Planar chiral ferrocene salen-type ligands featuring additional central and axial chirality

Article abstract of DOI:10.1016/j.jorganchem.2005.11.051

We report on novel chiral tridentate [NO₂]H₂ and tetradentate [N₂O₂]H₂ Schiff base ligands containing a planar chiral ferrocene moiety linked to hydroxyl-imine or diimine donors with central or axial chirality. Structurally, these ligands resemble half-salen and salen systems designed for stereoselective applications of their transition metal complexes in homogeneous catalysis. The modular synthesis involves diastereoselective metalation of chiral ferrocene or pentamethylferrocene acetals, followed by stereoconservative hydroxyalkylation and condensation with chiral hydroxyamines or diamines, respectively. In comparison to salen-type systems, an important advantage of these ligands is their tunable steric protection of the alkoxide donor site. A total of 18 different ligands varying in electronic and steric properties have been prepared and fully characterized by NMR, IR, mass spectroscopy and by single crystal structure analysis of nine precursors and representatives.

Full text of DOI:10.1016/j.jorganchem.2005.11.051

Journal of Organometallic Chemistry 691 (2006) 1197–1215
www.elsevier.com/locate/jorganchem
Planar chiral ferrocene salen-type ligands featuring additional
central and axial chirality
a
a
a
b
Heimo Wo¨lfle , Holger Kopacka , Klaus Wurst , Karl-Hans Ongania ,
c
c
a,
*
Hans-Helmut Gortz , Peter Preishuber-Pflugl , Benno Bildstein
¨
¨
a
Institute of General, Inorganic and Theoretical Chemistry, University of Innsbruck, Innrain 52a, A-6020 Innsbruck, Austria
b
Institute of Organic Chemistry, University of Innsbruck, Innrain 52a, 6020 Innsbruck, Austria
c
BASF Aktiengesellschaft, 67056 Ludwigshafen, Germany
Received 9 September 2005; received in revised form 16 November 2005; accepted 22 November 2005
Available online 4 January 2006
Abstract
We report on novel chiral tridentate [NO2]H2 and tetradentate [N2O2]H2 Schiff base ligands containing a planar chiral ferrocene moi-
ety linked to hydroxyl-imine or diimine donors with central or axial chirality. Structurally, these ligands resemble half-salen and salen
systems designed for stereoselective applications of their transition metal complexes in homogeneous catalysis. The modular synthesis
involves diastereoselective metalation of chiral ferrocene or pentamethylferrocene acetals, followed by stereoconservative hydroxyalky-
lation and condensation with chiral hydroxyamines or diamines, respectively. In comparison to salen-type systems, an important advan-
tage of these ligands is their tunable steric protection of the alkoxide donor site. A total of 18 different ligands varying in electronic and
steric properties have been prepared and fully characterized by NMR, IR, mass spectroscopy and by single crystal structure analysis of
nine precursors and representatives.
ꢀ 2005 Elsevier B.V. All rights reserved.
Keywords: Ferrocene; Planar chirality; Central chirality; Axial chirality; N,O-ligands
1. Introduction
alia chiral binaphthyl, metallocenyl, salen, bis(oxazoline),
and bis(phosphine) ligand frameworks.
Since the pioneering work by Knowles [1] in 1968, homo-
geneous enantioselective catalysis by chiral transition metal
complexes has been developed to an extremely valuable tool
for the synthesis of a myriad of chiral compounds. The
importance of this area of chemistry was recently acknowl-
edged by the Nobel Prize in Chemistry 2001 awarded to
William S. Knowles, Ryoji Noyori, and K. Barry Sharpless.
In enantioselective homogeneous catalysis, the chirality at
the active metal site of the catalyst is usually due to coordi-
nation of a suitable chelating chiral ligand which serves as
stereodirecting group in the key step of the catalytic cycle.
Among the many chiral ligands available, a few structural
moieties – termed ‘‘privileged ligands [2] – have been proven
as especially useful for a wide range of applications, inter
In this contribution, we report on a new family of tri-
dentate [NO2]H2 Schiff base as well as tetradentate
[N2O2]H2 salen-type ligands which combine the planar chi-
rality of 1,2-disubstituted ferrocenes with central and axial
chirality in the residual ligand backbone. An important
design criterion for these highly dissymetric ligand systems
is a modular synthetic approach which allows simple
improvements of the catalytic activity and selectivity by
variation of the steric properties of the ligands. Possible
applications of these ligands and their metal complexes
include epoxide ring-opening, Diels–Alder, imine cyana-
tion, conjugate addition, hydrogenation and other stereo-
selective reactions, in analogy to reactions of established
Schiff base and salen metal catalysts [2,3]. Our specific
interest lies in the stereoselective alternating copolymeriza-
tion of carbon monoxide with propylene oxide [4–6] to
yield enantiomerically enriched polyhydroxybutyrate.
*
Corresponding author. Tel.: +43 512 507 5141; fax: +43 512 507 2934.
E-mail address: benno.bildstein@uibk.ac.at (B. Bildstein).
0022-328X/$ - see front matter ꢀ 2005 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2005.11.051

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
A forthcoming publication will deal with this application
using the ligands reported in this paper.
Kagan and coworkers [7] with t-butyl lithium as base at
ꢀ80 ꢁC in diethyl ether as solvent, exclusive ortho-deproto-
nation to only one diastereoisomer 5a or 5b is possible.
Reaction with suitable electrophiles affords the correspond-
ing planar chiral ferrocenes in a completely stereoconserva-
tive manner. Kagan and coworkers [7] has already shown
that the following functional moieties can be stereoselec-
tively attached to the ferrocene moiety: trialkylsilyl, car-
boxylate, phosphine, halogen, thioether, carbaldehyde,
boronic acid, amine and hydroxyl. The latter derivative is
a precursor to 2-hydroxy-1-formyl-ferrocene – a planar chi-
ral analog of salicylaldehyde – and of special interest in
view of the anticipated applications of such compounds
as planar chiral nitrogen and oxygen-based ligands in ster-
eoselective catalysis. However, hydroxyferrocenes [9–12] in
general are only accessible in protected form by use of haz-
ardous reagents and quite difficult to handle due to their
facile oxidation by air, therefore this building block is of
limited use for practical applications.
2. Results and discussion
Our modular preparative approach to chiral Schiff base
and salen-type ligands is shown in Scheme 1: In the first
step, (pentamethyl)ferrocene aldehyde 1a or 1b is converted
to dimethylacetals 2a or 2b, followed by transacetalization
with chiral (S)-1,2,4-butanetriol to hydroxyacetals 3a or 3b,
respectively. This chemistry has been developed by Kagan
and coworkers [7] starting from ferrocenealdehyde 1a, but
not with pentamethylferrocenealdehyde [8] 1b. The note-
worthy feature of this acetalization is the selective forma-
tion of only one epimer in 80% yield on a preparative
scale of up to 50 g of starting ferrocenealdehyde.
In the following step, chiral hydroxyacetals 3a or 3b are
alkylated to the corresponding methyl ethers 4a or 4b in
quantitative yield by reaction with sodium hydride and
methyl iodide. Methoxyacetals 4a or 4b are the key precur-
sors for the diastereoselective metalation of the ferrocenyl
moiety. Under the experimental conditions developed by
On the other hand, the air sensitivity of hydroxyferroc-
enes can be simply circumvented by introduction of a sat-
urated one-carbon spacer between the redox active
Scheme 1. Synthetic route to planar chiral ferrocene salen-type ligands and metal complexes. Conditions: (a) H+, trimethyl orthoformate; (b) H+, (S)-
1,2,4-butanetriol; (c) NaH, CH3I; (d) t-butyl lithium; (e) R02C@O (acetone, benzophenone, 9-fluorenone, paraformaldehyde, adamantanone,
diisopropylketone); (f) H+; (g) dehydration, ꢀH2O; (h) chiral aminoalcohol H2Nꢁ ꢁ ꢁOH (see main text); (i) n-butyl lithium, MX3 (e.g., CrCl3); (j) chiral
diamine H2Nꢁ ꢁ ꢁNH2 (see main text).

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1199
ferrocene group and the hydroxyl functionality (Scheme 1).
This new design principle has the following advantageous
attributes: First, the hydroxyl functionality shows the com-
mon reactivity and has the same stability as in organic
alcohols. Second, the synthesis of such spacered hydroxy-
ferrocenes is easily achieved by simple hydroxyalkylation
of 5a or 5b with various aldehydes or ketones, thereby
allowing modular steric protection of the hydroxyl group
by use of carbonyl components of different steric bulk.
Third, if aldehydes R(C@O)H are used in this hydrox-
yalkylation, central chirality at the hydroxyl carbon will
result, allowing in principle further dissymmetry in the tar-
get ligands and chiral metal catalysts 39 and 40. However,
to avoid the problem of separation of the anticipated dias-
teromeric product mixtures, we did not explore this addi-
tional opportunity, only hydroxyalkylations with ketones
R2C@O (acetone, benzophenone, 9-fluorenone, formalde-
hyde, adamantanone, diisopropylketone) are reported in
this paper. Fourth, due to the one carbon spacer a 7-mem-
bered metal chelate is present in metal complexes 39 and
40, in contrast to salen complexes which have a 6-mem-
bered metal chelate coordination geometry.
pylketone is very simple and affords the products 6–12 in
41–81% isolated yield, dependent on the ease of nucleo-
philic addition of 5a or 5b to the differently substituted car-
bonyl groups of the ketone reagents. Spectroscopically, 1H
and 13C NMR spectra of 6–12 show one set of signals for
the chiral methoxyacetal moiety in addition to the expected
signals of the various diasterotopic alkylhydroxyl function-
alities; a detailed spectral analysis is given in the experimen-
tal section. Furthermore, mass spectra display the expected
molecular ions and in the IR spectra the anticipated hydro-
xyl bands >3000 cmꢀ1 are detected. Fig. 1 shows the molec-
ular structure of 8 obtained from a single crystal structure
analysis. The molecule crystallizes in the chiral space group
P21 and the chirality at the ferrocene moiety (RP) and in
the acetal group (S,S) is further corroborated by an abso-
lute structure parameter of ꢀ0.007(13). All bond distances
and angles are in the normal range and unexceptional but
from inspection of Fig. 1 the steric protection of the hydro-
xyl group [O(1)] by the large 9-fluorenyl substituent is
clearly evident.
The next step in the synthetic sequence (Scheme 1) con-
sists in removal of the acetal group of compounds 6–12 by
acidic hydrolysis. Planar chiral 2-hydroxyalkylated ferro-
cene-1-aldehydes 13–19 (Chart 1) are obtained in 36–84%
yield by simply stirring acetals 6–12 with p-toluenesulfonic
acid in dichloromethane solution for a few hours at ambi-
ent temperature. In the case of pentamethylated starting
material 19 the yield is rather poor due to an unavoidable
side reaction to dehydrated 2-propenyl-pentamethylferro-
Chart 1 gives an overview of the synthesized hydrox-
alkylated methoxyacetals 6–12 and of the corresponding
planar chiral 2-hydroxyalkylated ferrocene-1-aldehydes
13–19, respectively, showing the varying degree of steric
protection at the hydroxyl moiety. Synthetically, the reac-
tion of 5a or 5b with the ketones acetone, benzophenone,
9-fluorenone, formaldehyde, adamantanone, and diisopro-
Chart 1. Hydroxyalkylferrocene acetals 6–12 and their corresponding planar chiral hydroxyalkylferrocenealdehydes 13–19.

