New C-functionalized silacycloalkanes (CH2) nSi(CH2X)2 and (CH2) nSi(CH2X)CH2X′ (n = 3, 4; X, X′ = functional group): Synthesis and reactivity studies of analogous silacyclobutanes and silacyclopentanes

Article abstract of DOI:10.1016/j.jorganchem.2010.03.024

A series of novel bifunctional silacyclobutanes and silacyclopentanes of the formula types (CH₂)_nSi(CH₂X)₂ and (CH₂)_nSi(CH₂X)CH₂X′ (n = 3, 4; X, X′ = functional groups) was synthesized, starting from (CH ₂)₄Si(CH₂Cl)₂ and (CH ₂)₃Si(CH₂Cl)₂, respectively. The silacyclobutanes and silacyclopentanes were structurally characterized by elemental analyses (C, H, N, S) and multinuclear NMR spectroscopy, and their reactivity was explored. The aim of these investigations was to compare the different reactivity profiles of analogous silacyclobutanes and silacyclopentanes.

Full text of DOI:10.1016/j.jorganchem.2010.03.024

Journal of Organometallic Chemistry 695 (2010) 1700e1707
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
New C-functionalized silacycloalkanes (CH2)nSi(CH2X)2 and (CH2)nSi(CH2X)CH2X0
(n ¼ 3, 4; X, X0 ¼ functional group): Synthesis and reactivity studies of analogous
silacyclobutanes and silacyclopentanes
*
Dennis Troegel, W. Peter Lippert, Frank Möller, Christian Burschka, Reinhold Tacke
Universität Würzburg, Institut für Anorganische Chemie, Am Hubland, D-97074 Würzburg, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
A series of novel bifunctional silacyclobutanes and silacyclopentanes of the formula types (CH2)nSi
(CH2X)2 and (CH2)nSi(CH2X)CH2X0 (n ¼ 3, 4; X, X0 ¼ functional groups) was synthesized, starting from
(CH2)4Si(CH2Cl)2 and (CH2)3Si(CH2Cl)2, respectively. The silacyclobutanes and silacyclopentanes were
structurally characterized by elemental analyses (C, H, N, S) and multinuclear NMR spectroscopy, and
their reactivity was explored. The aim of these investigations was to compare the different reactivity
profiles of analogous silacyclobutanes and silacyclopentanes.
Received 21 January 2010
Received in revised form
16 March 2010
Accepted 25 March 2010
Available online 21 April 2010
Ó 2010 Elsevier B.V. All rights reserved.
Keywords:
Silacycloalkanes
1. Introduction
characterization by multinuclear NMR spectroscopy and single-
crystal X-ray diffraction (compound 6a∙p-TosOH only). In addition,
Silacyclobutanes represent prominent small-membered
heterocycles that are of great interest for organosilicon chemistry
due to their unusual reactivity.1 Since it was shown that 1,1-
dimethylsilacyclobutane is much more reactive than ordinary tet-
raalkylsilanes,2 many reactivity studies were carried out on the
silacyclobutane ring system.1 Apart from its synthetic use in orga-
nosilicon chemistry, the silacyclobutane skeleton might also be an
interesting structural unit in silicon-containing drugs and odorants.
Recently, the synthesis of a series of bifunctional silacyclo-
pentanes of the general formula type (CH2)4Si(CH2X)2
((CH2)4Si ¼ silacyclopentane-1,1-diyl; X ¼ functional group), e.g.
compounds 1ae4a, has been achieved.3e5 In continuation of these
studies, we were interested in the synthesis of 1,1-bis(chloro-
methyl)-1-silacyclobutane, (CH2)3Si(CH2Cl)2 (1b), and its synthetic
potential for the preparation of new silacyclobutanes of the formula
we report here on the failed syntheses of 2b, 3b, 4b, and 6b,
emphasizing the significant differences in the reactivity of analo-
gous silacyclobutanes and silacyclopentanes. In these studies,
a series of novel bifunctional silacyclobutanes and silacyclo-
pentanes were synthesized as intermediates and were also char-
acterized by multinuclear NMR-spectroscopic studies and crystal
structure analyses.
2. Results and discussion
2.1. Syntheses
1,1-Bis(chloromethyl)-1-silacyclobutane (1b) was prepared
according to Scheme 1 by applying the same synthetic method as it
was used for the synthesis of its silacyclopentane derivative 1a.4
Thus, treatment of 1,1-dichloro-1-silacyclobutane6 with (chlor-
omethyl)lithium, generated in situ from bromochloromethane and
n-butyllithium in tetrahydrofuran,7 afforded 1b in 34% yield. The
low yield of 1b can be explained by the additional formation of the
silacyclopentane derivative 1a as the main product (detection by
GC and 1H NMR analyses), caused by a ring enlargement, and 1b
could only be separated by fractional distillation using a spinning
band column due to the very similar boiling points of 1a and 1b. In
the synthesis of 1a from 1,1-dichloro-1-silacyclopentane, such kind
of ring extension (formation of 1,1-bis(chloromethyl)-1-silacyclo-
hexane) was not observed.4
type (CH2)3Si(CH2X)2 ((CH2)3Si
¼
silacyclobutane-1,1-diyl;
X ¼ functional group), compounds 2be5b. Additionally, we were
interested in the synthesis of the mixed functionalized derivatives
6a and 6b of the formula type (CH2)nSi(CH2NH2)CH2OH (n ¼ 3, 4) as
new potential building blocks for the preparation of silicon-con-
taining drugs. We report here on the synthesis of compounds 1b,
5a, 5b, and 6a∙p-TosOH (p-Tos
¼
p-tolylsulfonyl) and their
* Corresponding author. Tel.: þ49 931 31 85251; fax: þ49 931 31 84609.
E-mail address: r.tacke@uni-wuerzburg.de (R. Tacke).
0022-328X/$ e see front matter Ó 2010 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2010.03.024

D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
1701
Scheme 2.
treatment of 1b with sodium acetate and 18-crown-6 in toluene did
not give 1,1-bis(acetoxymethyl)-1-silacyclobutane (9). Instead, the
formation of 1-acetoxy-1-(chloromethyl)-1-silacyclopentane (10)
via ring enlargement was observed. Compound 10 was isolated in
For the attempted synthesis of 1,1-bis(mercaptomethyl)-1-sila-
cyclobutane (2b), in the first step 1b was treated with potassium
thioacetate and 18-crown-6 in toluene to furnish 1,1-bis(acetylthi-
omethyl)-1-silacyclobutane (7) in 72% yield (Scheme 2). However,
subsequent treatment of 7 with lithium aluminum hydride in
diethyl ether, followed by workup with hydrochloric acid, did not
afford the target compound 2b. Instead, ring opening occurred to
give bis(mercaptomethyl)propylsilanol (8), which was isolated in
72% yield. It is interesting to note that the silacyclopentane derivate
of 2b, compound 2a, can be easily prepared by using the strategy
for the attempted synthesis of 2b.4
The silanol 8 was found to be relatively stable against conden-
sation. It could be stored at ambient temperature for two weeks
without formation of the corresponding disiloxane.
