[Tris(alkoxydimethylsilyl)methyl]alkylferrocenes as new ferrocenyl multifunctional silyl ethers

Article abstract of DOI:10.1071/CH13632

[Tris(trimethylsilyl)methyl]alkylferrocenes and [tris(dimethylsilyl)methyl] alkylferrocenes were synthesized by treatment of tris(trimethylsilyl) methyllithium and tris(dimethylsilyl)methyllithium in THF with 3-bromopropylferrocene or 4-bromobutylferrocen

Full text of DOI:10.1071/CH13632

CSIRO PUBLISHING
Aust. J. Chem. 2014, 67, 784–789
Full Paper
http://dx.doi.org/10.1071/CH13632
[Tris(alkoxydimethylsilyl)methyl]alkylferrocenes
as New Ferrocenyl Multifunctional Silyl Ethers
A B
,
A
A
Kazem D. Safa,
Hassan Abbasi, Reza Teimuri-Mofrad,
A
and Farzaneh A. Charandabi
A
Organosilicon Research Laboratory, Department of Organic and Biochemistry,
Faculty of Chemistry, University of Tabriz, PO Box 51666-16471 Tabriz, Iran.
Corresponding author. Email: dsafa@tabrizu.ac.ir
B
[Tris(trimethylsilyl)methyl]alkylferrocenes and [tris(dimethylsilyl)methyl]alkylferrocenes were synthesized by treat-
ment of tris(trimethylsilyl)methyllithium and tris(dimethylsilyl)methyllithium in THF with 3-bromopropylferrocene or
4-bromobutylferrocene at 08C. [Tris(alkoxydimethylsilyl)methyl]alkylferrocenes were obtained by dehydrocoupling
with various aliphatic and benzylic alcohols in the presence of the Karstedt catalyst (platinum(0)-1,3-divinyl-1,1,3,3-
tetramethyldisiloxane in xylene) in good to excellent yields. 4-[Tris(benzyloxydimethylsilyl)methyl]butylferrocene was
also prepared from the transetherification of 4-[tris(methoxydimethylsilyl)methyl]butylferrocene with benzyl alcohol in
the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene as catalyst.
Manuscript received 17 November 2013.
Manuscript accepted: 24 December 2013.
Published online: 13 February 2014.
protecting agents for many functional groups,[29] and as anchor-
ing reagents and substrates for solid-supported synthesis,
organic synthesis,[30] and multistep synthesis.[31] They have
important applications in inorganic synthesis as precursors
in the preparation of sol gels and other condensed silo-
xane materials,[32] and prodrugs for drug delivery.[33] Here,
we report the synthesis of [tris(alkoxydimethylsilyl)methyl]
alkylferrocenes via dehydrocoupling reactions of some ferro-
cenyl organosilicon compounds with various aliphatic and
benzylic alcohols and the Karstedt catalyst.
Introduction
The discovery of bis(Z5-cyclopentadienyl)iron, ferrocene, in
1951,[1] and the subsequent characterization of its structure,
greatly stimulated research in organometallic chemistry. Since
then, metallocenes have attracted enormous interest from both
fundamental and applied points of view. The chemistry of
ferrocene-based structureshas received attention because of their
importance in fields such as redox electrochemistry, materials
science, novel materials, organic synthesis,[2–5] catalysis for
asymmetric synthesis,[6–9] biology,[10–12] and non-linear optical
materials.[13–15] Recent discoveries of a broad range of appli-
cations in the biomedical and aerospace industries and as coating
and catalysts greatly increased interest in the incorporation of
transition metals into organic monomers and polymers.[16–20]
Since the synthesis of the first silyl metal complex
(Z5-C5H5)Fe(CO)2SiMe3 by Wilkinson in 1956, research on
transition metal silyl compounds has continued because these
compounds are assumed to be key intermediates in several
important stoichiometric and catalytic transformations.[21,22]
Organosilicon reagents and compounds are also valuable in
organic synthesis, e.g. for making silyl ethers and silyl
