Asymmetric synthesis of planar chiral 2-mono- and 2,2′-disubstituted 1,1′-bisbenzoylferrocenes

Article abstract of DOI:10.1016/S0022-328X(01)00982-2

An efficient and flexible asymmetric synthesis of planar chiral 2-mono- and 2,2′-disubstituted 1,1′-bisbenzoylferrocenes 4 and 6 is reported. Key step is a highly diastereoselective ortho-metalation of 1,1′-bisbenzoylferrocene 1 via the corresponding bis-SAMP-hydrazone 2 (de≥96%), followed by trapping with various carbon, silicon, phosphorus and sulfur electrophiles. Cleavage of the monosubstituted hydrazones 3 led to monosubstituted ketones 4 (ee≥98%). Further ortho-substitution of the hydrazones 3 afforded 2,2′-disubstituted hydrazones 5, which could be cleaved to disubstituted ferrocenyl diketones 6 (ee≥99%). The new methodology allows a broad and flexible fine-tuning of ferrocenyl ligands desired in asymmetric catalysis. Ozonolysis or reductive hydrazone cleavage using TiCl₃ or SnCl₂ were the methods of choice to remove the auxiliary.

Full text of DOI:10.1016/S0022-328X(01)00982-2

Journal of Organometallic Chemistry 637–639 (2001) 698–709
www.elsevier.com/locate/jorganchem
Asymmetric synthesis of planar chiral 2-mono- and
2,2%-disubstituted 1,1%-bisbenzoylferrocenes
Dieter Enders *, Thomas Klumpen
Institut fu¨r Organische Chemie, Rheinisch-Westfa¨lische Technische Hochschule, Professor-Pirlet-Straße 1, D-52074 Aachen, Germany
Received 23 February 2001; accepted 17 April 2001
Abstract
An efficient and flexible asymmetric synthesis of planar chiral 2-mono- and 2,2%-disubstituted 1,1%-bisbenzoylferrocenes 4 and 6
is reported. Key step is a highly diastereoselective ortho-metalation of 1,1%-bisbenzoylferrocene 1 via the corresponding
bis-SAMP-hydrazone 2 (de]96%), followed by trapping with various carbon, silicon, phosphorus and sulfur electrophiles.
Cleavage of the monosubstituted hydrazones 3 led to monosubstituted ketones 4 (ee]98%). Further ortho-substitution of the
hydrazones 3 afforded 2,2%-disubstituted hydrazones 5, which could be cleaved to disubstituted ferrocenyl diketones 6 (ee]99%).
The new methodology allows a broad and flexible fine-tuning of ferrocenyl ligands desired in asymmetric catalysis. Ozonolysis or
reductive hydrazone cleavage using TiCl3 or SnCl2 were the methods of choice to remove the auxiliary. © 2001 Elsevier Science
B.V. All rights reserved.
Keywords: Asymmetric synthesis; ortho-Metalation; Hydrazones; 1,1%-Ferrocenyl diketones; Planar chirality
1. Introduction
2. Results and discussion
Planar chiral ferrocenes have received a surge of
interest over the last years [1]. Although various meth-
ods for the asymmetric synthesis of planar chiral ortho-
functionalised ferrocenes have been developed [2–11],
the asymmetric synthesis of planar chiral ferrocenyl
ketones turned out to be difficult. Predominantly, they
have been prepared by resolution methods [12] or by
oxidation of planar chiral alcohols [5,13], which in turn
are accessible from the corresponding amines or alde-
hydes. In our group, we have recently developed a
direct route to planar chiral ortho-functionalised ferro-
cenyl ketones, which turned out to be applicable in the
asymmetric synthesis of selectively substituted 1,1%-fer-
rocenyl diketones, too [14–16].
In this paper, we describe the enantioselective synthe-
sis of mono- and di-ortho-substituted ferrocenyl dike-
tones via our SAMP/RAMP-hydrazone method [17]
(SAMP and RAMP=(S)- and (R)-1-amino-2-
methoxymethylpyrrolidine). Key step is the stepwise
diastereoselective ortho-metalation of 1,1%-ferrocenyl
diketone bis-SAMP-hydrazone 2. We started from 1,1%-
bisbenzoylferrocene 1, easily prepared by Friedel–
Crafts-bisacylation of ferrocene in 87% yield [18]. For
the conversion of 1 to the corresponding bis-SAMP-hy-
drazone 2, a method previously described for the syn-
thesis of N,N-dimethylhydrazones [19] and successfully
applied in the synthesis of ferrocenyl mono-SAMP-hy-
drazones [16] was used. The usual methods for the
synthesis of SAMP-hydrazones failed, because of the
unfavourable steric and electronic effects. The conver-
sion of 1 led almost exclusively to the EE-isomer of the
bis-hydrazone 2. The subsequent diastereoselective or-
tho-metalation selectively occurred at one ring with
n
2–2.5 equivalents of BuLi in THF at −78 °C, fol-
lowed by trapping with various types of electrophiles
* Corresponding author. Tel.: +49-241-804-676; fax: +49-241-
888-127.
E-mail address: enders@rwth-aachen.de (D. Enders).
n
(Scheme 1). The use of BuLi turned out to be most
s
t
effective, because the application of BuLi and BuLi
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00982-2

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
699
Scheme 1.
allows the successive highly diastereoselective introduc-
tion of two different electrophiles.
Using 2.4 equivalents BuLi, it was possible to obtain
led to lower yields and the formation of disubstituted
products.
s
Within our studies, we demonstrate the broad appli-
cability of this method by using alkyl-, silyl-, phosphin-
and sulfur electrophiles (Table 1). We obtained the
desired products in very good yields (85–100%) and
high diastereoselectivities (de]96%). It was observed
that the phosphines prepared undergo a rapid oxidation
and thus needed to be protected. The use of BH3 turned
out to be advantageous, as the borane adducts are very
stable [16].
The absolute configuration of substituted mono-
SAMP-hydrazones of ferrocene has been determined
previously by NOE experiments and X-ray-structure
analysis [16]. The configuration given for the present
bishydrazones 3 are based on these assignments.
The monosubstituted bis-SAMP-hydrazones 3 pre-
pared, could either undergo a second diastereoselective
ortho-substitution under the same conditions to lead to
2,2%-substituted bis-SAMP-hydrazones 5 (Scheme 2) or
could be cleaved to produce mono-substituted dike-
tones 4 (Scheme 1).
the C2-symmetrical disubstituted hydrazone 5a in a
one-pot-reaction in 54% yield and a diasteriomeric ex-
cess of 92%. The diastereoselectivities of the planar
1
chiral hydrazones 3 and 5 were determined by H- and
13C-NMR spectroscopy.
To obtain the substituted diketones 4 and 6, it was
necessary to cleave the corresponding SAMP-hydra-
zones. For this purpose several methods turned out to
be very effective. Ozonolysis in dichloromethane at
−78 °C led to very good yields (92–99%). In some
cases, the reductive cleavage with Lewis acids like SnCl2
or TiCl3 in refluxing DME [20] turned out to be an
efficient alternative (Table 3).
Sn(II) and Ti(III) are oxidised to Sn(IV) and Ti(IV),
respectively, forming a colourless precipitate. We sup-
Table 1
Diastereoselective synthesis of planar chiral monosubstituted bis-
SAMP-hydrazones (3)
In case of second substitutions we applied alkylation,
silylation, phosphinylation, hydroxyalkylation and
sulfenylation reactions in good yields (45–89%) and
high diastereoselectivities (de]96%) (Table 2). In the
second electrophilic substitution, the phosphinylation
turned out to be more difficult probably due to steric
and electronic effects, combined with the increasing
tendency of oxidation. Nevertheless, the new method
E1
Yield (%)
de (%)
Configuration
3a
3b
3c
3d
3e
Me
85
90
85
86
100
]96
]96
]96
]96
]96
(S, S, Rp)
(S, S, Sp)
(S, S, Sp)
(S, S, Sp)
(S, S, Sp)
SiMe3
Ph2P·BH3
STol
SMe

700
D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
Scheme 2.
Table 2
Diastereoselective synthesis of planar chiral 1,1%-disubstituted bis-SAMP-hydrazones (5)
E1
E2
Yield (%)
de (%)
Configuration
5a
5b
5c
5d
5e
5f
Me
Me
Me
Ph2P·BH3
SMe
STol
Me
SiMe3
Ph2COH
Cy2P·BH3
Ph2P·BH3
SMe
54
59
77
45
46
89
92
]96
]96
]96
]96
]96
(S, S, Rp, Rp)
(S, S, Sp, Rp)
(S, S, Sp, Rp)
(S, S, Sp, Sp)
(S, S, Sp, Sp)
(S, S, Sp, Sp)
Table 3
Synthesis of the planar chiral ketones 4 and 6
E1
E2
Yield (%)
Cleavage reagent
ee (%)
Configuration
4a
4b
4c
4d
4e
6a
6b
Me
SiMe3
STol
SMe
Ph2P·BH3
Me
–
–
–
–
92
99
82
84
92
58
82
O3
O3
98
99
98
(Rp)
(Sp)
(Sp)
(Sp)
(Sp)
(Rp, Rp)
(Sp, Sp)
TiCl3
TiCl3
O3
SnCl2
TiCl3
98
–
n.d.
]99
]99
Ph2COH
STol
SMe
pose that the reducing agent first cleaved the NꢀN bond
leading to (S)-2-methoxymethylpyrrolidine (SMP) and
the corresponding ferrocenyl-ketimine, which was easily
hydrolysed to the ketone. A reductive cleavage of sul-
fur-substituted ferrocenes 3d and e and 5f with TiCl3
was very successful and resulted in the mono- and
bissulfenylated ketones 4c and d and 6b, in good yields
(82–84%) and excellent enantiomeric exesses (ee=98–
]99%).
3. Conclusions
In summary, we have developed a flexible synthesis
of 2-mono- and 2,2%-disubstituted 1,1%-ferrocenyl dike-
tones 4 and 6 in good yields and excellent enantioselec-
tivities employing the SAMP/RAMP hydrazone
method. The application of these novel compounds as
ligands in asymmetric catalysis remains to be
investigated.