The attempted synthesis of 1,1-bis(hydroxymethyl)-1-silacy-
clobutane (3b), following the strategy for the preparation of its
silacyclopentane derivative 3a,5 also failed (Scheme 3). Thus,
Scheme 1.
Scheme 3.

1702
D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
69% yield using a non-aqueous workup. When using an aqueous
workup, the disiloxane 1,1’-oxybis[1-(chloromethyl)-1-silacyclo-
pentane] (11) was obtained (75% yield). As can be seen from
Scheme 3, treatment of 1,1-bis(iodomethyl)-1-silacyclobutane (5b)
with sodium acetate and 18-crown-6 also resulted in a ring
extension to give 1-acetoxy-1-(iodomethyl)-1-silacyclopentane
(12), which was isolated in 50% yield.
Scheme 5 by treatment of the corresponding 1,1-bis(chloromethyl)-
1-silacycloalkanes 1a and 1b, respectively, with sodium iodide in
acetone (yield: 5a, 84%; 5b, 93%).
To synthesize 1-(aminomethyl)-1-(hydroxymethyl)-1-silacy-
clopentane (6a), two different routes were studied, starting from
1-(acetoxymethyl)-1-(chloromethyl)-1-silacyclopentane (14) and
1-(acetoxymethyl)-1-(iodomethyl)-1-silacyclopentane
(15)
Some years ago, the first synthesis of 1,1-bis(aminomethyl)-1-
silacyclopentane (4a) has been reported.3 Compound 4a was
obtained by treatment of 1a with sodium azide and subsequent
reaction of the resulting 1,1-bis(azidomethyl)-1-silacyclopentane
with lithium aluminum hydride. As multifunctional (azidomethyl)
silanes can be hazardous explosives,3,8 an alternative synthetic
route for the preparation of 4a and its derivative 1,1-bis(amino-
methyl)-1-silacyclobutane (4b) was studied by using the Gabriel
synthesis (Scheme 4). Thus, treatment of 1a with potassium
phthalimide and 18-crown-6 in N,N-dimethylformamide yielded
1,1-bis(phthalimidomethyl)-1-silacyclopentane (13a) (77% yield),
which, however, could not be converted into the corresponding
diamine 4a. Different synthetic methods for this transformation
were applied (Scheme 4) using various reaction conditions, but in
all cases SieCH2NH2 bond cleavage was observed. The sensitivity of
the SieCH2NH2 group against nucleophiles has already been
reported for some related (aminomethyl)silanes3,9; however, this
reactivity profile is not yet fully understood. All attempts to
synthesize the corresponding silacyclobutane derivative 4b also
failed. In this case, even the attempted intermediate, 1,1-bis-
(phthalimidomethyl)-1-silacyclobutane (13b), could not be
synthesized (Scheme 4). When using the same conditions as for the
synthesis of 13a, only a non-defined mixture of many products was
obtained.
(Scheme 6). Compounds 14 and 15 were obtained by treatment of
1a and 5a, respectively, with one molar equivalent of sodium
acetate and 18-crown-6 in N,N-dimethylformamide. Under the
reaction conditions chosen (temperature, 20 ꢀC; reaction time, 4
days), a mixture of the starting material 1a (21 mol%), the target
compound 14 (58 mol%), and the disubstituted product (CH2)4Si
(CH2OAc)2 (21 mol%) (GC analysis) was obtained, which upon
chromatographic separation and purification on silica gel afforded
14 in 45% yield. When using 5a as the starting material (tempera-
ture, 20 ꢀC; reaction time, 2 days), a mixture of 5a (29 mol%), 15
(42 mol%), and (CH2)4Si(CH2OAc)2 (29 mol%) was obtained, which
upon separation on silica gel gave the target compound 15 in 36%
yield. Subsequent treatment of 14 with potassium pthalimide
furnished 1-(acetoxymethyl)-1- (phthalimidomethyl)-1-silacyclo-
pentane (16) in 79% yield. However, all attempts to convert 16 into
the target compound 6a failed due to the same reasons as described
for the failed synthesis of 4a. Alternatively, compound 14 was then
treated with sodium azide to afford 1-(acetoxymethyl)-1-(azido-
methyl)-1-silacyclopentane (17) in 81% yield. Subsequent treat-
ment of 17 with triphenylphosphine, followed by hydrolysis with
hydrochloric acid,10 was expected to afford 6a∙HCl. However, under
the reaction conditions applied (see Experimental Section), an
additional transformation of the (hydroxymethyl) group into
a (chloromethyl) moiety occurred to give 1-(aminomethyl)-1-
(chloromethyl)-1-silacyclopentane hydrochloride (18∙HCl) (40%
yield). To prevent this OH/Cl exchange, the aqueous workup was
performed by using the non-nucleophilic p-toluenesulfonic acid (p-
TosOH) to give the target compound 6a as the salt 6a∙p-TosOH in
42% yield. All attempts to transform this salt into 6a failed due to
decomposition.
1,1-Bis(iodomethyl)-1-silacyclopentane (5a) and 1,1-bis(iodo-
methyl)-1-silacyclobutane (5b) were synthesized according to
Compounds 1b, 5a, 5b, 7, 8,10e12,14,15, and 17 were isolated as
liquids, whereas 6a∙p-TosOH, 13a, 16, and 18∙HCl were obtained as
crystalline solids. The identities of all these compounds were
established by elemental analyses (C, H, N, S) and NMR studies (1H,
13C, 15N (6a∙p-TosOH, 17, and 18∙HCl only), 29Si). In addition,
compounds 6a∙p-TosOH, 13a, and 18∙HCl were characterized by
crystal structure analyses.
2.2. Crystal structure analyses
Compounds 6a∙p-TosOH, 13a, and 18∙HCl were structurally
characterized by single-crystal X-ray diffraction. The crystal data
and the experimental parameters used for these studies are given
in Table 1. The molecular structure of the cation of 6a∙p-TosOH is
Scheme 4.
Scheme 5.