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
Fig. 3. Molecular structure of 15. Hydrogen atoms of the ferrocene group
are omitted for clarity.
group and the aldehyde functionality is observed. Note
that a 7-membered ring system is formed by this hydrogen
bridging, indicative of the analogous 7-membered coordi-
nation geometry in metal complexes 39 and 40 derived
from these precursors. The main difference in these two
structures is the different steric protection of the hydroxyl
groups O(1): steric shielding in 13 by the two rather small
methyl groups is much less compared to the situation in
15 containing the larger 9-fluorenyl substituent.
Besides these two hydroxyalkylferrocenealdehyde solid
state structures of 13 and 15, a crystal structure of the elim-
ination side product 20 was obtained (Fig. 4). In this planar
chiral molecule [space group P212121, absolute structure
parameter 0.013(15)] the steric bulk of the pentamethylcy-
clopentadienyl ring is the most prominent feature, in
comparison to the former structures containing non-meth-
ylated ferrocenes.
Hydroxalkylated ferrocene aldehydes 13–19 are the key
precursors for the target Schiff base ligands of this contri-
bution. Condensation with suitable aminoalcohols in con-
centrated methanolic solution affords the tridentate
[N2O]H2 ligands 21–34 in quantitative yield. Experimen-
tally, the progress of this simple condensation can be con-
veniently monitored by IR spectroscopy (detection of the
C@N imine stretching vibration versus the C@O band of
Fig. 1. Molecular structure of 8. Hydrogen atoms at the ferrocene group
are omitted for clarity.
cenealdehyde 20. This undesired olefinic product is formed
because the five electron-donating methyl groups facilitate
the elimination of water due to the efficient electronic sta-
bilization of the intermediate carbenium ion. Chart 1
shows the modular steric protection at the hydroxy func-
tionality of these planar chiral ferrocene aldehydes. Spec-
troscopic characterization of 13–19 was performed by
NMR, IR, and MS techniques, key properties include (i)
NMR low field signals of the aldehyde group [d(1H) =
9.50–9.99 ppm, d(13C) = 195.0–196.9 ppm], (ii) diastereo-
topic NMR signals for the substituents at the hydroxyl car-
bons, (iii) strong IR absorptions for the aldehyde
functionalities (mC@O = 1634–1657 cmꢀ1), (iv) broad IR
bands of the hydroxyl groups (mC–OH = 3288–3553 cmꢀ1),
and (v) molecular ions in the FAB mass spectra. Further
structural proof is given by two single crystal structures
(Figs. 2 and 3). Both compounds crystallize in chiral space
groups (13: P212121; 15: P21) and give excellent absolute
structure parameters [13: 0.015(18); 15: 0.011(10)] in line
with their planar chirality RP. As anticipated, all bond dis-
tances and angles are in the expected normal range and an
intramolecular hydrogen bridge between the hydroxyl
Fig. 2. Molecular structure of 13. Hydrogen atoms are omitted for clarity,
Fig. 4. Molecular structure of 20. Hydrogen atoms of the ferrocene
except for hydroxyl and aldehyde hydrogens.
moiety are omitted for clarity.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1201
the starting hydroxyalkylated aldehydes) but not by TLC
analysis; due to facile hydrolysis on the stationary phase
(silica or alumina) this common method is useless for this
class of compounds. Physically, [N2O]H2 ligands 21–34
are air-stable red to orange solids with melting points
mostly below 100 ꢁC. Stereochemically, all these com-
pounds are planar chiral (RP) due to the 1,2-disubstituted
ferrocene moiety and – with the exception of 21 – addition-
ally central chiral (22–32) or axial chiral (33–34) due to the
chirality of the corresponding aminoalcohol starting mate-
rials. Chart 2 shows stereochemical formulas with stereo-
chemical descriptors for all ligands, indicating the high
dissymmetry in this library of ligands, as well as the differ-
ent steric bulk of the various substituents, indicating the
modular steric protection possible. Note that the substitu-
ents point towards different spatial quadrants, thereby
blocking different reaction pathways in the metal catalysts
derived from these ligands. Both features – high chirality
and modular steric protection – are essential for enantiose-
lectivity in homogeneous catalysis. Spectroscopically,
NMR measurements show in general quite complex spectra
due to the high dissymmetry of these molecules. For a
detailed assignment compare the data in the experimental
section, only general features are discussed in this part:
(i) The ferrocene moiety is clearly evident from one signal
for the five isochronous hydrogens [21–31, 33–34:
d(1H) = 3.63–4.48 ppm; d(13C) = 68.6–71.2 ppm] or methyl
groups [32: d(1H) = 1.9 ppm; d(13C) = 11.3 and 73.4 ppm]
of the lower cyclopentadienyl ring, as well as three 1H
and five 13C signals of the substituted upper cyclopentadie-
nyl ring. (ii) The imine functionality is corroberated by low
field 1H and 13C signals [21–34: d(1H) = 8.16–9.12 ppm,
d(13C) = 164.6–167.6 ppm], slightly shifted to higher field
in comparison to the C@O funtionality of hydroxyalkylfer-
rocene aldehydes [13–19: d(1H) = 9.50–9.99 ppm, d(13C) =
195.0–196.9 ppm]. (iii) The diastereotopic substituents at
the hydroxyalkyl moiety give rise to a set of separated sig-
nals. Quite interestingly, in case of two of the R-hydroxy-S-
imineindanol ligands 29 and 31 two isomers ore observed
in solution, most likely corresponding to different hydro-
gen-bridged species. In addition to these NMR spectral
features, IR spectroscopic detection of the imine and
hydroxyl functionalities [21–34: mC@N = 1587–1638 cmꢀ1
,
broad mC–OH = 3092–3477 cmꢀ1], mass spectroscopic mea-
surements of the molecular ions, and elemental analysis
are further proof of the identity of compounds 21–34.
Figs. 5 and 6 show the single crystal X-ray structures of
21 and 33, respectively. Both chiral molecules [21: space
group P212121, absolute structure parameter 0.00(2); 33:
space group P21, absolute structure parameter
ꢀ0.008(17)] contain the same RP chiral hydroxyisopropyl
ferrocene subunit but differ in their hydroxyimine moiety.
Whereas 21 has an achiral hydroxyimine unit derived from
o-aminophenol, the additional axial chirality of 33 derived
Chart 2. Overview of chiral [NO2]H2 21–34 and [N2O2]H2 ligands 35–38.

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
(Figs. 7–9) of ligands 35, 37 and 38. All three compounds
crystallize in the chiral space group P212121 and give excel-
lent absolute structure parameters [35: 0.002(15); 37:
0.009(13); 38: ꢀ0.003(15)] in accordance with their chiral-
ity. Hydrogen bonding forming two 7-membered rings is
observed in all three cases, indicative of the anticipated
coordination geometry of metal complexes [N2O2]ML2 40
derived from these ligands. Compounds 37 and 38 are dia-
stereoisomers containing the same planar chiral ferrocene
subunit, but enantiomeric cyclohexanediamine building
blocks (37: R,R; 38: S,S), this is clearly seen by direct com-
parison of both molecular structures. Besides these general
features, in all three structures normal bond distances and
angles are observed, as anticipated.
Fig. 5. Molecular structure of 21. Hydrogen atoms of the ferrocene
moiety and of the methyl groups are omitted for clarity.
With this new library of highly chiral tridentate (21–34)
and tetradentate (35–38) ligand systems, a wide range of
chiral metal complexes 39 and 40 is obviously accessible
(Scheme 1). As mentioned in the introduction, applications
of such catalysts might include stereoselective epoxide ring-
opening, Diels–Alder, conjugate addition and other reac-
tions. We anticipate that the ligand design developed in this
work will lead to useful applications in stereoselective
homogeneous catalysis.
Fig. 6. Molecular structure of 33. Hydrogen atoms of the ferrocene
moiety and of the methyl groups are omitted for clarity.
from S-2-amino-20-hydroxy-1,10-binaphthyl is clearly visi-
ble. Similar as in other binaphthyl axial chiral systems,
the angle between the two naphthyl planes is 82ꢁ (mean
value of six independent molecules in the asymmetric unit).
Analogously as in the precursor aldehyde 13 (Fig. 2) where
intramolecular hydrogen bonding between the aldehyde
oxygen and the hydroxyl group was observed, both these
imine ligands contain a 7-membered ring formed by a
hydrogen-bridge between the imine nitrogen and the iso-
propylhydroxyl group.
Fig. 7. Molecular structure of 35. Hydrogen atoms of the ferrocene
moiety and of the methyl groups are omitted for clarity.
Hydroxalkylated ferrocene aldehydes 13 and 14 are also
the key precursors for tetradentate salen-type [N2O2]H2
ligands. Condensation under similar conditions as for the
tridentate systems with achiral ethylenediamine or chiral
cyclohexane-1,2-diamine affords ligands 35–38 in 67–99%
isolated yield. Chart 2 shows stereochemical formulas of
these compounds, indicating their structural diversity.
Physically, 35–38 are air-stable orange solids with melting
points ranging from 177 to 250 ꢁC, significantly higher than
for tridentate ligands 21–34. Spectroscopically, similar
features as discussed above are observed: (i) the imine
1
functionality is evident from H, 13C and IR spectroscopy
[d(1H) = 8.06–9.00 ppm; d(13C) = 163.4–165.7 ppm; mC@N
=
1635–1641 cmꢀ1], (ii) the hydroxyl groups are detected by
broad IR bands [mC–OH = 3019–3159 cmꢀ1], and (iii) the
substituents at the hydroxylalkyl group show two sets of
NMR signals due to their diastereotopicity. Unambiguous
structural proof is given by single crystal structure analysis
Fig. 8. Molecular structure of 37. Hydrogen atoms of the ferrocene
moiety and of the methyl groups are omitted for clarity.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1203
on a Nicolet 5700 FT-IR spectrometer equipped with a
Smart Orbit diamond ATR unit.
4.1. 10,20,3040,50-Pentamethylferrocene-1-aldehyde-
dimethylacetal 2b
A
Schlenk tube was charged with 1b (500 mg,
1.76 mmol), trimethyl orthoformate (373 mg, 3.5 mmol),
p-toluene sulfonic acid (20 mg, 0.1 mmol), and dry metha-
nol (20 mL). The mixture was refluxed over night. Workup:
after the mixture was allowed to cool to room temperature,
approximately 0.5 g potassium carbonate was added to
neutralize acids. Solvents and volatile materials were
removed on a rotary evaporator, the residue was dissolved
in diethyl ether, the organic solution was washed with
water, followed by saturated aqueous sodium bicarbonate
solution and brine solution. The organic layer was dried
over magnesium sulfate, filtered, and reduced to dryness,
yielding 2b as a brown oil (566 mg, 1.71 mmol, 97%). The
purity of this material is sufficient for the next step as evi-
Fig. 9. Molecular structure of 38. Hydrogen atoms of the ferrocene
moiety and of the methyl groups are omitted for clarity.
3. Conclusions
Two new families of chiral tridentate [NO2]H2 and tet-
radentate [N2O2]H2 ligands have been synthesized by a ver-
satile and modular synthetic sequence. Structurally, these
ligands were designed according to half-salen and salen sys-
tems. The novel structural features of this ligand library are
(i) combination of planar chirality based on 1,2-disubsti-
tuted ferrocenes with central and axial chirality in the resid-
ual ligand backbone, (ii) tunable steric protection at the
alkoxide donor site, and (iii) formation of a 7-membered
chelate ring in the metal catalysts derived from these
ligands. Key steps of the synthesis include (i) diasteroselec-
tive metalation of ferrocene and pentamethylferrocene ace-
tals, (ii) stereoconservative hydroxalkylation with various
ketones, (iii) deprotection of the stereodirecting acetal
group by acidic hydrolysis, and (iv) condensation with var-
ious chiral aminoalcohols and diamines, respectively. Eigh-
teen different ligands with varying stereoelectronic
properties have been synthesized and fully characterized
by spectroscopic methods (NMR, IR, MS) as well as by
single crystal structure analysis of selected precursors and
representatives.
1
denced by its NMR spectra: H NMR (CDCl3): 5.31 (1H,
s, H[8]); 3.76 (2H, t, H[7] and H[4]); 3.66 (2H, t, H[6] and
H[5]); 3.21 (6H, s, H[9] and H[10]); 1.87 (15H, s, H[1])
ppm. 13C NMR (CDCl3): 101.0 (C[8]); 83.9 (C[2]); 80.4
(C[3]); 71.9 (C[7], C[4]); 69.4 (C[6], C[5]); 51.3 (C[9],
C[10]); 11.0 (C[1]) ppm (see Fig. 10).
4.2. (2S,4S)-4-(Hydroxymethyl)-2-(10,20,30,40,50-pentame-
thylferrocene)-1,3-dioxane 3b
A dry 250 mL round bottom flask was charged with dry
˚
dichloromethane (50 mL), activated 3 A molecular sieve
(1 g), 2b (1.123 g, 3.4 mmol), (S)-1,2,4-butanetriol (0.361 g,
3.4 mmol), and p-toluene sulfonic acid (35 mg, 0.17 mmol).
The dark red mixture was stirred over night and worked
up: the molecular sieve was removed by filtration, the
organic solution was washed with aqueous sodium bicar-
bonate solution followed by water, the organic solution
was dried over magnesium sulfate, and reduced to dryness
on a rotary evaporator. The crude product was chromato-
graphed on a short alumina column using n-hexane/diethyl
ether as eluent, affording 3b as a yellow oil (0.588 mg,
4. Experimental
1
1.58 mmol) in 46% yield. H NMR (CDCl3): 5.31 (1H, s,
Reactions were performed in Schlenk glassware under
an Ar atmosphere by techniques common in organometal-
lic chemistry. Commercially available starting materials
were used as received. Solvents were dried, deoxygenated,
and saturated with Ar. Starting materials 2a, 3a, 4a [7] as
well as pentamethylferrocene carbaldehyde 1b [8] were pre-
pared according to literature procedures. NMR Spectros-
copy: 1H and 13C NMR spectra were recorded on a
Bruker DPX 300 spectrometer with signals referenced to
(residual) solvent peaks as internal standards. Mass spec-
troscopy: positive mode FAB spectra (20 kV, 2 lA; matrix,
m-nitrobenzyl alcohol) or EI mass spectra (70 eV) were
obtained on a Finnigan MAT95 spectrometer. IR Spec-
troscopy: IR spectra of the solid samples were measured
H[8]); 4.25–4.20 (1H, q, H[11]); 3.95–3.91 (2H, m, H[4]
and H[7]); 3.84 (2H, m, H[9]); 3.69–3.59 (4H, m, H[12],
H[6], H[5]); 2.20 (1H, t, H[120]); 1.89–1.76 (1H, d, H[2]);
1.85 (15H, s, H[1]); 1.38 (1H, d, H[2]) ppm. 13C NMR
(CDCl3): 99.9 (C[8]); 84.9 (C[11]); 80.5 (C[12]); 77.0
Fig. 10. Numbering of 2b for NMR assignment.

