Selective Si?C(sp3) Bond Cleavage in (Aminomethyl)silanes by Carbanionic Nucleophiles and Its Stereochemical Course

Article abstract of DOI:10.1002/anie.201702410

Selective cleavage of a silicon–carbon bond in tetraorganosilanes is still a great challenge. A new type of Si?C(sp³) bond cleavage in bench-stable (aminomethyl)silanes with common organolithium reagents as nucleophiles has now been identified. Suitable leaving groups are benzyl, allyl, and phenylthiomethyl groups. A β-donor function and polar solvents are essential for the reaction. Simple switching between α-deprotonation and substitution is possible through slight modifications of the reaction conditions. The stereochemical course of the reaction was elucidated by using a silicon-chiral benzylsilane. The new transformation proceeds stereospecifically with inversion of configuration and can be used for the targeted synthesis of enantiomerically pure tetraorganosilanes, which are otherwise difficult to access. Quantum chemical calculations provided insight into the mechanism of the new substitution.

Full text of DOI:10.1002/anie.201702410

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: Selective Si-C(sp3) Bond Cleavage in (Aminomethyl)silanes by
Carbanionic Nucleophiles and its Stereochemical Course
Authors: Stephan G. Koller, Jonathan O. Bauer, and Carsten
Strohmann
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201702410
Angew. Chem. 10.1002/ange.201702410
Link to VoR: http://dx.doi.org/10.1002/anie.201702410
http://dx.doi.org/10.1002/ange.201702410

10.1002/anie.201702410
Angewandte Chemie International Edition
DOI: 10.1002/anie.201((will be filled in by the editorial staff))
Chemistry of Si-C Bonds
Selective Si-C(sp3) Bond Cleavage in (Aminomethyl)silanes by
Carbanionic Nucleophiles and its Stereochemical Course
Stephan G. Koller, Jonathan O. Bauer†, and Carsten Strohmann*
Abstract: The utilization of tetraorganosilanes by selective cleavage
of a silicon-carbon bond is still a great challenge. Here we describe
a new type of Si-C(sp3) bond cleavage in bench-stable (amino-
functionalization in α-position next to a silicon center (Figure 1).[14]
The question we are facing here is whether organolithium reagents
can also enable a selective Si-C(sp3) bond cleavage in triorgano-
methyl)silanes with common organolithium reagents as nucleophiles. (aminomethyl)silanes, and which conditions are required to favor
Suitable leaving groups are benzyl, allyl, and phenylthiomethyl
groups. A β-donor function and polar solvents are essential.
Through slight modifications of the reaction conditions, easy
switching between α-deprotonation and substitution is possible.
Using a silicon-chiral benzylsilan, the stereochemical course of the
reaction was elucidated. The new transformation proceeds stereo-
specifically with inversion of configuration and can be used for a
targeted synthesis of optically pure tetraorganosilans, which are
otherwise difficult to access. Quantum chemical calculations
provided insight into the mechanism of the new substitution.
this reaction path. The presence of an intramolecular donor function,
allowing for pre-coordination might be crucial also for a Si-C bond
cleavage. Such a selective and convenient transformation would
lead to new protocols toward asymmetrically substituted tetra-
organosilans starting from all-C-substituted precursors, which are
normally inert against further reactions due to the low polarity of
their Si-C bonds (Figure 1).
T
he activation of silicon-carbon bonds has generated much interest
because of the recent developments in organosilicon-based cross-
coupling reactions.[1] Recently, selective metal-catalyzed Si-C bond
cleavage has also led to new synthetic applications of tetraorgano-
silanes.[2] Different from carbon-carbon bonds, silicon-carbon bonds
in tetraorganosilanes can also be cleaved heterolytically with strong
nucleophiles (SN@Si reaction). In this way, fluorides, alkoxides, or
siloxides can initiate Si-C bond cleavage accompanied by transfer of
the liberated organyl moieties onto carbonyl compounds and
imines.[3,4]
Figure 1. Competing reaction paths between organolithium reagents and
triorgano(aminomethyl)silanes. EWG = electron-withdrawing group.