D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
1703
Scheme 6.
depicted in Fig. 1; selected bond distances and angles are given in
the figure legend (for further details concerning the crystal struc-
ture analyses, see the Supporting Information).
products which were formed by opening or enlargement of the
silacyclobutane ring system or by SieC cleavage of the SieCH2X
moieties. Only in the case of soft nucleophiles (thioacetate, iodide),
compounds 1a and 1b reacted analogously. Additionally, some
bifunctional silacyclopentanes of the formula type (CH2)4Si(CH2X)
CH2X0 with two different functional groups were synthesized,
starting from 1a. With these studies, valuable information about
the synthetic potential of 1,1-bis(chloromethyl)-1-silacyclobutane
(1b) and 1,1-bis(chloromethyl)-1-silacyclopentane (1a) for
synthetic organosilicon chemistry was obtained.
The bond lengths and angles of 6a∙p-TosOH,13a, and 18∙HCl are
all in the expected ranges and therefore do not need any further
comments, except for the hydrogen-bonding system in the crystal
of 6a∙p-TosOH, where the ammonium cations are connected with
the p-tosylate anions via hydrogen bonds. All three NH units and
the OH group of the cation act as proton donors, and the oxygen
atom of the cation and the three oxygen atoms of the anion act as
proton acceptors to form a three-dimensional hydrogen-bonding
network consisting of intermolecular OeH/O and NeH/O
hydrogen bonds.11
4. Experimental
4.1. General procedures
3. Conclusions
All syntheses were carried out under dry nitrogen. The organic
solvents used were dried and purified according to standard
procedures and stored under dry nitrogen. A Büchi GKR-51 appa-
ratus was used for the bulb-to-bulb distillations. Melting points
were determined with a Büchi Melting Point B-540 apparatus using
samples in sealed glass capillaries. The 1H, 13C, 15N, and 29Si NMR
spectra were recorded at 23 ꢀC on a Bruker DRX-300 (1H,
300.1 MHz; 13C, 75.5 MHz; 15N, 30.4 MHz; 29Si, 59.6 MHz) or
a Bruker Avance 500 NMR spectrometer (1H, 500.1 MHz; 13C,
125.8 MHz; 29Si, 99.4 MHz). CDCl3 or [D6]DMSO was used as the
Multifunctional tetraorganylsilanes are versatile building blocks
for synthetic organosilicon chemistry. In this study, we have eval-
uated the synthetic potential of 1,1-bis(chloromethyl)-1-silacyclo-
butane (1b) and 1,1-bis(chloromethyl)-1-silacyclopentane (1a) as
starting materials for the preparation of a series of new bifunctional
silacyclobutanes and silacyclopentanes of the formula type (CH2)nSi
(CH2X)2 (n ¼ 3, 4; X ¼ functional group). In almost all cases, the
silacyclobutanes displayed a different reactivity profile than their
corresponding silacyclopentane analogues, leading to unexpected

1704
D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
CDCl3, [D6]DMSO), or external TMS (29Si,
d 0; CDCl3, [D6]DMSO).
Table 1
Analysis and assignment of the 1H NMR data were supported by
1H,1H COSY, 13C,1H HMQC, and 13C,1H HMBC experiments. Assign-
ment of the 13C NMR data was supported by DEPT 135, 13C,1H
HMQC, and 13C,1H HMBC experiments. Assignment of the 15N NMR
data was supported by 15N,1H HMQC and 15N,1H HMBC experi-
ments. The elemental analyses were performed by using an Vari-
oMicro apparatus. (Elementar Analysensysteme GmbH)
Crystal data and experimental parameters for the crystal structure analyses of 6a∙p-
TosOH, 13a, and 18∙HCl
6a∙p-TosOH
13a
18∙HCl
Formula
C13H23NO4SSi
317.47
C22H20N2O4Si
404.49
C6H15Cl2NSi
200.18
Formula mass
(g molꢁ1
)
Collection T (K)
(Mo K ) (Å)
Crystal system
193(2)
0.71073
monoclinic
193(2)
0.71073
193(2)
0.71073
l
a
monoclinic
P21/c (14)
7.4553(15)
16.489(3)
15.874(3)
99.11(3)
1926.8(7)
4
1.394
0.155
848
0.5 ꢃ 0.3 ꢃ 0.3
4.94e58.20
e10 ꢄ h ꢄ 10,
e22 ꢄ k ꢄ 22,
e21 ꢄ l ꢄ 21
26763
monoclinic
P21/c (14)
14.086(2)
6.3760(7)
11.5278(17)
95.894(18)
1029.8(2)
4
1.291
0.685
424
0.4 ꢃ 0.3 ꢃ 0.05
5.82e58.16
e19 ꢄ h ꢄ 19,
e8 ꢄ k ꢄ 8,
e14 ꢄ l ꢄ 14
14373
Space group (No.) P21/n (14)
4.2. 1,1-Bis(chloromethyl)-1-silacyclopentane (1a)
a (Å)
b (Å)
c (Å)
15.999(2)
6.2974(6)
16.875(2)
112.411(14)
1571.8(3)
4
1.342
0.294
680
This compound was synthesized according to ref. [4].
4.3. Preparation of 1,1-bis(chloromethyl)-1-silacyclobutane (1b)
b
(ꢀ)
V (Å3)
Z
rcalc. (g cmꢁ3
)
A 2.5 M solution of n-butyllithium in hexanes (151 mL,
378 mmol of n-BuLi) was added dropwise at ꢁ73 ꢀC (ꢂ3 ꢀC,
temperature measurement within the flask) within 7 h to a stirred
mixture of 1,1-dichloro-1-silacyclobutane6 (26.7 g, 189 mmol),
bromochloromethane (73.4 g, 567 mmol), and tetrahydrofuran
(200 mL) (the n-butyllithium solution was added via a special
horizontally elongated side neck of the three-necked flask, which
itself was immersed in the cooling bath to ensure precooling of the
n-butyllithium solution before making contact with the reaction
mixture). After the addition was complete, the mixture was stirred
at ꢁ78 ꢀC for 5 h and was then warmed to 20 ꢀC within 17 h. The
solvent was removed under reduced pressure (formation of
a precipitate), and the residue was extracted with water (300 mL)
and diethyl ether (300 mL). The organic extract was dried over
anhydrous sodium sulfate, the solvent was removed under reduced
pressure, and the residue was purified by fractional distillation
using a spinning band column to give 1b in 34% yield as a colorless
liquid (10.8 g, 63.9 mmol). Bp.: 76 ꢀC/10 mbar. Anal. Calc.