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
(C[9]); 72.4 (C[3]); 72.4 (C[4]); 68.9 (C[2]); 68.6 (C[7]); 66.2
(C[5]); 65.6 (C[6]); 26.7 (C[10]); 11.0 (C[1]) ppm (see
Fig. 11). MS (FAB): 273 (M+ + H), 272 (M+), 271
(M+ ꢀ H) m/e.
(1.566 g, 4.95 mmol). After cooling of the yellow solution
to ꢀ80 ꢁC, t-butyl lithium (5.00 mmol, 3.3 mL of a 1.5 M
solution in pentane) was added via syringe and the stirred
mixture was allowed to warm to ambient temperature. Stir-
ring was continued for 1 h, and dry acetone (10.9 mmol,
0.8 mL) was added in one portion. The mixture was stirred
overnight at room temperature, completeness of the reac-
tion was checked by TLC (no spot of starting material
(2S,4S)-4-methoxymethyl-2-ferrocenyl-1,3-dioxane 4a with
Rf = 0.71 on neutral silica with n-hexane/diethyl ether
v/v = 1/1 as eluent). Workup: solvents and volatile materi-
als were removed on a rotary evaporator, the residue was
dissolved in diethyl ether, the solution was washed with
water until the aqueous layer was neutral, the organic layer
was washed with a saturated aqueous sodium chloride
solution, the organic solution was dried over magnesium
sulfate and evaporated to dryness. The crude material
was chromatographed on a short column of basic silica,
affording 6 (1.197 g, 3.2 mmol) as an orange oil in 65%
yield. All compounds 6–12 were synthesized according to
this general procedure, details (starting materials, scale,
properties) are given below.
4.3. (2S,4S)-4-(Methoxymethyl)-2-(10,20,30,40,50-
pentamethylferrocenyl)-1,3-dioxane 4b
A Schlenk tube was charged with dry tetrahydrofuran
(20 mL) and 3b (588 mg, 1.58 mmol). The mixture was
cooled to ꢀ40 ꢁC and sodium hydride (57 mg, 2.37 mmol)
was added in one portion under protection from the atmo-
sphere. The resulting suspension was magnetically stirred
and allowed to warm to room temperature over a period
of 2.5 h. Methyl iodide (448 mg, 3.16 mmol) was added
and stirring was continued over night at ambient tempera-
ture. Workup: methanol was added in small portions until
a clear solution was obtained, all volatile materials were
removed on a rotary evaporator, the residue was dissolved
in diethyl ether, the organic solution was washed with three
portions of water followed by one portion of brine solu-
tion, the organic phase was dried over sodium sulfate, fil-
tered, and reduced to dryness, affording 4b (611 mg,
1.575 mmol) as a yellow-brown oil in 99% yield. 1H
NMR (CDCl3): 5.29 (1H, s, H[8]); 4.24–4.11 (1H, q,
H[11]); 4.05–3.84 (2H, m, H[12]); 3.84 (1H, s, H[4]); 3.80
(1H, s, H[5]); 3.66 (2H, s, H[6], H[7]); 3.58–3.36 (2H, m,
H[9]); 3.41 (3H, s, H[13]); 1.91 (1H, m, H[10]); 1.49 (1H,
d, H[10]); 1.89 (15H, s, H[1]) ppm. 13C NMR (CDCl3):
99.9 (C[8]), 84.9 (C[11]), 80.4 (C[3]), 75.8 (C[9]), 75.6
(C[12]), 72.1 (C[7], C[4]), 68.6 (C[5], C[6]), 66.4 (C[2]),
59.2 (C[13]), 27.9 (C[10]), 11.0 (C[1]) ppm (see Fig. 12).
MS (FAB): 387 (M+ + H), 386 (M+), 385 (M+ ꢀ H) m/e.
4.4.1. RP-(2S,4S)-4-(Methoxymethyl)-2-((2-methyl-2-
hydroxy)ethyl)ferrocenyl-1,3-dioxane 6
Starting materials and reagents: 4a (1.566 g, 4.95 mmol);
t-butyl lithium (5 mmol); acetone (0.8 mL, 10.9 mmol).
Yield: 6 as an orange oil (1.197 g, 3.2 mmol, 65%). 1H
NMR (CDCl3): 5.55 (1H, s, H[7]); 4.32 (1H, t, H[5]);
4.22–4.18 (5 + 1 H, m, H[1] and H[4]); 4.13–4.12 (1H, m,
H[6]); 4.05–4.01 (3H, m, H[14] and H[80]); 3.92–3.83 (1H,
t · d, H[13]); 3.49–3.34 (5H, m, H[11] and H[15]); 1.82–
1.67 (1H, d · q, H[12]); 1.55 (3H, s, H[9]); 1.46–1.39 (5H,
m, H[10] and H[12]) ppm. 13C NMR (CDCl3): 100.5
(C[7]), 96.4 (C[8]), 81.2 (C[13]), 76.0 (C[14]), 75.1 (C[11]),
69.2 (C[1]), 68.9 (C[2]), 68.28 (C[3]), 68.25 (C[6]), 66.5
(C[4]), 65.7 (C[5]), 59.0 (C[15]), 32.3 (C[9]), 30.2 (C[10]),
27.4 (C[12]) ppm (see Fig. 13).
4.4. Representative procedure for diastereoselective
hydroxyalkylation; synthesis of hydroxyalkylacetals 6–12
A Schlenk tube was charged under an atmosphere of
Ar with a stirring bar, dry tetrahydrofuran (50 mL),
and (2S,4S)-4-methoxymethyl-2-ferrocenyl-1,3-dioxane 4a
4.4.2. RP-(2S,4S)-4-(Methoxymethyl)-2-(2-hydroxy-2-
phenylbenzyl)ferrocenyl-1,3-dioxane 7
Starting materials and reagents: 4a (4.124 g, 13 mmol);
t-butyl lithium (17 mmol); benzophenone (1.21 g, 20.8
1
mmol). Yield: 7, yellow oil (4.428 g, 8.9 mmol, 68%). H
NMR (CD2Cl2): 7.49 (d, 1H, H[18]); 7.47 (d, 1H, H[13]);
7.32–7.16 (m, 8H, H[11, 12, 14, 15, 16, 17, 19, 20]); 5.82
(s, 1H, H[7]); 4.74 (s, 1H, H[80]); 4.38 (t, 1H, H[5]); 4.32
(s, 5H, H[1]); 4.03 (t, 1H, H[6]); 3.98 (d, 1H, H[4]); 3.75–
3.67 (m, 1H, H[23]); 3.48–3.28 (m, 7H, H[21, 24, 25]);
Fig. 11. Numbering of 3b for NMR assignment.
Fig. 12. Numbering of 4b for NMR assignment.
Fig. 13. Numbering of 6 for NMR assignment.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1205
1.61 (m, 1H, H[22]); 1.29 (d · m, 1H, H[22]) ppm. 13C
NMR (CD2Cl2): 148.2 (C[9]), 146.0 (C[10]), 127.6 (C[20]),
127.4 (C[15]), 127.2 (C[19, 17, 14, 12]), 127.2 (C[18, 13]),
126.6 (C[16]), 126.4 (C[11]), 99.3 (C[7]), 97.3 (C[8]), 82.4
(C[23]), 77.2 (C[2]), 76.0 (C[21]), 75.3 (C[24]), 73.2 (C[3]),
69.7 (C[1]), 68.9 (C[6]), 66.1 (C[4]), 65.4 (C[5]), 59.4
(C[25]), 27.4 (C[22]) ppm (see Fig. 14).
(C[11]), 84.3 (C[2]), 75.3 (C[9]),75.0 (C[12]), 67.0 (C[3]),
68.9 (C[1]), 67.4 (C[6]), 66.4 (C[4]), 66.1 (C[5]), 59.4
(C[13]), 58.8 (C[8]), 27.0 (C[10]) ppm (see Fig. 16).
4.4.5. RP-(2S,4S)-4-(Methoxymethyl)-2-(2-hydroxyadam-
antyl)ferrocenyl-1,3-dioxane 10
Starting materials and reagents: 4a (1.022 g, 3.23 mmol);
t-butyl lithium (3.87 mmol); adamantanone (0.720 g,
4.84 mmol). Yield: 10, orange oil, (1.067 g, 2.3 mmol,
71%). 13C NMR (CDCl3): 100.0 (C[7]), 98.2 (C[8]), 82.7
(C[20]), 75.9 (C[18]), 75.3 (C[21]), 73.0 (C[2]), 70.5 (C[3]),
69.3 (C[1]), 68.3 (C[6]), 66.6 (C[4]), 65.4 (C[5]), 59.2
(C[22]), 38.1 (C[14]), 37.6 (C[11]), 37.0 (C[13]), 36.4
(C[16]), 34.2 (C[17]), 33.7 (C[12]), 33.5 (C[15]), 27.8
(C[19]), 27.2 (C[9]), 27.0 (C[10]) ppm (see Fig. 17).
4.4.3. RP-(2S,4S)-2-[1-(4-Methoxymethyl-[1,3]dioxane-2-
yl)-ferrocenyl]-9H- fluorene-9-ol 8
Starting materials and reagents: 4a (2.700 g, 8.5 mmol);
t-butyl lithium (10.2 mmol); 9-fluorenone (3.060 g,
17 mmol). Yield: 8, orange solid, (1.716 g, 3.46 mmol,
1
41%). H NMR (CD2Cl2): 7.87 (1H, s, H[17]); 7.85 (1H,
s, H[14]); 7.65–7.55 (2H, m, H[18, 13]); 7.44–7.35 (2H, m,
H[20, 11]); 7.30–7.17 (2H, m, H[19, 12]); 5.55 (1H, s,
H[7]); 5.11 (1H, s, H[80]); 4.38 (8H, m, H[1, 4, 5, 6]); 3.98
(3H, m, H[23, 21]); 3.34 (5H, m, H[25, 24]); 1.49 (1H, d,
H[22]); 1.92–1.78 (1H, m, H[22]) ppm. 13C NMR (CD2Cl2):
151.8 (C[9]), 149.9 (C[10]), 139.9 (C[16]), 138.7 (C[15]),
129.0 (C[19, 12]), 128.5 (C[20]), 127.9 (C[11]), 127.5
(C[18, 13]), 125.6 (C[17]), 125.0 (C[14]), 100.5 (C[7]), 93.9
(C[8]), 81.5 (C[23]), 81.4 (C[2]), 76.6 (C[21]), 75.5 (C[24]),
70.3 (C[1]), 69.4 (C[3]), 69.3 (C[6]), 67.1 (C[4]), 66.9
(C[5]), 59.3 (C[25]), 27.8 (C[22]) ppm (see Fig. 15). X-ray
single crystal structure: Fig. 1 and Table 1.
4.4.6. RP-(2S,4S)-4-(Methoxymethyl)-2-(1-hydroxy-1-
isopropyl-2-methyl-propyl)ferrocenyl-1,3-dioxane 11
Starting materials and reagents: 4a (1.091 g, 3.45 mmol);
t-butyl lithium (4.14 mmol); 2,4-dimethylpentan-3-one
(0.594 g, 5.20 mmol). Yield: 11, orange oil, (2.102 g,
1
2.79 mmol, 81%). H NMR (CDCl3): 5.53 (1H, s, H[7]);
4.30 (1H, d · d, H[5]); 4.23 (2H, m, H[4, 6]); 4.16 (5H, s,
H[1]); 4.15–3.88 (3H, m, H[17, 18]); 3.83 (1H, s, H[80]);
3.48–3.35 (5H, m, H[15, 19]); 2.33 (1H, sept, H[9]); 1.97
(1H, sept, H[10]); 1.77 (1H, d · d, H[16]); 1.47 (1H, d · d,
H[16]); 1.24 (6H, 2d, H[11, 12]); 0.74 (3H, d, H[13]); 0.69
(3H, d, H[14]) ppm. 13C NMR (CDCl3): 100.7 (C[7]),
95.9 (C[8]), 82.6 (C[17]), 78.1 (C[18]), 76.3 (C[15]), 75.6
(C[2]), 70.4 (C[1]), 70.3 (C[3]), 67.0 (C[6]), 66.8 (C[4]),
66.5 (C[5]), 59.5 (C[19]), 38.5 (C[9]), 35.9 (C[10]), 28.0
(C[16]), 19.3 (C[11]), 19.0 (C[12]), 18.5 (C[13]), 18.2
(C[14]) ppm (see Fig. 18).
4.4.4. RP-(2S,4S)-4-(Methoxymethyl)-2-(hydroxymethyl)-
ferrocenyl-1,3-dioxane 9
Starting materials and reagents: 4a (2.833 g, 8.96 mmol);
t-butyl lithium (9.35 mmol); paraformaldehyde (0.545 g,
18 mmol). Yield: 9, yellow oil, (1.623 g, 4.7 mmol, 52%).
1H NMR (CDCl3): 5.56 (1H, s, H[7]); 4.57–4.52 (1H,
d · d, H[5]); 4.32 (1H, t, H[4]); 4.22–4.13 (3H, m, H[6,
8]); 4.10 (5H, s, H[1]); 4.03 (2H, t, H[9]); 3.91–3.82 (1H,
t · d, H[11]); 3.46–3.33 (3H, m, H[12, 80]); 3.32 (3H, s,
H[13]); 1.76–1.62 (1H, q · d, H[10]); 1.42–1.37 (1H, d,
H[10]) ppm. 13C NMR (CDCl3): 100.1 (C[7]), 85.5
4.4.7. RP-(2S,4S)-4-(Methoxymethyl)-2-((2-methyl-2-
hydroxy)ethyl)-10,20,30,40,50-pentamethylferrocenyl-1,3-
dioxane 12
Starting materials and reagents: 4b (611 mg, 1.58 mmol);
t-butyl lithium (1.74 mmol); acetone (186 mg, 3.2 mmol).
1
Yield: 12, yellow oil, (358 mg, 0.8 mmol, 51%). H NMR
(CDCl3): 5.47 (1H, s, H[8]); 4.24–4.20 (1H, m, H[14]);
4.08–4.00 (1H, m, H[15]); 3.95–3.87 (1H, m, H[15]); 3.92
(1H, s, H[90]); 3.83 (1H, s, H[5]); 3.65 (1H, s, H[6]); 3.56
(1H, t, H[7]); 3.53–3.38 (2H, m, H[12]); 3.36 (3H, s,
H[16]); 1.87 (15H, s, H[1]); 1.93–1.72 (1H, m, H[13]); 1.54
(3H, s, H[10]); 1.47 (1H, d, H[13]); 1.41 (3H, s, H[11])
ppm. 13C NMR (CDCl3): 100.3 (C[8]), 95.8 (C[9]), 80.5
(C[14]), 79.8 (C[3]), 75.9 (C[12]), 75.2 (C[15]), 71.8 (C[7]),
71.1 (C[5]), 69.4 (C[6]), 66.4 (C[2]), 59.0 (C[16]), 32.5
(C[10]), 29.7 (C[11]), 27.7 (C[13]), 11.1 (C[1]) ppm (see
Fig. 19).
Fig. 14. Numbering of 7 for NMR assignment.
4.5. General procedure for removal of acetal-stereodirecting
group; synthesis of hydroxyalkylaldehydes 13–19
A 100 ml round bottom flask was charged with a stirring
Fig. 15. Numbering of 8 for NMR assignment.
bar, 0.5–1.0 mmol of hydroxyalkylferroceneacetal 6–12,