Herein, we present a controlled substitution of activated alkyl
groups in bench-stable tetraorganosilanes using carbanionic nucleo-
philes. The reaction tolerates a variety of substituents and can be
used for stereospecific transformations at stereogenic silicon centers.
Studies concerning a highly enantiomerically enriched benzylsilane
and quantum chemical calculations gave information about the
mechanism of the new reaction.
There are only few examples in which carbanionic reagents fill
the role of a nucleophile that cleaves Si-C bonds but certain reaction
conditions are generally required. Among them are ring-opening
reactions with strained silacycles,[5] substitutions with dibenzo-
siloles,[6] or ring-closing reactions by intramolecular attack of a
metallated C-nucleophile at a silicon center.[7] An intermolecular
SN@Si reaction of acyclic silanes with organolithium reagents is
known only for dihydrofuryl-substituted silanes,[8] which turned out
to be sensitive toward protodesilylation because of the arylic nature
of the dihydrofuryl group.[9] Exploring synthetic methods for the
selective cleavage of a Si-C(sp3) bond in robust tetraorganosilanes is
still very challenging.[10,11]
Exploring the best reaction conditions for a nucleophilic substi-
tution, benzyldimethyl(piperidinomethyl)silane (1a) was chosen as a
model system, since the benzyl group was supposed to be an
appropriate leaving group (Table 1).[3g] Primary and sterically less
demanding alkyllithium compounds, like n-butyllithium, were
expected to be rather effective in nucleophilic attack than in depro-
tonation. Reaction of 1a with nBuLi in tetrahydrofuran at room
temperature for 1.5 h resulted in 92% conversion. After addition of
trimethylchlorosilane, both the products of a nucleophilic substitu-
tion (2a and 3) and the product of a deprotonation (4) were obtained
in a ratio of 55:45 (Table 1, entry 1). Lowering the temperature to
0°C under otherwise the same conditions considerably increased the
selectivity of the reaction in favor of the substitution (71:29) but the
conversion remained nearly the same (entry 2). Hence in THF, the
activation barrier of the substitution is below the barrier of the
deprotonation, which was also confirmed by quantum chemical
calculations (for details, see the Supporting Information). At –30°C
the substitution clearly becomes the dominating reaction (selectivity
up to 79:21, entries 3-7), although a reaction time of 24 h is required
for 95% conversion (entry 6). Further lowering of the temperature to
In our group, the reactivity of (aminomethyl)silanes has been in
the focus of interest for a long time.[12-14] The directing properties of
aminomethyl functions allow for selective deprotonation and
[ ]
[†]
Dr. S. G. Koller, Dr. J. O. Bauer, Prof. Dr. C. Strohmann
Anorganische Chemie, Technische Universität Dortmund
Otto-Hahn-Straße 6, D-44227 Dortmund (Germany)
E-Mail: mail@carsten-strohmann.de
Dr. J. O. Bauer, current address:
Institut für Anorganische Chemie, Universität Regensburg
Universitätsstraße 31, D-93053 Regensburg (Germany)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/anie.201xxxxxx.
1
This article is protected by copyright. All rights reserved.

10.1002/anie.201702410
Angewandte Chemie International Edition
Table 1. Optimization of the reaction conditions for the Si-C bond cleavage.[a]
Entry
Solvent
T [°C]
t [h]
Conversion [%][b]
2a : 4[b]
Figure 2. Substrates used for the substitution with carbanionic nucleophiles.
1
THF
RT
0
1.5
1.5
1
92
89
18
79
89
95
95
32
60
33
48
55:45
71:29
76:24
79:21
76:24
76:24
76:24
77:23
10:90
12:88
< 1:99
2
THF
2 and Table 2). For this purpose, a variety of triorgano(amino-
methyl)silanes (1a-i) was synthesized (Figure 2). Along with a
successive exchange of methyl by phenyl groups (1a-c), the number
and nature of the amino functions was varied as well (1d-g). For
studying the leaving group quality, the allyl- and (phenylthio-
methyl)silanes 1h and 1i were used (Figure 2).