ketals.[23] A special feature of hydrosilanes is their ability to
undergo alcoholysis (dehydrocoupling), leading to alkoxysi-
lanes and gaseous hydrogen. The rate of dehydrocoupling
depends significantly on the extent of Si–H bond polarization
in the silane, and the reaction occurs in the presence of
either nucleophilic or electrophilic catalysts.[24,25] Over the
years, there have been significant developments in the
synthesis of silyl ethers and their applications in organic
chemistry owing to their versatility, compatibility with a
wide range of reaction conditions, safety, and the ease
with which they can be handled. They are used to tether
reactants for stereospecific intramolecular reactions,[26–28] as
Results and Discussion
3-Chloropropyroylferrocene 1a and 4-chlorobutanoylferrocene
1b were prepared by Friedel–Crafts acylation of ferrocene with
3-chloropropanoyl chloride and 4-chlorobutanoyl chloride,
respectively, in CH2Cl2 in the presence of AlCl3 as catalyst.[34]
3-Chloropropanoylferrocene 2a and 4-chlorobutanoyl ferrocene
2b were obtained in high yields from the reduction of 1a and 1b
respectively by NaBH4 in diglyme.[35] 3-Bromopropylferrocene
3a and 4-bromobutylferrocene 3b were prepared from the reac-
tion of compounds 2a–b with ethyl bromide and sodium bromide
in NMP (N-methyl-2-pyrrolidone) as solvent (Scheme 1).[36]
Tris(trimethylsilyl)methane was prepared by the reaction of
chlorotrimethylsilane, chloroform, and Li in THF. A THF
solution of tris(trimethylsilyl)methyllithium, (Me3Si)3CLi,
was obtained by treatment of (Me3Si)3CH with MeLi under
reflux in THF (Scheme 2).[37] Various 4-halobutylferrocenes
were converted into [tris(trimethylsilyl)methyl]alkylferrocenes
4a–b and [tris(dimethylsilyl)methyl]alkylferrocenes 5a–b.
Initially, compound 2b was treated with (Me3Si)3CLi at low
temperatures (ꢀ78 and 08C) but after 24 h, no product was
obtained. CuI failed to catalyze this reaction (Table 1).[38]
Journal compilation Ó CSIRO 2014
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Synthesis of Tris(alkoxydimethylsilyl)methylalkylferrocenes
785
O
Cl
n
Table 2. Synthesis of [tris(alkoxydimethylsilyl)methyl]alkylferrocenes
AlCl3
Cl
ϩ
Fe
Fe
Cl
n
CH2Cl2
O
Entry
Compounds
Alcohol
CH3OH
Products
Yield [%]A
1 a–b
1
2
3
4
5
6
7
8
9
5b
5b
5b
5b
5b
5a
5a
5a
5a
6a
6b
6c
6d
6e
6f
94
90
88
85
91
93
90
87
82
Cl
CH3CH2OH
CH3CH2CH2OH
CH3(CH2)3OH
PhCH2OH
Diglyme
Br
n
EtBr, NMP
NaBr
n
Fe
Fe
NaBH4, 0ЊC
2 a–b
n ϭ 2, 3
3 a–b
CH3OH
CH3CH2OH
CH3CH2CH2OH
CH3(CH2)3OH
6g
6h
6i
Scheme 1. Synthesis of 3a and 3b.
AIsolated yields.
LDA
THF
THF
HMe2SiCl
Me3SiCl
ϩ
CHBr3
CHCl3
(HMe2Si)3CH
(Me3Si)3CH
(HMe2Si)3CLi
ROMe2Si SiMe2OR
SiMe2H
SiMe2H
HMe2Si
Alcohol
MeLi
n
n
(Me3Si)3CLi
Fe
ϩ
SiMe2OR
Fe
Karstedt catalyst
5 a–b
a, n
b, n
ϭ
ϭ
2
3
6 a–i
n ϭ 2, 3
SiMe3
Me3Si
Br
(Me3Si)3CLi
THF
n
n
Fe
Fe
SiMe3
Scheme 3. Synthesis of [tris(alkoxydimethylsilyl)methyl]alkylferrocenes.
4 a–b
3 a–b
ferrocenyl silyl ethers and for the attachment of ferrocenyl
groups to the cellulose acetate butyrate backbone.[43]
SiMe2H
HMe2Si
(HMe2Si)3CLi
THF
n
In order to explore the synthesis of silyl ethers derivatives of
[tris(dimethylsilyl)methyl]alkylferrocenes, compound 5b in
THF was first treated with methanol at room temperature and
the Karstedt catalyst but after 12h, the reaction was not com-
plete. The same result was obtained under reflux. With methanol
as solvent, none of the desired product was obtained after 12 h at
room temperature, but under reflux, the desired silyl ether 6a
was obtained after 4 h in excellent yield (entry 1, Table 2, 94 %)
(Scheme 3).
Fe
SiMe2H
5 a–b
n ϭ 2, 3
Scheme 2. Synthesis of 4a–b and 5a–b.
