Synthesis of bulky tris[(dimethyl(alkyl/aryl)silyl)methyl]stannanes as radical based reducing agents

Article abstract of DOI:10.1016/j.jorganchem.2011.05.011

The synthesis of novel bulky tris[dimethyl(ethyl/benzyl/p-tolyl/α- naphthyl)silylmethyl]stannanes (1-4) is described. Alkylation of SnCl ₄ with Me₂(ethyl/p-tolyl)SiCH₂MgBr (10-11) gave mainly the triorganotin chlorides [(Me₂(ethyl/p-tolyl)SiCH ₂)]₃SnCl 14 and 15, which were isolated by silica gel chromatography. Reduction of 14 and 15 with LiAlH₄ in THF gave the corresponding triorganotin hydrides 1 and 2, respectively. [Me ₂(benzyl/α-naphthyl)SiCH₂]₃SnCl 16 and 17, generated by the alkylation of SnCl₄ with Me₂(benzyl/ α-naphthyl)SiCH₂MgBr 12 and 13, were inseparable from the minor product [Me₂(benzyl/α-naphthyl)SiCH₂] ₂SnCl₂ 18 and 19, respectively. Treatment of the mixtures of 16/18 and 17/19 with NaOH furnished the corresponding mixtures of stannoxanes, from which the hexakisdistannoxanes [Me₂(benzyl/α- naphthyl)SiCH₂]₆Sn₂O 20 and 22 were isolated from the minor dialkyltin oxide derivatives [Me₂(benzyl/α- naphthyl)SiCH₂]₂SnO in good yields. Reduction of 20 and 22 with BH₃ in THF gave [Me₂(benzyl/α-naphthyl) SiCH₂]₃SnH (3 and 4), respectively in good yields. ¹H, ¹³C, ¹¹⁹Sn, ²⁹Si NMR characteristics of the newly synthesized compounds are included.

Full text of DOI:10.1016/j.jorganchem.2011.05.011

Journal of Organometallic Chemistry 696 (2011) 2971e2975
Contents lists available at ScienceDirect
Journal of Organometallic Chemistry
journal homepage: www.elsevier.com/locate/jorganchem
Synthesis of bulky tris[(dimethyl(alkyl/aryl)silyl)methyl]stannanes as radical
based reducing agents
,
b
,
a
c
Abdalla E.A. Hassan a , Ahmed F. El-Farargy , Terence N. Mitchell
*
a Department of Chemistry, Faculty of Science, Zagazig University, Zagazig, Egypt
b Applied Nucleic Acids Research Center, Electron Microscope Building, Zagazig University, Zagazig, Egypt
c Fachbereich Chemie, Universität Dortmund, D-44221 Dortmund, Germany
a r t i c l e i n f o
a b s t r a c t
Article history:
The synthesis of novel bulky tris[dimethyl(ethyl/benzyl/p-tolyl/a-naphthyl)silylmethyl]stannanes (1e4)
Received 24 February 2011
Received in revised form
12 April 2011
is described. Alkylation of SnCl4 with Me2(ethyl/p-tolyl)SiCH2MgBr (10e11) gave mainly the triorganotin
chlorides [(Me2(ethyl/p-tolyl)SiCH2)]3SnCl 14 and 15, which were isolated by silica gel chromatography.
Reduction of 14 and 15 with LiAlH4 in THF gave the corresponding triorganotin hydrides 1 and 2,
Accepted 3 May 2011
respectively. [Me2(benzyl/a-naphthyl)SiCH2]3SnCl 16 and 17, generated by the alkylation of SnCl4 with
Me2(benzyl/ -naphthyl)SiCH2MgBr 12 and 13, were inseparable from the minor product [Me2(benzyl/a-
naphthyl)SiCH2]2SnCl2 18 and 19, respectively. Treatment of the mixtures of 16/18 and 17/19 with NaOH
furnished the corresponding mixtures of stannoxanes, from which the hexakisdistannoxanes
a
Keywords:
Bromomethyl(chloro)dimethylsilane
Grignard reagents
Stannanes
Stannoxanes
Tris[dimethyl(alkyl/aryl)silyl)methyl]tin
hydride
[Me2(benzyl/
tives [Me2(benzyl/
[Me2(benzyl/
-naphthyl)SiCH2]3SnH (3 and 4), respectively in good yields. 1H, 13C, 119Sn, 29Si NMR
characteristics of the newly synthesized compounds are included.