3
THF
–30
–30
–30
–30
–30
–60
0
4
THF
6
5
THF
16
24
72
24
1.5
1.5
4.5
6
THF
7
THF
Reaction of 1a with methyllithium and aliphatic and aromatic
organolithium compounds led to good yields (Table 2, entries 1-4).
The best results were obtained with ethyl- and n-butyllithium, giving
2c and 2a in 67% and 69% isolated yield, respectively (entries 2 and
3). Exchange of one methyl group for phenyl only marginally
affected the reaction (Table 2, entries 5 and 6). However, the yield
decreased significantly in case of an exchange of both methyl
groups, with diphenylsilane 2f being formed in only 25% isolated
yield (compare entries 6 and 7). Seemingly, the substitution is
independent from the number and nature of the nitrogen donor
centers (entries 8-12). Significantly high yields were obtained in the
reactions of methyllithium with (R,R)-1f (53%) and 1g (67%)
(entries 11 and 12). Also phenylthiomethyl and allyl groups are well
8
THF
9
Pentane
Diethyl ether
Toluene
10
11
0
RT
[a] Reaction conditions: nBuLi (1.1 equiv.) was added to a solution of benzyl-
silane 1a (0.8 mmol) in the respective solvent (5 ml) at –78°C. The solution was
allowed to warm to the respective temperature and kept stirring. To identify the
products formed, the reaction was quenched with Me3SiCl (1.2 equiv.) at
–78°C. [b] Conversion of 1a and the ratio between 2a and 4 was determined by
1H NMR spectroscopy.
–60°C has no effect on the selectivity (entry 8). Performing the
reaction in pentane or diethyl ether at 0°C for 1.5 h, the substitution
products were obtained in only negligible amounts (entries 9 and 10).
In accordance with previous investigations concerning α-lithiation
of 1a, the reaction with nBuLi in toluene at room temperature for
4.5 h led to the deprotonation product 4 with high selectivity, albeit
with moderate conversion (48%, entry 11). However, compound 4
can be obtained in high yield either by heating the reaction mixture
in toluene at reflux, by an exchange of nBuLi for tBuLi, or by an
addition of external diamin ligands.[14a,c]
suited as leaving groups in
a nucleophilic substitution at
(aminomethyl)silanes (entries 13-15) due to efficient stabilization of
the negative charge. When carrying out the reaction of silanes 1h
Table 2. Nucleophilic substitution reactions at triorgano(aminomethyl)silanes.[a]
X = Ph, SPh, CH=CH2; Nu = carbanionic nucleophile.
Apparently, the polarity of the solvent has a significant effect on
the reactivity of (aminomethyl)benzylsilanes. Unpolar solvents like
pentane, diethyl ether, and toluene favor the α-deprotonation but the
substitution proceeds smoothly in polar solvents like THF. It is
likely that the substitution passes through short-living lithium
pentaorganosilicates, which are particularly stabilized by THF. The
important role of a coordinating solvent in stabilizing pentaorgano-
silicates was thoroughly studied by Klumpp.[15] This is also sup-
ported by several isolated pentacoordinate silicon species having
five Si-C bonds.[16] In our case of an unusual Si-C(sp3) bond
cleavage in tetraorganosilanes that lack appropriate substituents for
stabilizing higher-coordination at silicon,[16d,17] most likely a kinetic
effect of the intramolecular aminomethyl function becomes
eminently important. It was shown that a β-donor atom is indeed
required for the substitution pathway.[18] This facilitates a controlled
approach of the reactive centers by pre-coordination of the alkyl-
lithium compound. Consequently, the same effect which is crucial
for deprotonations and known as complex-induced proximity effect
(CIPE),[19] may be relevant also for the substitution at silicon. The
Si-C bond cleavage by carbanionic nucleophiles can therefore be
considered a yet unknown reactivity of (aminomethyl)silanes.