Table 1. Reaction of 2a c and 3a b with LiC (SiMe ) in THF
]
]
3
3
For other alcohols, heating at 70–808C gave the desired silyl
ethers in good to excellent yields (Table 2).
Entry
Compound
Temperature [8C]
Yield [%]A
Time [h]
1
2
3
4
5
2a
2b
2c
3a
3b
ꢀ70 and 0
0
0
24
24
24
4
Primary aliphatic alcohols with long alkyl chains are less
reactive than with short chains (Table 2). Alcohols with an
aromatic ring such as benzyl alcohol gave the corresponding
silyl ethers in high yield (entry 5, Table 1, 91 %), but phenols
failed to give the desired phenolic silyl ethers.
Finally, from the transetherification[44] of 6a with benzyl
alcohol in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene
(DBU) as catalyst, 4-[tris(benzyloxydimethylsilyl)methyl]butyl
ferrocene 6e was obtained in 73 % yield (Scheme 4).
The 1H NMR spectrum of compound 6e (Fig. 1) shows the
benzylic CH2 at 4.6 ppm and aromatic protons at 7.2–7.3 ppm.
The peak from ferrocenyl protons appears at 4–4.1 ppm and the
singlet ascribed to SiMe2 is at 0.3 ppm. Transetherification
reactions of ferrocenyl silyl ethers with other alcohols and
polymers bearing hydroxyl groups are under investigation.
ꢀ70 and 0
ꢀ70 and 0
0
0
0
90
93
4
AIsolated yields.
Similarly, under the same conditions, 4-iodobutylferrocene
2c was treated with (Me3Si)3CLi, but again none of the desired
product was obtained. Finally, the reaction of 3-bromopropyl-
ferrocene 3a and 4-bromobutylferrocene 3b with tris(trimethyl-
silyl)methyllithium at 08C in THF gave 3-[tris(trimethylsilyl)
methyl]propylferrocene 4a and 4-[tris(trimethylsilyl)methyl]
butylferrocene 4b in 90 and 93 % yields after 4 h (Scheme 2).
Similarly, 3-[tris(dimethylsilyl)methyl]propylferrocene 5a
and 4-[tris(dimethylsilyl)methyl]butylferrocene 5b were syn-
thesized in 87 and 90 % yields, respectively, from compounds 3a
and 3b and (HMe2Si)3CLi in THF at 08C.
The precursor (HMe2Si)3CH was made by the reaction of
CHBr3 and Mg with HMe2SiCl in THF[39,40] and (HMe2Si)3CLi
was prepared by lithiation of (HSiMe2)3CH with LDA (lithium
diisopropylamide) at room temperature (Scheme 2).[40]
We recently used dehydrocoupling reactions for the prepa-
ration of tris(alkoxydimethylsilyl)methanes,[41] calix[4]arenes
bearing silyl ether groups,[39] and functionalized poly(methyl-
alkoxy)siloxanes[42] under mild conditions with Karstedt catal-
ysis. We also applied this methodology in the synthesis of
Conclusion
In summary, we report the synthesis of [tris(trimethylsilyl)
methyl]alkylferrocenes and [tris(dimethylsilyl)methyl]alkyl-
ferrocenes. [Tris(alkoxydimethylsilyl)methyl]alkylferrocenes
were prepared by dehydrocoupling reactions of hydrosilane
derivatives with various aliphatic and benzylic alcohols in the
presence of the Karstedt catalyst (platinum(0)-1,3-divinyl-
1,1,3,3-tetramethyldisiloxane in xylene). The results show that
tris(alkoxydimethylsilyl)methyl-functionalized alkylferrocenes
prepared from bromoalkylferrocenes are useful building blocks
for the preparation of several kinds of ferrocenyl silyl ethers.

786
K. D. Safa et al.
with brine and distilled water. The solvent was removed and the
product purified by column chromatography on silica. A brown
band was eluted with a hexane/ethyl acetate (6 : 2) mixture to
give the product.