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
701
+
m/z (relative intensity, %): 395 ([M+ +1], 6) 291 ([M
’
4. Experimental
+
’
−COC6H5], 12), 290 (68), 190 (11), 105 ([C6H5CO ],
4.1. General remarks
100), 78 (32), 77 (78), 51 (15). Anal. Found: C, 73.28;
H, 4.68. Calc. for C24H18FeO2 (394.24): C, 73.12; H,
4.60%.
All reactions with moisture- and air-sensitive com-
pounds were carried out under an argon atmosphere
using standard Schlenk techniques. All solvents were
dried and distilled prior to use. Column chromatogra-
phy: Merck silica gel 60, 0.040–0.063 mm (230–400
mesh). Optical rotation values: Perkin–Elmer P 241
(254 nm), solvents Merck UVASOL quality. Melting
points (uncorrected): Bu¨chi 510. IR: Perkin–Elmer FT/
IR 1750. Assinments of signals: w, weak; m, medium; s,
strong; vs, very strong. NMR: Varian Gemini 300 (300
and 75 MHz for 1H- and 13C-, respectively), Varian
4.3. 1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-(E)-[phenylmethylideneamino]}-
ferrocene (2)
In a Schlenk flask with an attached reflux condenser,
a solution of AlMe3 (21 ml, 42.0 mmol, 2 M in toluene)
in 80 ml toluene was placed and treated slowly with
SAMP (5.48 g, 42.0 mmol). After the evolution of
methane subsided, the mixture was refluxed for 7 h. A
solution of ketone 1 (3.94 g, 10.0 mmol), dissolved in 40
ml toluene was added dropwise to the red–brown
solution. The mixture was refluxed for additional 7 h,
cooled to 0 °C and poured onto crushed ice–aqueous
saturated NaHCO3. The organic layer was separated
and washed with saturated aqueous NaHCO3 and
brine. After drying over MgSO4 and concentrating
under reduced pressure, the crude product was purified
by column chromatography on silica gel (pentane–
Et2O 4:1)
Inova 400 (400, 100 and 162 MHz for H-, 13C- and
1
31P-, respectively), Varian Unity 500 (500, 125, 202 and
160 MHz for 1H-, 13C-, 31P- and 11B-, respectively),
C6D6 or CDCl3 as solvent, TMS as internal standard.
MS Finnigan MAT 212 (100 eV) and Finnigan SSQ
7000 (70 eV). Elemental analyses (C, H, N): Elementar
Vario EL. High-resolution MS: Finnigan MAT, MAT
95. The diastereomeric excesses were determined by
NMR-spectroscopy. The enantiomeric excesses were
determined by HPLC employing chiral stationary
phases.
Yield: 4.69 g (76%, dark red crystals); m.p.: 72 °C.
Rf=0.42 (pentane–Et2O 2:1). [h]2D5= −813.6 (c=0.76,
CHCl3). IR (CHCl3, cm−1): w 3081 (m), 3056 (m), 2971
(s), 2924 (s), 2874 (vs), 2826 (s), 2731 (w), 1565 (m),
1492 (m), 1460 (s), 1443 (s), 1382 (m), 1337 (m), 1321
(m), 1295 (m), 1280 (m), 1219 (s), 1195 (s), 1112 (vs),
1072 (s), 1053 (s), 1025 (s), 1002 (m), 970 (m), 904 (m),
877 (m), 825 (m), 774 (s), 757 (s), 721 (m), 700 (vs), 667
(m), 620 (w), 601 (w), 576 (m), 505 (s). 1H-NMR
(CDCl3, 400 MHz): l 1.49–1.93 (m, 8H, b-ring-CH2),
2.27 (m, 2H, NCHH), 2.55 (m, 2H, NCHH), 3.42 (s,
6H, OCH3), 3.50 (m, 2H, OCHH), 3.70 (dd, 2H, J=
9.0, 3.9 Hz, NCH), 4.21 (m, 4H, Cp-H), 4.38 (m, 4H,
Cp-H), 7.27–7.38 (m, 6H, m-C6H5, p-C6H5), 7.43 (m,
4H, o-C6H5). 13C-NMR (CDCl3, 100 MHz): l 23.05,
26.79, 54.55, 59.20, 66.30, 67.98, 68.17, 70.51, 70.55,
76.04, 86.93, 127.26, 127.66, 128.56, 138.02, 148.64.
CIMS (100 eV, H2O); m/z (relative intensity, %): 619
4.2. 1,1%-Bisbenzoylferrocene (1)
To a suspension of AlCl3 (15.20 g, 114.0 mmol) in 30
ml CH2Cl2 benzoylchloride (15.26 g, 108.6 mmol) was
added. The resulting mixture was stirred until the dis-
solvation of the AlCl3 was nearly over and then slowly
added to a solution of ferrocene (10.0 g, 53.8 mmol) in
40 ml CH2Cl2. After 3 days stirring at room tempera-
ture (r.t.), the reaction mixture was poured onto
crushed ice–aqueous saturated NaHCO3. The aqueous
phase was extracted four times with CH2Cl2. The col-
lected organic phase was washed twice with saturated
aqueous NaHCO3 and three times with brine. After
drying over MgSO4 the solution was concentrated un-
der reduced pressure. Finally, the crude product was
purified by column chromatography on silica gel (pen-
tane–Et2O 2:1).
+
+
([M+ +1], 100), 618 ([M ], 14), 617 ([M −1], 11),
507 (19), 376 (18), 225 (11). Anal. Found: C, 69.89; H,
6.78; N, 8.90. Calc. for C36H42FeN4O2 (618.59): C,
69.90; H, 6.84; N, 9.06%.
’
’
’
Yield: 18.48 g (87%, dark red crystals); m.p.: 105 °C.
Rf=0.24 (pentane–Et2O 2:1). IR (KBr, cm−1): w 3109
(w), 3100 (w), 3084 (m), 3064 (w), 3036 (w), 1633 (vs),
1598 (m), 1577 (m), 1528 (w), 1449 (m), 1440 (m), 1400
(w), 1374 (m), 1318 (w), 1310 (w), 1289 (s), 1171 (m),
1053 (w), 1027 (m), 954 (w), 859 (m), 843 (w), 899 (w),
4.4. General procedure for the preparation of the
ortho-substituted hydrazones 3 and 5 (GP1)
1
800 (w), 728 (w), 699 (m), 670 (w), 505 (w). H-NMR
(CDCl3, 400 MHz): l 4.58 (t, 4H, J=2.1 Hz, Cp-H),
4.92 (t, 4H, J=2.1 Hz, Cp-H), 7.43 (m, 4H, m-C6H5),
7.54 (m, 2H, p-C6H5), 7.79 (m, 4H, o-C6H5). 13C-NMR
(CDCl3, 100 MHz): l 72.99, 74.53, 79.36, 127.92,
128.13, 131.71, 138.89, 197.66. MS (100 eV, CI, H2O);
A Schlenk flask was charged under argon with a
solution of the hydrazone in dry THF (20–40
ml mmol−1) and cooled to −78 °C. After the addition
of BuLi (1.6 M in hexane) the reaction mixture was
stirred for 9 h at −78 °C before the electrophile was
n