Ó 2011 Elsevier B.V. All rights reserved.
a-naphthyl)SiCH2]6Sn2O 20 and 22 were isolated from the minor dialkyltin oxide deriva-
a
-naphthyl)SiCH2]2SnO in good yields. Reduction of 20 and 22 with BH3 in THF gave
a
1. Introduction
organic ligands that preserve a minimal distortion of the tete-
trahedral geometry of the triorganotin hydride affect not only
better reactivity but also stereoselectivity compared with those
causing serious distortion of the tetetrahedral geometry [16a]. For
instance, the rigid of 9-triptycyclydimethyltin hydride (I) [17b,d] is
less reactive, though stereoselective hydrostannating agent
compared with trineophyltin hydride (II) and tris[(phenyl-
dimethylsilyl)methyl]tin hydride (III) (Chart 1) [17d]. In view of
these facts, we decided to further derivatize the dimethylsilyl
methyl moiety of the latter tin hydride, III with bulkier alkyl/aryl
moieties. In addition, triorganotin hydrides that are UV detectable
would easily be removed from compounds of pharmaceutical
applications [18]. Herein, we wish to report on the synthesis and
the characterization of novel tris[dimethyl(alkyl/aryl)silylmethyl]
tin hydrides (1e4) as potential reducing and hydrostannation
reagents (Chart 1).
Organotin hydrides are versatile reagents that have a plethora of
applications in organic synthesis [1]. For instance, tributyltin
hydride is widely used for the reduction of alkyl, vinyl, aryl halides,
thiols, isonitriles, nitrates,
a,b-unsaturated aldhydes, and for
Barton-McCombie deoxygenation of alcohols [2e6]. The reagent is
also used for the preparation of vinyl stannanes, useful interme-
diates in organic synthesis [7]. However, the toxicity associated
with some organotin compounds stimulated the development
methods to minimize the exposure to the tin reagents [11e15], and
devising alternatives to organotin hydrides [8e10]. Yet, organotin
hydrides are advantageous reagents to carry out chain radical
reactions by virtue of the weak nature of SneH bond, and thus
mitigating the search for novel organotin hydride reagents. Bulky
organotin hydrides are important hydrostannating agents and the
relationship between the steric volume of the organic substituents
attached to the tin atom with the reactivity as well as the stereo-
selectivity has been a subject of several investigations [16,17]. Bulky
2. Results and discussion
Bulky triorganotin hydrides of the type [Me2(alkyl/aryl)
SiCH2]3SnH could be prepared by the reduction of the corre-
sponding triorganotin chlorides [Me2(alkyl/aryl)SiCH2]3SnCl,
which are accessible via the alkylation of SnCl4 with Grignard
* Corresponding author. Department of Chemistry, Faculty of Science, Zagazig
University, Zagazig, Egypt. Tel.: þ20 141101581.
E-mail address: abdallaelsayed@zu.edu.eg (A.E.A. Hassan).