1206
H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
Table 1
Crystallographic data for 8, 13, 15, 20, 21, 33, 35, 37, 38
8
13
15
20
21
Molecular formula
Molecular weight
Crystal system
Space group
C29H28FeO4
496.36
Monoclinic
P21
829.37(3)
1278.84(3)
1155.87(4)
90
105.312(2)
90
C14H16FeO2
272.12
C24H18FeO2
394.23
Monoclinic
P21
744.21(2)
1248.00(4)
956.68(3)
90
95.934(2)
90
C19H24FeO
324.23
Orthorhombic
P212121
751.06(2)
1378.09(4)
1599.57(5)
90
C20H21FeNO2
363.23
Orthorhombic
P212121
749.27(2)
1178.90(4)
1420.71(5)
90
Orthorhombic
P212121
884.61(4)
1166.31(3)
1711.03(7)
90
˚
a (A)
˚
b (A)
˚
c (A)
a (deg)
b (deg)
c (deg)
90
90
90
90
90
90
3
˚
V (A )
1.18243(7)
2
1.25493(7)
4
0.88378(5)
2
1.65560(8)
4
1.76532(12)
4
Z
Temperature (K)
233(2)
1.394
0.672
520
233(2)
1.440
1.188
568
233(2)
1.481
0.870
408
233(2)
1.301
0.907
688
233(2)
1.367
0.865
760
Dc (Mg mꢀ3
)
l (mmꢀ1
F(000)
)
Color, habit
Crystal size (mm)
h Limit (deg)
Orange prism
0.4 · 0.2 · 0.12
1.83–25.00
ꢀ9 6 h 6 9;
ꢀ14 6 k 6 15;
ꢀ13 6 l 6 13
6097
3898
3769
3898/2/312
Red prism
0.3 · 0.2 · 0.15
2.24–25.99
ꢀ8 6 h 6 9;
ꢀ14 6 k 6 14;
ꢀ17 6 l 6 15
7518
2459
2359
2459/0/159
Red prism
0.35 · 0.2 · 0.15
2.14–25.99
ꢀ9 6 h 6 8;
ꢀ14 6 k 6 15;
ꢀ11 6 l 6 11
5885
3291
3239
3291/2/249
Red prism
0.45 · 0.2 · 0.15 0.35 · 0.15 · 0.05
1.95–26.00
ꢀ9 6 h 6 7;
ꢀ16 6 k 6 16;
ꢀ19 6 l 6 19
10430
3239
3101
3239/0/197
Red plate
2.11–24.00
ꢀ9 6 h 6 10;
ꢀ13 6 k 6 13;
ꢀ19 6 l 6 17
8740
2767
2413
2767/2/226
Index ranges hkl
No. of refections collected
No. of independent reflections
No. of reflections with I P 2r(I)
No. of data/restraints/
parameters
Goodness-of-fit on F2
1.048
1.070
1.036
1.046
1.048
Final R indices (I P 2r(I))
R1 = 0.027
wR2 = 0.066
R1 = 0.029
wR2 = 0.068
ꢀ0.007(13)
411 and ꢀ277
R1 = 0.022
wR2 = 0.055
R1 = 0.024
wR2 = 0.056
0.015(18)
R1 = 0.020
wR2 = 0.048
R1 = 0.020
wR2 = 0.049
0.011(10)
R1 = 0.023
wR2 = 0.057
R1 = 0.025
wR2 = 0.058
0.013(15)
R1 = 0.038
wR2 = 0.091
R1 = 0.048
wR2 = 0.095
0.00(2)
R indices (all data)
Absolute structure parameters
Largest difference peak
190 and ꢀ205
221 and ꢀ153
174 and ꢀ197
469 and ꢀ328
and hole (e nmꢀ3
)
33
35
37
38
Molecular formula
Molecular weight
Crystal system
Space group
C
588.85
34H29FeNO2 · 0.667 Et2O C30H36Fe2N2O2
C34H42Fe2N2O2 · C7H8 C34H42Fe2N2O2
568.31
Orthorhombic
P212121
802.32(2)
1215.60(3)
2776.26(7)
90
714.53
Orthorhombic
P212121
1024.77(2)
1393.56(2)
2606.91(6)
90
622.40
Monoclinic
P21
2205.85(6)
1982.21(8)
2241.61(9)
90
109.495(2)
90
9.2394(6)
12
Orthorhombic
P212121
2595.64(6)
741.64(2)
800.35(2)
90
˚
a (A)
˚
b (A)
˚
c (A)
a (deg)
b (deg)
c (deg)
90
90
90
90
90
90
3
˚
V (A )
2.70769(12)
4
3.72287(12)
4
1.54070(7)
2
Z
Temperature (K)
233(2)
1.270
0.525
3720
233(2)
1.394
1.101
1192
233(2)
1.275
0.815
1512
233(2)
1.342
0.974
656
Dc (Mg mꢀ3
)
l (mmꢀ1
F(000)
)
Color, habit
Crystal size (mm)
h Limit (deg)
Red prism
0.3 · 0.1 · 0.05
1.59–21.50
ꢀ22 6 h 6 22;
ꢀ20 6 k 6 20;
ꢀ23 6 l 6 23
40514
Red prism
0.3 · 0.15 · 0.15 0.45 · 0.4 · 0.15
1.83–24.99
ꢀ9 6 h 6 9;
ꢀ14 6 k 6 14;
ꢀ33 6 l 6 32
14138
Red plate
Red prism
0.4 · 0.4 · 0.15
2.66–25.99
ꢀ31 6 h 6 32;
ꢀ9 6 k 6 7;
ꢀ9 6 l 6 9
6364
2.14–24.99
ꢀ9 6 h 6 12;
ꢀ14 6 k 6 16;
ꢀ27 6 l 6 31
16885
Index ranges hkl
No. of reflections collected
No. of independent reflections
No. of reflections with I P 2r(I)
21203
14039
4751
4363
6469
6035
2813
2753
No. of data/restraints/parameters 21203/1/2245
4751/2/334
1.033
6469/2/428
1.052
2813/1/186
1.055
Goodness-of-fit on F2
1.014

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1207
Table 1 (continued)
33
35
37
38
Final R indices (I P 2r(I))
R indices (all data)
R1 = 0.068
wR2 = 0.143
R1 = 0.115
wR2 = 0.161
ꢀ0.008(17)
309 and ꢀ249
R1 = 0.028
wR2 = 0.061
R1 = 0.033
wR2 = 0.063
0.002(15)
R1 = 0.031
wR2 = 0.074
R1 = 0.036
wR2 = 0.077
0.009(13)
R1 = 0.024
wR2 = 0.056
R1 = 0.0243
wR2 = 0.0566
ꢀ0.003(15)
Absolute structure parameters
Largest difference peak and hole (e nmꢀ3
)
190 and ꢀ190
248 and ꢀ229
227 and ꢀ160
4.5.1. RP-2-(2-Methyl-2-hydroxyethyl)ferrocenealdehyde 13
Starting materials and reagents: 6 (1.197 g, 3.2 mmol); p-
toluenesulfonic acid (0.269 g, 2 mmol). Yield: 13, red waxy
solid, m.p. 67.6–70.2 ꢁC (0.711 g, 2.6 mmol, 82%). 1H
NMR (CDCl3): 9.82 (1H, s, H[7]); 5.45 (1H, s, H[80]);
4.66–4.64 (1H, m, H[5]); 4.63–4.62 (1H, m, H[4]); 4.53
(1H, t, H[6]); 4.35 (5H, s, H[1]); 1.60 (3H, s, H[9]); 1.35
(3H, s, H[10]) ppm. 13C NMR (CDCl3): 196.9 (C[7]),
102.2 (C[8]), 74.4 (C[2]), 74.1 (C[3]), 73.4 (C[6]), 71.5
(C[4]), 70.5 (C[1]), 67.9 (C[5]), 33.2 (C[9]), 28.6 (C[10])
ppm (see Fig. 20). IR (ATR): 3373 br (mOH), 3089 w,
2975 m, 1709 w, 1634 s (mC@O), 1444 w, 1410 w, 1372 w,
1355 m, 1344 m, 1268 w, 1249 m, 1208 w, 1181 m, 1137
w, 1106 w, 1087 w, 1045 w, 1001 m, 955 m, 820 s, 757 m,
Fig. 16. Numbering of 9 for NMR assignment.
691 w, 617 m, 538 w, 498 m, 475 m, 459 m, 445 m cmꢀ1
.
MS (EI): 273 (M+ + H), 272 (M+) m/e. X-ray single crystal
Fig. 17. Numbering of 10 for NMR assignment.
structure: Fig. 2 and Table 1.
4.5.2. RP-2-(2-Phenyl-2-hydroxybenzyl)-ferrocenealdehyde
14
Starting materials and reagents: 7 (4.428 g, 8.9 mmol); p-
toluenesulfonic acid (1.859 g, 9.7 mmol). Yield: 14, red-
orange solid, m.p. 194.9–195.5 ꢁC (1.270 g, 3.2 mmol,
1
36%). H NMR (CD2Cl2): 9.68 (1H, s, H[7]); 7.46 (2H, d,
H[18, 13]); 7.35–7.25 (3H, m, H[20, 19, 17]); 7.16 (3H, m,
H[11, 12, 14]); 7.10 (2H, m, H[16, 15]); 6.61 (1H, s,
H[80]); 4.77 (1H, t, H[5]); 4.59 (1H, t, H[4]); 4.34 (5H, s,
H[1]); 4.08 (1H, t, H[6]) ppm. 13C NMR (CD2Cl2): 196.9
(C[7]), 149.4 (C[9]), 145.8 (C[10]), 127.9 (C[13, 18]), 127.7
(C[12, 17]), 127.5 (C[14, 19]), 127.4 (C[11, 20]), 127.1
(C[15, 16]), 101.6 (C[8]), 78.8 (C[2]), 77.0 (C[3]), 75.2
(C[6]), 74.2 (C[4]), 72.0 (C[5]), 71.1 (C[1]) ppm (see
Fig. 21). IR (KBr): 3288 s (mOH), 3052 w, 2827 w, 1643 s
(mC@O), 1489 m, 1448 s, 1376 m, 1344 m, 1235 m, 1177
m, 1154 w, 1108 w, 1041 s, 999 w, 903 w, 828 s, 756 s,
703 s, 665 w, 631 w, 525 m, 482 m, 456 m cmꢀ1. MS
(EI): 398.2 (M+ + 2H), 397.2 (M+ + H), 396.2 (M+) m/e.
Fig. 18. Numbering of 11 for NMR assignment.
Fig. 19. Numbering of 12 for NMR assignment.
dichloromethane (7 mL), water (3 mL), and p-toluenesulf-
onic acid (200 mg). The mixture was stirred at ambient
temperature for 1–5 h, until complete deprotection was evi-
denced by TLC analysis. Workup: 50 mL dichloromethane
were added, the organic solution was washed with four
portions of an aqueous saturated sodium bicarbonate solu-
tion followed by one portion of water as well as one por-
tion of brine solution. The organic solution was dried
with magnesium sulfate, filtered, and reduced to dryness
on a rotary evaporator, affording the crude product. Chro-
matography on silica yielded the pure products 13–19 with
properties detailed below.
4.5.3. RP-2-(9H-9-Hydroxyfluorenyl)ferrocenealdehyde 15
Starting materials and reagents: 8 (1.716 g, 3.46 mmol);
p-toluenesulfonic acid (0.80 g, 4.20 mmol). Yield: 15, red
Fig. 20. Numbering of 13 for NMR assignment.