(C5H10Cl2Si): C, 35.51; H, 5.96; M, 169.13. Found: C, 35.5; H, 5.9%. 1H
m
(mmꢁ1
)
F(000)
Crystal size (mm) 0.5 ꢃ 0.4 ꢃ 0.4
2q
Range(ꢀ)
5.22e58.18
e21 ꢄ h ꢄ 21,
e8 ꢄ k ꢄ 8,
e23 ꢄ l ꢄ 23
15189
Index ranges
No. of collected
reflections
No. of independent 4159
reflections
5086
2591
Rint
0.0412
0.0325
5086
0.0443
2591
No. of reflections 4159
used
No. of parameters 194
262
1.039
0.0521/0.4923
100
1.051
0.0443/0.2844
Sa
1.066
Weight parameters 0.0582/0.4008
a/bb
R1c [I > 2
s
(I)]
0.0347
0.0989
0.0354
0.0963
þ0.295/ꢁ0.209
0.0319
0.0820
þ0.323/ꢁ0.306
wR2d (all data)
Max./min. residual þ0.524/ꢁ0.416
electron density,
e Åꢁ3
NMR (300.1 MHz, CDCl3):
H, m, CCH2C), 3.08 (4 H, s, SiCH2Cl). 13C NMR (75.5 Hz, CDCl3):
(SiCH2C), 17.7 (CCH2C), 27.1 (SiCH2Cl). 29Si NMR (59.6 Hz, CDCl3):
14.9.
d
1.26e1.31 (4 H, m, SiCH2C), 2.09e2.20 (2
a
b
c
2
S ¼ {S[w(Fo ꢁ Fc2)2]/(n ꢁ p)}0.5; n ¼ no. of reflections; p ¼ no. of parameters.
d
12.1
wꢁ1
¼
s
2(Fo2) þ (aP)2 þ bP, with P ¼ [max(Fo2,0) þ 2Fc2]/3.
R1 ¼ SkFoj ꢁ jFck/SjFoj.
d
2
wR2 ¼ {S[w(Fo ꢁ Fc2)2]/S[w(Fo2)2]}0.5
.
d
4.4. Preparation of 1,1-bis(iodomethyl)-1-silacyclopentane (5a)
solvent. Chemical shifts (ppm) were determined relative to internal
CHCl3 (1H, 7.24; CDCl3), internal CDCl3 (13C,
77.0; CDCl3), internal
[D5]DMSO (1H, 2.49; [D6]DMSO), internal [D6]DMSO (13C,
39.5;
[D6]DMSO), external H2NC(O)H (90% in [D6]DMSO; 15N,
ꢁ268.0;
d
d
Compound 1a (1.03 g, 5.62 mmol) was added in a single portion
at 20 ꢀC to a stirred solution of sodium iodide (3.27 g, 21.8 mmol) in
acetone (30 mL), and the resulting mixture was then stirred at 20 ꢀC
for 18 h. The solvent was removed under reduced pressure, n-
pentane (150 mL) and water (150 mL) were added to the residue,
the organic layer was separated, and the aqueous phase was
extracted with n-pentane (2 ꢃ 150 mL) and discarded. The
combined organic extracts were dried over anhydrous sodium
sulfate, the solvent was removed under reduced pressure, and the
residue was purified by bulb-to-bulb distillation (100 ꢀC/0.2 mbar)
to give 5a in 84% yield as a yellowish liquid (1.72 g, 4.70 mmol).
Anal. Calc. (C6H12I2Si): C, 19.69; H, 3.30; M, 366.06. Found: C, 20.0;
d
d
d
H, 3.4%. 1H NMR (300.1 MHz, CDCl3):
d 0.77e0.82 (4 H, m, SiCH2C),
1.67e1.72 (4 H, m, CCH2C), 2.19 (4 H, s, SiCH2I). 13C NMR (75.5 MHz,
CDCl3):
d
ꢁ17.0 (SiCH2I), 11.6 (SiCH2C), 26.9 (CCH2C). 29Si NMR
(59.6 MHz, CDCl3):
d 23.9.
4.5. Preparation of 1,1-bis(iodomethyl)-1-silacyclobutane (5b)
Fig. 1. Molecular structure of the cation of 6a∙p-TosOH in the crystal (probability level
of displacement ellipsoids 50%). Bond distances (Å) and angles (ꢀ): SieC1 1.8887(14),
Si1eC2 1.8965(13), Si1eC3 1.8748(13), Si1eC4 1.8826(13), O1eC1 1.4443(17), N1eC2
1.4930(17), C3eC6 1.5434(19), C4eC5 1.5367(19), C5eC6 1.530(2); C1eSi1eC2 104.87
(6), C1eSi1eC3 115.11(6), C1eSi1eC4 112.13(7), C2eSi1eC3 112.86(6), C2eSi1eC4
116.12(6), C3eSi1eC4 96.12(6), Si1eC1eO1 112.84(9), Si1eC2eN1 116.73(9),
Si1eC3eC6 104.40(9), Si1eC4eC5 102.88(9), C4eC5eC6 108.79(12).
Compound 1b (1.53 g, 9.05 mmol) was added in a single portion
at 20 ꢀC to a stirred solution of sodium iodide (5.43 g, 36.2 mmol) in
acetone (50 mL), and the resulting mixture was then stirred at 20 ꢀC
for 24 h. The solvent was removed under reduced pressure, n-
pentane (250 mL) and water (250 mL) were added to the residue,

D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
1705
the organic layer was separated, and the aqueous phase was
4.8. Preparation of bis(mercaptomethyl)propylsilanol (8)
extracted with n-pentane (2 ꢃ 250 mL) and discarded. The
combined organic extracts were dried over anhydrous sodium
sulfate, the solvent was removed under reduced pressure, and the
residue was purified by bulb-to-bulb distillation (140 ꢀC/8 mbar) to
give 5b in 93% yield as a yellowish liquid (2.95 g, 8.38 mmol). Anal.
Calc. (C5H10I2Si): C, 17.06; H, 2.86; M, 352.03. Found: C, 17.2; H, 2.7%.
A solution of 7 (962 mg, 3.87 mmol) in diethyl ether (10 mL) was
added dropwise at 0 ꢀC within 10 min to a stirred suspension of
lithium aluminum hydride (747 mg, 19.7 mmol) in diethyl ether
(22 mL), and the resulting mixture was stirred at 0 ꢀC for 90 min
and then at 20 ꢀC for a further 17 h. Subsequently, hydrochloric acid
(2 M, 15 mL) was added dropwise under stirring at 0 ꢀC within
15 min, and the resulting mixture was then warmed to 20 ꢀC, fol-
lowed by the addition of water (120 mL) and diethyl ether (120 mL).
The organic phase was separated, the aqueous phase was extracted
with diethyl ether (2 ꢃ 120 mL), the combined organic extracts
were dried over anhydrous sodium sulfate, the solvent was
removed under reduced pressure, and the residue was purified by
bulb-to-bulb distillation (oven temperature 80e85 ꢀC, 0.2 mbar) to
give 8 in 65% yield as a colorless liquid (457 mg, 2.51 mmol). Anal.