0022-328X/$ e see front matter Ó 2011 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2011.05.011

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A.E.A. Hassan et al. / Journal of Organometallic Chemistry 696 (2011) 2971e2975
The structure of the tin hydride 1 was confirmed by the spec-
troscopic data: 1H NMR signal of the SneH group appeared as
singlet at 5.2 ppm; its 119Sn signal was upfield shifted at ꢀ86.1 ppm;
and the IR ySneH absorption band appeared at 1814 cmꢀ1. Alkylation
of SnCl4 with Me2(benzyl,
similar conditions performed with 10 and 11, gave mixtures of the
[Me2(benzyl, -naphthyl)SiCH2]3SnCl 16, 17 and the tin dichlorides
a-naphthyl)SiCH2MgBr 12 and 13 under
a
derivatives 18, 19, respectively in an average ratio of w13:1,
determined from 119Sn NMR spectra of the mixtures. 119Sn NMR
signals of the 16/18 mixture appeared at 171.2, and 135.5 ppm, and
their 29Si NMR signals appeared at
d 3.16, 3.31 ppm, respectively.
Unlike the triorganotin chloride derivatives 14 and 15, attempts to
purify 16, 17 by silica gel chromatography under several eluting
systems or by crystallization, however were unsuccessful. It is
worth noting that these mixtures are highly soluble in most organic
solvents even at low temperatures (0e25 Cꢁ). Given that the
insolubility characteristics of dialkyltin oxides, a conversion of
a mixture of R3SnCl/R2SnCl2 into the corresponding stannoxanes
would facilitate the isolation of the soluble stannoxanes generated
from the R3SnCl from the dialkyltin oxide generated from the
R2SnCl2 [16a]. Adapting this approach enabled us to isolate the
stannoxanes derivatives 20 and 22 from the mixtures containing
the dialkyltin oxides 21 and 23 respectively. Thus, the tin chloride
mixtures 16/18 and 17/19 were treated with aqueous NaOH fol-
lowed by two phase partitioning (Et2O/H2O) to furnish the hexakis
Chart 1.
reagents Me2(R)SiCH2MgBr (14e17) (Scheme 1). The later
compounds were prepared in two steps from bromomethyl(chloro)
dimethylsilane (5) according to literature procedures [19e23].
Alkylation of 5 with Grignard reagents Ethyl/Benzyl/p-Tolyl/
NaphthylMgBr gave the corresponding bromomethyl(ethyl, p-tolyl,
benzyl, and -naphthyl)dimethylsilanes 6e9, which were in turn
transformed into the corresponding Grignard reagents Me2(ethyl,
p-tolyl, benzyl, -naphthyl)SiCH2MgBr 10e13, respectively. Alkyl-
ation of SnCl4 [19] with Grignard reagents 10 and 11 using a ratio
SnCl4/Grignard ¼ 1/3 gave the corresponding triorganotin chlorides
[Me2(ethyl, p-tolyl)SiCH2]3SnCl 14 and 15, respectively good yields.
Fortunately enough, the triorganotin chlorides 14 and 15 were
separable from the expected, though not isolated, minor alkylation
products [Me2(ethyl, p-tolyl)SiCH2]2SnCl2 by silica gel chromatog-
raphy. 119Sn and 29Si NMR signals of 14 appeared at 177.1 and
4.9 ppm, respectively. Reduction of the tin chlorides 14 and 15 with
LiAlH4 in dry Et2O afforded the corresponding tin hydrides 1 and 2,
respectively in good yields (Scheme 1).
a-
a
a
[dimethyl(benzyl/a-naphthyl)silylmethyl]distannoxanes 20 and
22, respectively in good yields. 119Sn NMR signals of 20 and 22
appeared at 109.6 and 126.3 ppm, and their 29Si signals appeared at
2.4 and ꢀ3.1 ppm, respectively. Reduction of the stannoxanes 20
and 22 with BH3 [23] in THF gave the corresponding tris[dime-
thyl(benzyl/a-naphthyl)methyl]tin hydrides 3 and 4, respectively in
good yields. Applications of the newly synthesized triorganotin
hydrides 1e4 as radical chain reducing and hydrostannation agents
will be reported in due course.