Using the optimized conditions, the substrate scope of the
nucleophilic Si-C bond cleavage was studied in more detail (Figure
Entry
1
Nu
2
Isolated Yield [%]
1
1a
Me
Et
2b
2c
52
67
69
50
51
66
25
42
47
17
53
67
55
79
81
2
1a
3
1a
nBu
Ph
2a
4
1a
2d
5
(rac)-1b
(rac)-1b
1c
Me
nBu
nBu
Me
nBu
Me
Me
Me
Me
nBu
nBu
2d
6
(rac)-2e
2f
7
8
1d
2g
9
1d
2h
10
11
12
13
14
15
1e
2i
(R,R)-1f
1g
(R,R)-2j
2k
1h
2b
1h
2a
1i
2a
[a] Reaction conditions: NuLi (1.1 equiv.) was added to a solution of 1 in THF
(25 ml) at –78°C. The solution was allowed to warm to –30°C and kept stirring
for 20 h. The reaction was quenched either with Me3SiCl (1.2 equiv.) or ethanol
(excess) at –78°C.
2
This article is protected by copyright. All rights reserved.

10.1002/anie.201702410
Angewandte Chemie International Edition
can also be applied for controlled stereospecific transformations at
silicon-chiral centers.
and 1i[20] with nBuLi (entries 14 and 15), the substitution product 2a
was obtained in isolated yields up to 81%. As expected, sterically
demanding alkyllithium compounds like tBuLi react with
benzylsilanes solely under deprotonation.[14a]
Acknowledgements
This research was supported by the Deutsche Forschungsgemein-
schaft. J.O.B. thanks the Alexander von Humboldt Foundation for
the award of a Feodor Lynen Return Fellowship.
Next, it was of special interest for us to explore the capability of
this new reaction for stereochemically controlled transformations of
silicon-chiral tetraorganosilanes, also aiming at deeper mechanistic
insight into this substitution reaction at triorgano(aminomethyl)-
silanes. In recent times, substantial progress in constructing asym-
metrically substituted silicon centers and in developing new
procedures for the transfer of stereochemical information has been
achieved.[21,22] The silicon-chiral benzylsilane (S)-1b (Scheme 1,
top) is obtained in highly enantiomerically enriched form
(e.r. = 99:1) by resolution.[23] According to our general procedure,
(S)-1b reacted smoothly with n-butyllithium in THF at –30°C with
substitution of the benzyl group. The enantiomeric ratio of n-butyl-
Keywords: alkyllithium compounds · chirality · density functional
calculations · nucleophilic substitution · silanes
[1] For reviews, see: a) T. Hiyama, E. Shirakawa, Top. Curr. Chem. 2002,
219, 61; b) S. E. Denmark, R. F. Sweis, Acc. Chem. Res. 2002, 35,
835; c) S. E. Denmark, R. F. Sweis, Metal-Catalyzed Cross-Coupling
Reactions (Eds.: A. de Meijere, F. Diederich), Wiley-VCH, Weinheim,
2004, chapt. 4; d) A. K. Sahoo, T. Oda, Y. Nakao, T. Hiyama, Adv.
Synth. Catal. 2004, 346, 1715; e) Y. Nakao, A. K. Sahoo, H. Imanaka,
A. Yada, T. Hiyama, Pure. Appl. Chem. 2006, 78, 435; f) S. E.
Denmark, J. Org. Chem. 2009, 74, 2915; g) S. E. Denmark, J. H.-C.
Liu, Angew. Chem. 2010, 122, 3040; Angew. Chem. Int. Ed. 2010, 49,
2978.
[2] For recent examples, see: a) M. Tobisu, M. Onoe, Y. Kita, N. Chatani,
J. Am. Chem. Soc. 2009, 131, 7506; b) T. Seiser, N. Cramer, Angew.
Chem. Int. Ed. 2010, 49, 10163; Angew. Chem. 2010, 122, 10361; c)
R. Shintani, K. Moriya, T. Hayashi, J. Am. Chem. Soc. 2011, 133,
16440; d) R. Shintani, E. E. Maciver, F. Tamakuni, T. Hayashi, J. Am.
Chem. Soc. 2012, 134, 16955; e) M. Onoe, K. Baba, Y. Kim, Y. Kita,
M. Tobisu, N. Chatani, J. Am. Chem. Soc. 2012, 134, 19477.
1
silane 2e (e.r. = 81:19) was determined by H NMR spectroscopy
using (R)-mandelic acid. By comparing with literature data,[24] the
stereogenic silicon center of the major diastereomer could be
assigned (R) configuration. Hence the reaction proceeds with 81%
inversion of configuration.
