.

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453
Safety Note. CAUTION! Although we have not encoun-
tered any problems it should be noted that perchlorate salts
of metal complexes with organic ligands are potentially
explosive and should be handled only in small quantities
and with great care.
with diethyl (2-oxopropyl)phosphonate (1.0 mL, 5.2 mmol)
whereupon the solid hydride dissolved with effervescence.
After stirring at 0 °C for another 15 min, a solution of
(Sp)-4 (798 mg, 2.0 mmol) in warm toluene (20 mL) was
added. The resulting mixture was transferred to an oil bath
kept at 60 °C and stirred for 18 h (the colour changed from
orange to orange red). The reaction was terminated by
addition of brine; the organic layer was separated, washed
with brine, dried over magnesium sulfate, and evaporated
under vacuum. Subsequent purification of the dark red res-
idue by column chromatography (silica gel, hexane–ether
1:2; first red band collected) afforded pure (Sp)-6 as a deep
red solid. Yield: 746 mg (85%). The compound can be
recrystallised from hot heptane.
4.2. Preparation of (Sp)-1-(diphenylphosphanyl)-2-(2,2-
diphenylvinyl)ferrocene [(Sp)-5]
Butyl lithium (0.8 mL of 2.5 M solution in hexanes,
2.0 mmol) was added to a stirred solution of Ph2CHP(O)-
(OEt)2 (760 mg, 2.5 mmol) in dry THF (10 mL) with cool-
ing in an ice bath. After the formed brown solution was
stirred at 0 °C for 30 min, a solution of aldehyde (Sp)-4
(399 mg, 1.0 mmol) in THF (10 mL) was added. The cool-
ing bath was removed and the reaction mixture was stirred
for 16 h, whereupon its colour changed to bright orange
red. The reaction was terminated by addition of brine
and the mixture diluted with diethyl ether. The organic
layer was separated, washed with brine and dried over
MgSO4. Subsequent evaporation afforded crude product
as a red orange oil, which was purified by column chroma-
tography (silica gel, hexane–diethyl ether 1:1). The first
orange band was collected and evaporated to give (Sp)-5
as an orange brown solid. Yield: 498 mg (91%).
1H NMR (CDCl3): d 2.24 (s, 3H, C(O)CH3), 4.01 (dt,
1H, CH of C5H3), 4.06 (s, 5H, C5H5), 4.58 (t, 1H, CH of
3
C5H3), 4.85 (dt, 1H, CH of C5H3), 6.38 (dd, JHH = 16.1,
5JPH = 1.2 Hz, 1H, CH@CHC(O)CH3), 7.08–7.62 (m,
3
4
10H, PPh2), 7.71 (dd, JHH = 16.1, JPH = 2.8 Hz, 1H,
CH@CHC(O)CH3). 13C{1H} NMR (CDCl3): d 26.66
(C(O)CH3), 68.99 (d, JPC = 3 Hz, CH of C5H3), 70.87
(C5H5), 72.39 (CH of C5H3), 74.52 (d, JPC = 4 Hz, CH of
1
C5H3), 79.29 (d, JPC = 12 Hz, C–P of C5H3), 83.88 (d,
2JPC = 21 Hz, C–CH@CH of C5H3), 126.01 (d,
4JPC ꢁ 2 Hz, CH@CHC(O)CH3), 128.13 (d, JPC = 15 Hz),
128.27, 128.32 (d, JPC = 9 Hz), 129.45, 132.04 (d,
JPC = 18 Hz), 135.06 (d, JPC = 21 Hz) (CH of PPh2);
1H NMR (CDCl3): d 3.61 (dt, 1H, CH of C5H3), 3.70 (dt,
1H, CH of C5H3), 4.04 (s, 5H, C5H5), 4.10 (t, 1H, CH of
C5H3), 7.14–7.82 (m, 21H, Ph and @CH). 13C{1H} NMR
(CDCl3): d 70.20 (C5H5), 70.38 (CH of C5H3), 70.60 (d,
JPC = 2 Hz, CH of C5H3), 71.61 (d, JPC = 4 Hz, CH of
1
136.58, 139.24 (2ꢃ d, JPC = 10 Hz, Cipso of PPh2),
3
143.63 (d, JPC = 12 Hz, CH@CHC(O)CH3), 198.20
(C(O)CH3). Note: tentative assignment is given for CH car-
bons of PPh2 due to extensive overlaps in the region
around dC 128.2. 31P{1H} NMR (CDCl3): d ꢀ22.8 (s). IR
(Nujol): m 1683 (s), 1599 (s), 1260 (m), 1236 (s), 1170 (s),
1106 (m), 1068 (m), 1042 (s), 1000 (s), 976 (s), 915 (s),
743 (s), 830 (s), 808 (s), 751 (vs), 700 (vs), 591 (s), 509 (s),
479 (vs), 464 (s) cmꢀ1. MS (EI+): m/z (relative abundance)
438 (29, M+ꢀ), 395 (100, [MꢀCOMe]+), 372 (12), 318 (23).