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1657 s (mC@O), 1466 m, 1437 m, 1408 m, 1381 m, 1359 w,
1268 s, 1213 w, 1140 w, 1105 w, 1053 w, 1003 m, 901 w,
857 w, 836 m, 766 w, 730 w, 650 w, 639 m, 497 s, 461 w
cmꢀ1. MS (FAB): 245 (M+ + 1); 244 (M+) m/e.
4.5.5. RP-2-(2-Hydroxyadamantyl)ferrocenealdehyde 17
Starting materials and reagents: 10 (1.076 g, 2.3 mmol);
p-toluenesulfonic acid (0.60 g, 3.16 mmol). Yield: 17, red
solid, m.p. 143.7–144.8 ꢁC (0.615 g, 1.7 mmol, 74%). 1H
NMR (CDCl3): 9.99 (1H, s, H[7]); 5.03 (1H, s, H[80]);
4.64 (1H, t, H[5]); 4.58–4.57 (2H, m, H[4, 6]); 4.32 (5H, s,
H[1]); 2.52 (2H, t, H[14]); 2.22 (2H, m, H[12, 15]); 1.81–
1.51 (12H, m, H[9–17]) ppm. 13C NMR (CDCl3): 195.3
(C[7]), 103.3 (C[8]); 75.9 (C[2]), 74.4 (C[7]), 72.5 (C[6, 4]),
70.8 (C[1]), 70.6 (C[5]), 40.2 (C[14]), 38.1 (C[13]), 36.4
(C[11]), 34.0 (C[16, 17]), 33.7 (C[12]), 33.6 (C[15]), 27.2
(C[9]), 27.1 (C[10]) ppm (see Fig. 24). IR (ATR): 3396 br
(mOH), 2896 m, 2848 m, 1665 m, 1638 s (mC@O), 1519 w,
1491 w, 1468 m, 1448 m, 1438 m, 1427 w, 1410 w, 1383
w, 1352 w, 1333 w, 1280 w, 1263 w, 1234 w, 1218 w,
1188 m, 1137 w, 1101 m, 1085 w, 1058 w, 1043 w, 1012
m, 960 w, 935 w, 902 w, 882 w, 856 w, 832 w, 819 w, 792
w, 755 s, 694 m, 677 w, 573 m, 529 m, 509 m, 480 w, 455
m, 436 m, 417 w cmꢀ1. MS (FAB): 365 (M+ + H), 364
(M+) m/e.
Fig. 21. Numbering of 14 for NMR assignment.
crystals, m.p. 176.5–181.0 ꢁC (0.641 g, 2.51 mmol, 73%).
1H NMR (CD2Cl2): 9.96 (1H, s, H[7]); 7.87–7.86 (1H,
d · d, H[17]); 7.84–7.71 (1H, d · d, H[14]); 7.58–7.56 (1H,
d · d, H[18]); 7.46 (2H, q · q, H[19, 12]); 7.34–7.31 (1H,
d · d, H[13]); 7.27 (1H, d · t, H[20]); 7.11 (1H, d · t,
H[11]); 6.76 (1H, s, H[80]), 4.76 (1H, t, H[5]); 4.54 (5H, s,
H[1]); 4.44 (1H, t, H[4]); 3.85 (1H, t, H[6]) ppm. 13C
NMR (CD2Cl2): 196.9 (C[7]), 152.1 (C[9]), 148.0 (C[10]),
140.3 (C[16]), 138.2 (C[15]), 129.4 (C[19]), 128.7 (C[20]),
128.2 (C[12]),127.8 (C[11]), 125.5 (C[18]), 123.5 (C[13]),
120.3 (C[17]), 120.2 (C[14]), 99.5 (C[8]), 80.2 (C[2]), 75.8
(C[3]), 75.0 (C[6]), 73.5 (C[4]), 72.4 (C[5]), 71.4 (C[1])
ppm (see Fig. 22). IR (KBr): 3289 s (mOH), 3092 w, 2855
w, 1637 s (mC@O), 1440 m, 1416 m, 1376 w, 1343 w, 1281
w, 1233 m, 1196 m, 1105 w, 1052 m, 828 m, 748 s, 731 s,
673 m, 645 m, 550 w, 484 w cmꢀ1. MS (FAB): 395
(M+ + H), 394 (M+) m/e. X-ray single crystal structure:
Fig. 3 and Table 1.
4.5.6. RP-2-(1-Hydroxy-1-isopropyl-2-methyl-propyl)-
ferrocenealdehyde 18
Starting materials and reagents: 11 (1.201 g, 2.79 mmol);
p-toluenesulfonic acid (0.60 g, 3.16 mmol). Yield: 18, red
solid, m.p. 109.2–111.5 ꢁC (0.535 g, 1.67 mmol, 63%). H
4.5.4. RP-2-Hydroxymethylferrocenealdehyde 16
Starting materials and reagents: 9 (1.600 g, 4.6 mmol); p-
toluenesulfonic acid (1.00 g, 5.26 mmol). Yield: 16, red
solid, m.p. 87.6–90.3 ꢁC (0.709 g, 3.85 mmol, 84%). 1H
NMR (CDCl3): 9.93 (1H, s, H[7]); 4.70 (1H, s, H[5]);
4.67 (1H, s, H[4]); 4.51 (3H, m, H[6, 8]); 4.30 (5H, s,
H[1]); 3.94 (1H, d, H[80]) ppm. 13C NMR (CDCl3): 196.1
(C[7]), 90.4 (C[8]), 74.9 (C[2]), 73.2 (C[3]), 71.6 (C[6]),
70.2 (C[1]), 59.4 (C[5, 4]) ppm (see Fig. 23). IR (KBr):
3441 s (mOH), 3087 w, 2955 s, 2988 s, 2860 s, 2823 w,
1
NMR (CDCl3): 9.81 (1H, s, H[7]); 5.19 (1H, s, H[80]);
4.69 (1H, t, H[5]); 4.63 (1H, d · d, H[4]); 4.55 (1H, bs,
H[6]); 4.28 (5H, bs, H[1]); 2.22 (1H, sept, H[9]); 2.02 (1H,
sept., H[10]); 1.49 (3H, d, H[11]); 1.09 (3H, d, H[12]);
0.62 (3H, d, H[13]); 0.57 (3H, d, H[14]) ppm. 13C NMR
(CDCl3): 195.0 (C[7]), 97.7 (C[8]), 77.2 (C[2]), 74.5 (C[3]),
72.1 (C[6]), 71.8 (C[4]), 71.7 (C[1, 5]), 38.4 (C[9]), 33.1
(C[10]), 19.9 (C[11]), 18.5 (C[12]), 18.3 (C[13]), 17.8
(C[14]) ppm (see Fig. 25). IR (ATR): 3553 m (mOH), 3112
Fig. 22. Numbering of 15 for NMR assignment.
Fig. 24. Numbering of 17 for NMR assignment.
Fig. 23. Numbering of 16 for NMR assignment.
Fig. 25. Numbering of 18 for NMR assignment.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1209
w, 2970 m, 2863 w, 1648 s (mC@O), 1521 w, 1475 m, 1419 w,
1411 w, 1384 m, 1353 w, 1314 m, 1297 w, 1282 w, 1256 m,
1206 m, 1176 w, 1157 w, 1138 w, 1118 w, 1107 m, 1076 m,
1043 m, 1020 w, 996 s, 957 m, 915 w, 857 s, 843 w, 826 m,
760 s, 684 m, 638 w, 617 w, 587 m, 589 w, 507 s, 482 s, 461
w, 433 w cmꢀ1. MS (FAB): 329 (M+ + H), 328 (M+) m/e.
4.6. General procedure for the synthesis of tridentate [ONO]
ligands 21–34
A small Schlenk tube was charged under an atmosphere
of Ar with a stirring bar, hydroxyalkylferrocenealdehyde
13–19 and the respective aminoalcohol (see below) in equi-
molar amounts. Dry methanol was added to obtain a con-
centrated solution. This mixture was stirred at ambient
temperature or at reflux temperature for 1–2 days, until
complete condensation was evidenced by IR spectroscopy
(note: TLC analysis of the reaction mixture is useless,
because these Schiff bases hydrolyze at least in part to the
starting materials on silica or alumina, therefore progress
of the reaction cannot be monitored by this common
method). Workup: solvents and volatile materials were
removed on a rotary evaporator, the residue was dissolved
in dichloromethane or diethyl ether, the solution was fil-
tered through a short pad of celiteꢂ, and all volatiles were
removed in vacuo, affording the product in quantitative
yield as solid powders. Details and properties for 21–34
are given below.
4.5.7. RP-2-((2-Methyl-2-hydroxy)ethyl)-10,20,30,40,50-
pentamethylferrocenyl-1-aldehyde 19 and RP-2-((2-
propenyl)-10,20,30,40,50-pentamethylferrocenyl)-1-aldehyde
20
Starting materials and reagents: 12 (134 mg, 0.3 mmol);
p-toluenesulfonic acid (125 mg, 0.66 mmol).
Yield target product: 19, red oil, (60 mg, 0.17 mmol,
1
57%). H NMR (CDCl3): 9.50 (1H, s, H[8]); 5.47 (1H, s,
H[90]); 4.19 (1H, m, H[6]); 4.14 (1H, s, H[5]), 4.13 (1H, s,
H[7]); 1.81 (15H, s, H[1]); 1.54 (3H, s, H[10]); 1.25 (3H, s,
H[11]) ppm. 13C NMR (CDCl3): 195.8 (C[8]), 100.4
(C[9]), 83.0 (C[7]), 77.9 (C[5]), 73.7 (C[2]), 68.3 (C[6]),
34.4 (C[10]), 27.5 (C[11]), 11.1 (C[1]) ppm (see Fig. 26).
IR (ATR): 3364 br (mOH), 2969 m, 2904 m, 1638 s (mC@O),
1475 m, 1444 m, 1427 m, 1374 m, 1354 m, 1249 w, 1210
w, 1180 w, 1136 w, 1071 w, 1030 m, 992 w, 956 m, 823
m, 759 m, 686 w, 655 w, 648 w, 641 w, 634 w, 626 w, 618
w, 604 w, 596 w, 588 w, 581 w, 573 w, 530 m cmꢀ1. MS
(FAB): 343 (M+ + H), 342 (M+) m/e.
4.6.1. RP-2-{[1-[2-(1-Hydroxy-1-methylethyl)ferrocenyl]-
meth-(E)-ylidene]amino}phenol 21
Starting materials: 13 (500 mg, 1.84 mmol); o-aminophe-
nol (201 mg, 1.84 mmol); methanol (6 mL). Yield: 21
(662 mg, 1.82 mmol, 99%) as purple crystals, m.p. 167.5–
Yield side product: 20, orange oil, (39 mg, 0.12 mmol,
1
1
40%). H NMR (CDCl3): 9.90 (s, 1H, H[8]); 5.14 (t, 1H,
169.3 ꢁC. H NMR (CDCl3): 8.66 (1H, s, H[7]); 7.20–7.12
H[10b]); 5.11 (s, 1H, H[10a]); 4.34 (d · d, 1H, H[7]); 4.28
(d · d, 1H, H[5]); 4.17 (t, 1H, H[6]); 2.08 (s, 3H, H[11]);
1.75 (s, 15H, H[1])ppm. 13C NMR (CDCl3): 191.2 (C[8]);
136.6 (C[9]); 112.7 (C[10]); 89.9 (C[3, 4]); 80.7 (C[6]); 75.5
(C[7]); 75.0 (C[5]); 70.8 (C[2]); 21.2 (C[10]); 8.8 (C[1])
ppm (see Fig. 27). IR (ATR): 3091 w, 2952 s, 2916 s,
2853 s, 1728 m (mC@C), 1656 s (mC@O), 1456 w, 1426 w,
1380 m, 1337 w, 1288 w, 1261 m, 1232 m, 1207 w, 1120
w, 1070 w, 1030 m, 879 m, 823 w, 800 w, 777 w, 737 w,
(2H, m, H[13, 14]); 7.00 (1H, d, H[12]); 6.90 (1H, t,
H[15]); 6.62 (1H, bs, H[80]); 4.68 (1H, m, H[5]); 4.53 (1H,
m, H[4]); 4.47 (1H, t, H[6]); 4.31 (5H, s, H[1]); 1.71 (3H,
s, H[9]); 1.49 (3H, s, H[10]) ppm. 13C NMR (CDCl3):
163.1 (C[7]), 150.7 (C[16]), 136.5 (C[11]), 127.8 (C[14]),
120.4 (C[13]), 116.6 (C[12]), 115.5 (C[15]), 100.4 (C[8]),
74.7 (C[2]), 73.0 (C[3]), 72.3 (C[6]), 70.1 (C[4]), 69.8
(C[1]), 68.7 (C[5]), 32.7 (C[9]), 29.5 (C[10]) ppm (see
Fig. 28). IR (ATR): 3374 m, 3302 m, 3095 bm (mOH),
2970 m, 1620 s (mC@N), 1590 s, 1509 m, 1488 w, 1455 m,
1411 w, 1373 w, 1346 m, 1292 w, 1274 w, 1254 s, 1241 m,
1212 w, 1195 w, 1178 w, 1158 w, 1140 w, 1104 m, 1089
m, 1002 bs, 974 w, 954 m, 924 m, 897 w, 875 w, 843 w,
815 s, 798 s, 749 s, 740 s, 697 w, 624 w, 598 w, 573 w,
703 w, 669 w, 636 w, 578 w, 528 w, 491 w, 460 m cmꢀ1
.
MS (FAB): 325 (M+ + H), 324 (M+) m/e. X-ray single
crystal structure: Fig. 4 and Table 1.
563 w, 540 w, 527 w, 503 w, 470 s, 449 s, 418 w cmꢀ1
.
MS (EI): 364.0 (M+ + H); 363.0 (M+) m/e. Anal. Calc.
for C20H21FeNO2 (363.07 g molꢀ1): C, 66.13; H, 5.83; N,
3.86. Found: C, 64.3; H, 6.0; N, 4.1. X-ray single crystal
structure: Fig. 5 and Table 1.
Fig. 26. Numbering of 19 for NMR assignment.
Fig. 28. Numbering of 21 for NMR assignment.
Fig. 27. Numbering of 20 for NMR assignment.