[3] For selected examples of fluoride-mediated Si-C bond cleavage, see:
a) A. Hosomi, A. Shirahata, H. Sakurai, Tetrahedron Lett. 1978, 19,
3043; b) A. Hosomi, Acc. Chem. Res. 1988, 21, 200; c) G. K. S.
Prakash, M. Mandal, G. A. Olah, Angew. Chem. Int. Ed. 2001, 40,
589; Angew. Chem. 2001, 113, 609; d) S. E. Denmark, J. Fu, Chem.
Rev. 2003, 103, 2763; e) W.-X. Zhang, C.-H. Ding, Z.-B. Luo, X.-L.
Hou, L.-X. Dai, Tetrahedron Lett. 2006, 47, 8391; f) Y. Li, J. Hu,
Angew. Chem. Int. Ed. 2007, 46, 2489; Angew. Chem. 2007, 119,
2541; g) M. Das, D. F. O'Shea, Tetrahedron 2013, 69, 6448.
[4] For selected examples of alkoxide- and siloxide-mediated Si-C bond
cleavage, see: a) K. Tomooka, A. Nakazaki, T. Nakai, J. Am. Chem.
Soc. 2000, 122, 408; b) R. B. Lettan II, K. A. Scheidt, Org. Lett. 2005,
7, 3227; c) M. Michida, T. Mukaiyama, Chem. Asian. J. 2008, 3,
1592; d) M. Das, D. F. O'Shea, J. Org. Chem. 2014, 79, 5595; e) M.
Das, D. F. O'Shea, Org. Lett. 2015, 17, 1962; f) M. Das, D. F. O'Shea,
Chem. Eur. J. 2015, 21, 18717.
[5] a) D. Seyferth, G. H. Wiseman, D. C. Annarelli, M. L. Shannon, J.
Organomet. Chem. 1984, 264, 149; b) Y. Kakihana, K. Uenishi, I.
Imae, Y. Kawakami, Macromolecules 2005, 38, 6321; c) S.
Tangbunsuk, G. R. Whittell, M. G. Ryadnov, G. W. M. Vandermeulen,
D. N. Woolfson, I. Manners, Chem. Eur. J. 2012, 18, 2524.
Scheme 1. Stereospecificity of the nucleophilic Si-C bond cleavage (top).
Calculated activation barriers [∆Gǂ (–30°C)] of two plausible transition states for
the nucleophilic attack of methyllithium at silicon [D = Me2O; M06-2X/6-31+G(d)]
(bottom).
Quantum chemical calculations on a slightly simplified model
system supported the experimental findings regarding the stereo-
chemical course of the substitution. Scheme 1 (bottom) shows the
first step of the substitution leading to a pentacoordinate intermedi-
ate (for details, see the Supporting Information). Initially, dimeric
methyllithium is pre-coordinated via the aminomethyl function of
the benzylsilane. The nucleophilic attack at the silicon center
proceeds in an intramolecular fashion either from the backside (TS1,
78 kJ mol–1) or from the front side (TS2, 83 kJ mol–1), only the first
leading to inversion of configuration at silicon.[25] The energetic
difference of 5 kJ mol–1 between both transition states, favoring a
backside attack, corresponds excellent to the observed enantiomeric
ratio (Scheme 1), even though a partial racemization via pseudo-
rotation in pentacoordinate intermediates cannot be excluded.
[6] M. Ishikawa, T. Tabohashi, H. Sugisawa, K. Nishimura, M. Kumada,
J. Organomet. Chem. 1983, 250, 109.
[7] a) D. Wittenberg, H. Gilman, J. Am. Chem. Soc. 1958, 80, 2677; b) E.
Vedejs, O. Daugulis, S. T. Diver, D. R. Powell, J. Org. Chem. 1998,
63, 2338; c) G. P. M. van Klink, H. J. R. de Boer, G. Schat, O. S.
Akkerman, F. Bickelhaupt, A. L. Spek, Organometallics 2002, 21,
2119; d) P. F. Hudrlik, D. Dai, A. M. Hudrlik, J. Organomet. Chem.