702
D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
added dropwise. The reaction mixture was warmed up
to r.t. overnight, cooled to 0 °C, quenched with satu-
rated aqueous NH4Cl and washed twice with brine.
After drying over MgSO4 and concentrating under
reduced pressure, the crude product was purified by
column chromatography on silica gel. Because depro-
tected phosphines are extremely sensitive to oxidation,
in case of EX=R2PCl, the reaction mixture was
treated with borane dimethylsulfide complex (2.5 equiv-
alents, 2 M in THF) for 2 h at 0 °C before quenching.
with nBuLi (3.0 ml, 4.8 mmol) and afterwards with
trimethylsilylchloride (570 ml, 5.0 mmol). The hydra-
zone 3b was obtained by aqueous work up and purifica-
tion by column chromatography on silica gel
(pentane–Et2O 4:1).
Yield: 1.25 g (90%, red oil). Rf=0.45 (pentane–
Et2O=4:1). de]96%. [h]2D5= +246.4 (c=0.43,
CHCl3). IR (KBr, cm−1): w 3675 (m), 3438 (m), 3082
(m), 3057 (m), 3024 (m), 2949 (s), 2871 (s), 2825 (s),
2185 (w), 1725 (m), 1661 (m), 1627 (m), 1562 (m), 1446
(s), 1383 (m), 1342 (m), 1295 (m), 1242 (s), 1197 (s),
1110 (vs), 1020 (s), 970 (m), 901 (m), 832 (vs), 773 (s),
4.5. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Rp)-2-methyl]ferrocene (3a)
1
720 (m), 697 (s), 632 (m), 576 (w), 508 (m). H-NMR
(C6D6, 400 MHz): l 0.51 (s, 9H, Si(CH3)3), 1.44 (m,
4H, NCH2CH2), 1.58 (m, 2H, N(CH2)2CHH, 1.89 (m,
2H, N(CH2)2CHH), 2.40 (q, 1H, J=7.6 Hz, NCHH),
2.54 (q, 1H, J=8.2 Hz, NCHH), 2.75 (m, 2H,
NCHH), 3.21 (s, 3H, OCH3), 3.23 (s, 3H, OCH3), 3.27
(t, 1H, J=8.5 Hz, OCHH), 3.43 (m, 1H, OCHH), 3.64
(dd, 1H, J=9.1, 3.9 Hz, OCHH), 3.77 (m, 2H, OCHH,
NCH), 3.90 (m, 1H, NCH), 4.05 (q, 1H, J=1.1 Hz,
Cp-H), 4.28 (m, 2H, Cp-H), 4.31 (m, 1H, Cp-H), 4.39
(m, 2H, Cp-H), 4.93 (m, 1H, Cp-H), 7.10–7.24 (m, 6H,
m-C6H5, p-C6H5), 7.48 (d, 2H, J=7.2 Hz, o-C6H5),
7.56 (d, 2H, J=7.2 Hz, o-C6H5). 13C-NMR (C6D6, 100
MHz): l 1.78, 23.46, 23.71, 27.22, 27.62, 55.43, 56.04,
58.86, 65.64, 66.88, 67.80, 69.37, 69.62, 70.91, 71.80,
73.50, 74.11, 76.20, 76.36, 79.55, 86.76, 92.10, 127.43,
127.96, 128.85, 129.03, 138.58, 139.37, 147.82, 152.13.
The remaining aromatic signals are covered by the
solvent. EIMS (70 eV); m/z: (relative intensity, %)=
According to GP1, a solution of the hydrazone 2
(590 mg, 0.95 mmol) in THF (15 ml) was first treated
with BuLi (1.4 ml, 2.3 mmol) and afterwards with MeI
(156 ml, 2.5 mmol). The hydrazone 3a was obtained by
aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 6:1).
n
Yield: 522 mg (85%, dark red oil). Rf=0.51 (pen-
tane–Et2O 2:1). de]96%. [h]2D5= +447.0 (c=0.44,
CHCl3). IR (CHCl3, cm−1): w 3080 (w), 3057 (w), 3006
(m), 2972 (m), 2925 (m), 2875 (m), 2827 (m), 2737 (w),
2676 (w), 1564 (w), 1459 (s), 1443 (s), 1378 (m), 1353
(w), 1337 (m), 1322 (w), 1294 (m), 1280 (m), 1218 (m),
1197 (m), 1100 (s), 1072 (m), 1055 (m), 1025 (m), 970
(m), 903 (w), 875 (w), 818 (m), 757 (vs), 723 (m), 700
1
(s), 667 (m), 508 (m). H-NMR (CDCl6, 400 MHz): l
1.59 (m, 6H, b-ring-CH2), 1.93 (m, 2H, N(CH2)2CHH),
2.06 (s, 3H, CH3), 2.31 (m, 2H, NCHH), 2.59 (m, 2H,
NCHH), 2.76 (m, 2H, NCHH), 3.38 (s, 3H, OCH3),
3.41 (s, 3H, OCH3), 3.68 (qd, 2H, J=9.1, 3.9 Hz,
OCHH), 3.85 (m, 1H, OCHH), 3.90 (m, 1H, NCH),
4.00 (t, 1H, J=2.5 Hz, Cp-H), 4.14 (m, 2H, Cp-H),
4.23 (m, 1H, Cp-H), 4.36 (dt, 2H, J=9.6, 1.1 Hz,
Cp-H), 7.27–7.37 (m, 6H, m-C6H5, p-C6H5), 7.44 (m,
4H, o-C6H5). 13C-NMR (C6D6, 100 MHz): l 16.22,
22.96, 23.10, 26.77, 54.61, 54.68, 59.18, 66.39, 66.43,
67.59, 68.09, 69.60, 70.45, 70.80, 72.41, 74.54, 75.79,
76.02, 83.39, 84.17, 86.70, 127.21, 127.28, 127.62,
127.68, 128.63, 138.05, 138.63, 148.39, 150.53. EIMS
+
+
692 ([M+ +1], 18), 691 ([M ], 48), 690 ([M −1],
100), 448 (13), 409 (26), 365 (10), 364 (47), 306 (10), 300
(34), 296 (15), 292 (11), 266 (34), 246 (11), 231 (54), 224
(10). Anal. Found: C, 68.04; H, 6.89; N, 7.85. Calc. for
C39H50FeN4O2Si (690.77): C, 67.81; H, 7.30; N, 8.11%.
’
’
’
4.7. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Sp)-2-(1-boranato-1,1-diphenylphosphino]ferrocene
(3c)
According to GP1, a solution of the hydrazone 2
(1.13 g, 1.82 mmol) in THF (30 ml) was first treated
with nBuLi (2.5 ml, 4.0 mmol) and afterwards with
chloro diphenylphosphine (738 ml, 4.0 mmol). Before
quenching the reaction mixture was treated with borane
dimethylsulfide complex (2.28 ml, 4.6 mmol, 2 M in
THF) for 2 h at 0 °C. The hydrazone 3c was obtained
by aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 8:1).
Yield: 1.26 g (85%, orange–red oil). Rf=0.15 (pen-
tane–Et2O 4:1). de]96%. [h]2D5= +244.7 (c=0.41,
CHCl3). IR (CHCl3, cm−1): w 3077 (w), 3056 (m), 2967
(m), 2924 (m), 2873 (s), 2826 (m), 2428 (m), 2390 (m),
2350 (m), 1562 (m), 1484 (m), 1458 (m), 1437 (m), 1383
(70 eV); m/z: (relative intensity, %)=634 ([M+ +1],
’
40), 633 ([M+ ], 100), 390 (21), 351 (20), 337 (12), 306
’
(46), 292 (337−[CH2OCH+3 ], 21), 271 (17), 246 (26),
238 (12), 237 (29), 224 (21), 203 (17), 202 (46), 201 (10),
189 (15), 188 (29), 180 (11), 134 ([CH3C5H3Fe+], 12),
123 (13), 121 ([CpFe+], 15). HRMS; m/z: 632.2813
([M+]; exact mass calc. for C37H44 56FeN4O2: 632.2814).
4.6. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Sp)-2-(trimethylsilyl)]ferrocene (3b)
According to GP1, a solution of the hydrazone 2
(1.24 g, 2.00 mmol) in THF (20 ml) was first treated

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
703
4.00 (t, 1H, J=2.6 Hz, Cp-H), 4.26 (m, 4H, Cp-H),
4.55 (m, 1H, Cp-H), 4.92 (m, 1H, Cp-H), 6.85 (d, 2H,
J=8.0 Hz, C6H4), 7.03–7.11 (m, 2H, p-C6H5), 7.22 (t,
4H, J=7.7 Hz, m-C6H5), 7.35 (dt, 2H, J=8.2, 1.9 Hz,
C6H4), 7.70 (m, 4H, o-C6H5). 13C-NMR (C6D6, 100
MHz): l 20.94, 23.59, 27.14, 27.52, 55.61, 55.69, 58.88,
58.98, 66.64, 67.14, 68.44, 68.92, 71.38, 71.59, 71.64,
72.08, 74.68, 75.66, 76.58, 85.54, 88.31, 89.94, 127.48,
127.59, 127.72, 127.84, 127.97, 128.08, 129.53, 130.02,
135.25, 136.27, 138.60, 138.84, 144.87, 146.20. EIMS
(w), 1342 (m), 1322 (m), 1295 (m), 1283 (m), 1220 (m),
1197 (m), 1158 (m), 1106 (s), 1071 (s), 1023 (m), 1001
(w), 971 (m), 900 (m), 878 (w), 830 (m), 756 (vs), 723
(m), 698 (s), 667 (m), 636 (w), 525 (m), 499 (m), 481
1
(m), 457 (m). H-NMR (C6D6, 300 MHz): l 1.31 (m,
4H, NCH2CH2), 1.58 (m, 2H, N(CH2)2CHH), 1.89 (m,
2H, N(CH2)2CHH), 2.21 (m, 1H, NCHH), 2.60 (m,
3H, NCHH, OCHH), 2.82 (m, 1H, NCHH), 2.96 (m,
1H, NCHH), 3.04 (s, 3H, OCH3), 3.21 (s, 3H, OCH3),
3.40 (t, 1H, J=7.7 Hz, OCHH), 3.65 (m, 2H, OCHH,
NCH), 3.83 (m, 1H, NCH), 3.88 (br s, 1H, Cp-H), 4.29
(t, 1H, J=2.5 Hz, Cp-H), 4.43 (br s, 1H, Cp-H), 4.48
(br s, 1H, Cp-H), 4.90 (br s, 1H, Cp-H), 4.97 (br s, 1H,
Cp-H), 5.25 (br s, 1H, Cp-H), 6.95–7.27 (m, 14H,
p-C6H5, m-C6H5, o-C6H5), 7.72–7.93 (m, 6H, o-C6H5).
13C-NMR (C6D6, 75 MHz): l 23.43, 24.36, 26.97,
27.02, 55.17, 57.28, 58.65, 59.00, 64.99, 66.85, 69.17,
71.04, 73.75, 73.87, 73.94, 74.50, 75.33, 76.15, 76.50,
88.58, 94.10, 94.23, 127.14, 128.17, 128.23, 128.98,
129.52, 129.87, 130.34, 132.68 (d), 134.67 (d), 138.54,
139.34, 141.89, 146.77. The remaining aromatic signals
are covered by the solvent. 31P-NMR (C6D6, 162 MHz):
l 18.74 (s). 11B-NMR (C6D6, 160 MHz): l −34.47 (s).
EIMS (70 eV); m/z: (relative intensity, %)=691 (11),
(70 eV); m/z: (relative intensity, %) 743 ([M+ +2], 13),
’
+
742 ([M+ +1], 46), 741 ([M ], 100), 459 (12), 337
(12), 325 (13), 292 (14). Anal. Found: C, 69.31; H, 6.47;
N, 7.36. Calc. for C43H48FeN4O2S (740.79): C, 69.72;
H, 6.53; N, 7.56%.
’
’
4.9. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Sp)-2-methylsulfanyl]ferrocene (3e)
According to GP1, a solution of the hydrazone 2
(563 mg, 0.91 mmol) in THF (15 ml) was first treated
n
with BuLi (1.25 ml, 2.0 mmol) and afterwards with
methyl disulfide (270 ml, 3.0 mmol). The hydrazone 3e
was obtained by aqueous work up and purification by
column chromatography on silica gel (pentane–Et2O
9:1).
690 (41), 689 ([M+ −C6H15NOB], 100), 406 (25), 337
’
(406−[C4H7N+], 37), 322 (28), 292 (406−[C6H12NO+
], 27), 287 (18). HRMS; m/z: 688.2182 (C48H54-
56FeBN4O2PꢀC6H15NOB; exact mass calc. for
C42H39 56FeN3OP: 688.2180).
Yield: 605 mg (100%, red powder); m.p.: 49 °C.
Rf=0.23 (pentane–Et2O 4:1). de]96%. [h]2D5= −53.1
(c=0.39, CHCl3). IR (CHCl3, cm−1): w 3080 (w), 3057
(w), 2972 (m), 2920 (m), 2874 (m), 2828 (m), 1565 (w),
1491 (m), 1460 (m), 1443 (m), 1386 (m), 1334 (m), 1296
(m), 1279 (m), 1263 (m), 1218 (m), 1196 (m), 1135 (m),
1111 (s), 1094 (s), 1072 (m), 1054 (m), 1024 (m), 970
(m), 924 (w), 902 (w), 892 (m), 876 (m), 823 (m), 757
(vs), 723 (m), 701 (s), 667(m), 520 (m). 1H-NMR (C6D6,
400 MHz): l 1.37 (m, 4H, NCH2CH2), 1.62 (m, 2H,
N(CH2)2CHH), 1.90 (m, 2H, N(CH2)2CHH), 2.14 (s,
3H, SCH3), 2.35 (m, 1H, NCHH), 2.46 (m, 1H,
NCHH), 2.79 (m, 2H, NCHH), 3.25 (s, 3H, OCH3),
3.31 (s, 3H, OCH3), 3.45 (t, 1H, J=8.8 Hz, OCHH),
3.64 (t, 1H, J=8.2 Hz, OCHH), 3.84 (m, 2H, OCHH),
3.98 (t, 1H, J=2.6 Hz, Cp-H), 4.05 (m, 1H, Cp-H),
4.07 (m, 2H, NCH), 4.15 (dd, 1H, J=2.5, 1.7 Hz,
Cp-H), 4.19 (m, 1H, Cp-H), 4.25 (m, 1H, Cp-H), 4.32
(m, 1H, Cp-H), 4.89 (m, 1H, Cp-H), 7.06–7.11 (m, 2H,
p-C6H5), 7.21 (t, 4H, J=7.7 Hz, m-C6H5), 7.69 (m, 4H,
o-C6H5). 13C-NMR (C6D6, 100 MHz): l 16.84, 23.46,
23.56, 27.30, 27.52, 55.52, 55.78, 58.97, 59.04, 66.62,
67.17, 67.29, 67.81, 69.69, 70.07, 70.13, 71.15, 72.81,
75.99, 76.53, 86.36, 88.64, 89.45, 127.59, 127.72, 127.84,
127.94, 129.41, 129.44, 138.56, 138.64, 146.32, 147.30.
4.8. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Sp)-2-(4-methylphenyl)sulfanyl]ferrocene (3d)
According to GP1, a solution of the hydrazone 2
(563 mg, 0.91 mmol) in THF (15 ml) was first treated
n
with BuLi (1.25 ml, 2.0 mmol) and afterwards with
di-p-toluoyl disulfide (740 mg, 3.0 mmol). The hydra-
zone 3d was obtained by aqueous work up and purifica-
tion by column chromatography on silica gel
(pentane–Et2O 12:1).
Yield: 580 mg (86%, orange oil). Rf=0.20 (pentane–
Et2O 4:1). de]96%. [h]2D5= +395.2 (c=0.38, CHCl3).
IR (CHCl3, cm−1): w 3055 (w), 2971 (m), 2923 (m),
2873 (m), 2827 (m), 1597 (w), 1565 (w), 1492 (m), 1459
(m), 1445 (m), 1385 (m), 1339 (m), 1323 (m), 1296 (m),
1279 (m), 1218 (m), 1197 (m), 1113 (s), 1090 (s), 1072
(m), 1054 (m), 1024 (m), 970 (w), 891 (w), 877 (w), 812
(m), 803 (m), 757 (vs), 723 (m), 701 (m), 667 (w), 506
1
(m), 486 (m). H-NMR (C6D6, 400 MHz): l 1.34 (m,
4H, NCH2CH2), 1.62 (m, 2H, N(CH2)2CHH), 1.87 (m,
2H, N(CH2)2CHH), 2.05 (s, 3H, C6H4-CH3), 2.43 (m,
2H, NCHH), 2.76 (m, 2H, NCHH), 3.23 (s, 3H,
OCH3), 3.25 (s, 3H, OCH3), 3.45 (m, 2H, OCHH), 3.73
(dd, 2H, J=9.2, 3.7 Hz, OCHH), 3.90 (m, 2H, NCH),
EIMS (70 eV); m/z: (relative intensity, %) 667 ([M+
+
’
+
2], 13), 666 ([M+ +1], 43), 665 ([M ], 88), 422 (18),
’
’
400 (22), 399 (100), 391 (11), 383 (13), 369 (13), 368