HR MS calcd. for C26H2356FeOP 438.0836, found
438.0839. Anal. Calc. for C26H23FeOP (438.26): C, 71.25;
H, 5.29. Found: C, 70.87; H, 5.27%.
1
C5H3), 78.10 (d, JPC = 7 Hz, C–P of C5H3), 87.48 (d,
2JPC = 10 Hz, C–CH@CPh2 of C5H3), 124.31 (d,
3JPC = 15 Hz, CH@CPh2), 126.81, 126.91 (2C), 127.14,
127.84 (CH of @CPh2); 128.09 (d, JPC = 6 Hz, CH of
PPh2), 128.11 (2C, CH of @CPh2), 128.22 (d, JPC = 7 Hz,
CH of PPh2), 128.53 (CH of PPh2), 129.11, 130.03 (CH of
@CPh2); 130.19 (CH of PPh2), 132.20 (d, JPC = 18 Hz,
CH of PPh2), 132.38 (CH of @CPh2), 135.08 (d,
1
JPC = 21 Hz, CH of PPh2), 137.34 (d, JPC = 9 Hz, Cipso
of PPh2), 139.61 (Cipso of @CPh2 or @CPh2), 139.73 (d,
1JPC = 11 Hz, Cipso of PPh2), 141.13, 142.37 (Cipso of
@CPh2 or @CPh2). Note: tentative assignment is given for
phenyl carbon atoms due to extensive overlaps in the aro-
matic region. 31P{1H} NMR (CDCl3): d ꢀ21.6 (s). IR
(Nujol): m 1660 (m), 1597 (m), 1317 (m), 1276 (m), 1166
(m), 1106 (m), 1071 (m), 1027 (m), 1000 (m), 940 (m), 918
(m), 817 (s), 763 (s), 742 (vs), 698 (vs), 638 (s), 627 (s), 584
(m), 526 (s), 500 (s), 483 (s), 467 (s), 451 (s) cmꢀ1. MS
(EI+): m/z (relative abundance) 548 (2, M+ꢀ), 364 (9), 340
(8), 182 (28), 105 (100), 77 (85), 51 (39). HR MS calcd.
for C36H2956FeP 548.1356, found: 548.1342.
4.4. Preparation of ethyl (E,Sp)-[2-(diphenylphosphanyl)-
ferrocenyl]propenoate [(Sp)-7]
Triethyl phosphonoacetate (3.0 mL, 15 mmol) was
slowly added to an ice-cooled suspension of sodium
hydride (0.246 g, 10 mmol) in toluene (15 mL). The hydride
dissolved rapidly with copious gas evolution (hydrogen) to
give a clear colourless solution. After stirring for 15 min at
0 °C, a solution of (Sp)-4 (2.005 g, 5.0 mmol) in warm tol-
uene (35 mL) was introduced and the reaction vessel was
transferred to an oil bath kept at 60 °C. After stirring at
this temperature for 16 h (the reaction solution turns from
orange to deep orange red), the mixture was quenched by
addition of water and diluted with little diethyl ether.