Calc. (C5H14OS2Si): C, 32.93; H, 7.74; S, 35.16; M, 182.38. Found: C,
1H NMR (300.1 MHz, CDCl3):
d 1.22e1.30 (4 H, m, SiCH2C),
1.93e2.04 (2 H, m, CCH2C), 2.31 (4 H, s, SiCH2I). 13C NMR (75.5 MHz,
CDCl3):
(59.6 MHz, CDCl3):
d
ꢁ15.9 (SiCH2I), 16.07 (SiCH2C), 16.13 (CCH2C). 29Si NMR
d 17.4.
4.6. Preparation of 1-(aminomethyl)-1-(hydroxymethyl)-1-
silacyclopentane hydro-p-tosylate (6a∙p-TosOH)
Compound 17 (1.69 g, 7.92 mmol) was added at 20 ꢀC in a single
portion to a solution of triphenylphosphine (2.34 g, 8.92 mmol) in
toluene (16 mL), and the mixture was then stirred at 20 ꢀC for 24 h.
The solvent was removed under reduced pressure, a solution of p-
toluenesulfonic acid monohydrate (1.70 g, 8.94 mmol) in water
(8 mL) was added to the residue, and the mixture was then heated
under reflux for 4 h, cooled to 20 ꢀC, and stirred for a further 15 h at
20 ꢀC. Subsequently, the mixture was diluted with water (20 mL)
and extracted with dichloromethane (3 ꢃ 25 mL). The solvent of the
aqueous phase was removed under reduced pressure, the residue
was dissolved in methanol (15 mL), and the mixture was then
heated under reflux for 7 h. The solvent was removed under
reduced pressure, and the residue was crystallized from acetonitrile
(5 mL; slow cooling to ꢁ20 ꢀC and crystallization over a period of 6
days). The product was isolated by removal of the mother liquor via
a syringe, washed with n-pentane (3 ꢃ 2 mL), and dried in vacuo
(0.04 mbar, 20 ꢀC, 3 h) to give 6a∙HOTos in 42% yield as a colorless
crystalline solid (1.05 g, 3.31 mmol). Mp.: 93e94 ꢀC. Anal. Calc.
(C13H23NO4SSi): C, 49.18; H, 7.30; N, 4.41; S, 10.10; M, 317.48. Found:
C, 48.8; H, 7.3; N, 4.6; S, 10.3%. 1H NMR (500.1 MHz, [D6]DMSO):
32.9; H, 7.6; S, 35.2%. 1H NMR (300.1 MHz, CDCl3):
d 0.76e0.82 (2 H,
m, SiCH2C), 0.98 (3 H, t, 3JHH ¼ 7.3 Hz, CCH3), 1.30 (dX), 1.79 (dA), and
2
3
3
1.81 (dB) (6 H, JAB ¼ 14.4 Hz, JAX ¼ 7.5 Hz, JBX ¼ 7.4 Hz,
SiCHAHBSHX), 1.37e1.50 (2 H, m, CCH2C), 2.55 (1 H, s, SiOH). 13C
NMR (75.5 MHz, CDCl3):
d
5.2 (SiCH2S), 15.3 (SiCH2C), 16.4 (CCH2C),
7.6.
18.0 (CCH3). 29Si NMR (59.6 MHz, CDCl3):
d
4.9. Preparation of 1-acetoxy-1-(chloromethyl)-1-silacyclopentane
(10)
Compound 1b (2.93 g, 17.3 mmol) was added in a single portion
at 20 ꢀC to a stirred mixture of sodium acetate (1.42 g, 17.3 mmol),
18-crown-6 (56.0 mg, 212
mmol), and toluene (30 mL), and the
resulting mixture was then stirred at 20 ꢀC for 4 days. The precip-
itate was removed by filtration, washed with toluene (20 mL), and
discarded. The filtrate and wash solutions were combined, the
solvent was removed under reduced pressure, and the residue was
purified by distillation (Vigreux column) to give 10 in 69% yield as
a colorless liquid (2.30 g, 11.9 mmol). Bp.: 29 ꢀC/0.1 mbar. Anal. Calc.
(C7H13ClO2Si): C, 43.63; H, 6.80; M, 192.72. Found: C, 43.6; H, 6.9%.
d
0.59e0.74 (4 H, m, SiCH2C), 1.48e1.59 (4 H, m, CCH2C), 2.28 (3 H, s,
CH3), 2.38 (2 H, q, 3JHH ¼ 6.2 Hz, SiCH2N), 3.36 (2 H, s, SiCH2O), 4.22
(1 H, br. s, OH), 7.10e7.13 (2 H, m, H-3/H-5, C6H4), 7.47e7.49 (2 H, m,
H-2/H-6, C6H4), 7.56 (3 H, br. s, NH3). 13C NMR (125.8 MHz, [D6]
1H NMR (300.1 MHz, CDCl3):
1.55e1.77 (4 H, m, CCH2C), 2.05 (3 H, s, C(O)CH3), 3.06 (2 H, s,
SiCH2Cl). 13C NMR (75.5 MHz, CDCl3):
9.6 (SiCH2C), 22.3 (C(O)CH3),
25.7 (CCH2C), 26.9 (SiCH2Cl), 171.9 (C(O)CH3). 29Si NMR (59.6 MHz,
CDCl3): 32.2.
d 0.73e0.92 (4 H, m, SiCH2C),
d
DMSO):
(SiCH2O), 125.5 (C-2/C-6, C6H4), 128.1 (C-3/C-5, C6H4), 137.8 (C-1,
C6H4), 145.4 (C-4, C6H4). 15N NMR (30.4 MHz, [D6]DMSO):
ꢁ358.5.
29Si NMR (99.4 MHz, [D6]DMSO):
15.5.
d 8.0 (SiCH2C), 20.8 (CH3), 24.4 (SiCH2N), 26.4 (CCH2C), 49.9
d
d
d
4.10. Preparation of 1,1’-oxybis[1-(chloromethyl)-1-
silacyclopentane] (11)
4.7. Preparation of 1,1-bis(acetylthiomethyl)-1-silacyclobutane (7)
Compound 1b (2.00 g, 11.8 mmol) was added in a single portion
Compound 1b (1.01 g, 5.97 mmol) was added in a single portion
at 20 ꢀC to a stirred mixture of sodium acetate (970 mg, 11.8 mmol),
18-crown-6 (31.0 mg, 117 mmol), and toluene (20 mL), and the
at 20 ꢀC to a stirred mixture of potassium thioacetate (2.02 g,
17.7 mmol), 18-crown-6 (60.0 mg, 227
m
mol), and toluene (20 mL),
resulting mixture was then stirred at 20 ꢀC for 7 days. The solvent
was removed under reduced pressure, diethyl ether (100 mL) and
water (100 mL) were added to the residue, the organic layer was
separated, and the aqueous phase was extracted with diethyl ether
(3 ꢃ 100 mL) and discarded. The combined organic extracts were
dried over anhydrous sodium sulfate, the solvent was removed
under reduced pressure, and the residue was stored at 20 ꢀC for 4
days (formation of water drops) and then purified by bulb-to-bulb
distillation (oven temperature 85e100 ꢀC, 0.3 mbar) to give 11 in
75% yield as a colorless liquid (1.26 g, 4.45 mmol). Anal. Calc.