704
D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
(26), 353 (422−[C4H7N+], 10), 352 (32), 338 (23), 337
(62), 336 (14), 292 (43), 288 (14), 287 (31), 286 (45), 281
(21), 280 (13), 253 (14), 246 (15), 245 (11), 237 (15), 236
(22), 235 (18), 234 (10), 224 (15), 222 (10), 218 (15), 216
(21), 211 (14), 198 (12), 189 (18), 170 (12), 168 (18), 167
(12), 152 (10), 123 (14), 114 ([C6H12NO+], 13), 105 (15),
77 (16), 65 (10), 45 ([CH2OCH+3 ], 41). Anal. Found: C,
66.45; H, 6.54; N, 8.16. Calc. for C37H44FeN4O2S
(664.69): C, 66.86; H, 6.67; N, 8.43%.
43). HRMS; m/z: 646.2971 ([M+]; exact mass calc. for
C38H46 56FeN4O2: 646.2970).
4.11. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)-phenylmethylideneamino]}]-
{(Rp)-2-methyl-(Sp)-2%-trimethylsilyl}ferrocene (5b)
According to GP1, a solution of the hydrazone 3a (100
mg, 0.16 mmol) in THF (10 ml) was first treated with
nBuLi (0.15 ml, 0.2 mmol) and afterwards with
trimethylsilyl chloride (47 ml, 0.4 mmol). The hydrazone
5b was obtained by aqueous work up and purification by
column chromatography on silica gel (pentane–Et2O
9:1).
4.10. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)phenylmethylideneamino]}]-
[(Rp)-2,2%-bismethyl)]ferrocene (5a)
A heated Schlenk flask was charged under argon with
a solution of the hydrazone 3a (155 mg, 0.25 mmol) in
THF (10 ml) and cooled to −78 °C. After the addition
Yield: 66 mg (59%, dark red oil). Rf=0.55 (pentane–
Et2O 4:1). de]96%. [h]2D5= −611.6 (c=0.47, CHCl3).
IR (CHCl3, cm−1): w 3082 (m), 3056 (m), 2951 (s), 2923
(s), 2874 (s), 2826 (m), 1565 (w), 1490 (m), 1458 (m), 1445
(s), 1382 (m), 1345 (m), 1321 (w), 1279 (m), 1241 (s), 1199
(s), 1150 (s), 1111 (s), 1075 (s), 1019 (m), 970 (m), 924
(m), 901 (m), 859 (m), 833 (vs), 772 (s), 757 (s), 723 (m),
s
of BuLi (0.46 ml, 0.6 mmol, 1.3 M in hexane) the
reaction mixture was stirred for 9 h at −78 °C before
MeI (47 ml, 0.8 mmol) was added dropwise. The reaction
mixture was warmed up to r.t. overnight, cooled to 0 °C,
quenched with saturated aqueous NH4Cl and washed
twice with brine. After drying over MgSO4 and concen-
trating under reduced pressure, the crude product was
purified by column chromatography on silica gel (pen-
tane–Et2O 9:1).
1
698 (s), 629 (w), 594 (w), 578 (w), 512 (m). H-NMR
(C6D6, 400 MHz): l 0.60 (s, 9H, Si(CH3)3), 1.33–1.62
(m, 8H, b-ring-CH2), 1.89 (m, 2H, N(CH2)2CHH), 2.36
(s, 3H,CH3), 2.53 (m, 1H, NCHH), 2.74 (dm, 2H,
NCHH), 3.22 (s, 3H, OCH3), 3.23 (s, 3H, OCH3), 3.44
(m, 1H, OCHH), 3.63 (m, 1H, OCHH), 3.68 (dd, 1H,
J=9.1, 3.9 Hz, OCHH), 3.75 (dd, 1H, J=9.1, 3.9 Hz,
OCHH), 3.93 (m, 1H, NCH), 4.05 (t, 1H, J=2.5 Hz,
Cp-H), 4.14 (m, 1H, Cp-H), 4.21 (m, 2H, Cp-H), 4.29
(t, 1H, J=2.5 Hz, Cp-H), 4.45 (t, 1H, J=1.9 Hz,
Cp-H), 7.08-7.16 (m, 6H, m-C6H5, p-C6H5), 7.40 (m,
2H, o-C6H5), 7.58 (m, 2H, o-C6H5). 13C-NMR (C6D6,
100 MHz): l 1.89, 16.99, 23.18, 23.76, 27.20, 27.76,
55.09, 56.12, 58.93, 65.73, 66.94, 68.87, 69.08, 72.57,
75.04, 76.74, 76.11, 76.54, 82.77, 84.76, 92.10, 127.04,
127.41, 128.67, 128.89, 129.15, 139.25, 139.50, 151.35,
152.69. The remaining aromatic signals are covered by
Yield: 87 mg (54%, dark red oil). Rf=0.45 (pentane–
Et2O 4:1). de=92%. [h]2D5= −105.0 (c=0.20, CHCl3).
IR (Kapillar, cm−1): w 3080 (m), 3057 (m), 3022 (m),
2971 (s), 2922 (s), 2875 (s), 2827 (s), 2732 (w), 2245 (w),
1641 (m), 1599 (m), 1577 (m), 1565 (m), 1490 (m), 1459
(vs), 1444 (vs), 1428 (s), 1376 (s), 1352 (s), 1100 (vs), 1038
(s), 1028 (s), 970 (s), 909 (s), 876 (m), 811 (m), 775 (s),
733 (vs), 700 (vs), 671 (m), 648 (m), 623 (w), 594 (m), 581
1
(m), 509 (s), 481 (m). H-NMR (C6D6, 400 MHz): l
1.48–1.68 (m, 6H, b-ring-CH2), 1.92 (m, 2H,
N(CH2)2CHH), 2.14 (s, 6H, CH3), 2.36 (m, 2H,
NCHH), 2.58 (m, 2H, NCHH), 3.38 (s, 6H, OCH3), 3.48
(m, 2H, OCHH), 3.66 (dd, 1H, J=9.1, 3.8 Hz, OCHH),
3.82 (t, 2H, J=1.9 Hz, NCH), 4.04 (d, 4H, J=2.2 Hz,
Cp-H), 4.19 (m, 2H, Cp-H), 7.25–7.37 (m, 6H, m-C6H5,
p-C6H5), 7.43 (m, 4H, o-C6H5). 13C-NMR (C6D6, 100
MHz): l 15.80, 22.97, 26.71, 54.67, 59.15, 66.47, 68.53,
70.68, 75.76, 83.21, 83.69, 127.17, 127.63, 128.57, 138.65,
150.63. EIMS (70 eV); m/z: (relative intensity, %) 647
the solvent. EIMS (70 eV); m/z: (relative intensity, %)
+
705 ([M+ +1], 26), 704 ([M ], 100), 364 (21), 307 (13),
306 (13), 238 (307−[C4H7N+], 26), 188 (12). HRMS;
m/z: 704.3208 ([M+]; exact mass calc. for
C40H52 56FeN4O2Si: 704.3209).
’
’
([M+ ], 100), 364 (16), 352 (12), 351 (50), 315 (12), 307
4.12. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)-phenylmethylideneamino]}]-
{(Rp)-2-methyl-(Sp)-2%-[diphenyl(hydroxy)methyl]}-
ferrocene (5c)
’
(19), 306 (351−[CH2OCH+3 ], 96), 279 (10), 278 (65), 251
(19), 249 (23), 248 (19), 247 (13), 246 (46), 244 (48), 239
(145), 238 (61), 237 (351−[C6H12NO+], 17), 236 (14),
216 (22), 210 (15), 209 (90), 208 (14), 203 (33), 188 (61),
182 (14), 180 (32), 165 (13), 160 (12), 153 (11), 149 (23),
135 (28), 134 ([CH3C5H3Fe+], 30), 133 (11), 125 (13), 123
(14), 121 ([CpFe+], 11), 111 (13), 104 (12), 97 (19), 95
(10), 85 (20), 84 (12), 83 (30), 82 (16), 81 (12), 79 (20),
77 (27), 73 (10), 71 (32), 70 (29), 69 (24), 67 (11), 60 (14),
57 (58), 56 ([Fe+], 29), 55 (38), 46 (24), 45 ([CH2OCH+3 ],
According to GP1, a solution of the hydrazone 3a (154
mg, 0.24 mmol) in THF (10 ml) was first treated with
nBuLi (0.3 ml, 0.5 mmol) and afterwards with benzophe-
none (118 mg, 0.6 mmol). The hydrazone 5c was ob-
tained by aqueous work up and purification by column
chromatography on silica gel (pentane–Et2O 4:1).