The organic layer was separated, washed with brine, dried
(MgSO4), and evaporated. The deep red oily residue was
4.3. Preparation of (E,Sp)-1-(diphenylphosphanyl)-2-(3-
oxobut-1-en-1-yl)ferrocene [(Sp)-6]
An ice-cooled suspension of sodium hydride (92 mg,
3.8 mmol) in dry toluene (20 mL) was treated dropwise

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454
purified by chromatography on silica gel with diethyl
ether–hexane (2:1) as the eluent. Collecting the first red
band and careful evaporation gave (Sp)-7 as a deep red
gummy material, which solidifies upon standing at room
temperature. Yield: 2.082 g (89%).
(d, JPC = 4 Hz, CH of C5H3), 74.26 (br s, C–P of C5H3),
96.22 (d, JPC = 24 Hz, C–Et of C5H3), 128.03 (d,
2
JPC = 7 Hz, CH of PPh2), 128.10 (d, JPC = 7 Hz, CH of
PPh2), 128.14 (d, JPC ꢁ 1 Hz, CH of PPh2), 129.08 (d,
JPC ꢁ 1 Hz, CH of PPh2), 132.39 (d, JPC = 18 Hz, CH of
PPh2), 134.87 (d, JPC = 20 Hz, CH of PPh2), 136.98 (d,
3
1H NMR (CDCl3): d 1.29 (t, JHH = 7.2 Hz, 3H,
1
CH2CH3), 3.94 (dt, 1H, CH of C5H3), 4.05 (s, 5H,
1JPC = 6 Hz, Cipso of PPh2), 139.25 (d, JPC = 8 Hz, Cipso
3
C5H5), 4.18 (q, JHH = 7.2 Hz, 2H, CH2CH3), 4.53 (t,
of PPh2). 31P{1H} NMR (CDCl3): d ꢀ22.1 (s). IR (Nujol):
m 1583 (m), 1306 (m), 1169 (s), 1105 (s), 1087 (m), 1069 (m),
1036 (s), 1001 (s), 836 (m), 827 (s), 814 (s), 743 (s), 698 (s),
572 (m), 497 (s), 483 (s), 455 (s) cmꢀ1. MS (EI+): m/z (rel-
ative abundance) 399 (29), 398 (100, M+ꢀ), 396 (7), 321 (4),
277 (4), 213 (16, [MꢀPPh2]+), 212 (7), 183 (11,
[PPh2ꢀ2H]+), 121 (9, [C5H5Fe]+), 56 (4, Fe+). HR MS
1H, CH of C5H3), 4.82 (dt, 1H, CH of C5H3), 6.12 (d,
3JHH = 15.7 Hz, 1 H, CH@CHCO2Et), 7.05–7.62 (m,
3
4
10H, PPh2), 7.86 (dd, JHH = 15.7 Hz, JPH = 2.2 Hz, 1H,
CH@CHCO2Et). 13C{1H} NMR (CDCl3):
d
14.34
(CH2CH3), 60.13 (CH2CH3), 69.12 (d, JPC = 3 Hz, CH of
C5H3), 70.77 (C5H5), 72.03 (CH of C5H3), 74.11 (d,
JPC = 4 Hz, CH of C5H3), 78.87 (d, JPC = 12 Hz, C–P of
calcd. for C24H2356FeP 398.0887, found 398.0876.
1
2
22 °C
C5H3), 84.14 (d, JPC = 22 Hz, C–CH@CH of C5H3),
[a]D
ꢀ265 (c = 0.5, CHCl3) [27].