Scheme 1. Reagents and conditions: a) RMgX (R ¼ ethyl, p-tolyl, benzyl, and
a-naphthyl), Et2O, references 18e21; b) Mg turnings, Et2O, reflux, 1 h, and 15 h, rt; c) SnCl4, Et2O, reflux,
4 h; d) LiAlH4, Et2O, reflux, 3 h, then Rochelle salt, rt, 1 h; e) 10% aq. NaOH, Et2O, 30 min; f) BH3, THF, reflux, 3 h.

A.E.A. Hassan et al. / Journal of Organometallic Chemistry 696 (2011) 2971e2975
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3. Conclusions
1J ¼ 52.6 Hz), 125.1 (Ar), 126.2 (Ar), 126.5 (Ar), 128.4 (Ar), 129.5 (Ar),
129.7 (Ar), 132.2 (Ar), 132.4 (Ar), 135.3 (Ar), and 136.7 (Ar). Anal.
Calcd for C13H15BrSi (279.25) C, 55.91; H, 5.41; Found: C, 55.81; H,
5.48.
Novel sterically hindered tris[dimethyl(ethyl/benzyl/p-tolyl/a-
naphthyl)silylmethyl]stannanes 1e4 were synthesized starting
from bromomethyl(chloro)dimethylsilane. The bulkiness and the
flexibility of the ligands of the tin hydrides 1e4 is anticipated to
translate into higher reactivity and stereoselectivity in radical chain
reduction and hydrostannation reactions. The newly synthesized
tin hydrides 1e4 would be useful tools for effecting functional
group transformations and for studying mechanistic aspects of
organometallic chemistry. The UV detectabtability and the high
solubility of the aryl containing tin hydrides 2e4 would facilitate
the elimination of the toxic tin residuals from compounds of
pharmaceutical applications.
4.5. Tris[(dimethyl(ethyl)silyl)methyl]tin chloride (14)
A solution of bromomethyl(ethyl)dimethyl-silane 6 (3.93 g,
0.0217 mol) in dry Et2O (15 mL) was added dropwise to magne-
sium turnings (0.58 g, 0.0239 mol) in dry Et2O (5 mL) under argon
atmosphere at rt. The mixture was refluxed for 1 h and was
further stirred for 15 h at room temperature to give Grignard
reagent 10 (1.24 M solution). To a solution of SnCl4 (10.4 mL,
23.0 g, 0.088 mol) in dry benzene (200 mL) was added Grignard
reagent 10 (1.24 M, 213 mL, 0.264 mol) dropwise at 0 ꢁC. The
mixture was stirred for 1 h at rt, and for 4 h at reflux temperature.
The mixture was cooled down gradually to 0 ꢁC and treated with
saturated solution of NH4Cl (ca. 200 mL). The organic layer was
separated, and the aqueous phase was washed with Et2O
(100 mL ꢂ 3 times). The combined organic phases were dried
(MgSO4), and the volatiles were removed under vacuum. The
crude oil residue was purified by flash silica gel column chroma-
tography (eluate: 30% ethylacetate in n-hexane) to give 14 (26.9 g,
67% yield, based on SnCl4) as pale yellow oil: 1H NMR (CDCl3)
4. Experimental section
NMR spectra were recorded on a Bruker ARX 300 MHz. Infrared
spectra were recorded on Nicolet Nexus FT spectrometer. Mass
spectra were recorded on a Finnegan MAT Model 8230. Reactions
were monitored with glass-backed TLC plates pre-coated with silica
gel 60 F254 (EMD Chemicals). Flash column chromatography was
carried out using Fluka silica gel (60 Å pore, 230e400 mesh) that
was packed in glass columns and pressurized with nitrogen. The
chemical shifts are expressed on the
d
in ppm with respect to TMS
d
0.06 (s, 6H, 2CH3, C2eH), 0.25 (s, 2H, CH2, C1eH), 0.55 (q, 2H,
(1H and 29Si spectra) and Me4Sn (119Sn spectra). All solvents and
starting materials were dried prior to use. Bromomethyl(ethyl)
dimethylsilane (6), (bromomethyl)dimethyl(p-tolyl)silane (7),
benzyl(bromomethyl)dimethylsilan (8), and (bromomethyl)dime-
CH2CH3), 0.92 (t, 3H, CH2CH3), 13C NMR (CDCl3):
d 0.9 (C-2), 4.7
(1J ¼ 263.1 Hz C-1), 7.4 (CH3CH2), 9.7 (CH2CH3); 119Sn NMR
d
SneCH2 177.1 [1J(SneCH2)
¼
263.4 Hz]; 29Si NMR
d 4.9
[1J(SieCH3) ¼ 52.5 Hz]; MS m/z 458 [M]þ, Sn-pattern; Anal. Calcd.