2006, 691, 1257; e) C. Wang, Q. Luo, H. Sun, X. Guo, Z. Xi, J. Am.
Chem. Soc. 2007, 129, 3094; f) J. Zhao, D. Qiu, J. Shi, H. Wang, J.
Org. Chem. 2012, 77, 2929; g) M. Onoe, T. Morioka, M. Tobisu, N.
Chatani, Chem. Lett. 2013, 42, 238.
[8] D. Labrecque, K. T. Nwe, T. H. Chan, Organometallics 1994, 13, 332.
[9] V. P. Colquhoun, PhD thesis, TU Dortmund, Dortmund (Germany),
2011.
[10] M. A. Brook, Silicon in Organic, Organometallic, and Polymer
Chemistry, John Wiley & Sons, Inc., New York, 2000.
In summary, we opened access to a new kind of convenient
transformations at triorgano(aminomethyl)silanes by nucleophilic
substitution of alkyl groups using organolithium reagents. In
addition to selective α-lithiation, a second reaction pathway is now
accessible for this type of bench-stable tetraorganosilanes, which
[11] For examples of selective electrophilic Si-C bond cleavage, see: a) K.
Itami, K. Terakawa, J. Yoshida, O. Kajimoto, J. Am. Chem. Soc. 2003,
3
This article is protected by copyright. All rights reserved.

10.1002/anie.201702410
Angewandte Chemie International Edition
[18] Reaction of benzylmethyldiphenylsilane with nBuLi or MeLi under
the optimized conditions resulted in deprotonation rather than
substitution (for details, see the Supporting Information).
[19] M. C. Whisler, S. MacNeil, V. Snieckus, P. Beak, Angew. Chem. Int.
Ed. 2004, 43, 2206; Angew. Chem. 2004, 116, 2256.
125, 6058; b) M. Shindo, K. Matsumoto, K. Shishido, Angew. Chem.
Int. Ed. 2004, 43, 104; Angew. Chem. 2004, 116, 106.
[20] C. Strohmann, K. Lehmen, S. Dilsky, J. Am. Chem. Soc. 2006, 128,
8102.
[21] For reviews, see: a) M. Oestreich, Synlett 2007, 1629; b) L.-W. Xu, L.
Li, G.-Q. Lai, J.-X. Jiang, Chem. Soc. Rev. 2011, 40, 1777; c) R.
Shintani, Asian J. Org. Chem. 2015, 4, 510; d) J. O. Bauer, C.
Strohmann, Eur. J. Inorg. Chem. 2016, 2868.
[22] For some recent examples, see: a) J. O. Bauer, C. Strohmann, Angew.
Chem. Int. Ed. 2014, 53, 720; Angew. Chem. 2014, 126, 738; b) J. O.
Bauer, C. Strohmann, Angew. Chem. Int. Ed. 2014, 53, 8167; Angew.
Chem. 2014, 126, 8306; c) J. O. Bauer, C. Strohmann, J. Am. Chem.
Soc. 2015, 137, 4304; d) T. Fallon, M. Oestreich, Angew. Chem. Int.
Ed. 2015, 54, 12488; Angew. Chem. 2015, 127, 12666; e) R. Kumar,
Y. Hoshimoto, H. Yabuki, M. Ohashi, S. Ogoshi, J. Am. Chem. Soc.
2015, 137, 11838; f) K. Igawa, D. Yoshihiro, Y. Abe, K. Tomooka,
Angew. Chem. Int. Ed. 2016, 55, 5814; Angew. Chem. 2016, 128,
5908; g) L. Chen, J.-B. Huang, Z. Xu, Z.-J. Zheng, K.-F. Yang, Y.-M.
Cui, J. Cao, L.-W. Xu, RSC Adv. 2016, 6, 67113; h) R. Shintani, R.
Takano, K. Nozaki, Chem. Sci. 2016, 7, 1205; i) Q.-W. Zhang, K. An,
L.-C. Liu, Q. Zhang, H. Guo, W. He, Angew. Chem. Int. Ed. 2017, 56,
1125; Angew. Chem. 2017, 129, 1145.