4
116.09 (d, JPC = 3 Hz, CH@CHCO2Et), 127.88, 128.15
(d, JPC = 6 Hz), 128.23 (d, JPC = 8 Hz), 129.35, 132.01 (d,
4.6. General procedure for allylic alkylation of 9 [28,29]
JPC = 18 Hz), 135.17 (d, JPC = 21 Hz) (CH of PPh2);
1
136.91, 139.91 (2ꢃ d, JPC = 10 Hz, Cipso of PPh2),
Ligand (13 lmol) and [{Pd(l-Cl)(g3-C3H5)}2] (2.3 mg,
6 lmol) were dissolved in dichloromethane (1 mL). The
formed solution was stirred at room temperature for
15 min and then added to a mixture of rac-1,3-diphe-
nylprop-2-en-1-yl acetate (9; 63 mg, 0.25 mmol), the
appropriate base (0.025 mmol, see Table 2), and
dichloromethane (2 mL). After stirring for another
5 min, N,O-bis(trimethylsilyl)acetamide (BSA; 0.2 mL,
0.8 mmol) and dimethyl malonate (0.1 mL, 0.8 mmol)
were successively introduced and stirring was continued
at room temperature for 20 h. Then, the reaction mix-
ture was diluted with dichloromethane (5 mL) and
washed with saturated aqueous NH4Cl solution
(2 ꢃ 5 mL). The organic layer was separated, dried over
MgSO4 and concentrated under vacuum. Subsequent
purification by flash chromatography (silica gel; hex-
ane–ethyl acetate 3:1) afforded the alkylation product
(in cases of incomplete conversion as mixtures with
unreacted 9).
143.88 (d, 3JPC = 11 Hz, CH@CHCO2Et), 166.98 (CO2Et).
31P{1H} NMR (CDCl3): d ꢀ22.8 (s). IR (Nujol): m 1705 (s),
1626 (s), 1336 (m), 1300 (m), 1262 (m), 1236 (m), 1157 (s),
1039 (m), 846 (m), 821 (s), 742 (vs), 697 (vs), 644 (m), 505
(s), 479 (s) cmꢀ1. MS (EI+): m/z (relative abundance) 468
(91, M+ꢀ), 439 (84, [MꢀEt]+), 411 (24), 395 (100,
[MꢀCO2Et]+), 373 (12), 183 (42, [Ph2Pꢀ2H]+), 165 (57),
121 (58, [C5H5Fe]+), 56 (34, Fe+). HR MS calcd. for
C27H2556FeO2P 468.0942, found 468.0939.
4.5. Preparation of (Sp)-1-(diphenylphosphanyl)-2-
ethylferrocene [(Sp)-8]
Alkene (Sp)-2 (120 mg, 0.30 mmol) and p-toluenesulfo-
nyl hydrazine (0.560 g, 3.0 mmol) were dissolved in dry
THF (15 mL). To the obtained solution was added sodium
acetate dissolved in water (0.248 g, 3.0 mmol) and the
resulting biphasic mixture was heated at reflux and stirred
for 20 h (the colour of the reaction mixture turned gradu-
ally from orange to yellow). The reaction was terminated
by addition of saturated aqueous K2CO3 solution
(15 mL) and stirring for another 1 h. Then, the reaction
mixture was diluted with diethyl ether, the organic layer
was separated, washed twice with brine, dried (MgSO4)
and evaporated. The yellow orange residue was purified
by column chromatography (silica gel, hexane–diethyl
ether 5:1) to give, after evaporation under vacuum, (Sp)-8
as a yellow gummy residue, which solidifies to a waxy yel-
low solid. Yield: 98 mg (81%).
1
Enantiomeric excesses were determined from H NMR
spectra recorded in C6D6 in the presence of chiral lantha-
nide shift reagent tris(3-trifluoroacetyl-d-camphorato)euro-
pium(III), Eu(facam)3 while the configuration of the major
component was assigned on the basis of optical rotation of
the mixture [30]. The results presented in Table 2 are an
average of two independent runs.