O
Si
O
O
Si
O
Si
Catalyst
Si
Si
Si
PhCH2OH
Fe
O
3-Bromopropylferrocene 3a
O
Fe
From 3.94 g 3-chloropropylferrocene, 4.42 g of brown oil (96 %
yield) was obtained. nmax (KBr)/cmꢀ1 3090 (Cp–H), 2929
(C–H), 1636, 1437 (C¼C), 1103, 1000, (Cp), 816 (C–Br).
dH (400 MHz, CDCl3) 2.02–2.09 (m, 2H, Cp–CH2–CH2), 2.49–
2.55 (t, 2H, Cp–CH2), 3.41–3.44 (t, 2H, CH2–Br), 4.08–4.13
(d, 9H, Cp). dC (100 MHz, CDCl3) 26.8, 32.6, 32.87 (–CH2–),
66.2, 67.0, 67.4 (Cp), 68.1 (C1 Cp). m/z (electron ionization (EI))
306 [M]þ, 308 [M þ 2]þ, 199 [FcCH2]þ (Fc ¼ ferrocene),
121 [CpFe]þ. Calc. for C13H15BrFe: C 50.8, H 4.9. Found:
C 50.5, H 4.7 %.
6a
6e
Scheme 4. Synthesis of 6e via transetherification.
4-Bromobutylferrocene 3b
From 4.15 g 4-chlorobutylferrocene, 4.72 g brown oil (98 %
yield) was obtained. nmax (KBr)/cmꢀ1 3090 (Cp–H), 2928
(C–H), 1684, 1454 (C¼C), 1103, 1000, (Cp), 815 (C–Br), 485
(Fc). dH (400 MHz, CDCl3) 1.62–1.69 (m, 2H, Cp–CH2–CH2),
1.85–1.92 (m, 2H, CH2–CH2–Br), 2.34–2.38 (t, 2H, Cp–CH2),
3.41–3.44 (t, 2H, CH2–Br), 4.05 (s, 4H, Cp), 4.10 (s, 5H, Cp).
dC (100 MHz, CDCl3) 27.6, 28.4, 31.4, 32.8 (–CH2–), 66.1, 66.9,
67.3, 67.4 (Cp), 87.4 (C1 Cp). m/z (EI) 320 [M]þ, 322 [M þ 2]þ,
199 [FcCH2]þ, 121 [CpFe]þ. Anal. Calc. for C14H17BrFe:
C 52.3, H 5.3. Found: C 52.0, H 5.5 %.
ppm 14
12
10
8
6
4
2
0
Ϫ2
2.2
2.0
1.8
1.6
Fig. 1. 1H NMR (ppm) spectra of 4-[tris(benzyloxydimethylsilyl)methyl]
butylferrocene.
Preparation of Tris(trimethylsilyl)methyllithium,
(Me3Si)3CLi
The reagent was preparedasdescribed byGro¨bel and Seebach.[37]
Some of them can be used in the synthesis of new organosilyl
macromolecules and dendrimers. The transetherification of
4-[tris(methoxydimethylsilyl)methyl]butylferrocene with vari-
ous alcohols in the presence of DBU as catalyst appears to be
a simple but effective way to synthesize other ferrocene-
substituted tris(alkoxydimethylsilyl)methanes.
Preparation of Tris(dimethylsilyl)methyllithium,
(HSiMe2)3CLi
A 50-mL round-bottom flask equipped with a stirrer, septum,
and gas-inlet needle was charged with diisopropylamine (0.53 g,
5.3 mmol) and 15 mL of THF. The flask was placed in a water–
ice bath and then n-BuLi (3.8 mL, 1.5 M solution in hexane) was
added dropwise with stirring to form a clear yellow solution. The
solution was stirred for an additional 30 min. The LDA solution
was transferred into a dropping funnel after which it was added
dropwise to a 50-mL round-bottom flask containing tris(dime-
thylsilyl)methane, (HSiMe2)3CH, (1.0 g, 5.3 mmol), in 10 mL
THF under argon at room temperature. The orange-red solution
was stirred at ambient temperature for 10h.
Experimental
Chemicals were either prepared in our laboratory or purchased
from Merck, Fluka, and Aldrich. Commercial products were
used without purification. 1H and 13C NMR spectra were
recorded with a Bruker FT-400 MHz spectrometer at room
temperature with CDCl3 solvent. Fourier-transform (FT)IR
spectra were recorded on a Bruker Tensor 270 spectrometer.
Mass spectra were obtained with a GC-Mass Agilent quadrupole
mode 5973N instrument, operating at 70 eV. Elemental analyses
were carried out with an Elementar Vario EL III instrument.