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
705
Yield: 150 mg (77%, orange crystals); m.p.: 66 °C.
Rf=0.11 (pentane–Et2O 4:1). de]96%. [h]2D5=
−717.8 (c=0.56, CHCl3). IR (KBr, cm−1): w 3752 (w),
3676 (m), 3654 (m), 3432 (s), 3056 (s), 3025 (s), 2922 (s),
2871 (vs), 2188 (m), 1596 (m), 1489 (m), 1445 (s), 1384
(s), 1347 (s), 1281 (m), 1226 (s), 1179 (s), 1114 (vs), 1029
(s), 971 (s), 905 (s), 824 (m), 756 (s), 701 (vs), 516 (m).
1H-NMR (C6D6, 400 MHz): l 1.20–1.40 (m, 8H, b-
ring-CH2), 1.45–1.59 (m, 2H, N(CH2)2CHH), 1.65 (m,
1H, N(CH2)2CHH), 1.81 (m, 1H, N(CH2)2CHH), 1.89
(s, 3H, CH3), 2.35 (m, 1H, NCHH), 2.53 (m, 3H,
NCHH), 2.70 (m, 2H, NCHH), 3.04 (s, 3H, OCH3),
3.19 (s, 3H, OCH3), 3.26 (m, 1H, OCHH), 3.44 (dd,
1H, J=9.1, 7.4 Hz, OCHH), 3.61 (m, 1H, OCHH),
3.70 (dd, 1H, J=9.1, 3.8 Hz, OCHH), 3.75 (dd, 1H,
J=9.1, 3.9 Hz, OCHH), 3.98 (m, 1H, NCH), 4.14 (t,
1H, J=2.6 Hz, Cp-H), 4.25 (t, 1H, J=2.5 Hz, Cp-H),
4.28 (m, 1H, Cp-H), 4.43 (m, 1H, Cp-H), 5.18 (t, 1H,
J=1.9 Hz, Cp-H), 7.00–7.17 (m, 12H, m-C6H5, p-
C6H5), 7.21–7.47 (m, 6H, o-C6H5), 7.55 (br d, 2H,
J=7.4 Hz, o-C6H5), 7.90 (br s, 2H, o-C6H5), 9.14 (s,
1H, OH). 13C-NMR (C6D6, 100 MHz): l 15.95, 22.85,
23.31, 26.93, 27.24, 55.16, 56.10, 58.52, 58.94, 66.43,
66.80, 72.36, 72.84, 74.28, 75.40, 76.04, 76.14, 77.61,
79.55, 79.01, 83.64, 86.51, 126.33, 126.50, 127.22,
127.49, 128.30, 128.76, 129.07, 139.02, 139.28, 147.54,
151.31. The remaining aromatic signals are covered by
the solvent. EIMS (70 eV); m/z: (relative intensity, %)
3023 (w), 2925 (vs), 2852 (s), 2377 (s), 2345 (m), 2259
(m), 1656 (w), 1561 (m), 1485 (m), 1439 (m), 1382 (w),
1343 (m), 1323 (m), 1281 (m), 1219 (m), 1198 (m), 1109
(s), 1061 (s), 1019 (m), 971 (m), 921 (w), 900 (m), 832
(m), 741 (s), 697 (s), 634 (w), 613 (w), 520 (m), 496 (m),
1
458 (m). H-NMR (C6D6, 300 MHz): l 0.80–1.01 (m,
8H, C6H11), 1.35 (m, 4H, NCH2CH2), 1.40–1.62 (m,
10H, C6H11), 1.72 (m, 2H, N(CH2)2CHH), 1.90 (m, 2H,
N(CH2)2CHH), 2.19 (m, 2H, C6H11), 2.49 (m, 2H,
C6H11), 2.61 (m, 1H, NCHH), 2.71 (m, 2H, NCHH),
2.89 (m, 2H, NCHH), 3.04 (s, 3H, OCH3), 3.21 (s, 3H,
OCH3), 3.41 (m, 2H, OCHH), 3.79 (m, 2H, NCH),
4.57 (br s, 1H, Cp-H), 4.66 (br s, 1H, Cp-H), 4.95 (br
s, 2H, Cp-H), 5.11 (m, 1H, Cp-H), 6.01 (br s, 1H,
Cp-H), 6.94–7.27 (m, 12H, p-C6H5, m-C6H5), 7.36 (d,
2H, J=7.7 Hz, o-C6H5), 7.52 (d, 2H, J=7.4 Hz,
o-C6H5), 7.73 (m, 2H, o-P(C6H5)2), 8.03 (m, 2H, o-
P(C6H5)2). 13C-NMR (C6D6, 75 MHz): l 23.70, 24.25,
26.26, 26.33, 26.80, 27.09, 27.15, 27.23, 27.31, 27.43,
27.56, 27.65, 27.92, 28.51, 33.63, 34.05, 55.78, 56.73,
58.67, 59.03, 65.26, 66.66, 74.47, 74.90, 75.24, 77.02,
77.79, 77.87, 78.53, 80.92 (d), 94.77 (d), 95.06, 95.02,
127.41, 127.82, 128.25, 128.69, 128.81, 129.50, 129.65,
129.68, 130.02, 131.01, 131.03, 132.56 (d), 134.79 (d),
139.03, 139.25, 141.13, 144.26. 31P-NMR (C6D6, 162
MHz): l 18.13 (s, P(C6H5)2), 30.67 (s, P(C6H11)2).
EIMS (70 eV); m/z: (relative intensity, %) 900 (23), 899
([M+−C6H15NOB], 39), 898 (12), 887 (17), 886 (56),
814 ([M+ ], 3), 446 (35), 407 (20), 406 (96), 405 (20),
885 (899−[BH3], 100), 689 (12), 688 ([M+
’
’
−
402 (30), 401 (446−[CH2OCH+3 ], 100), 333 (25), 332
(446−[C6H12NO+], 96), 330 (11), 327 (11), 296 (13),
285 (12), 284 (23), 254 (24), 251 (17), 239 (11), 237 (14),
229 (42), 228 (77), 227 (29), 226 (15), 202 (14), 182 (19),
149 (19), 105 (27), 97 (13), 83 (18), 81 (12), 79 (30), 77
(32), 74 (11), 72 (14), 70 (21), 69 (20), 68 (10), 61 (12),
57 (12), 55 (34). HRMS; m/z: 814.3547 ([M+]; exact
mass calc. for C50H54 56FeN4O3: 814.3545).
C18H39NOPB2], 35), 406 (25), 337 (406−[C4H7N+],
12), 126 (26), 82 (28). HRMS; m/z: 688.2184
(C60H78FeB2N4O2P2ꢀC18H39NOPB2; exact mass calc.
for C42H39 56FeN3OP: 688.2180).
4.14. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)-phenylmethylideneamino]}]-
{(Sp)-2%-(1-boranato-1,1-diphenylphosphino)-(Sp)-2-
methylsulfanyl}ferrocene (5e)
4.13. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)-phenylmethylideneamino]}]-
{(Sp)-2%-(1-boranato-1,1-dicyclohexylphosphino)-(Sp)-
2-(1-boranato-1,1-diphenylphosphino)}ferrocene (5d)
According to GP1, a solution of the hydrazone 3e
(258 mg, 0.39 mmol) in THF (10 ml) was first treated
with nBuLi (0.4 ml, 0.6 mmol) and afterwards with
chloro diphenylphosphine (148 ml, 0.8 mmol). Before
quenching the reaction mixture was treated with borane
dimethylsulfide complex (0.5 ml, 1 mmol, 2 M in THF)
for 2 h at 0 °C. The hydrazone 5e was obtained by
aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 9:1).
According to GP1, a solution of the hydrazone 3c
(162 mg, 0.20 mmol) in THF (15 ml) was first treated
with nBuLi (0.2 ml, 0.3 mmol) and afterwards with
chloro dicyclohexylphosphine (77 ml, 0.4 mmol). Before
quenching the reaction mixture was treated with borane
dimethylsulfide complex (0.2 ml, 0.4 mmol, 2 M in
THF) for 2 h at 0 °C. The hydrazone 5d was obtained
by aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 8:1).
Yield: 92 mg (45%, orange oil). Rf=0.18 (pentane–
Et2O 4:1). de]96%. [h]2D5= −219.3 (c=0.40, CHCl3).
IR (KBr, cm−1): w 3691 (w), 3677 (w), 3652 (w), 3631
(w), 3618 (w), 3590 (w), 3569 (w), 3434 (m), 3055 (m),
Yield: 154 mg (46%, orange oil). Rf=0.12 (pentane–
Et2O 4:1). de]96%. [h]2D5= −260.0 (c=0.40, CHCl3).
IR (CHCl3, cm−1): w 058 (w), 3004 (m), 2958 (m), 2925
(m), 2854 (m), 2389 (w), 1438 (m), 1384 (m), 1346 (w),
1216 (m), 1105 (m), 1072 (m), 1021 (w), 757 (vs), 699
1
(m), 668 (m). H-NMR (C6D6, 400 MHz): l 1.36 (m,
4H, NCH2CH2), 1.50 (s, 3H, SCH3), 1.60 (m, 2H,
N(CH2)2CHH), 1.84 (m, 2H, N(CH2)2CHH), 2.41 (m,