thyl(
a
-naphthyl)silane (9) were synthesized by treatment of (bro-
for C15H39ClSi3Sn: C, 39.35; H, 8.58. Found: C, 39.58; H, 8.26.
momethyl)dimethyl(chloro)silane (5) with the appropriate
Grignard reagents in dry ether or benzene, according to the liter-
ature procedure with minor modification [19e22].
4.6. Tris[(dimethyl(p-tolyl)silyl)methyl]tin chloride (15)
This compound was synthesized from 7 in 63% yield, in a similar
procedure to that conducted for the synthesis 14: Yellow oil; 1H
4.1. (Bromomethyl)ethyldimethylsilane (6)
NMR (CDCl3) d
0.45 (s, 6H, 2CH3, C2eH),1.52 (s, 2H, CH2, C1eH), 2.48
B.p. 126e127 ꢁC (lit [19]. 127e127.8 ꢁC) was prepared in an 80%
(s, 3H, PeCH3) 7.26 (d, 2H, J ¼ 8.23 Hz, AreH), 7.63 (d, 2H,
yield; 1H NMR (CDCl3)
d
0.08 (s, 6H, 2CH3,C2eH), 0.9 (q, 2H,
J ¼ 8.25 Hz, AreH). 13C NMR (CDCl3)
d
ꢀ0.1 (C-2), 5.2 (1J ¼ 265.3 Hz,
CH3CH2), 0.93 (t, 3H, CH3CH2), 2.44 (s, 2H, CH2, C1eH); 13C NMR
C-1), 21.4 (p-CH3), 126.3 (Ar), 128.0 (Ar), 136.1 (Ar), 138.8 (Ar); 119Sn
(CDCl3)
d
ꢀ4.6 (C-2, 1J ¼ 54.4 Hz), 5.80 (CH3CH2), 7.0 (CH3CH2), 16.7
NMR
d
SneCH2 168.4 [1J(SneCH2) ¼ 265.0 Hz]; 29Si NMR
d
ꢀ3.2
(C-1, 1J ¼ 49.6 Hz).
[1J(SieCH3) ¼ 53.2 Hz]; MS m/z 644.1 [M]þ, Sn-pattern; Anal. Calcd.
for C30H45ClSi3Sn: C, 55.94; H, 7.04. Found: C, 56.12; H, 6.89.
4.2. Benzyl(bromomethyl)dimethylsilane (7)
4.7. Tris[(dimethyl(benzyl)silyl)methyl]tin chloride (16) and bis
[(benzyldimethylsilyl)methyl]-dichlorostannane (18)
B.p. 122e124 ꢁC (Lit [20]. 120e124 ꢁC); 87% yield; 1H NMR
(CDCl3)
d
0.18 (s, 6H, 2CH3, C2eH), 2.29 (s, 2H, CH2, C1eH), 2.47 (s,
2H, CH2Ph), 7.08e7.30 (m, 5H, AreH); 13C NMR (CDCl3)
d
ꢀ4.4
A mixture of 16 and 18 was synthesized in 66% yield (16:18;
12.4:1; Yellow oil) from 8 in a similar procedure to that performed
for the synthesis of 14: The physical data for 16; 1H NMR (CDCl3)
(1J ¼ 52.5 Hz, C-2), 16.2 (1J ¼ 50.5 Hz, C-1), 23.9 (CH2Ph), 124.3 (Ar),
124.9 (Ar), 134.8 (Ar), 138.9 (Ar).