General Procedure for Preparation
Preparation of Chloroalkylferrocenes 2a–b
of Compounds 4a–b and 5a–b
3-Chloropropyroylferrocene 1a, 4-chlorobutyroylferrocene 1b,
3-chloropropylferrocene 2a, and 4-chlorobutylferrocene 2b
were prepared according to the procedures described by
Graindorge et al.[34] and Fort et al.[35]
To a stirred solution of (Me3Si)3CLi or (HSiMe2)3CLi
(5.3 mmol) in THF at 08C was added 3-bromopropylferrocene
3a or 4-bromobutylferrocene 3b (5.0 mmol) in 10 mL THF, and
the mixture was stirred for another 3 h at room temperature. It
was then poured into saturated aqueous ammonium chloride
solution (50 mL) and extracted with CH2Cl2 (2 ꢁ 50 mL). The
organic phase was washed with water (100 mL) and dried
(Na2SO4), and the solvent was removed to yield a viscous oil.
General Procedure for Preparation
of Bromoalkylferrocene 3a–b
A mixture of 0.015 mol of chloroalkylferrocene derivatives,
15 mL of ethyl bromide, and 0.003 mol of sodium bromide
(0.32 g) was heated at 658C for 3 days. The mixture was allowed
to cool and then poured into a mixture of ice, water, and brine in
a separatory funnel. The lower layer was removed and washed
3-[Tris(trimethylsilyl)methyl]propylferrocene 4a
From 3 g 3-bromopropylferrocene, 4.04 g (96 % yield) of
yellowish oil was obtained. nmax (KBr)/cmꢀ1 3093 (Cp–H),

Synthesis of Tris(alkoxydimethylsilyl)methylalkylferrocenes
787
2953 (C–H), 1412 (C¼C), 1252, 841 (Si–C), 1104, 1020 (Cp),
484 (Fc). dH (400 MHz, CDCl3) 0.13 (s, 27H, SiMe3), 1.66–1.75
(m, 4H, –CH2–), 2.25–2.29 (t, 2H, Cp–CH2), 4.04 (s, 4H, Cp),
4.10 (s, 5H, Cp). dC (100 MHz, CDCl3) 1.75 (SiMe3), 4.9
(C(SiMe3)3), 29.8, 30.0, 30.3 (–CH2–), 65.1, 66.9, 67.3 (Cp),
87.8 (C1 Cp). m/z (EI) 458 [M]þ, 199 [FcCH2]þ, 121 [CpFe]þ,
73 [SiMe3]þ. Anal. Calc. for C23H42FeSi3: C 68.5, H 10.5.
Found: C 68.2, H 10.3 %.
4-[Tris(methoxydimethylsilyl)methyl]butylferrocene 6a
Yellowish oil. nmax (KBr)/cmꢀ1 3093 (Cp–H), 2933 (C–H),
1628, 1461 (C¼C), 1252, 855 (Si–C), 1088 (Cp), 999 (Si–O),
485. dH (400 MHz, CDCl3) 0.18 (s, 18H, SiMe2), 1.42–1.48 (m,
2H, –CH2–), 1.52–1.57 (m, 2H, –CH2–), 1.69–1.73 (t, 2H,
–CH2–), 2.29–2.33 (t, 2H, Cp–CH2), 3.37 (s, 9H, OCH3), 4.02–
4.04 (d, 4H, Cp), 4.09 (s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ0.9
(SiMe2), 16.1 (–C(SiMe2OCH3)), 27.4, 28.4, 29.3, 31.6 (–CH2–),
48.9 (OCH3), 65.9, 66.9, 67.3 (Cp), 88.4 (C1 Cp). m/z (EI)
520 [M]þ, 400 [M–FeCp]þ, 199 [FcCH2]þ, 121 [CpFe]þ. Anal.
Calc. for C24H44FeO3Si3: C 55.3, H 8.5. Found: C 54.9, H 8.2 %.
4-[Tris(trimethylsilyl)methyl]butylferrocene 4b
From 3 g 4-bromobutylferrocene, 4.11 g (93 % yield) of a
yellowish oil was obtained. nmax (KBr)/cmꢀ1 3094 (Cp–H),
2952 (C–H), 2903 (C–H), 1630, 1409 (C¼C), 1255, 840 (Si–C),
1105, 1000 (Cp), 490 (Fc). dH (400 MHz, CDCl3) 0.11 (s, 27H,
SiMe3), 1.41–1.54 (m, 4H, –CH2–), 1.60–1.64 (m, 2H, Cp–
CH2–CH2), 2.30–2.34 (t, 2H, Cp–CH2), 4.03–4.04 (d, 4H, Cp),
4.09 (s, 5H). dC (100 MHz, CDCl3) 1.7 (SiMe3), 5.1
(C(SiMe3)3), 28.5, 29.2, 30.0, 31.7 (–CH2–), 66.0, 67.0, 67.4
(Cp), 88.2 (C1 Cp). m/z (EI) 472 [M]þ, 199 [FcCH2]þ, 121
[CpFe]þ, 73 [SiMe3]þ. Anal. Calc. for C24H44FeSi3: C 60.9,
H 9.3. Found: C 60.4, H 9.1 %.