706
D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
1H, NCHH), 2.59 (m, 1H, NCHH), 2.65 (m, 2H,
NCHH), 2.94 (m, 1H, OCHH), 3.02 (s, 3H, OCH3),
3.24 (s, 3H, OCH3), 3.58 (dd, 1H, J=9.7, 7.7 Hz,
OCHH), 3.71 (m, 1H, OCHH), 3.85 (m, 1H, NCH),
3.94 (dd, 1H, J=9.7, 3.6 Hz, OCHH), 4.11 (m, 1H,
Cp-H), 4.32 (m, 1H, Cp-H), 4.35 (t, 1H, J=2.6 Hz,
Cp-H), 4.48 (m, 1H, Cp-H), 4.77 (m, 1H, Cp-H), 5.04
(t, 1H, J=2.6 Hz, Cp-H), 6.95–7.13 (m, 12H, p-C6H5,
m-C6H5), 7.29 (m, 2H, o-C6H5), 7.52 (m, 2H, o-C6H5),
7.74 (m, 2H, o-P(C6H5)2), 8.05 (m, 2H, o-P(C6H5)2).
13C-NMR (75 MHz): l 15.91, 23.43, 24.36, 26.86,
27.11, 55.28, 57.06, 58.66, 59.08, 65.10, 66.61, 69.47,
70.57, 74.51, 75.35, 75.58, 76.36, 77.92, 79.66, 85.52,
85.77, 90.51, 90.59, 127.41, 128.21, 129.34, 129.54,
130.02, 130.43, 132.43 (d), 135.24 (d), 138.40, 139.52,
140.77, 146.26. 31P-NMR (C6D6, 162 MHz): l 17.47 (s)
ppm. EIMS (70 eV); m/z: (relative intensity, %) 737
58.99, 59.18, 65.89, 66.75, 67.21, 67.47, 68.77, 72.57,
73.16, 73.53, 75.79, 76.17, 84.09, 88.16, 88.35, 90.34,
128.22, 129.77, 130.09, 131.89, 135.55, 136.11, 138.21,
138.46, 144.47, 144.62. The remaining aromatic signals
are covered by the solvent. EIMS (70 eV); m/z (relative
+
intensity, %): 788 ([M+ +1], 52), 787 ([M ], 100), 460
(21), 459 (63), 383 (26), 369 (12), 368 (44), 348 (19), 346
(19), 345 (15), 338 (17), 323 (10), 280 (18), 260 (14), 256
(10), 255 (10), 243 (11), 242 (30), 235 (13), 184 (10), 170
(19), 157 (10), 57 (21), 55 (14), 45 ([CH2OCH+3 ], 18).
HRMS; m/z: 786.2726 ([M+]; exact mass calc. for
C44H50 56FeO2N4O2S2: 786.2726).
’
’
4.16. General procedure for hydrazone clea6age with
ozone (GP2)
A
solution of the hydrazone in CH2Cl2 (50
(20), 735 (51), 734 ([M+ −C6H15NOB], 100), 407 (17),
ml mmol−1) was cooled to −78 °C. O3 was bubbled
through the solution (50 l h−1) under TLC control.
After warming up to r.t. and concentrating in vacuo,
the crude product was purified by column chromatog-
raphy on silica gel.
’
406 (59), 384 (10), 383 (38), 369 (11), 368 (48), 345 (19),
338 (11), 310 (10), 303 (19), 280 (12). Anal. Found: C,
68.24; H, 6.68; N, 6.26. Calc. for C49H56FeBN4PO2S
(862.70): C, 68.22; H, 6.54; N, 6.49%.
4.15. [1,1%-Bis{N-[(2S)-2-(methoxymethyl)tetrahydro-
1H-1-pyrrolyl]-N-[(E)-phenylmethylideneamino]}]-
{(Sp)-2%-(4-methylphenyl)sulfanyl-(Sp)-2-methylsul-
fanyl}ferrocene (5f)
4.17. General procedure for hydrazone clea6age with
TiCl3 (GP3)
A 20% aqueous solution of TiCl3 was added to a
solution of the hydrazone in DME (40 ml mmol−1
)
According to GP1, a solution of the hydrazone 3d
(243 mg, 0.33 mmol) in THF (15 ml) was first treated
with BuLi (0.41 ml, 0.66 mmol) and afterwards with
methyl disulfide (95 ml, 1.0 mmol). The hydrazone 5f
was obtained by aqueous work up and purification by
column chromatography on silica gel (pentane–Et2O
9:1).
under argon. The reaction mixture was refluxed under
TLC control. Afterwards the mixture was diluted with
Et2O and washed with aqueous buffer (pH 9) and
brine. The organic layer was dried over MgSO4 and
concentrated in vacuo. Finally the crude product was
purified by column chromatography on silica gel.
n
Yield: 230 mg (89%, red oil). Rf=0.22 (pentane–
Et2O 4:1). de]96%. [h]2D5= −332.9 (c=0.50, CHCl3).
IR (CHCl3, cm−1): w 3056 (w), 2972 (m), 2922 (m),
2873 (m), 2829 (m), 1565 (w), 1492 (m), 1447 (m), 1388
(m), 1343 (w), 1331 (w), 1299 (w), 1279 (w), 1262 (w),
1217 (w), 1199 (m), 1153 (m), 1114 (m), 1091 (m), 1073
(m), 1019 (m), 969 (w), 892 (w), 812 (m), 757 (vs), 726
(m), 702 (m), 667 (m), 508 (m), 485 (w). 1H-NMR
(C6D6, 300 MHz): l 1.35 (m, 4H, NCH2CH2), 1.65 (m,
2H, N(CH2)2CHH), 1.87 (m, 1H, N(CH2)2CHH), 1.97
(m, 1H, N(CH2)2CHH), 2.06 (s, 3H, C6H4ꢀCH3), 2.16
(s, 3H, SCH3), 2.38 (m, 2H, NCHH), 2.80 (m, 2H,
NCHH), 3.23 (s, 3H, OCH3), 3.33 (s, 3H, OCH3), 3.44
(m, 1H, OCHH), 3.66 (m, 1H, OCHH), 3.78 (dd, 1H,
J=9.1, 3.6 Hz, OCHH), 4.02 (m, 2H, NCH), 4.05 (br
s, 4H, Cp-H), 4.12 (m, 1H, Cp-H), 4.16 (m, 1H, Cp-H),
6.90 (d, 2H, J=7.7 Hz, C6H4), 7.02–7.11 (m, 2H,
p-C6H5), 7.22 (m, 4H, m-C6H5), 7.50 (br d, 2H, J=8.0
Hz, C6H4), 7.77 (d, 2H, J=7.2 Hz, o-C6H5), 7.84 (d,
2H, J=6.9 Hz, o-C6H5). 13C-NMR (C6D6, 75 MHz): l
16.79, 21.03, 23.64, 23.76, 27.32, 27.52, 55.88, 56.18,
4.18. 1,1%-Bisbenzoyl-(Rp)-2-methylferrocene (4a)
According to GP2, a solution of the hydrazone 3a
(242 mg, 0.38 mmol) in CH2Cl2 (30 ml) was ozonolysed
for 90 s. The ketone 4a was obtained after purification
by column chromatography on silica gel (pentane–
Et2O 4:1).
Yield: 144 mg (92%, dark red oil). Rf=0.19 (pen-
tane–Et2O 4:1). ee=98%. [h]2D5= +165.1 (c=0.42,
CHCl3). IR (CHCl3, cm−1): w 3083 (w), 3060 (w), 3014
(m), 2956 (w), 2923 (m), 2852 (w), 1642 (vs), 1598 (m),
1578 (m), 1450 (s), 1417 (s), 1375 (m), 1349 (m), 1314
(m), 1285 (s), 1226 (m), 1178 (m), 1075 (w), 1052 (m),
1027 (m), 887 (m), 854 (m), 799 (m), 757 (s), 730 (s),
1
699 (s), 668 (m), 494 (m). H-NMR (C6D6, 300 MHz):
l 2.23 (s, 3H, CH3), 3.98 (t, 1H, J=2.6 Hz, Cp-H),
4.10 (m, 1H, Cp-H), 4.12 (m, 1H, Cp-H), 4.15 (m, 1H,
Cp-H), 4.29 (m, 1H, Cp-H), 4.76 (m, 1H, Cp-H), 4.79
(m, 1H, Cp-H), 7.02–7.14 (m, 6H, m-C6H5, p-C6H5),
7.78 (m, 4H, o-C6H5). 13C-NMR (C6D6, 75 MHz): l
14.15, 71.21, 73.35, 73.72, 74.23, 75.23, 75.86, 76.33,