(C10H20Cl2OSi2): C, 42.39; H, 7.11; M, 283.34. Found: C, 42.4; H, 7.3%.
and the resulting mixture was then stirred at 20 ꢀC for 24 h. The
solvent was removed under reduced pressure, diethyl ether
(100 mL) and water (75 mL) were added, the organic phase was
separated, and the aqueous phase was extracted with diethyl ether
(2 ꢃ 100 mL). The combined organic extracts were dried over
anhydrous sodium sulfate, the solvent was removed under reduced
pressure, and the residue was purified by bulb-to-bulb distillation
(oven temperature 95 ꢀC, 0.01 mbar) to give 7 in 72% yield as
a yellowish liquid (1.06 g, 4.27 mmol). Anal. Calc. (C9H16O2S2Si): C,
43.51; H, 6.49; S, 25.81; M, 248.44. Found: C, 43.4; H, 6.5; S, 25.7%.
1H NMR (300.1 MHz, CDCl3):
(2 H, m, CCH2C), 2.28 (4 H, s, SiCH2S), 2.31 (6 H, s, C(O)CH3). 13C NMR
(75.5 MHz, CDCl3): 12.5 (SiCH2S), 14.0 (SiCH2C), 17.6 (CCH2C), 29.9
(C(O)CH3), 196.5 (C(O)CH3). 29Si NMR (59.6 MHz, CDCl3):
16.2.
d
1.06e1.14 (4 H, m, SiCH2C),1.96e2.08
1H NMR (300.1 MHz, CDCl3):
1.50e1.73 (8 H, m, CCH2C), 2.85 (4 H, s, SiCH2Cl). 13C NMR
(75.5 MHz, CDCl3):
11.4 (SiCH2C), 25.8 (CCH2C), 29.0 (SiCH2Cl). 29Si
NMR (59.6 MHz, CDCl3): 20.9.
d 0.53e0.79 (8 H, m, SiCH2C),
d
d
d
d

1706
D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
4.11. Preparation of 1-acetoxy-1-(iodomethyl)-1-silacyclopentane
(12)
1H NMR (500.1 MHz, CDCl3):
1.56e1.65 (4 H, m, CCH2C), 2.01 (3 H, s, C(O)CH3), 2.92 (2 H, s,
SiCH2Cl), 3.91 (2 H, s, SiCH2O). 13C NMR (125.8 MHz, CDCl3):
8.7
d 0.64e0.79 (4 H, m, SiCH2C),
d
Compound 5b (4.19 g, 11.9 mmol) was added in a single portion
(SiCH2C), 20.6 (C(O)CH3), 26.9 (CCH2C), 27.1 (SiCH2Cl), 54.4
at 20 ꢀC to a stirred mixture of sodium acetate (4.46 g, 54.4 mmol),
(SiCH2O), 171.7 (C(O)CH3). 29Si NMR (99.4 MHz, CDCl3):
d 17.7.
18-crown-6 (206 mg, 779
mmol), and toluene (30 mL), and the
resulting mixture was then stirred at 20 ꢀC for 2 days. The precip-
itate was removed by filtration, washed with toluene (15 mL), and
discarded. The filtrate and wash solutions were combined, the
solvent was removed under reduced pressure, and the residue was
purified by distillation (Vigreux column) to give 12 in 50% yield as
a colorless liquid (1.68 g, 5.91 mmol). Bp.: 62 ꢀC/0.6 mbar. Anal.
Calc. (C7H13IO2Si): C, 29.59; H, 4.61; M, 284.17. Found: C, 30.0; H,
4.14. Preparation of 1-(acetoxymethyl)-1-(iodomethyl)-1-
silacyclopentane (15)
Compound 5a (10.0 g, 27.3 mmol) was added in a single portion
to a stirred mixture of sodium acetate (2.24g, 27.3 mmol), 18-
crown-6 (96.0 mg, 363
mmol), and N,N-dimethylformamide
(50 mL), and the resulting mixture was then stirred at 20 ꢀC for 2
days. The solvent was removed by distillation (45 ꢀC/10 mbar),
diethyl ether (150 mL) and water (150 mL) were added to the
residue, the organic phase was separated, and the aqueous phase
was extracted with diethyl ether (2 ꢃ 150 mL) and discarded. The
combined organic extracts were dried over anhydrous sodium
sulfate, the solvent was removed under reduced pressure, and the
residue was purified by column chromatography on silica gel (silica
4.7%. 1H NMR (300.1 MHz, CDCl3):
1.61e1.76 (4 H, m, CCH2C), 2.06 (3 H, s, C(O)CH3), 2.27 (2 H, s,
SiCH2I). 13C NMR (75.5 MHz, CDCl3):
ꢁ18.5 (SiCH2I), 10.7 (SiCH2C),
22.4 (C(O)CH3), 25.8 (CCH2C), 171.9 (C(O)CH3). 29Si NMR (59.6 MHz,
CDCl3): 33.8.
d 0.80e0.91 (4 H, m, SiCH2C),
d
d
4.12. Preparation of 1,1-bis(phthalimidomethyl)-1-silacyclopentane
(13a)
gel, 32e63 mm (ICN 02826); eluent, n-hexane/ethyl acetate (9:1 (v/
v))). The relevant fractions (GC analysis) were combined, and the
Compound 1a (3.00 g, 16.4 mmol) was added in a single portion
to a stirred mixture of potassium phthalimide (6.07 g, 32.8 mmol),
18-crown-6 (335 mg, 1.27 mmol), and N,N-dimethylformamide
(60 mL), and the resulting mixture was then stirred at 20 ꢀC for 19 h.