4.7. Preparation of (g3-1,3-diphenylallyl)[(Sp)-1-
(diphenylphosphanyl-jP)-2-(g2-vinyl)ferrocene]-
palladium(II) perchlorate [(Sp)-12]
3
1H NMR (CDCl3): d 1.03 (t, JHH = 7.6 Hz, 3H,
2
3
4
CH2CH3), 2.38 (dqd, JHH ꢁ JHH ꢁ 7.5 Hz, JPH
=
Complex 11 (33.5 mg, 50 lmol) and (Sp)-2 (40 mg,
0.10 mmol) were dissolved in dichloromethane (2 mL) to
give a clear orange solution. The solution was stirred at
room temperature for 5 min and treated with a solution
of AgClO4 (21 mg, 0.10 mmol) in acetone (1 mL). An off-
white (AgCl) precipitate formed immediately while the col-
our of the reaction mixture turned to deep red. The mixture
2
3
1.6 Hz, 1H, CH2CH3), 2.54 (dq, JHH ꢁ JHH ꢁ 7.5 Hz,
1H, CH2CH3), 3.63 (dt, 1H, C5H3), 4.02 (s, 5H, C5H5),
4.19 (td, 1H, C5H3), 4.34 (m, C5H3), 7.14–7.56 (m, 10H,
PPh2). 13C{1H} NMR (CDCl3): d 14.84 (s, CH2CH3),
3
21.46 (d, JPC = 10 Hz, CH2CH3), 68.44 (CH of C5H3),
69.52 (C5H5), 70.12 (d, JPC = 4 Hz, CH of C5H3), 70.55

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455
was stirred for another 15 min, filtered (PTFE syringe fil-
ter, 0.45 lm) and the filtering device washed with dichloro-
methane (1 mL). The clear filtrate was layered with diethyl
ether and the mixture allowed to stand at +4 °C for several
days. The separated product was filtered off, washed with
diethyl ether and dried under vacuum to give solvated
(Sp)-12 as dark red crystalline solid. Yield: 69 mg.
54.2° for (Sp)-12 ꢂ CH2Cl2) were collected on a Nonius
KappaCCD diffractometer equipped with a Cryostream
Cooler (Oxford Cryosystems) at 150(2) K using graphite
˚
monochromatised Mo Ka radiation (k = 0.71073 A) and
analyzed with the HKL program package [31]. The data
for (Sp)-12 ꢂ CH2Cl2 were corrected for absorption by using
a Gaussian method based on the indexed crystal shape,
which is the part of the diffractometer software (the range
of transmission factors is given in Table 4).
31P{1H} NMR (CD2Cl2, ꢀ25 °C): d 17.6 (ca. 13%), 24.1
(ca. 48%), 26.2 (ca. 11%), and 28.4 (ca. 28%). 31P{1H}
NMR (CD2Cl2, 0 °C): d 18.3, 24.3, 26.3, 28.1 (all broad).
IR (Nujol): m 1553 (m), 1541 (m), 12228 (m), 1168 (m),
m3(ClO4) 1098 (vs, broad); 1027 (m), 1000 (m), 949 (m),
759 (s), 695 (vs), m4(ClO4) 622 (s); 523 (s), 517 (s), 494 (s),
The structures were solved by direct methods (SIR97
[32]) and refined by full-matrix least-squares routine on
F2 (SHELXL97 [33]). The non-hydrogen atoms were refined
with anisotropic displacement parameters while all
hydrogens were included in the calculated positions and
refined as riding atoms with Uiso(H) assigned to a multi-
ple of Ueq of their bonding atom. Because the solvate in
the structure of (Sp)-12 ꢂ CH2Cl2 is disordered in struc-
tural voids, its contribution to the scattering was
removed using SQUEEZE routine as incorporated in the
468 (s), 453 (m) cmꢀ1
.