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
707
78.83, 80.21, 89.93, 128.27, 128.58, 128.80, 131.60,
131.64, 140.36, 142.46, 196.98, 198.64. The remaining
aromatic signals are covered by the solvent. EIMS (70
854 (m), 813 (m), 729 (s), 698 (s), 674 (m), 501 (s).
1H-NMR (C6D6, 300 MHz): l 1.99 (s, 3H, C6H4ꢀCH3),
4.01 (t, 1H, J=2.6 Hz, Cp-H), 4.29 (m, 1H, Cp-H),
4.34 (m, 1H, Cp-H), 4.39 (m, 2H, Cp-H), 4.88 (m, 2H,
Cp-H), 6.80 (d, 2H, J=8.0 Hz, C6H4), 6.98–7.14 (m,
6H, p-C6H5, m-C6H5), 7.31 (br d, 2H, C6H4), 7.80 (m,
4H, o-C6H5). 13C-NMR (C6D6, 75 MHz): l 16.45,
72.02, 73.66, 74.53, 74.60, 75.88, 77.03, 77.09, 79.71,
80.79, 92.54, 128.70, 128.92, 130.11, 131.70, 131.89,
132.70, 132.98, 137.46, 139.51, 139.84, 196.31, 196.47.
The remaining aromatic signals are covered by the
solvent. EIMS (70 eV); m/z: (relative intensity, %) 517
eV); m/z: (relative intensity, %) 409 ([M+ +1], 30), 408
’
+
([M+ ], 100), 303 (408−[C6H5CO ], 26), 165 (10), 153
’
(13), 133 (13), 56 (Fe+, 11). HRMS; m/z: 408.0811
([M+]; exact mass calc. for C25H20 56FeO2: 408.0813).
4.19. 1,1%-Bisbenzoyl-(Sp)-2-trimethylsilyl-ferrocene
(4b)
According to GP2, a solution of the hydrazone 3b
(173 mg, 0.25 mmol) in CH2Cl2 (30 ml) was ozonolysed
for 90 s. The ketone 4b was obtained after purification
by column chromatography on silica gel (pentane–
Et2O 15:1).
+
+
([M+ +1], 29), 516 ([M ], 100), 105 ([C6H5CO ], 24).
HRMS; m/z: 516.0847 ([M+]; exact mass calc. for
C31H24 56FeO2S: 516.0846).
’
’
Yield: 116 mg (99%, red oil). Rf=0.24 (pentane–
Et2O 4:1). ee=99%. [h]2D5= −20.0 (c=0.32, CHCl3).
IR (CHCl3, cm−1): w 3084 (w), 3060 (w), 3012 (w), 2952
(m), 2897 (m), 1643 (vs), 1599 (m), 1578 (m), 1491 (w),
1449 (s), 1424 (m), 1400 (m), 1376 (s), 1329 (s), 1316
(m), 1286 (s), 1247 (s), 1217 (m), 1194 (m), 1176 (m),
1157 (m), 1110 (w), 1082 (m), 1053 (m), 1027 (m), 1009
(m), 955 (w), 884 (m), 834 (vs), 800 (m), 755 (s), 729 (s),
4.21. 1,1%-Bisbenzoyl-(Sp)-2-methylsulfanylferrocene
(4d)
According to GP3, a solution of the hydrazone 3e
(260 mg, 0.39 mmol) in DME (16 ml) was treated with
a 20% aqueous solution of TiCl3 (2.0 ml, 2 mmol) and
refluxed for 1.5 h. The ketone 4d was obtained by
aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 4:1).
1
698 (s), 672 (m), 638 (w), 510 (m). H-NMR (C6D6, 300
MHz): l 0.45 (s, 9H, Si(CH3)3), 4.26 (m, 2H, Cp-H),
4.35 (d, J=1.9 Hz, 2H, Cp-H), 4.57 (t, 1H, J=1.8 Hz,
Cp-H), 4.78 (m, 1H, Cp-H), 4.93 (m, 1H, Cp-H),
7.04–7.62 (m, 6H, m-C6H5, p-C6H5), 7.72–7.85 (m, 4H,
o-C6H5). 13C-NMR (C6D6, 75 MHz): l 0.61, 72.79,
73.62, 74.40, 74.64, 76.07, 78.08, 81.64, 77.88, 79.60,
84.62, 129.15, 129.24, 129.33, 131.66, 131.79, 139.81,
139.89, 196.67, 198.18. The remaining aromatic signals
Yield: 144 mg (84%, dark red oil). Rf=0.08 (pen-
tane–Et2O 4:1). ee=98%. [h]2D5= +60.6 (c=0.32,
CHCl3). IR (Kapillar, cm−1): w 3085 (w), 3060 (w),
2919 (w), 1742 (w), 1641 (vs), 1598 (m), 1577 (m), 1448
(s), 1423 (s), 1394 (m), 1374 (m), 1334 (s), 1317 (m),
1286 (s), 1261 (s), 1195 (w), 1172 (m), 1075 (w), 1052
(m), 1027 (m), 1014 (m), 954 (w), 873 (m), 854 (m), 814
(m), 799 (m), 730 (s), 699 (s), 673 (m), 520 (m), 502 (s).
1H-NMR (C6D6, 300 MHz): l 1.95 (s, 3H, SCH3), 4.03
(t, 1H, J=2.6 Hz, Cp-H), 4.18 (m, 1H, Cp-H), 4.26 (br
s, 2H, Cp-H), 4.37 (m, 1H, Cp-H), 4.78 (t, 1H, J=1.4
Hz, Cp-H), 4.86 (t, 1H, J=1.4 Hz, Cp-H), 7.02–7.14
(m, 6H, m-C6H5, p-C6H5), 7.80 (m, 4H, o-C6H5). 13C-
NMR (C6D6, 75 MHz): l 16.45, 71.24, 71.46, 73.53,
73.66, 75.34, 76.04, 77.15, 77.97, 80.46, 95.85, 128.65,
128.69, 131.72, 131.75, 139.84, 139.96, 196.67, 197.24.
The remaining aromatic signals are covered by the
solvent. EIMS (70 eV); m/z: (relative intensity, %) 441
are covered by the solvent. EIMS (70 eV); m/z: (relative
+
intensity, %) 467 ([M+ +1], 17), 466 ([M ], 48), 452
(31), 451 (100), 225 (16), 197 (225−CO, 13), 141
(197−[Fe+], 13), 133 (16), 105 (12). HRMS; m/z:
466.1051 ([M+]; exact mass calc. for C27H26 56FeO2Si:
466.1052).
’
’
4.20. 1,1%-Bisbenzoyl-(Sp)-2-((4-methylphenyl)-
sulfanyl)ferrocene (4c)
([M+ +1], 24), 440 ([M+ ], 83), 335 ([M+
’
’
’
According to GP3, a solution of the hydrazone 3d
(218 mg, 0.29 mmol) in DME (12 ml) was treated with
a 20% aqueous solution of TiCl3 (1.5 ml, 1.5 mmol) and
refluxed for 1.5 h. The ketone 4c was obtained by
aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 4:1).
−C6H5CO+], 12), 202 (14), 172 (16), 171 (12), 141 (10),
133 (10), 105 ([C6H5CO+], 100), 77 (133−[Fe+], 15).
HRMS; m/z: 440.0535 ([M+]; exact mass calc. for
C25H20 56FeO2S: 440.0533).
Yield: 125 mg (82%, orange oil). Rf=0.16 (pentane–
Et2O 4:1). ee=98%. [h]2D5= +17.0 (c=0.54, CHCl3).
IR (Kapillar, cm−1): w 3084 (w), 3059 (m), 3025 (w),
2964 (w), 2922 (m), 2866 (w), 2279 (w), 1642 (vs), 1598
(m), 1578 (m), 1492 (m), 1449 (s), 1424 (s), 1375 (s),
1331 (s), 1286 (s), 1262 (s), 1176 (m), 1105 (w), 1075
(m), 1051 (m), 1027 (m), 1006 (m), 954 (w), 873 (m),
4.22. 1,1%-Bisbenzoyl-(Sp)-2-(1-boranato-1,1-
diphenylphosphino]ferrocene (4e)
According to GP2, a solution of the hydrazone 3c
(100 mg, 0.12 mmol) in CH2Cl2 (12 ml) was ozonolysed
for 60 s. The ketone 4e was obtained after purification
by column chromatography on silica gel (CH2Cl2).