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H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
4.6.2. RP-2-{[1-[2-(Hydroxydiphenylmethyl)ferrocenyl]-
meth-(E)-ylidene]amino}phenol 22
Starting materials: 14 (202 mg, 0.50 mmol); o-aminophe-
nol (60 mg, 0.56 mmol); methanol (10 mL). Yield: 22
(242 mg, 0.50 mmol, >99%) as burgundy solid, m.p. 82.1–
1
86.7 ꢁC. H NMR (CD2Cl2): 8.40 (1H, s, H[7]); 7.49 (3H,
m, H[18, 13, 25]); 7.37–7.18 (8H, m, H[11, 12, 14, 15, 16,
17, 19, 20]); 7.11–7.06 (2H, t, H[80, 23]); 6.86 (1H, t,
H[24]); 6.75 (1H, d, H[22]); 4.83 (1H, bs, H[260]); 4.83
(1H, s, H[5]); 4.51 (1H, s, H[4]); 4.35 (5H, s, H[1]); 3.95
(1H, s, H[6]) ppm. 13C NMR (CD2Cl2): 164.6 (C[7]),
150.4 (C[26]), 149.9 (C[9]), 146.2 (C[10]), 136.8 (C[21]),
128.3 (C[24]), 128.0 (C[18]), 127.9 (C[13]),127.5 (C[12,
17]), 127.3 (C[14, 19]), 127.2 (C[11, 20]), 127.0 (C[15, 16]),
120.6 (C[23]), 117.0 (C[22]), 115.2 (C[25]), 99.8 (C[8]),
77.6 (C[2]), 77.4 (C[3]), 74.9 (C[6]), 70.7 (C[1]), 70.2
(C[4]), 65.9 (C[5]) ppm (see Fig. 29). IR (KBr): 3477 s
(mOH), 3055 w, 1617 s (mC@N), 1596 s, 1489 s, 1446 s, 1357
m, 1288 m, 1256 m, 1216 m, 1175 m, 1149 w, 1106 m,
1031 s, 817 s, 749 s, 698 s, 676 s, 533 m, 466 s cmꢀ1. MS
(FAB): 488 (M+ + H); 487 (M+) m/e. Anal. Calc. for
C30H35FeNO2 (487.41 g molꢀ1): C, 72.43; H, 7.09; N,
2.82. Found: C, 73.6; H, 5.8; N, 3.0.
Fig. 30. Numbering of 23 for NMR assignment.
4.6.4. RP-2-(2-{[(E)-2-Hydroxy-(1S,2R)-1,2-diphenyleth-
ylimino]methyl}ferrocenyl)propan-2-ol 24
Starting materials: 13 (163 mg, 0.60 mmol); (1S,2R)-2-
amino-1,2-diphenylethanol (140 mg, 0.66 mmol); methanol
(5 mL). Yield: 24 (278 mg, 0.60 mmol, >99%) as an orange
1
solid, m.p. 53.0–56.5 ꢁC. H NMR (CD2Cl2): 7.85 (1H, s,
H[7]), 7.63 (1H, s, H[80]); 7.46–7.19 (10H, m, H[14–18,
20–24]); 5.09 (1H, d, H[12]); 4.41 (1H, d, H[11]); 4.30
(1H, s, H[5]); 4.29 (2H, d, H[4, 6]); 3.96 (5H, s, H[1]);
2.24 (1H, bs, H[120]); 1.54 (3H, s, H[9]); 1.25 (3H, s,
H[10]) ppm. 13C NMR (CD2Cl2): 166.2 (C[7]), 141.9
(C[19]), 141.5 (C[13]), 129.0 (C[17, 15, 23, 21]), 128.3
(C[22]), 128.0 (C[24, 20]), 127.9 (C[18, 14]), 127.7 (C[16]),
101.0 (C[8]), 81.4 (C[12]), 77.9 (C[11]), 73.8 (C[2]), 73.6
(C[3]), 71.8 (C[6]), 69.9 (C[1]), 68.9 (C[4]), 68.1 (C[5]),
33.4 (C[9]), 29.3 (C[10]) ppm (see Fig. 31). IR (ATR):
3088 bm (mOH), 3028 m, 2976 m, 2858 m, 1635 s (mC@N),
1519 m, 1492 m, 1452 m, 1427 w, 1373 w, 1354 w, 1266
w, 1248 w, 1188 s, 1163 m, 1141 w, 1107 w, 1080 w, 1047
w, 1021 w, 1000 m, 957 s, 914 w, 844 m, 813 m, 753 s,
697 s, 648 w, 615 w, 585 m, 537 w, 511 m, 486 m, 478 m,
449 s cmꢀ1. MS (FAB): 469 (M+ + 2H); 468 (M+ +
H); 467 (M+) m/e. Anal. Calc. for C28H29FeNO2
(467.41 g molꢀ1): C, 71.95; H, 6.25; N, 3.00. Found: C,
71.9; H, 6.4; N, 3.0.
4.6.3. RP-2-(2-{[(E)-2-Hydroxy-(1R,2S)-1,2-
diphenylethylimino]methyl}ferrocenyl)propan-2-ol 23
Starting materials: 13 (136 mg, 0.50 mmol); (1R,2S)-2-
amino-1,2-diphenylethanol (117 mg, 0.55 mmol); methanol
(5 mL). Yield: 23 (226 mg, 0.48 mmol, 96%) as brown-red
1
solid, m.p. 65.8–68.2 ꢁC. H NMR (CD2Cl2): 7.92 (1H, s,
H[7]); 7.48–7.19 (11H, m, H[80, 13–18, 20–24]); 5.05 (1H,
d, H[12]); 4.47 (1H, d, H[11]); 4.26 (1H, d, H[6]); 4.20
(1H, s, H[4]); 4.17 (1H, t, H[5]); 3.88 (5H, s, H[1]); 2.19
(1H, bs, H[120]); 1.53 (3H, s, H[9]); 1.25 (3H, s, H[10])
ppm. 13C NMR (CD2Cl2): 166.2 (C[7]), 142.0 (C[19]),
141.6 (C[13]), 128.8 (C[17, 15, 23, 21]), 128.4 (C[22]),
128.3 (C[24, 20]), 128.0 (C[18, 14]), 127.9 (C[16]), 100.4
(C[8]), 81.9 (C[12]), 78.2 (C[11]), 73.8 (C[2]), 73.6 (C[3]),
72.0 (C[6]), 67.0 (C[1]), 68.7 (C[4]), 68.0 (C[5]), 32.8
(C[9]), 29.3 (C[10]) ppm (see Fig. 30). IR (KBr): 3400 bs
(mOH), 3086 w, 2975 m, 2864 m, 1638 s (mC@N), 1452 m,
1025 s, 817 m, 754 m, 701 s cmꢀ1. MS (EI): 469.2
(M+ + 2H); 468.2 (M+ + H); 467.2 (M+) m/e. Anal. Calc.
for C28H29FeNO2 (467.41 g molꢀ1): C, 71.95; H, 6.25; N,
3.00. Found: C, 72.1; H, 6.6; N, 3.8.
4.6.5. RP-2-{[1-[2(R)-(1-Hydroxy-1-methylethyl)ferro-
cenyl]meth-(E)-ylidene]amino}indan-1(S)-ol 25
Starting materials: 13 (136 mg, 0.50 mmol); (1R,2S)-(+)-
cis-1-aminoindan-2-ol (75 mg, 0.5 mmol); methanol
(5 mL). Yield: 25 (200 mg, 0.50 mmol, >99%) as orange-
1
brown solid, m.p. 39.8–42.3 ꢁC. H NMR (CD2Cl2): 8.45
(1H, s, H[7]); 7.29–7.21 (4H, m, H[15–18]); 6.76 (1H, bs,
H[80]); 4.66 (1H, d, H[11]); 4.57 (1H, q, H[12]); 4.52 (1H,
s, H[5]); 4.41 (1H, s, H[4]); 4.36 (1H, t, H[6]); 4.24 (5H, s,
H[1]); 3.10 (2H, d · d · d, H[13]); 2.37 (1H, bs, H[120]);
1.53 (3H, s, H[9]); 1.33 (3H, s, H[10]) ppm. 13C NMR
Fig. 29. Numbering of 22 for NMR assignment.
Fig. 31. Numbering of 24 for NMR assignment.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1211
(CD2Cl2): 167.6 (C[7]), 141.7 (C[14]), 141.5 (C[19]), 128.5
4.6.7. RP-2(S)-{[1-[2-(Hydroxydiphenylmethyl)ferro-
cenyl]meth-(E)-ylidene]amino}indan-1(R)-ol 27
(C[16]), 127.3 (C[18]), 125.7 (C[15]), 124.5 (C[17]), 100.8
(C[8]), 76.5 (C[12]), 75.6 (C[2]), 74.4 (C[3]), 73.8 (C[6]),
72.1 (C[4]), 70.3 (C[1]), 69.4 (C[11]), 68.1 (C[5]), 40.1
(C[13]), 32.9 (C[9]), 29.3 (C[10]) ppm (see Fig. 32). IR
(KBr): 3286 bs (mOH), 3092 w, 2976 m, 2890 m, 2846 m,
1638 s (mC@N), 1560 w, 1429 w, 1356 m, 1318 w, 1188 m,
Starting materials: 14 (340 mg, 1.00 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (150 mg, 1.00 mmol); methanol
(5 mL). Yield: 27 (453 mg, 0.94 mmol, 94%) as orange
1
solid, m.p. 71.1–75.1 ꢁC. H NMR: complex, non-assign-
able spectrum. 13C NMR (CD2Cl2): 166.6 (C[7]), 149.8
(C[24]), 146.8 (C[29]), 141.1 (C[9]), 140.4 (C[10]), 128.2–
125.4 (C[11–20, 25–28]), 100.9 (C[8]), 76.1 (C[22]), 75.5
(C[21]), 74.5 (C[2]), 73.7 (C[3]), 70.7 (C[1]), 69.8 (C[6]),
69. 6 (C[4]), 68.8 (C[5]), 39.6 (C[23]) ppm (see Fig. 34).
IR (ATR): 3544 w, 3024 bw (mOH), 2843 bw, 2319 w,
1635 s (mC@N), 1520 w, 1489 m, 1446 m, 1412 w, 1312 w,
1263 w, 1237 w, 1174 m, 1106 m, 1045 m, 1028 m, 1001
w, 972 w, 950 w, 932 w, 902 w, 850 w, 815 s, 751 s, 699
s, 678 m, 631 w, 567 w, 536 m, 489 m cmꢀ1. MS (FAB):
527 (M+), 528 (M+ + H), 529 (M+ + 2H) m/e. Anal. Calc.
for C33H29NO2 (471.59 g molꢀ1): C, 84.05; H, 6.20; N,
2.97. Found: C, 84.8; H, 5.8; N, 2.9.
1104 m, 1056 w, 954 w, 817 s, 744 s, 638 w, 508 w cmꢀ1
.
MS (EI): 403.2 (M+), 404.2 (M+ + H), 405.2 (M+ + 2H)
m/e. Anal. Calc. for C23H25FeNO2 (403.32 g molꢀ1): C,
68.50; H, 6.25; N, 3.47. Found: C, 67.5; H, 6.5; N, 3.4.
4.6.6. RP-2-{[1-[2(S)-(1-Hydroxy-1-methylethyl)ferro-
cenyl]meth-(E)-ylidene]amino}indan-1(R)-ol 26
Starting materials: 13 (500 mg, 1.80 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (283 mg, 1.9 mmol); methanol
(5 mL). Yield: 26 (724 mg, 1.79 mmol, >99%) as orange
1
solid, m.p. 47.7–50.5 ꢁC. H NMR: complex, non-assign-
able spectrum. 13C NMR (CD2Cl2): main isomer: 166.6
(C[7]), 141.8 (C[19]), 141.3 (C[14]), 128.4 (C[15]), 127.0
(C[17]), 125.6 (C[16]), 124.9 (C[18]), 100.9 (C[8]), 76.4
(C[12]), 75.8 (C[11]), 73.4 (C[2]), 71.7 (C[3]), 70.4 (C[5]),
69.5 (C[6]), 69.1 (C[4]), 68.4 (C[5]), 40.2 (C[13]), 32.8
(C[9]), 29.4 (C[10]); minor isomer (<10%): 142.9, 141.5,
128.6, 127.4, 125.8, 125.1, 89.0, 80.2, 74.6, 70.8, 70.2,
69.3, 68.5, 68.4, 65.8, 39.8, 32.9, 30.4 ppm (see Fig. 33).
IR (ATR): 3286 bw (mOH), 3094 w, 2976 w, 2847 w, 1636
s (mC@N), 1560 w, 1519 m, 1491 w, 1478 w, 1459 w, 1426
m, 1372 w, 1355 w, 1312 w, 1248 w, 1210 w, 1186 m,
1166 m, 1137 w, 1105 m, 1096 m, 1044 w, 1018 w, 1000
m, 952 s, 895 w, 843 m, 809 s, 743 s, 692 w, 669 m,
636 w, 593 m, 539 m, 519 w, 482 w, 472 w, 448 m,
416 s cmꢀ1. MS (FAB): 403 (M+), 404 (M+ + H),
405 M+ + 2H) m/e. Anal. Calc. for C23H25FeNO2
(403.32 g molꢀ1): C, 68.50; H, 6.25; N, 3.47. Found: C,
68.2; H, 6.8; N, 3.1.
4.6.8. RP-9-(2-{[(E)-1(R)-Hydroxyindan-2(S)-ylimino]-
methyl}ferrocenyl)-9H-fluoren-9-ol 28
Starting materials: 15 (335 mg, 0.86 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (128 mg, 0.86 mmol); methanol
(10 mL). Yield: 28 (446 mg, 0.85 mmol, 99%) as brown
1
solid, m.p. 102.7–107.3 ꢁC. H NMR (CD2Cl2): 9.12 (1H,
s, H[7]); 8.50 (1H, s, H[80]); 7.94 (1H, m, H[17]); 7.62
(1H, m, H[14]); 7.49–7.42 (3H, m, H[27, 28, fluorenyl]);
7.32–7.24 (5H, m, H[fluorenyl]); 7.10 (1H, t, H[fluorenyl]);
7.02 (1H, d, H[25]); 6.74 (1H, t, H[26]); 4.78 (1H, d, H[21]);
4.69 (1H, d, H[22]); 4.60 (1H, d, H[6]); 4.48 (5H, s, H[1]);
4.20 (1H, t, H[5]); 3.50 (1H, s, H[4]); 3.25–3.03 (2H,
d · d · d, H[23]); 2.69 (1H, bs, H[220]) ppm (see Fig. 35).
13C NMR (CD2Cl2): 165.9 (C[7]), 153.1 (C[9]), 148.9
(C[10]), 141.3 (C[29]), 140.3 (C[24]), 137.8 (C[15, 16]);
129.1, 128.7, 128.1, 127.7, 127.6, 127.1, 125.7, 125.0,
Fig. 32. Numbering of 25 for NMR assignment.
Fig. 34. Numbering of 27 for NMR assignment.
Fig. 33. Numbering of 26 for NMR assignment.
Fig. 35. Numbering of 28 for NMR assignment.