4-[Tris(ethoxydimethylsilyl)methyl]butylferrocene 6b
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2969 (C–H),
1632, 1388 (C¼C), 1251, 849 (Si–C), 1107, 1079 (Cp), 1000
(Si–O), 485. dH (400 MHz, CDCl3) 0.19 (s, 18H, SiMe2), 1.12–
1.16 (t, 9H, –CH3), 1.42–1.46 (m, 2H, –CH2–), 1.58–1.62
(m, 2H, –CH2–), 1.71–1.75 (t, 2H, –CH2–), 2.29–2.33 (s, 2H,
Cp–CH2), 3.58, 3.63 (q, 6H, OCH2), 4.02–4.05 (d, 4H, Cp), 4.09
(s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ0.34 (SiMe2), 15.4 (–CH3),
17.5, 27.5, 28.5, 28.6, 29.2, 21.7, 56.6 (OCH2), 65.9, 66.9, 67.3
(Cp), 88.5 (C1 Cp). m/z (EI) 562 [M]þ, 199 [FcCH2]þ,
121 [CpFe]þ. Anal. Calc. for C27H50FeO3Si3: C 57.6, H 8.9.
Found: C 57.3, H 8.7 %.
3-[Tris(dimethylsilyl)methyl]propylferrocene 5a
From 3 g 3-bromopropylferrocene, 3.54 g (87 % yield) of a
yellowish oil was obtained. nmax (KBr)/cmꢀ1 3093 (Cp–H),
2955 (C–H), 2107 (Si–H), 1631, 1416 (C¼C, Cp), 1253, 839
(Si–C), 1104, 973, 896 (C–H). dH (400 MHz, CDCl3) 0.16–0.17
(d, 18H, SiMe2), 1.64–1.76 (m, 4H, –CH2–), 2.25–2.29 (t, 2H,
Cp–CH2), 4.01–4.02 (m, 3H, Si–H), 4.04 (s, 4H, Cp), 4.09
(s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ4.12 (SiMe2), 0.33
(C(SiMe2)3), 29.1, 29.4, 29.5 (–CH2–), 66.0, 66.9, 67.4 (Cp), 87.8
(C1 Cp). m/z (EI) 416 [M]þ, 199 [FcCH2]þ, 121 [CpFe]þ. Anal.
Calc. for C20H36FeSi3: C 57.6, H 8.7. Found: C 57.3, H 8.9 %.
4-[Tris(propoxydimethylsilyl)methyl]butylferrocene 6c
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2958 (C–H),
1631, 1459 (C¼C), 1252, 857 (Si–C), 1085, 1004, 486. dH
(400 MHz, CDCl3) 0.18 (s, 18H, SiMe2), 0.87–0.90 (t, 9H,
–CH3), 1.41–1.45 (t, 2H, –CH2–), 1.51–1.55 (m, 6H, –CH2–),
1.54–1.64 (m, 2H, –CH2–), 1.71–1.75 (t, 2H, –CH2–), 2.28–2.32
(t, 2H, Cp–CH2), 3.45–3.48 (t, 6H, OCH2), 4.02–4.04 (d, 4H, p),
4.09 (s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ0.4 (SiMe2), 9.6
(–CH3), 15.3, 24.8, 27.5, 28.6, 29.2, 31.7, 62.9 (OCH2), 65.9,
67.0, 67.4 (Cp), 88.4 (C1 Cp). m/z (EI) 604 [M]þ, 199 [FcCH2]þ,
121 [CpFe]þ. Calc. for C30H56FeO3Si3: C 59.5, H 9.3. Found:
C 59.1, H 9.4 %.