The solvent was removed by distillation (45 ꢀC/10 mbar), diethyl
ether (200 mL) and water (200 ml) were added to the residue, the
organic phase was separated, and the aqueous phase was extracted
with dichloromethane (2 ꢃ 100 mL) and discarded. The combined
organic extracts were dried over anhydrous sodium sulfate, the
solvent was removed under reduced pressure, and the residue was
crystallized from dichloromethane (40 mL; crystallization by slow
evaporation of the solvent at 20 ꢀC over a period of 2 days). The
product was isolated by removal of the mother liquor via a syringe
and then dried in vacuo (0.1 mbar, 20 ꢀC, 2 h) to give 13a in 77%
yield as a colorless crystalline solid (5.14 g, 12.7 mmol). Mp.:
148e149 ꢀC. Anal. Calc. (C22H20N2O4Si): C, 65.33; H, 4.98; N, 6.93;
M, 404.50. Found: C, 65.0; H, 4.9; N, 7.0%. 1H NMR (300.1 MHz,
solvent was removed under reduced pressure to give 15 in 36%
yield as
(C8H15IO2Si): C, 32.22; H, 5.07; M, 298.20. Found: C, 32.1; H, 5.0%. 1H
NMR (300.1 MHz, CDCl3): 0.69e0.74 (4 H, m, SiCH2C), 1.55e1.71 (4
H, m, CCH2C), 2.02 (3 H, s, C(O)CH3), 2.10 (2 H, s, SiCH2I), 3.92 (2 H, s,
SiCH2O). 13C NMR (75.5 MHz, CDCl3):
ꢁ18.9 (SiCH2I), 10.4
(SiCH2C), 20.7 (C(O)CH3), 26.9 (CCH2C), 55.4 (SiCH2O), 171.6 (C(O)
CH3). 29Si NMR (59.6 MHz, CDCl3):
19.5.
a colorless liquid (2.94 g, 9.86 mmol). Anal. Calc.
d
d
d
4.15. Preparation of 1-(acetoxymethyl)-1-(phthalimidomethyl)-1-
silacyclopentane (16)
Compound 14 (1.51 g, 7.30 mmol) was added in a single portion
at 20 ꢀC to a mixture of potassium phthalimide (1.36 g, 7.34 mmol),
18-crown-6 (35.0 mg, 132 mmol), and dimethylformamide (15 mL),
and the resulting mixture was then stirred at 20 ꢀC for 20 h. The
solvent was removed by distillation (45 ꢀC/10 mbar), water
(100 mL) and diethylether (100 mL) were added to the residue, the
organic phase was separated, and the aqueous phase was extracted
with diethyl ether (3 ꢃ 100 mL) and discarded. The combined
organic extracts were dried over anhydrous sodium sulfate, and the
solvent was removed under reduced pressure to give 16 in 79%
yield as a colorless crystalline solid (1.83 g, 5.77 mmol). Anal. Calc.
(C16H19NO4Si): C, 60.54; H, 6.03; N, 4.41; M, 317.42. Found: C, 60.4;
CDCl3):
d 0.71e0.76 (4 H, m, SiCH2C), 1.53e1.57 (4 H, m, CCH2C),
3.32 (4 H, s, SiCH2N), 7.62e7.65 (4 H, m, H‑5/H-6, Phth
(¼ phthalimido)), 7.72e7.75 (4 H, m, H-4/H-7, Phth). 13C NMR
(75.5 MHz, CDCl3):
d 11.2 (SiCH2C), 26.7 (SiCH2N), 26.8 (CCH2C),
123.0 (C-4/C-7, Phth), 132.1 (C-3a/C-7a, Phth), 133.7 (C-5/C-6, Phth),
168.6 (C-1/C-3, Phth). 29Si NMR (59.6 MHz, CDCl3):
d
19.0.
4.13. Preparation of 1-(acetoxymethyl)-1-(chloromethyl)-1-
H, 5.9; N, 4.5%. 1H NMR (300.1 MHz, CDCl3):
d 0.68e0.73 (4 H, m,
silacyclopentane (14)
SiCH2C), 1.54e1.59 (4 H, m, CCH2C), 1.93 (3 H, s, C(O)CH3), 3.26 (2 H,
s, SiCH2N), 3.93 (2 H, s, SiCH2O), 7.65e7.68 (2 H, m, H‑5/H-6, Phth),
7.77e7.80 (2 H, m, H-4/H-7, Phth). 13C NMR (75.5 MHz, CDCl3):
Compound 1a (3.00 g, 16.4 mmol) was added in a single portion
to a stirred mixture of sodium acetate (1.34 g, 16.3 mmol), 18-
d 10.1 (SiCH2C), 20.5 (C(O)CH3), 25.6 (SiCH2N), 26.8 (CCH2C), 55.8
crown-6 (62.0 mg, 235
m
mol), and N,N-dimethylformamide
(SiCH2O), 123.0 (C-4/C-7, Phth), 132.1 (C-3a/C-7a, Phth), 133.8 (C-5/
(30 mL), and the resulting mixture was then stirred at 20 ꢀC for 4
days. The solvent was removed by distillation (45 ꢀC/10 mbar),
diethyl ether (100 mL) and water (100 mL) were added to the
residue, the organic phase was separated, and the aqueous phase
was extracted with diethyl ether (2 ꢃ 100 mL) and discarded. The
combined organic extracts were dried over anhydrous sodium
sulfate, the solvent was removed under reduced pressure, and the
residue was purified by column chromatography on silica gel (silica
C-6, Phth), 168.6 (C-1/C-3, Phth), 171.7 (C(O)CH3). 29Si NMR
(59.6 MHz, CDCl3):
d 16.9.
4.16. Preparation of 1-(acetoxymethyl)-1-(azidomethyl)-1-
silacyclopentane (17)
Compound 14 (4.29 g, 20.8 mmol) was added in a single portion
at 20 ꢀC to a stirred suspension of sodium azide (4.63 g, 71.2 mmol)
and sodium carbonate (280 mg, 2.64 mmol) in acetone (25 mL), and
the resulting mixture was then stirred at 20 ꢀC for 10 days. The
precipitate was removed by filtration, washed with acetone (20 ml),
and discarded. The filtrate and the wash solution were combined,
the solvent was removed under reduced pressure, and the residue
gel, 32e63 mm (ICN 02826); eluent, n-hexane/ethyl acetate (9:1 (v/
v))). The relevant fractions (GC analysis) were combined, and the
solvent was removed under reduced pressure to give 14 in 45%
yield as
a colorless liquid (1.51 g, 7.30 mmol). Anal. Calc.
(C8H15ClO2Si): C, 46.48; H, 7.31; M, 206.74. Found: C, 46.3; H, 7.4%.

D. Troegel et al. / Journal of Organometallic Chemistry 695 (2010) 1700e1707
1707
was purified by column chromatography on silica gel (silica gel,
32e63 m (ICN 02826); eluent, n-hexane/ethyl acetate (9:1 (v/v))).
The relevant fractions (GC analysis) were combined, and the
solvent was removed under reduced pressure to give 17 in 81%
yield as a yellowish liquid (3.61 g, 16.9 mmol). Anal. Calc.