1212
H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
123.9 (C[9–13, 18–20, 25–28]); 112.0 (C[17]), 119.8 (C[14]),
98.4 (C[8]), 80.7 (C[22]), 76.3 (C[21]), 75.5 (C[2]), 73.9
(C[3]), 73.8 (C[6]), 72.8 (C[4]), 71.0 (C[1]), 69.4 (C[5]),
34.0 (C[23]) ppm. IR (ATR): 3352 bm, 3063 bm (mOH),
2850 bs, 1713 w, 1634 s (mC@N), 1585 m, 1519 w, 1490 w,
1476 w, 1459 w, 1445 m, 1412 w, 1383 w, 1367 w, 1347
w, 1310 w, 1282 w, 1264 w, 1233 w, 1199 m, 1168 w,
1152 w, 1106 s, 1049 m, 1018 w, 1001 w, 951 m, 911 w,
883 w, 850 w, 812 s, 770 s, 748 s, 729 s, 692 w, 673 m,
643 w, 629 w, 619 w, 605 w, 591 w, 580 w, 558 w, 523 s
(C[5]), 70.0 (C[4]), 68.6 (C[1]), 40.1 (C[20]), 39.9 (C[9]),
38.4 (C[10]), 37.9 (C[12]), 36.7 (C[15]), 34.4 (C[11]), 33.9
(C[13]), 27.7 (C[16]), 27.6 (C[17]) ppm (see Fig. 37). IR
(ATR): 3531 w, 3092 w (mOH), 2899 s, 2847 m, 1634 s
(mC@N), 1571 w, 1520 m, 1477 s, 1447 s, 1352 w, 1329 m,
1264 m, 1221 w, 1189 s, 1167 s, 1101 s, 1056 w, 999 m,
963 w, 934 w, 894 w, 844 m, 815 m, 803 m, 733 s, 696 w,
650 w, 632 w, 580 m, 527 m, 479 m, 460 m, 454 m, 445
m, 438 s cmꢀ1. MS (FAB): 495 (M+), 496 (M+ + H),
497 (M+ + 2H) m/e. Anal. Calc. for C30H33FeNO2
(495.43 g molꢀ1): C, 72.73; H, 6.71; N, 2.83. Found: C,
72.9; H, 7.2; N, 2.7.
.
cmꢀ1 MS (FAB): 525 (M+), 526 (M+ + H), 527
(M+ + 2H) m/e. Anal. Calc. for C33H25FeNO2 (523.4
g molꢀ1): C, 75.73; H, 4.81; N, 2.68. Found: C, 74.4; H,
5.7; N, 2.7.
4.6.11. RP-1-{[1-[2-(1(S)-Hydroxy-1-isopropyl-2-
methylpropyl)ferrocenyl]meth-(Z)-ylidene]amino}indan-
2(R)-ol 31
4.6.9. RP-2-{[1-(2(S)-Hydroxymethylferrocenyl)meth-
(E)-ylidene]amino}indan-1(R)-ol 29
Starting materials: 18 (243 mg, 0.8 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (120 mg, 0.8 mmol); methanol
(5 mL). Yield: 31 (340 mg, 0.78 mmol, 98%) as orange
Starting materials: 16 (150 mg, 0.61 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (92 mg, 0.61 mmol); methanol
(5 mL). Yield: 29 (225 mg, 0.60 mmol, >99%) as red-brown
1
solid, m.p. 44.3–47.9 ꢁC. H NMR (CD2Cl2): 8.45 (1H, s,
1
solid, m.p. 48.4–52.2 ꢁC. H NMR (CD2Cl2): 8.49 (1H, s,
H[7]); 7.28–7.1 (4H, m, H[19–22]); 6.59 (1H, s, H[80]);
4.66 (1H, s, H[16]), 4.56 (1H, s, H[15]); 4.49 (1H, s, H[6]);
4.33 (1H, s, H[4]), 4.23 (5H, s, H[1]), 4.17 (1H, s, H[5]);
3.23–3.00 (3H, m, H[17, 160); 2.20 (1H, sept, H[9]), 1.90,
(1H, sept, H[10]); 1,43 (3H, d, H[11]); 1.03 (3H, d,
H[14]); 0.51 (6H, d, H[12, 13]) ppm (see Fig. 38). 13C
NMR (CD2Cl2): major isomer: 166.5 (C[7]), 141.8
(C[23]), 141.5 (C[18]), 128.3 (C[19]), 126.9 (C[21]), 125.5
(C[20]), 125.0 (C[22]), 97.2 (C[8]), 77.4 (C[16]), 76.4
(C[15]), 75.5 (C[2]), 74.1 (C[3]), 71.5 (C[6]), 71.2 (C[1]),
70.2 (C[4]), 68.9 (C[5]), 40.0 (C[17]), 38.7 (C[9]), 33.3
(C[10]), 20.0 (C[11]), 18.5 (C[12]), 18.4 (C[13]), 17.9
(C[14]); minor isomer: 142.9, 141.4, 128.5, 127.4, 126.0,
97.3, 89.4, 88.7, 83.0, 80.7, 80.1, 77.7, 74.7, 69.9, 66.9,
66.3, 65.8, 39.9, 38.4, 36.8, 36.3, 19.1, 18.9, 18.2,
17.8 ppm. IR (ATR): 3352 bs (mOH), 3085 w, 2961 m,
2873 m, 1635 s (mC@N), 1518 w, 1476 m, 1436 w, 1382 w,
H[7]); 7.41–7.15 (5H, m, H[13, 14, 15, 16, 80]); 5.08–4.07
(12H, m, H[1, 4, 5, 6, 8, 10, 9]); 3.34–3.01 (3H, m, H[11,
100]) ppm. 13C NMR (CD2Cl2): 2 isomers in a 1:1 ratio:
165.5 (C[7]); 142.9, 141.8 (C[17]); 141.4, 141.2 (C[12]);
128.7, 128.4 (C[13]); 127.5, 127.0 (C[15]); 125.9, 125.6
(C[14]); 125.1, 124.8 (C[16]); 88.8, 88.7 (C[9]); 86.5, 84.9
(C[10]); 80.3, 78.9 (C[2]); 76.5, 75.4 (C[3]); 72.9, 72.5
(C[6]); 70.1, 69.4 (C[1]); 69.3, 68.6 (C[4]); 67.1, 66.3
(C[5]); 59.9, 59.7 (C[8]) ppm (see Fig. 36). IR (ATR):
3293 bs (mOH), 3078 w, 2921 s, 1630 s (mC@N), 1478 w,
1459 w, 1424 w, 1379 w, 1334 w, 1258 w, 1187 w, 1105
m, 1037 m, 998 m, 947 w, 899 w, 811 s, 743 s, 685 w, 638
w, 580 w, 558 w, 533 w, 484 m cmꢀ1. MS (FAB): 375
(M+), 376 (M+ + H), 377 (M+ + 2H) m/e. Anal. Calc.
for C21H21FeNO2 (375.24 g molꢀ1): C, 67.22; H, 5.64; N,
3.73. Found: C, 68.7; H, 6.5; N, 3.9.
4.6.10. RP-2-(2-{[(E)-1(R)-Hydroxyindan-2(S)-
ylimino]- methyl}ferrocenyl)adamantan-2-ol 30
Starting materials: 17 (245 mg, 0.67 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (100 mg, 0.67 mmol); methanol
(5 mL). Yield: 30 (282 mg, 0.57 mmol, 85%) as orange-
1
brown solid, m.p. 78.1–81.2 ꢁC. H NMR: complex, non-
assignable spectrum. 13C NMR (CD2Cl2): 165.5 (C[7]),
142.0 (C[26]), 141.7 (C[21]), 128.2 (C[22]), 126.8 (C[23]),
125.7 (C[24]), 124.6 (C[25]), 102.1 (C[8]), 75.8 (C[19]),
75.0 (C[18]), 73.2 (C[2]), 73.1 (C[3]), 71.1 (C[6]), 70.2
Fig. 37. Numbering of 30 for NMR assignment.
Fig. 36. Numbering of 29 for NMR assignment.
Fig. 38. Numbering of 31 for NMR assignment.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1213
1297 m, 1231 w, 1175 w, 1106 m, 1049 w, 1002 s, 951 w,
894 w, 814 s, 739 s, 691 w, 675 w, 635 w, 580 w, 549 w,
527 m cmꢀ1. MS (FAB): 459 (M+), 460 (M+ + H), 461
(M+ + 2H) m/e. Anal. Calc. for C25H33FeNO2 (435.38
g molꢀ1): C, 68.97; H, 7.64; N, 3.22. Found: C, 69.9; H,
7.4; N, 3.1.
(C[19]), 132.2 (C[14]), 129.7 (C[17]), 129.5 (C[12]), 129.3
(C[18]), 128.4 (C[13]), 128.3 (C[30]), 126.9 (C[24]), 126.7
(C[26]), 125.9 (C[15]), 125.3 (C[28]), 124.6 (C[16]), 124.4
(C[27]), 123.0 (C[29]), 120.6 (C[20]), 119.9 (C[21]), 116.9
(C[23]), 100.3 (C[8]), 74.1 (C[2]), 74.0 (C[3]), 72.1 (C[6]),
70.2 (C[1]), 69.4 (C[4]), 68.6 (C[5]), 32.0 (C[9]), 28.5
(C[10]) ppm (see Fig. 40). IR (ATR): 3047, 2972 bs
(mOH), 1607, 1587 s (mC@N),1504 s, 1427 m, 1373 w, 1344
w, 1302 w, 1280 w, 1247 w, 1205 w, 1182 w, 1161 w,
1140 w, 1108 w, 1072 w, 1048 w, 1000 w, 981 w, 956 w,
927 w, 860 w, 846 w, 814 m, 798 w, 774 w, 742 m, 693 w,
667 w, 622 w, 609 w, 594 w, 582 w, 553 w, 526 w, 505 w,
489 w, 473 w, 451 m cmꢀ1. MS (FAB): 539 (M+), 540
(M+ + H), 541 (M+ + 2H) m/e. Anal. Calc. for C34H29-
FeNO2 (539.44 g molꢀ1): C, 75.70; H, 5.42; N, 2.60.
Found: C, 75.3; H, 6.3; N, 2.5.
4.6.12. RP-2-{[1-[2(S)-(1-Hydroxy-1-methylethyl)-10,20,
30,40,50-pentamethylferrocenyl]meth-(E)-ylidene]amino}-
indan-1(R)-ol 32
Starting materials: 19 (60 mg, 0.17 mmol); (1S,2R)-(ꢀ)-
cis-1-aminoindan-2-ol (26 mg, 0.17 mmol); methanol
(3 mL). Yield: 32 (80 mg, 0.17 mmol, >99%) as orange-
brown solid, m.p. 111.4–116.7 ꢁC. 1H NMR (CD2Cl2):
8.16 (1H, s, H[8]); 7.29–7.19 (4H, m, H[16–19]); 7.09 (1H,
d, H[90]); 4.73 (1H, d, H[13]); 4.65 (1H, d, H[12]); 3.95
(3H, m, H[5, 6, 7]); 3.10 (2H, d · d · d, H[14]); 1.85
(15H, s, H[1]); 1.72 (1H, s, H[130]); 1.52 (3H, s, H[10]);
1.17 (3H, s, H[11]) ppm (see Fig. 39). 13C NMR (CD2Cl2):
167.2 (C[8]), 141.8 (C[20]), 141.3 (C[15]), 128.2 (C[19]),
126.8 (C[17]), 125.6 (C[18]), 124.7 (C[16]), 99.5 (C[9]),
81.9 (C[13]), 77.9 (C[12]), 76.6 (C[3]), 76.0 (C[4]), 75.0
(C[7]), 74.2 (C[5]), 73.4 (C[2]), 68.7 (C[6]), 40.1 (C[14]),
33.9 (C[10]), 28.2 (C[11]), 11.3 (C[1]) ppm. IR (ATR):
3309 bs (mOH), 2900 bs, 2853 bs, 1628 s (mC@N), 1521 w,
1476 w, 1457 w, 1426 w, 1374 w, 1351 w, 1307 w, 1262
w, 1248 w, 1185 m, 1100 m, 1058 w, 1031 m, 992 w, 954
m, 861 w, 843 w, 811 m, 737 s, 687 w, 669 w, 579 m, 535
m, 497 w, 463 s cmꢀ1. MS (FAB): 473 (M+), 474
(M+ + H), 475 (M+ + 2H) m/e. Anal. Calc. for
C28H35FeNO2 (473.43 g molꢀ1): C, 71.03; H, 7.45; N,
2.96. Found: C, 71.3; H, 8.1; N, 3.1.
4.6.14. RP-20-{[1-[2-(1-Hydroxy-1-methylethyl)ferrocenyl]-
meth-(E)-ylidene]amino}-[1,10]binaphthalenyl-2-ol 34
Starting materials: 13 (165 mg, 0.61 mmol); S-(+)-2-
amino-20-hydroxy-1,10-binaphthyl (174 mg, 0.61 mmol);
methanol (5 mL). Yield: 34 (297 mg, 0.55 mmol, 90%) as
1
red solid (crystallized from toluene), m.p. 111–114 ꢁC. H
NMR (CD2Cl2): 8.41 (1H, s, H[7]); 8.02 (1H, d, H[13–
29]); 7.92 (2H, t, H[13–29]); 7.82 (1H, d, H[13–29]); 7.52
(1H, d, H[13–29]); 7.44–7.10 (10H, m, H[13–29, 220]);
6.90 (1H, d, H[80]); 4.41 (1H, t, H[5]), 4.28 (2H, d, H[4,
6]); 4.10 (5H, s, H[1]); 1.41 (3H, s, H[9]); 0.44 (3H, s;
H[10]) ppm. 13C NMR (CD2Cl2): 164.6 (C[7]), 152.3
(C[22]), 147.1 (C[11]); 134.6, 134.0, 132.5, 130.0, 129.5,
129.5, 129.2, 128.3, 128.25, 127.0, 126.4, 126.2, 125.6,
124.6, 122.9, 119.2, 118.7, 117.0 (C[12–30]); 100.6 (C[8]),
74.4 (C[2]), 74.1 (C[3]), 75.3 (C[6]), 70.3 (C[1]), 69.6
(C[4]), 68.3 (C[5]), 31.7 (C[9]), 28.8 (C[10]) ppm (see
Fig. 41). IR (ATR): 3503 w, 3053 bm (mOH), 2975 m,
2922 m, 1621 s (mC@N), 1606 s, 1586 s, 1513 m, 1503 m,
1433 m, 1344 m, 1305 w, 1274 w, 1248 w, 1203 w, 1178
w, 1141 w, 1127 w, 1106 w, 1090 w, 1072 w, 1047 w,
1025 w, 1001 w, 977 w, 956 s, 861 w, 812 s, 774 w, 744 s,
4.6.13. RP-20-{[1-[2-(1-Hydroxy-1-methylethyl)ferrocenyl]-
meth-(E)-ylidene]amino}-[1,10]binaphthalenyl-2-ol 33
Starting materials: 13 (190 mg, 0.7 mmol); R-(–)-2-
amino-20-hydroxy-1,10-binaphthyl (200 mg, 0.7 mmol);
methanol (5 mL). Yield: 33 (231 mg, 0.43 mmol, 61%) as
red solid (crystallized from diethylether), m.p. 121.6–
1
123.8 ꢁC. H NMR (CD2Cl2): 8.37 (1H, bs, H[220]); 8.24
(1H, s, H[7]); 8.02–7.90 (3H, m, H[13–29]); 7.83–7.80
(1H, m, H[13–29]); 7.67 (1H, bs, H[80]); 7.52 (1H, d,
H[13–29]); 7.45–7.40 (1H, d · t, H[13–29]); 7.30–7.21 (5H,
m, H[13–29]); 6.98–6.95 (1H, m, H[13–29]); 4.34–4.25
(3H, 3s, H[4, 5, 6]); 3.63 (5H, s, H[1]); 1.40 (3H, s, H[9]);
1.05 (3H, s, H[10]) ppm. 13C NMR (CD2Cl2): 166.3
(C[7]), 152.5 (C[11]), 148.9 (C[22]), 134.9 (C[25]), 133.8
Fig. 40. Numbering of 33 for NMR assignment.
Fig. 39. Numbering of 32 for NMR assignment.
Fig. 41. Numbering of 34 for NMR assignment.