4-[Tris(dimethylsilyl)methyl]butylferrocene 5b
From 3.94 g 4-bromobutylferrocene, 3.62 g (90 % yield) of a
yellowish oil was obtained. nmax (KBr)/cmꢀ1 3093 (Cp–H),
2955, 2845, 2107 (Si–H), 1416, 1253, 1104, 873, 839, 689, 489.
dH (400 MHz, CDCl3,) 0.15–0.16 (d, 18H, SiMe2), 1.44–1.55
(m, 4H, –CH2–), 1.61–1.65 (t, 2H, Cp–CH2–CH2), 2.30–2.34
(t, 2H, Cp–CH2), 3.99–4.02 (m, 3H, Si–H), 4.03–4.04 (d, 4H,
Cp), 4.09 (s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ4.1 (SiMe2), 0.39
(C(SiMe2)3), 28.2, 28.3, 29.0, 31.3 (–CH2–), 66.2, 67.1, 67.3
(Cp), 88.4 (C1 Cp). m/z (EI) 430 [M]þ, 199 [FcCH2]þ. Anal.
Calc. for C21H38FeSi3: C 58.5, H 8.8. Found: C 58.1, H 8.6 %.
4-[Tris(butoxydimethylsilyl)methyl]butylferrocene 6d
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2957 (C–H),
1647, 1540 (C¼C), 1250, 847 (Si–C), 1090, 1035 (Cp), 977
(Si–O), 483. dH (400 MHz, CDCl3) 0.18 (s, 18H, SiMe2), 0.89–
0.92 (t, 9H, –CH3), 1.30–1.38 (m, 6H, –CH2–), 1.39–1.50
(m, 8H, –CH2–), 1.56–1.61 (t, 2H, –CH2–), 1.70–1.74 (t, 2H,
–CH2–), 2.28–2.32 (t, 2H, Cp–CH2), 3.49–3.52 (t, 6H, OCH2),
4.02–4.05 (d, 4H), 4.09 (s, 5H). dC (100 MHz, CDCl3) ꢀ0.4
(SiMe2), 12.9, 15.2, 18.1, 27.5, 28.5, 28.6, 29.3, 31.7, 33.8, 60.8
(OCH2), 65.9, 66.9, 67.3 (Cp), 88.5 (C1 Cp). m/z (EI) 646 [M]þ,
199 [FcCH2]þ, 121 [CpFe]þ. Anal. Calc. for C33H62FeO3Si3:
C 61.2, H 9.6. Found: C 61.6, H 9.4 %.
General Procedure for the Synthesis of [Tris
(alkoxydimethylsilyl)methyl]alkylferrocene 6a–i
A 50-mL round-bottom two-neck flask with a magnetic stirrer
was charged with 5a or 5b (0.20 g, 0.48 mmol 5a, or 0.46 mmol
5b) and ROH (20 mL) under dry argon. Karstedt catalyst
([Pt]/[Si–H] ¼ 7.2 ꢁ 10ꢀ3) was then added and the reaction
progress was monitored; several samples were taken over time
and were analysed by FTIR spectroscopy. The mixture was
stirred at 60–808C until complete disappearance of the Si–H
bond in the FTIR spectra. After completion of the reaction, the
mixture was allowed to cool to room temperature. Then the
alcohol was evaporated under reduced pressure and the residue
purified by flash column chromatography (silica gel, 10 : 1
n-hexane/ethyl acetate) to give a highly viscous oily product.
4-[Tris(benzyloxydimethylsilyl)methyl]butylferrocene 6e
Yellowish oil. nmax (KBr)/cmꢀ1 3089 (Ar–H), 3029, 2924
(C–H), 1649, 1496 (C¼C), 1254, 858 (Si–C), 1064, 728, 484.
dH (400 MHz, CDCl3) 0.30 (s, 18H, SiMe2), 1.44–1.52 (m, 2H,
–CH2–), 1.69–1.75 (m, 2H, –CH2–), 1.86–1.90 (t, 2H, –CH2–),
2.29–2.33 (t, 2H, Cp–CH2–), 4.05 (s, 4H, Cp), 4.12 (s, 5H, Cp),
4.68 (s, 6H, OCH2), 7.26–7.29 (m, 3H, Ar–H), 7.34–7.35
(d, 12H, Ar–H). dC (100 MHz, CDCl3) ꢀ0.1 (SiMe2), 15.8, 27.5,
28.5, 28.6, 29.3, 31.8, 63.5 (OCH2), 65.9, 67.0, 67.4 (Cp), 88.3
(C1 Cp), 125.5, 125.7, 127.0, 140.3 (Ar). Anal. Calc. for
C42H56FeO3Si3: C 67.3, H 7.5. Found: C 67.1, H 7.4 %.