MS (ESI+): m/z 695.3
([Pd(Ph2C3H3)(2)]+); the observed isotopic distribution
agrees with the calculated one. Anal. Calc. for C39H34Fe-
ClO4PPd ꢂ 0.35CH2Cl2 (825.05): C, 57.28; H, 4.24. Found:
C, 57.25; H 4.29%.
3
˚
4.8. X-ray crystallography
PLATON program (two areas of 268 A and 65 electrons
per the unit cell) [34]. Selected crystallographic data are
given in Table 4. Geometric parameters and structural
drawings were obtained with a recent version of the PLA-
TON program [33]. The calculated numerical values are
rounded with respect to their estimated standard devia-
tions (esd’s) given with one decimal; parameters involv-
ing hydrogen atoms in the calculated positions are
given without esd’s.
Crystals suitable for single-crystal X-ray diffraction
analysis were selected directly from the reaction batch
((Sp)-12 ꢂ CH2Cl2: deep red plate, 0.08 ꢃ 0.28 ꢃ
0.37 mm3) or grown by recrystallisation from hot heptane
((Sp)-6: ruby red block, 0.08 ꢃ 0.15 ꢃ 0.42 mm3). Full-set
diffraction data ( h
k
l; 2h 6 42.0° for (Sp)-6 and
5. Supplementary material
Table 4
Crystallographic data, data collection and structure refinement parameters
for (Sp)-6 and (Sp)-12 ꢂ CH2Cl2
Compound
CCDC 653505 and 653506 contain the supplementary
crystallographic data for compounds (Sp)-6 and (Sp)-
12 ꢂ CH2Cl2. These data can be obtained free of charge
from The Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif.
(Sp)-6
C26H23FeOP
438.26
Orthorhombic
P212121 (no. 19) C2 (no. 5)
(Sp)-12 ꢂ CH2Cl2
C40H36Cl3FeO4PPda
880.26
Formula
M (g molꢀ1
)
Crystal system
Space group
T (K)
Monoclinic
150(2)
150(2)
˚
Acknowledgements
a (A)
11.1584(3)
11.1584(3)
14.4122(3)
33.4732(9)
12.3188(3)
9.2526(2)
104.074(1)
3700.8(2)
4
1.580
1.179
0.744–0.911
30943
8106/7451
4.94
˚
b (A)
˚
c (A)
This work was financially supported by the Czech Sci-
ence Foundation (Grant no. 203/05/0276) and is a part
of the long-term research project supported by the Ministry
of Education, Youth and Sports of the Czech Republic (no.
MSM0021620857).
b (°)
3
˚
V (A )
2122.85(9)
4
Z
Dcalculated (g mLꢀ1
)
)
1.371
0.800
l (Mo Ka) (mmꢀ1
b
c
T
–
Diffractions total
22728
References
Unique/observedd diffractions 4175/3823
Rint (%)e
4.5
2.90
3.52, 6.68
0.00(1)
0.39, ꢀ0.33
R (observed data) (%)f
R, wR (all data) (%)f
2.98
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3.50, 6.75
–0.01(1)
0.40, ꢀ0.54
Flack’s ꢀp3arameter
˚
Dq (e A
)
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a
[C36H34FePPd]ClO4 ꢂ CH2Cl2.
b
c
The range of transmission coefficients.
Not corrected.
´
(c) R.G. Arrayas, A. Adrio, J.C. Carretero, Angew. Chem. Int. Ed.
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e
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P
2
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f
P
P
P
P
R = ||Fo| ꢀ |Fc||/ |Fo|, wR = [ {w(Fo ꢀ Fc2)2}/ w(Fo2)2]1/2
.
2

ˇ
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¨
¨
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¨
ˇ
´
ˇ
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´
ˇ
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ˇ
´
ˇ
´
ˇ
ˇ
´
´
˚
˚
˚
˚
0.059(2) A for C(23), 0.077(2) A for C(24), 0.009(2) A for C(25),
˚
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