[12] For examples of selective Si-C bond cleavage in (aminomethyl)-
silanes using lithium, see: a) C. Strohmann, D. Schildbach, D. Auer, J.
Am. Chem. Soc. 2005, 127, 7968; b) C. Strohmann, C. Däschlein, M.
Kellert, D. Auer, Angew. Chem. Int. Ed. 2007, 46, 4780; Angew.
Chem. 2007, 119, 4864.
[13] For a cleavage of the Si-O bond in (aminomethyl)siloxanes, see: C.
Däschlein, J. O. Bauer, C. Strohmann, Angew. Chem. Int. Ed. 2009, 48,
8074; Angew. Chem. 2009, 121, 8218.
[14] For selected examples on α-lithiation in (aminomethyl)silanes, see: a)
C. Strohmann, K. Lehmen, A. Ludwig, D. Schildbach,
Organometallics 2001, 20, 4138; b) C. Strohmann, B. C. Abele, K.
Lehmen, D. Schildbach, Angew. Chem. 2005, 117, 3196; Angew.
Chem. Int. Ed. 2005, 44, 3136; c) S. G. Koller, U. Kroesen, C.
Strohmann, Chem. Eur. J. 2015, 21, 641.
[15] A. H. J. F. de Keijzer, F. J. J. de Kanter, M. Schakel, R. F. Schmitz, G.
W. Klumpp, Angew. Chem. Int. Ed. Engl., 1996, 35, 1127; Angew.
Chem. 1996, 108, 1183.
[16] For selected examples of pentaorganosilicates, see: a) A. Kolomeitsev,
G. Bissky, E. Lork, V. Movchun, E. Rusanov, P. Kirsch, G.-V.
Röschenthaler, Chem. Commun. 1999, 1017; b) S. Deerenberg, M.
Schakel, A. H. J. F. de Keijzer, M. Kranenburg, M. Lutz, A. L. Spek,
K. Lammertsma, Chem. Commun. 2002, 348; c) E. P. A. Couzijn, M.
Schakel, F. J. J. de Kanter, A. W. Ehlers, M. Lutz, A. L. Spek, K.
Lammertsma, Angew. Chem. Int. Ed., 2004, 43, 3440; Angew. Chem.
2004, 116, 3522; d) E. P. A. Couzijn, A. W. Ehlers, M. Schakel, K.
Lammertsma, J. Am. Chem. Soc. 2006, 128, 13634.
[23] C. Strohmann, M. Bindl, V. C. Fraaß, J. Hörnig, Angew. Chem. Int. Ed.
2004, 43, 1011; Angew. Chem. 2004, 116, 1029.
[24] J. Hörnig, PhD thesis, Universität Würzburg, Würzburg (Germany),
2004.
[25] a) A. R. Bassindale, S. J. Glynn, P. G. Taylor in The Chemistry of
Organic Silicon Compounds, Vol. 2 (Eds.: Z. Rappoport, Y. Apeloig),
John Wiley & Sons, Ltd., Chichester, 1998, pp. 495-511; b) A. P.
Bento, F. M. Bickelhaupt, Chem. Asian J. 2008, 3, 1783.
[17] For a thermodynamic investigation of substitution reactions with
pentacoordinate aminomethoxysilanes involved, see also: J. O. Bauer,
C. Strohmann, Chem. Commun. 2012, 48, 7212.
4
This article is protected by copyright. All rights reserved.

10.1002/anie.201702410
Angewandte Chemie International Edition
Chemistry of Si-C Bonds
S. G. Koller, J. O. Bauer, C.
Strohmann* __________ Page
– Page
Selective Si-C(sp3) Bond
Cleavage in
(Aminomethyl)silanes by
Carbanionic Nucleophiles and
its Stereochemical Course
(Aminomethyl)silanes show versatile reactivity. In addition to the well-established α-
deprotonation, a new reaction pathway was explored for this class of compounds enabling
synthetic applications also for all-C-substituted silanes. Through simple variation of the
reaction conditions, carbanionic nucleophiles are able to substitute activated alkyl groups
attached to silicon. In this way, also enantiomerically pure organosilanes are accessible,
which are otherwise only difficult to prepare.
5
This article is protected by copyright. All rights reserved.