788
K. D. Safa et al.
3-[Tris(methoxydimethylsilyl)methyl]propylferrocene 6f
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Yellowish oil. nmax (KBr)/cmꢀ1 3093 (Cp–H), 2953 (C–H),
1628, 1462 (C¼C), 1252, 856 (C–Si), 1088 (Cp), 999 (Si–O),
483. dH (400 MHz, CDCl3) 0.20 (s, 18H, SiMe2), 1.78–1.81
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OCH3), 4.03 (d, 4H, Cp), 4.1 (s, 5H, Cp). dC (100 MHz, CDCl3)
ꢀ0.9 (SiMe2), 16.0, 27.5, 29.7, 30.2 (–CH2–), 48.9 (OCH3),
65.8, 66.8, 67.3 (Cp), 88.3 (C1 Cp). m/z (EI) 506 [M]þ, 199
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C 54.5, H 8.3. Found: C 54.1, H 8.1 %.
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3-[Tris(ethoxydimethylsilyl)methyl]propylferrocene 6g
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2970 (C–H),
1631, 1388 (C¼C), 1252, 853 (Si–C), 1106, 1079 (Cp), 999
(Si–O), 483. dH (400 MHz, CDCl3) 0.21 (s,18H, SiMe2), 1.13–
1.16 (t, 9H, –CH3), 1.77–1.87 (m, 4H, –CH2–), 2.22–2.26 (t, 2H,
Cp–CH2), 3.59–3.64 (q, 6H, OCH2), 4.03 (d, 4H, Cp), 4.1 (s, 5H,
Cp). dC (100 MHz, CDCl3) ꢀ0.3 (SiMe2), 15.3, 17.5 (–CH3),
27.6, 29.7, 29.9 (–CH2), 56.6 (OCH2), 65.8, 66.8, 67.3 (Cp), 88.4
(C1 Cp). m/z (EI) 548 [M]þ, 199 [FcCH2]þ, 121 [CpFe]þ. Anal.
Calc. for C26H53FeO3Si3: C 56.9, H 8.8. Found: C 56.7, H 8.6 %.
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3-[Tris(propoxydimethylsilyl)methyl]propylferrocene 6h
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2959 (C–H),
1646, 1254, 849 (Si–C), 1083, 1002 (Cp), 882 (Si–O), 483.
dH (400 MHz, CDCl3) 0.22 (s, 18H, SiMe2), 0.88–0.92 (t, 9H,
–CH3), 1.51–1.58 (m, 6H, –CH2–), 1.76–1.87 (m, 4H), 2.25–
2.29 (t, 2H, Cp–CH2), 3.49–3.52 (t, 6H, OCH2), 4.02 (s, 4H, Cp),
4.09 (5H, Cp). dC (100 MHz, CDCl3) ꢀ0.3 (SiMe2), 9.6 (–CH3),
16.1, 24.7, 27.7, 29.8, 30.6 (–CH2), 63.2 (OCH2), 65.9, 66.9,
67.3 (Cp), 87.9 (C1 Cp). m/z (EI) 590 [M]þ, 199 [FcCH2]þ, 121
[CpFe]þ. Anal. Calc. for C29H54FeO3Si3: C 58.9, H 9.21. Found:
C 58.6, H 8.9 %.
3-[Tris(butoxydimethylsilyl)methyl]propylferrocene 6i
Yellowish oil. nmax (KBr)/cmꢀ1 3094 (Cp–H), 2953 (C–H),
1647, 1462 (C¼C), 1252, 851 (Si–C), 1091, 1036 (Cp), 964
(Si–O), 887, 484. dH (400 MHz, CDCl3) 0.20 (s, 18H, SiMe2),
0.88–0.92 (t, 9H, –CH3), 1.34–1.44 (m, 6H, –CH2–), 1.46–1.51
(m, 6H, –CH2–), 1.7–1.84 (m, 4H, –CH2–), 2.23–2.26 (t, 2H,
Cp–CH2), 3.45–3.50 (t, 6H, OCH2), 4.02–4.03 (d, 4H, Cp), 4.10
(s, 5H, Cp). dC (100 MHz, CDCl3) ꢀ0.4 (SiMe2), 12.9 (–CH3),
15.2, 18.1, 27.7, 29.8, 30.1, 33.8 (CH2), 60.9 (OCH2), 65.8, 66.8,
67.3 (Cp), 88.4 (C1 Cp). m/z (EI) 632 [M]þ, 199 [FcCH2]þ, 121
[CpFe]þ. Anal. Calc. for C32H65FeO3Si3: C 60.7, H 9.5. Found:
C 60.2, H 9.2 %.
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Acknowledgements
Financial support by Tabriz University is gratefully appreciated and also we
thank Dr J. D. Smith for his helpful comments.
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