708
D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
Yield: 66 mg (92%, dark red oil). Rf=0.04 (pentane–
90.45, 106.91, 126.83, 126.91, 127.41, 127.48, 127.52,
128.57, 131.55, 131.69, 139.60, 139.81, 146.15, 149.47,
197.97, 202.42. The remaining aromatic signals are
Et2O 4:1). [h]2D5= −113.5 (c=0.16, CHCl3). IR
(CHCl3, cm−1): w 3060 (m), 3007 (m), 2928 (w), 2389
(m), 2351 (m), 2260 (w), 2112 (w), 1970 (w), 1907 (w),
1818 (w), 1646 (s), 1599 (m), 1579 (m), 1485 (m), 1450
(m), 1438 (m), 1426 (m), 1377 (m), 1330 (m), 1316 (m),
1286 (s), 1251 (m), 1217 (m), 1197 (m), 1168 (m), 1136
(w), 1105 (m), 1058 (m), 1028 (m), 1011 (m), 1001 (m),
955 (m), 877 (m), 853 (m), 799 (m), 755 (vs), 697 (s),
covered by the solvent. EIMS (70 eV); m/z: (relative
’
intensity, %) 590 ([M+ ], 1), 407 (M+ ]−Ph2COH, 20),
’
369 (25), 368 (100), 350 (34), 334 (23), 309 (16), 254
(30), 251 (11), 237 (19), 229 (31), 228 (19), 226 (11), 202
(11), 186 (21), 182 (10), 180 (11), 105 ([C6H5CO+], 28),
79 (12), 77 ([C6H+5 ], 26), 57 (17), 55 (15). HRMS; m/z:
590.2996 ([M+]; exact mass calc. for C38H30 56FeO3:
590.1544).
1
672 (m), 639 (m), 612 (w), 521 (w). H-NMR (CDCl3,
400 MHz): l 4.41 (s, 1H, Cp-H), 4.62 (s, 1H, Cp-H),
4.86 (s, 1H, Cp-H), 4.92 (m, 3H, Cp-H), 5.02 (s, 1H,
Cp-H), 6.98-7.43 (m, 14H, p-C6H5, m-C6H5, o-C6H5),
7.50–7.80 (m, 6H, o-C6H5). 13C-NMR (CDCl3, 100
MHz): l 73.97, 74.67, 75.16, 75.23, 76.82, 78.34, 78.38,
79.93, 80.01, 84.82, 127.92, 128.04, 128.11, 128.14,
128.24, 128.31, 130.52, 130.71, 131.98, 132.10, 132.43,
132.52, 132.68, 132.78, 137.98, 138.40, 194.74, 197.10.
31P-NMR (C6D6, 162 MHz): l 19.49 (s) ppm. EIMS (70
4.24. 1,1%-Bisbenzoyl-(Sp)-2%-(4-methylphenyl)sulfanyl-
(Sp)-2-methylsulfanylferrocene (6b)
According to GP3, a solution of the hydrazone 5f
(174 mg, 0.22 mmol) in DME (11 ml) was treated with
a 20% aqueous solution of TiCl3 (1.1 ml, 1.1 mmol) and
refluxed for 1.5 h. The ketone 6b was obtained by
aqueous work up and purification by column chro-
matography on silica gel (pentane–Et2O 4:1).
eV); m/z: (relative intensity, %) 592 ([M+ ], 3), 579 (36),
’
578 ([M+ −BH3], 100), 576 (18), 550 (11), 549 (5), 474
’
(15), 473 (578−[C6H5CO+], 45), 410 (7), 409 (10), 408
(22), 354 (7), 349 (8), 338 (14), 337 (17), 229 (7), 228 (6),
183 (7), 170 (9), 154 (7), 153 (12), 152 (8), 105
([C6H5CO+], 10), 77 (7). HRMS; m/z: 592.1426 ([M+];
exact mass calc. for C36H30 56FeO2BP: 592.1426).
Yield: 101 mg (82%, orange oil). Rf=0.17 (pentane–
Et2O 4:1). ee]99%. [h]2D5= −1146.4 (c=0.27,
CHCl3). IR (CHCl3, cm−1): w 3057 (w), 3016 (m), 2963
(w), 2921 (m), 2856 (w), 1637 (vs), 1597 (m), 1577 (m),
1491 (m), 1447 (s), 1423 (s), 1392 (m), 1378 (m), 1333
(s), 1262 (s), 1216 (w), 1195 (w), 1176 (m), 1105 (w),
1074 (m), 1051 (m), 1015 (m), 872 (s), 848 (m), 813 (m),
4.23. 1,1%-Bisbenzoyl-(Rp)-2-methyl-(Sp)-2%-
diphenyl(hydroxy)methylferrocene (6a)
1
756 (s), 728 (s), 699 (m), 675 (m), 501 (m). H-NMR
A solution of the hydrazone 5c (140 mg, 0.12 mmol)
in DME (5 ml) was first treated with SnCl2·2H2O (0.09
g, 0.3 mmol) and afterwards with H2O (0.43 ml). The
reaction mixture was refluxed for 4 h. To drive the
reaction to completion, it was necessary to add two
further portions of SnCl2·2H2O as the Sn(II)-species
was deactivated after some time. The mixture was
diluted with Et2O and washed with aqueous buffer (pH
9) and brine. The organic layer was dried over MgSO4
and concentrated in vacuo. Finally the crude product
was purified by preparative HPLC (pentane–Et2O 4:1).
Yield: 42 mg (58%, dark red crystals); m.p.: 184 °C.
Rf=0.59 (pentane–Et2O 4:1). ee]99%. [h]2D5=
−215.1 (c=0.27, CHCl3). IR (CHCl3, cm−1): w 3299
(w), 3060 (w), 3016 (m), 2955 (w), 2918 (m), 2850 (w),
1627 (m), 1598 (m), 1578 (m), 1490 (m), 1449 (s), 1421
(m), 1382 (m), 1339 (m), 1271 (m), 1264 (m), 1218 (m),
1179 (m), 1074 (w), 1044 (w), 1026 (m), 938 (w), 906
(w), 888 (w), 843 (w), 756 (vs), 700 (s), 668 (m), 518
(C6D6, 300 MHz): l 1.99 (s, 3H, C6H4ꢀCH3), 2.20 (s,
3H, SCH3), 4.08 (q, 1H, J=2.7 Hz, Cp-H), 4.25 (q,
1H, J=2.7 Hz, Cp-H), 4.38 (m, 1H, Cp-H), 4.43 (m,
2H, Cp-H), 4.50 (m, 1H, Cp-H), 6.86 (d, 2H, J=8.0
Hz, C6H4), 6.96–7.12 (m, 6H, p-C6H5, m-C6H5), 7.51
(br d, 2H, C6H4), 7.69 (m, 4H, o-C6H5). 13C-NMR
(C6D6, 75 MHz): l 16.48, 20.96, 73.33, 73.65, 74.11,
74.23, 74.32, 77.51, 79.18, 93.83, 97.49, 127.12, 128.55,
128.89, 130.12, 131.56, 131.91, 133.14, 133.56, 137.53,
139.47, 139.89, 196.59, 197.24. The remaining aromatic
signals are covered by the solvent. EIMS (70 eV); m/z:
+
(relative intensity, %) 564 ([M+ +1], 15), 563 ([M ],
’
’
36), 562 ([M+ −1], 100), 392 (17), 292 (20), 229 (10),
’
216 (15), 172 (10), 171 (11), 105 ([C6H5CO+], 90), 77
(22). HRMS; m/z: 562.0723 ([M+]; exact mass calc. for
C32H26 56FeO2S2: 562.0724).
1
(m). H-NMR (C6D6, 400 MHz): l 2.04 (s, 3H, CH3),
Acknowledgements
4.02 (dd, 1H, J=2.8, 1.7 Hz, Cp-H), 4.10 (t, 1H,
J=2.6 Hz, Cp-H), 4.40 (dd, 1H, J=2.8, 1.7 Hz,
Cp-H), 4.53 (m, 1H, Cp-H), 4.56 (dd, 1H, J=2.8, 1.4
Hz, Cp-H), 4.82 (t, 1H, J=2.6 Hz, Cp-H), 6.80–7.80
(m, 20H, C6H5). 13C-NMR (C6D6, 100 MHz): l 13.86,
73.65, 74.23, 75.03, 76.36, 76.96, 77.13, 77.26, 79.53,
This work was supported by the Fonds der Chemis-
chen Industrie and the Forschungsverbund Katalyse
Nordrhein-Westfalen. We thank Degussa AG, BASF
AG, the former Hoechst AG, Bayer AG and Wacker
Chemie for the donation of chemicals.

D. Enders, T. Klumpen / Journal of Organometallic Chemistry 637–639 (2001) 698–709
[11] D. Price, N.S. Simpkins, Tetrahedron Lett. 36 (1995) 6135.
709
References
[12] (a) J.B. Thomson, Tetrahedron Lett. (1959) 26;
(b) K. Schlo¨gl, Top. Stereochem. 1 (1967) 39;
(c) K. Schlo¨gl, H. Falk, Methodicum Chimicum, vol. 8, Thieme,
Stuttgart, 1973, p. 433.
[1] (a) C.J. Richards, A.J. Locke, Tetrahedron Asymmetry 9 (1998)
2377;
(b) A. Togni, T. Hayashi, Ferrocenes: Homogeneous Catalysis,
Organic Synthesis, Material Science, VCH, Weinheim, 1995.
[2] D. Marquarding, H. Klusacek, G. Gockel, P. Hoffmann, I. Ugi,
J. Am. Chem. Soc. 92 (1970) 5389.
[3] F. Rebiere, O. Riant, L. Ricard, H.B. Kagan, Angew. Chem. 105
(1993) 644; Angew. Chem., Int. Ed. Engl. 32 (1993) 568.
[4] Y. Nishibayashi, S. Uemura, Synlett (1995) 79.
[5] T. Sammakia, H.A. Latham, D.R. Schaad, J. Org. Chem. 60
(1995) 10.
[6] C.J. Richards, T. Damalidis, D.E. Hibbs, M.B. Hursthouse,
Synlett (1995) 74.
[7] C. Ganter, T. Wagner, Chem. Ber. 128 (1995) 1157.
[8] O. Riant, O. Samuel, H.B. Kagan, J. Am. Chem. Soc. 115 (1993)
5835.
[9] M. Tsukazaki, M. Tinkl, A. Roglans, B.J. Chapell, N.J. Taylor,
V. Snieckus, J. Am. Chem. Soc. 118 (1996) 685.
[10] Y. Nishibayashi, Y. Arikawa, K. Ohe, S. Uemura, J. Org. Chem.
61 (1996) 1172.
[13] D. Marquarding, H. Burghard, R. Urban, I. Ugi, J. Chem. Res.
(1977) 915.
[14] D. Enders, R. Peters, R. Lochtman, J. Runsink, Synlett (1997)
1462.
[15] D. Enders, R. Peters, R. Lochtman, G. Raabe, Angew. Chem.
111 (1999) 2579; Angew. Chem., Int. Ed. Engl. 38 (1999) 2421.
[16] (a) R. Peters, Dissertation, RWTH Aachen, 2000;
(b) D. Enders, R. Peters, R. Lochtman, G. Raabe, J. Runsink,
J.W. Bats, Eur. J. Org. Chem. (2000) 3399.
[17] (a) D. Enders, in: J.D. Morrison (Ed.), Asymmetric Synthesis,
vol. 3, Academic Press, Orlando, 1984, p. 275;
(b) D. Enders, P. Fey, H. Kipphardt, Org. Synth. 65 (1987) 173.
[18] R.B. Woodward, M. Rosenblum, M.C. Whiting, J. Am. Soc. 74
(1952) 3458.
[19] B. Bildstein, P. Denifl, Synthesis (1994) 158.
[20] D. Enders, L. Wortmann, R. Peters, Acc. Chem. Rev. 33 (2000)
157.