d
0.44 (s, 6H, 2CH3, C2eH), 0.49 (s, 2H, CH2, C1eH), 1.20 (s, 2H, CH2,
4.3. (Bromomethyl)dimethyl(p-tolyl)silane (8)
C3eH), 7.25e7.82 (m, SH, AreH); 13C NMR (CDCl3)
d 0.92 (C-2), 5.1
(1J ¼ 264.5 Hz, C-1),10.8 (C-3),126.2 (Ar),126.8 (Ar),137.3 (Ar),138.5
B.p. 115e118 ꢁC (Lit [21]. 116e118 ꢁC); 85% yield; 1H NMR
(Ar); 119Sn NMR (CDCl3)
d
SneCH2 171.2 [1J(SneCH2) ¼ 266.5 Hz];
(CDCl3):
3H, CH3eP), 7.32 (d, 2H, J ¼ 8.20 Hz, AreH), 7.60 (d, 2H, J ¼ 8.25 Hz,
AreH); 13C NMR (CDCl3)
d
0.56 (s, 6H, 2CH3, C2eH), 2.48 (s, 2H, CH2, C1eH), 2.74 (s,
29Si NMR (CDCl3)
d
3.16 [1J(SieCH3) ¼ 51.10 Hz]. The physical data for
18: 119Sn NMR (CDCl3)
d
135.5 [1J(SneCH2) ¼ 266.8 Hz]; 29Si NMR
d
ꢀ3.8 (J ¼ 53.2 Hz, C-2), 17.2 (C-1,
(CDCl3)
d
3.18 [1J(SieCH3) ¼ 51.5 Hz].
J ¼ 51.2 Hz), 21.6 (PeCH3), 126.9 (Ar), 127.8 (Ar), 135.8 (Ar), 139.6
(Ar).
4.8. Tris[(dimethyl(
a-naphthyl)silyl)methyl]tin chloride (17) and
bis[(dimethyl( -naphthyl)silyl)-methyl]tin dichloride (19)
a
4.4. (Bromomethyl)dimethyl(a-naphthyl)silane (9)
A mixture of 17 and 19 was synthesized in 65% yield (17:19;
13:1) from 9 in a similar manner performed for the synthesis of 14:
B.p.123e125 ꢁC; 83% yield after reflux for 10 day followed by
hydrolysis with dil. HCl and extraction with diethyl ether, drying
Yellow oil; The physical data for 17: 1H NMR (CDCl3) of:
d 0.68 (s, 6H,
over MgSO4. 1H NMR (CDCl3):
d
0.70 (s, 6H, 2CH3, C2eH), 7.50e8.09
d
2CH3, C2eH), 0.59 (s, 2H, CH2, C1eH), 7.50e8.30 (m, 9H, AreH); 13
C
(m, 7H, AreH); 13C NMR (CDCl3)
ꢀ2.3 (C-2, 1J ¼ 53.4 Hz), 17.6 (C-1,
NMR (CDCl3)
d
1.15 (C-2), 5.2 (1J ¼ 267.2 Hz, C-1), 125.1, 125.7, 127.7,

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A.E.A. Hassan et al. / Journal of Organometallic Chemistry 696 (2011) 2971e2975
129.1, 129.2, 129.9, 133.5, 136.5, 137.4 and 137.5 (AreC); 119Sn NMR
4.13. Tris[(benzyl(ldimethyl)silyl)methyl]tin hydride (3)
d
SneCH2 130.1 [1J(SneCH2) ¼ 268.1 Hz], 29Si NMR
d
ꢀ2.6
[1J(SieCH2) ¼ 54.3 Hz]. The physical data for 19: 119Sn NMR 165.9
A solution of borane in THF (25 mL, 0.025 mol, 1 M solution) was
added dropwise to a solution of 20 (11 g, 0.017 mol) in THF (110 mL)
at room temperature, then the mixture was heated for 3 h at reflux
temperature. The mixture was cooled to room temperature, and the
volatiles were removed under reduced pressure. The residue was
dissolved in Et2O (150 mL) and washed with H2O (100 mL ꢂ 2
times). The organic layer separated, dried (MgSO4), and the solvent
was removed under reduced pressure to afford 3 (6.62 g, 65% yield)
[1J(SneCH2) ¼ 267.2 Hz]; 29Si NMR
d
ꢀ2.3 [1J(SieCH2) ¼ 53.8 Hz].