1214
H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
692 w, 666 w, 629 w, 578 w, 528 m, 503 w, 489 m, 472 m,
450 m cmꢀ1. MS (FAB): 539 (M+), 540 (M+ + H), 541
(M+ + 2H) m/e. Anal. Calc. for C34H29FeNO2
(539.44 g molꢀ1): C, 75.70; H, 5.42; N, 2.60. Found: C,
78.3; H, 6.2; N, 2.5. X-ray single crystal structure: Fig. 6
and Table 1.
550 w, 528 m, 521 s, 493 m, 481 s, 450 s, 436 w, 424 w
cmꢀ1. MS (EI): 568.0 (M+), 569.1 (M+ + 1H) m/e. Anal.
Calc. for C30H36Fe2N2O2 (568.31 g molꢀ1): C, 63.40; H,
6.38; N, 4.93. Found: C, 62.8; H, 7.0; N, 4.6. X-ray single
crystal structure: Fig. 7 and Table 1.
4.7.2. RP-{5-[((E)-2-{[1-[2-(Hydroxy diphenylmethyl)-
ferrocenyl]meth-(E)-ylidene]amino}ethylimino)methyl]-
ferrocenyl} diphenylmethanol 36
4.7. General procedure for the synthesis of tetradentate
[O2N2] ligands 35–38
Starting materials: 14 (214 mg, 0.54 mmol); ethylenedia-
mine (32 mg, 0.54 mmol); methanol (10 mL). Yield: 36
(294 mg, 0.36 mmol, 67%) as orange solid, m.p. 250 ꢁC
A small Schlenk tube was charged under an atmosphere
of Ar with a stirring bar and hydroxyalkylferrocenealde-
hyde 13 or 14. Dry methanol was added to obtain a con-
centrated solution. To this solution, 0.5 mole equivalents
of diamine dissolved in dry methanol was added dropwise
under efficient stirring. After the addition was completed,
the mixture was stirred for 24 h at ambient temperature.
IR spectroscopy showed quantitative reaction after this
reaction period (Note. TLC analysis of the reaction mixture
is useless, because these Schiff bases hydrolyze at least in
part to the starting materials on silica or alumina, therefore
progress of the reaction cannot be monitored by this com-
mon method.). Workup: solvents and volatile materials
were removed on a rotary evaporator, the residue was trit-
urated with a small amount of diethyl ether, and all vola-
tiles were removed in vacuo, affording the product in
quantitative yield as solid powder. Details and properties
for 35–38 are given below.
1
(dec.). H NMR (CD2Cl2): 9.00 (1H, s, H[7]); 7.48 (2H,
d, H[11–20]); 7.32–7.07 (8H, m, H[11–20]); 6.90 (H[80]);
4.35 (1H, s, H[5]); 4.25 (1H, t, H[4]); 4.18 (5H, s, H[1]);
3.72 (1H, s, H[6]); 3.57 (1H, d, H[21]); 2.68 (1H, d, 21)
ppm. 13C NMR (CD2Cl2): 165.4 (C[7]), 150.3 (C[9]),
147.0 (C[10]), 128.1 (C[13, 18]), 127.7 (C[12, 17]), 127.5
(C[14, 19]), 127.3 (C[11, 20]), 126.7 (C[15]), 126.5 (C[16]),
100.5 (C[8]), 76.9 (C[2]), 75.4 (C[3]), 74.8 (C[6]), 73.7
(C[4]), 70.4 (C[1]), 68.3 (C[5]), 59.4 (C[21]) ppm (see
Fig. 43). IR (ATR): 3019 bs (mOH), 2798 bs, 1639 s (mC@N),
1595 m, 1519 m, 1487 m, 1444 m, 1334 m, 1271 w, 1239 w,
1220 w, 1197 w, 1166 m, 1124 w, 1106 m, 1058 w, 1047 w,
1027 w, 998 m, 972 w, 950 w, 901 w, 848 m, 816 s, 809 s,
753 s, 689 s, 674 w, 637 w, 609 w, 567 w, 557 w, 534 m,
515 m, 488 m, 460 m cmꢀ1. MS (FAB): 816 (M+), 817
(M+ + 1H), 818 (M+ + 2H) m/e. Anal. Calc. for
C50H44Fe2N2O2 (816.66 g molꢀ1): C, 73.54; H, 5.43; N,
3.43. Found: C, 72.7; H, 5.2; N, 3.6.
4.7.1. RP-2-{5-[((E)-2-{[1-[2-(1-Hydroxy-1-methylethyl)-
ferrocenyl]meth-(E)-ylidene]amino}ethylimino)methyl]-
ferrocenyl}propan-2-ol 35
4.7.3. RP-2-{5-[((E)-2R-{[1R-[2-(1-Hydroxy-1-methyle-
thyl)ferrocenyl]-meth-(E)-ylidene]amino}cyclohexy-
limino)methyl]ferrocenyl}propan-2-ol 37
Starting materials: 13 (751 mg, 2.76 mmol); ethylenedia-
mine (166 mg, 2.76 mmol); methanol (12 mL). Yield: 35
(648 mg, 1.14 mmol, 83%) as orange solid (crystallized
from toluene), m.p. 177.7–179.4 ꢁC. 1H NMR (CDCl3):
8.09 (1H, s, H[7]); 7.72 (1H, s, H[80]); 4.31 (2H, d, H[11]);
4.24 (6H, bs, H[5, 1]); 3.86 (1H, d, H[4]); 3.66 (1H, d,
H[6]); 1.58 (3H, s, H[9]); 1.24 (3H, s, H[10]) ppm. 13C
NMR (CDCl3): 165.7 (C[7]), 100.5 (C[8]), 74.1 (C[2]),
73.0 (C[3]), 71.0 (C[6]), 69.9 (C[1]), 68.2 (C[4]), 67.7
(C[5]), 60.4 (C[11]), 32.7 (C[9]), 29.3 (C[10]) ppm (see
Fig. 42). IR (ATR): 3159 bs (mOH), 2971 m, 2927 w, 2837
w, 2362 m, 2342 w, 1772 w, 1641 s (mC@N), 1488 w, 1463
w, 1448 w, 1427 w, 1410 w, 1368 w, 1349 w, 1287 w,
1248 m, 1213 w, 1187 m, 1163 w, 1140 w, 1123 w, 1105
m, 1046 w, 1014 m, 1001 m, 974 w, 958 m, 892 w, 849 w,
841 w, 821 s (Fec), 781 w, 732 s, 693 w, 619 w, 573 w,
Starting materials: 13 (220 mg, 0.8 mmol); (1R,2R)-cylo-
hexane-1,2-diamine (46 mg, 0.4 mmol); methanol (5 mL).
Yield: 37 (233 mg, 0.37 mmol, 92.5%) as orange solid,
1
m.p. 194–196 ꢁC. H NMR (CDCl3): 8.06 (1H, bs, H[80]);
7.99 (1H, s, H[7]); 4.23 (1H, s, H[5]); 4.22 (1H, s, H[4]);
4.18 (5H, s, H[1]); 4.16 (1H, t, H[6]); 3.24 (1H, t, H[11]);
1.83 (2H, m, H[12]); 1.54 (3H, s, H[9]); 1.47–1.20 (2H, m,
H[13]); 1.15 (3H, s, H[10]) ppm. 13C NMR (CDCl3):
163.5 (C[7]), 100.5 (C[8]), 73.9 (C[2]), 73.3 (C[3]), 72.8
(C[6]), 70.9 (C[4]), 70.0 (C[1]), 68.1 (C[5]), 67.6 (C[11]),
33.2 (C[12]), 32.8 (C[9]), 29.1 (C[10]), 24.2 (C[13]) ppm
(see Fig. 44). IR (KBr): 3092 bw (mOH), 2970 w, 2921 w,
Fig. 42. Numbering of 35 for NMR assignment.
Fig. 43. Numbering of 36 for NMR assignment.

H. Wo¨lfle et al. / Journal of Organometallic Chemistry 691 (2006) 1197–1215
1215
or diethyl ether. The data collection was performed on a
Nonius Kappa-CCD equipped with graphite-monochro-
˚
mated Mo Ka radiation (k = 0.71073 A) and a nominal
crystal-to-area-detector distance of 36 mm. Intensities were
integrated using DENZO and scaled with SCALEPACK [13]. Sev-
eral scans in u and x direction were made to increase the
number of redundant reflections, which were averaged in
the refinement cycles. This procedure replaces an empirical
absorption correction. The structures were solved by direct
methods (SHELXS-86) and refined against F2 (SHELXL-97)
[14]. Hydrogen atoms at carbon atoms were added geomet-
rically and refined using a riding model. All non-hydrogen
atoms were refined with anisotropic displacement parame-
ters. Crystallographic data for 8, 13, 15, 20, 21, 33, 35, 37,
38 are given in Table 1. CIF files for compounds 8, 13, 15,
20, 21, 33, 35, 37, 38 are available in the supplementary
material.
Fig. 44. Numbering of 37 for NMR assignment.
2852 w, 1640 s (mC@N), 1518 w, 1483 w, 1446 w, 1424 w,
1370 w, 1351 m, 1291 w, 1248 m, 1189 m, 1162 w, 1135
w, 1106 w, 1092 w, 1079 w, 1042 w, 1000 m, 959 m, 935
w, 877 w, 861 w, 815 s, 775 w, 750 w, 724 w, 694 w, 626
w, 612 w, 586 w, 573 w, 549 w, 540 m, 524 w, 509 w, 498
w, 480 s cmꢀ1. MS (FAB): 621.1 (M+ ꢀ 1H), 622.1 (M+),
623.1 (M+ + 1H), 624.1 (M+ + 2H) m/e. Anal. Calc. for
C34H42Fe2N2O2 (622.43 g molꢀ1): C, 65.61; H, 6.80; N,
4.50. Found: C, 65.3; H, 7.1: N, 4.5. X-ray single crystal
structure: Fig. 8 and Table 1.
5. Supplementary material
4.7.4. RP-2-{5-[((Z)-2S-{[1S-[2-(1-Hydroxy-1-methyl-
ethyl)ferrocenyl]meth-(E)-ylidene]amino}cyclohexy-
limino)methyl]ferrocenyl}propan-2-ol 38
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic Data
Centre, CCDC Nos. 292619, 292620, 292621, 292622,
292623, 292624, 292625, 292626, 292627 for compounds
8, 13, 15, 20, 21, 33, 35, 37, 38. Copies of this information
may be obtained free of charge from: The Director, CCDC,
12 Union Road, Cambridge, CB2 1EZ UK. Fax. (int code)
+44 1223 336 003 or e-mail: deposit@ccdc.cam.ac.uk or
www: http://www.ccdc.cam.ac.uk.
Starting materials: 13 (220 mg, 0.8 mmol); (1S,2S)-cylo-
hexane-1,2-diamine (46 mg, 0.4 mmol); methanol (5 mL).
Yield: 38 (250 mg, 0.4 mmol, >99%) as orange solid, m.p.
1
235 ꢁC (dec.). H NMR (CDCl3): 8.28 (1H, s, H[7]); 7.42
(1H, bs, H[80]); 4.44 (1H, s, H[5]); 4.25 (7H, bs, H[4, 6,
1]); 3.36 (1H, s, H[11]); 1.86–1.41 (10H, m, H[12, 13, 9,
10]) ppm. 13C NMR (CDCl3): 163.4 (C[7]), 100.3 (C[8]),
75.0 (C[2]), 72.2 (C[3]), 72.1 (C[6]), 70.7 (C[4]), 69.9
(C[1]), 68.2 (C[5]), 68.19 (C[11]), 32.6 (C[9]), 32.0 (C[12]),
29.7 (C[10]), 22.9 (C[13]) ppm (see Fig. 45). IR (ATR):
3106 bm (mOH), 2980 w, 2962 m, 2930 m, 2853 m, 1635 s
(mC@N), 1519 w, 1494 w, 1457 w, 1430 w, 1386 w, 1369 w,
1350 w, 1291 w, 1267 w, 1247 w, 1192 m, 1159 w, 1140
w, 1117 w, 1105 m, 1015 m, 1000 w, 960 m, 902 w, 866
w, 850 w, 820 s, 754 s, 697 w, 682 w, 606 w, 589 w, 552
m, 525 m, 504 m, 481 s, 468 s cmꢀ1. MS (FAB): 621
(M+ ꢀ 1H), 622 (M+), 623 (M+ + 1H), 624 (M+ + 2H)
m/e. Anal. Calc. for C34H42Fe2N2O2 (622.43 g molꢀ1): C,
65.61; H, 6.80; N, 4.50. Found: C, 65.3; H, 7.2; N, 4.3.
X-ray single crystal structure: Fig. 9 and Table 1.
Acknowledgment
H.W. and B.B. thank BASF Aktiengesellschaft, Lud-
wigshafen, Germany for financial support.
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Fig. 45. Numbering of 38 for NMR assignment.