(C8H15N3O2Si): C, 45.05; H, 7.09; N, 19.70; M, 213.31. Found: C, 45.2;
compounds (see 4.1; Syntheses). The crystals were mounted in
inert oil (perfluoropolyalkyl ether, ABCR) on a glass fiber and then
transferred to the cold nitrogen gas stream of the diffractometer
m
(Stoe IPDS, graphite-monochromated Mo
Ka
radiation
(
l
¼ 0.71073 Å)). The structures were solved by direct methods
(SHELXS-97).12 All non-hydrogen atoms were refined anisotropi-
cally (SHELXL-97).12 A riding model was employed in the refine-
ment of the Hydrogen atoms.
H, 7.0; N, 19.5%. 1H NMR (300.1 MHz, CDCl3):
d
0.67e0.73 (4 H, m,
SiCH2C), 1.58e1.63 (4 H, m, CCH2C), 2.03 (3 H, s, C(O)CH3), 2.97 (2 H,
s, SiCH2N), 3.87 (2 H, s, SiCH2O). 13C NMR (75.5 MHz, CDCl3):
8.9
(SiCH2C), 20.6 (C(O)CH3), 26.8 (CCH2C), 38.4 (SiCH2N), 54.6
(SiCH2O), 171.7 (C(O)CH3). 15N NMR (30.4 MHz, CDCl3):
ꢁ319.7
(CH2NNN; lower intensity), ꢁ129.8 (CH2NNN; higher intensity),
CH2NNN not detected. 29Si NMR (59.6 MHz, CDCl3):
16.9.
d
Appendix. Supplementary data
d
Supporting information available: Crystallographic data for
6a∙p-TosOH, 13a, and 18∙HCl.
d
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.jorganchem.2010.03.024
4.17. Preparation of 1-(aminomethyl)-1-(chloromethyl)-1-
silacyclopentane hydrochloride (18∙HCl)
Compound 17 (1.79 g, 8.39 mmol) was added at 20 ꢀC in a single
portion to a solution of triphenylphosphine (2.43 g, 9.26 mmol) in
toluene (17 mL), and the resulting mixture was then stirred at 20 ꢀC
for 23 h. The solvent was removed under reduced pressure, 6 M
hydrochloric acid (32 mL) was added to the residue, and the
mixture was then heated under reflux for 2 h, cooled to 20 ꢀC, and
extracted with dichloromethane (3 ꢃ 30 mL). The aqueous phase
was concentrated under reduced pressure to a volume of ca. 20 mL
and was then stored at ꢁ20 ꢀC for 24 h. The resulting precipitate
was isolated by filtration and dried in vacuo (0.4 mbar, 20 ꢀC, 2 h) to
give 18∙HCl in 40% yield as a colorless crystalline solid (672 mg,
3.36 mmol). Mp.: 223e223 ꢀC (dec.). Anal. Calc. (C6H15Cl2NSi): C,
36.00; H, 7.55; N, 7.00; M, 200.18. Found: C, 36.0; H, 7.5; N, 7.0%. 1H
References
[1] R. Damrauer, Organomet. Chem. Rev. A 8 (1972) 67e133.
[2] L.H. Sommer, G.A. Baum, J. Am. Chem. Soc. 76 (1954) 5002.
[3] W.K. Anderson, R. Kasliwal, D.M. Houston, Y.-s. Wang, V.L. Narayanan, R.
D. Haugwitz, J. Plowman, J. Med. Chem. 38 (1995) 3789e3797.
[4] U.-P. Apfel, D. Troegel, Y. Halpin, S. Tschierlei, U. Uhlemann, M. Schmitt, J.
Popp, H. Görls, P. Dunne, M. Venkatesan, M. Coey, J.G. Vos, M. Rudolph, R.
Tacke, W. Weigand, unpublished results.
[5] C. Evangelisti, T.M. Klapötke, B. Krumm, A. Nieder, R.J.F. Berger, S.A. Hayes, N.
W. Mitzel, D. Troegel, R. Tacke, in press, doi:10.1021/ic902387y.
[6] R. Damrauer, R.A. Davis, M.T. Burke, R.A. Karn, G.T. Goodman, J. Organomet,
Chem. 43 (1972) 121e125.
[7] (a) T. Kobayashi, K.H. Pannell, Organometallics 9 (1990) 2201e2203;
(b) T. Kobayashi, K.H. Pannell, Organometallics 10 (1991) 1960e1964;
(c) J.O. Daiss, K.A. Barth, C. Burschka, P. Hey, R. Ilg, K. Klemm, I. Richter, S.
A. Wagner, R. Tacke, Organometallics 23 (2004) 5193e5197;
(d) D. Troegel, T. Walter, C. Burschka, R. Tacke, Organometallics 28 (2009)
2756e2761.
NMR (500.1 MHz, [D6]DMSO):
d 0.65e0.89 (4 H, m, SiCH2C),
1.54e1.63 (4 H, m, CCH2C), 2.40 (2 H, q, 3JHH ¼ 6.1 Hz, SiCH2N), 3.24
[8] T.M. Klapötke, B. Krumm, R. Ilg, D. Troegel, R. Tacke, J. Am, Chem. Soc. 129
(2007) 6908e6915.
[9] (a) J. Goubeau, H.D. Fromm, Z. Anorg, Allg. Chem. 317 (1962) 41e53;
(b) V. van Dorsselaer, D. Schirlin, P. Marchal, F. Weber, C. Danzin, Bioorg.
Chem. 24 (1996) 178e193;
(2 H, s, SiCH2Cl), 8.14 (3 H, br. s, NH3). 13C NMR (125.8 MHz, [D6]
DMSO):
15N NMR (30.4 MHz, [D6]DMSO):
[D6]DMSO): 19.5.
d 8.5 (SiCH2C), 23.8 (SiCH2N), 26.4 (CCH2C), 27.8 (SiCH2Cl).
d
ꢁ354.7. 29Si NMR (99.4 MHz,
d
(c) D. Troegel, F. Möller, C. Burschka, R. Tacke, Organometallics 28 (2009)
5765e5770.
[10] J.O. Daiss, C. Burschka, R. Tacke, J. Organomet, Chem. 690 (2005) 678e684.
[11] The hydrogen-bonding system was analyzed by using the program system
PLATON, A.L. Spek, PLATON. University of Utrecht, Utrecht, The Netherlands,
1998.
4.18. Crystal structure analyses
Suitable single crystals of 6a∙p-TosOH, 13a, and 18∙HCl were
obtained directly from the preparation of the respective
[12] G.M. Sheldrick, Acta Crystallogr., Sect. A 64 (2008) 112e122.