4.9. Hexakis[(dimethylbenzylsilyl)methyl]distannoxane (20)
To a solution of the mixture 16 and 18 in a ratio of 13:1 (12.1 g) in
Et2O (100 mL) was add 10% aqueous solution of NaOH (20 mL) and
the mixture was vigorously stirred for 30 min at room temperature.
The organic layer was decanted and washed with aqueous NaOH
and H2O (20 mL ꢂ 3 times), dried (MgSO4), and evaporated under
vacuum. The oil residue was redissolved in n-hexane and was
further dried over Al2O3, the volatiles were removed under reduced
pressure to afford 20 (11.5 g, 93.0% yield) as pale yellow oil: 1H NMR
as a colorless oil: IR (NuJol): ySnꢀH 1808.9 cmꢀ1; 1H NMR (C6D6)
d 0.11
(s, 6H, 2CH3, C2eH), 0.13 (s, 2H, CH2, C1eH), 2.8 (s, 2H, CH2, C3eH),
5.18 (s, 1 H, SneH), 7.05e7.24 (m, 5H, AreH); 13C NMR (C6D6)
d
ꢀ0.6
(1J ¼ 240.7 Hz, C-1), 0.7 (C-2), 28.5 (C-3),124.6 (Ar),126.8 (Ar),138.2
(Ar), 140.5 (Ar); 119Sn NMR:
d
(SneCH2) ¼ ꢀ85.7; 29Si NMR
d 3.1
[1J(SieCH3) ¼ 51.6 Hz]; MS-FAB m/z 609.4 [M ꢀ H]þ, Sn-pattern;
(CDCl3) d
0.14 (s, 6H, 2CH3, C2eH), 0.17(s, 2H, CH2, C1eH), 2.21(s, 2H,
Anal. Calcd for C30H46Si3Sn: C, 59.10; H, 7.61. Found: C, 59.18; H, 7.70.
CH2, C3eH), 7.09e7.40 (m, 5H, AreH); 13C NMR (CDCl3)
d 0.50 (C-2),
4.28 (1J ¼ 283.8 Hz, C-1), 28.6 (C-3), 123.8, 126.4, 135.3 and 141.7
(AreC). 119Sn NMR
d
(SneCH2) 109.6 [1J(SneCH2) ¼ 282.6 Hz]; 29Si
4.14. Tris[(dimethyl(a-naphthyl)silyl)methyl]tin hydride (4)
NMR
d
2.4 [1J(SieCH3) ¼ 51.4 Hz].
The tin hydride derivative 4 was synthesized from 22 in 63%
yield, in a similar procedure to that conducted for the synthesis of
3; IR (NuJol): ySnꢀH 1819.8 cmꢀ1; 1H NMR (C6D6)
d 0.14 (s, 2H, CH2,
4.10. Hexakis[dimethyl(a-naphthyl)silylmethyl]distannoxane (22)
C1eH), 0.41 (s, 6H, 2CH3, C2eH), 0.5 (s, 2H, SneH), 7.32e8.15 (m, 7H,
AreH); 13C NMR (C6D6)
d
ꢀ3.6 (1J ¼ 247.6 Hz, C-1), 0.8 (C-2), 125.8
The distannoxane derivative 22 was synthesized from the
mixture 17 and 19 in 94.5% yield, in a similar procedure to that
conducted for the synthesis 20: Pale yellow oil; 1H NMR (CDCl3)
(Ar), 126.2 (Ar), 127.3 (Ar), 129.8 (Ar), 130.2 (Ar), 131.8 (Ar), 133.0
(Ar), 137.2 (Ar), 137.9 (Ar), 139.0 (Ar); 119Sn NMR
(SneCH2) ¼ ꢀ85.5; 29Si NMR
d
ꢀ2.4[1J(SieCH3) ¼ 52.1 Hz]; MS-
d
0.39 (s, 6H, 2CH3, C2eH), 0.53(s, 2H, CH2, C1eH), 7.26e7.90 (m, 7H,
d
AreH); 13C NMR (CDCl3)
d
1.1 (C-2), 3.6 (1J ¼ 285.2 Hz, C-1), 125.1
FAB m/z 717.8 [M ꢀ H]þ, Sn-pattern; Anal. Calcd. for C39H46Si3Sn:
(Ar), 126.3 (Ar), 128.0 (Ar), 128.9 (Ar), 130.2 (Ar), 132.1 (Ar), 133.4
C, 65.26; H, 6.46. Found: C, 65.38; H, 6.38.
(Ar), 135.2 (Ar), 137.8 (Ar), 138.2 (Ar). 119Sn NMR:
d (SneCH2) 126.3
[1J(SneCH2) ¼ 285.2 Hz]. 29Si NMR:
d
ꢀ3.1 [1J(SieCH3) ¼ 54.2 Hz].
Acknowledgments
We are indebted to Prof. Dr. M. Krause, Dortmund University,
Chemistry department and also DFG for financial support of the
work and analysis.
4.11. Tris[(dimethyl(ethyl)silyl)methyl]tin hydride (1)
To a solution of 14 (26 g, 0.056 mol) in dry Et2O (300 mL) was
add a solution of LiAlH4 in Et2O (84 mL, 0.084 mol, 1 M solution)
dropwise at room temperature. The mixture was stirred for 3 h at
reflux temperature, cooled to room temperature, and then treated
with aqueous solution of Rochelle salt and the mixture was stirred
for further 1 h at room temperature. The organic layer was sepa-
rated and the aqueous phase was washed with Et2O (150 mL ꢂ 3
times). The combined organic phases were dried (MgSO4) and the
volatiles were removed under reduced pressure to give 1 (17.5 g,
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74% yield) as colorless oil: IR (NuJol): ySnꢀH 1814 cmꢀ1
;
1H NMR
(C6D6)
d
0.17 (s, 6H, 2CH3, C2eH), 0.29 (s, 2H, CH2, C1eH), 0.62 (q,
2H, CH2CH3), 1.07 (t, 3H, CH2CH3), 5.2 (s,1H, SneH); 13C NMR (C6D6)
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4.12. Tris[(dimethyl(p-tolyl)silyl)methyl]tin hydride (2)
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The tin hydride derivative 2 was synthesized from15 in 86% yield,
in a similar procedure to that conducted for the synthesis of 1; IR
(NuJol): ySnꢀH 1809 cmꢀ1. 1H NMR (C6D6)
d
ꢀ0.03 (s, 2H, CH2, C1eH),
0.35 (s, 6H, 2CH3, C2eH), 2.23 (s, 3H, p-CH3), 5.2 (s,1H, SneH), 7.13 (d,
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d
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d
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ꢀ2.7
d
[1J(SieCH3) ¼ 53.4 Hz]; MS-FAB m/z 609.4 [M ꢀ H] þ, Sn-pattern;
Anal. Calcd. for C30H46Si3Sn: C, 59.10; H, 7.61, Found: C, 59.20; H, 7.53.

A.E.A. Hassan et al. / Journal of Organometallic Chemistry 696 (2011) 2971e2975
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