Chemoselective silylative reduction of conjugated nitriles under metal-free catalytic conditions: β-silyl amines and enamines

Article abstract of DOI:10.1002/anie.201502366

Abstract The B(C₆F₅)₃-catalyzed silylative reduction of conjugated nitriles has been developed to afford synthetically valuable β-silyl amines. The reaction is chemoselective and proceeds under mild conditions. Mechanistic elucidation indicates that it proceeds by rapid double hydrosilylation of the conjugated nitrile to an enamine intermediate which is subsequently reduced to the β-silyl amine, thus forming a new C(sp³)-Si bond. Based on this mechanistic understanding, a preparative route to enamines was also established using bulky silanes. Triple whammy: The B(C₆F₅)₃-catalyzed silylative reduction of conjugated nitriles has been developed to afford synthetically valuable β-silyl amines. Based on the mechanistic understanding, a preparative route to enamines was also established using bulky silanes. The reaction is chemoselective, has a broad scope, and proceeds under mild reaction conditions. The mechanism of the triple hydrosilylation is discussed.

Full text of DOI:10.1002/anie.201502366

Angewandte
Chemie
International Edition: DOI: 10.1002/anie.201502366
German Edition: DOI: 10.1002/ange.201502366
Hydrosilylation
Chemoselective Silylative Reduction of Conjugated Nitriles under
Metal-Free Catalytic Conditions: b-Silyl Amines and Enamines**
Narasimhulu Gandhamsetty, Juhyeon Park, Jinseong Jeong, Sung-Woo Park, Sehoon Park, and
Sukbok Chang*
Dedicated to Professor Mahn-Joo Kim on the occasion of his 60th birthday
Abstract: The B(C6F5)3-catalyzed silylative reduction of con-
jugated nitriles has been developed to afford synthetically
valuable b-silyl amines. The reaction is chemoselective and
proceeds under mild conditions. Mechanistic elucidation
indicates that it proceeds by rapid double hydrosilylation of
the conjugated nitrile to an enamine intermediate which is
adducts.[10] While conjugated nitriles are known to be partially
reduced to a-silylated nitriles under metal-catalyzed condi-
tions,[11] a chemoselective reduction to silylated amines is
unprecedented to the best of our knowledge.
Recently, we developed a silylative reduction of quino-
3
À
lines to form a new C(sp ) Si bond, b to the nitrogen atom of
subsequently reduced to the b-silyl amine, thus forming a new
tetrahydroquinoline products, with excellent chemo-, regio-,
and stereoselectivity.[12] In this context, we anticipated that
conjugated nitriles would undergo silylative reduction to
afford b-silyl amines, a synthetic equivalent to b-amino
alcohols (Scheme 1). Described herein is the successful
3
À
C(sp ) Si bond. Based on this mechanistic understanding,
a preparative route to enamines was also established using
bulky silanes.
F
unctional-group-containing organosilanes are known to be
highly useful as synthetic intermediates in organic synthe-
sis[1,2] and as monomeric units for crosslinking in industrial
polymer chemistry.[3] One convenient approach to those
compounds is to utilize hydrosilylation of olefins containing
functional groups,[4] thus allowing selective installation of
C(sp ) Si bonds in the molecular backbone.[3a,5] Since
3
À
carbon–silicon bonds are readily converted into hydroxy
groups under oxidative conditions, we anticipated that 1,n-
amino alcohols (n = 2 or 3), which are key components in
synthetic and medicinal chemistry,[6] could be accessed by
selective hydrosilylation of (conjugated) nitriles followed by
oxidation. Several preparative methods of hydrogenation or
hydrosilylation are available for the reduction of nitriles to
primary amines.[7] In contrast, tris(pentafluorophenyl)borane
[B(C6F5)3] and its derivatives have been used in the reduction
of olefins, imines, ethers, carbonyls, and N-heteroarenes with
either hydrosilanes[5a,c,8] or hydrogen.[9] In spite of the broad
substrate scope of the boron catalysis, reduction of (con-
jugated) nitriles still remains little explored. Along these lines,
Stephan and co-workers reported an elegant example show-
ing that frustrated Lewis pairs (FLP) generated in situ from
phosphine and borane can hydrogenate nitrile–boron
Scheme 1. Silylative reduction of conjugated nitriles.
realization of this transformation and mechanistic elucidation
to reveal a stepwise pathway which offers an additional
opportunity to establish a facile route to isolable enamine
compounds.
Table 1: Optimization of reduction of conjugated nitriles.[a]
Entry
Changes from the “standard conditions”
Yield [%]
1
none
86
85
82
81
34
66
71
93
73
<1
<1
29
2
3
CHCl3 solvent in Schlenk flask
CHCl3 in reaction vial
[*] Dr. N. Gandhamsetty, J. Park, J. Jeong, Dr. S.-W. Park, Dr. S. Park,
Prof. Dr. S. Chang
4
5
3 mol% of B(C6F5)3 instead of 5 mol% (36h)
6h instead of 24h
Center for Catalytic Hydrocarbon Functionalizations
Institute for Basic Science (IBS), Daejeon 305-701 (Korea)
and
Department of Chemistry, Korea Advanced Institute of Science and
Technology (KAIST), Daejeon 305-701 (Korea)
E-mail: sbchang@kaist.ac.kr
6
CD2Cl2 instead of CDCl3
7
8
9
10
11
12
[D8]Toluene instead of CDCl3
Et2SiH2 (4 equiv) instead of Ph2SiH2 (30min)
PhMeSiH2 (4 equiv) instead of Ph2SiH2 (2 h)
PhMe2SiH (4 equiv) instead of Ph2SiH2
Et3SiH (4 equiv) instead of Ph2SiH2
PhSiH3 instead of Ph2SiH2
[**] This work was supported financially by the Institute for Basic
Science (IBS-R010-D1).
[a] Reactions were carried out on a 0.5 mmol scale and yields were
determined by 1H NMR spectroscopy (1,1,2,2-tetrachloroethane used as
the internal standard).
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/anie.201502366.
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

.
Angewandte
Communications
We commenced our optimization study from a silylative
reduction of conjugated nitriles using cinnamonitrile as
a model substrate (Table 1; also see the Supporting Informa-
tion for details). While the reaction was found to be facile
with 4 equivalents of diphenylsilane (Ph2SiH2) in the presence
of the B(C6F5)3 catalyst (5 mol%) in CDCl3 at room temper-
ature to afford the b-silyl-N,N-disilylamine, as determined by
1H NMR analysis (entry 1), additional reaction parameters
were examined under various reaction conditions. A similar
range of efficiency was observed for reactions run either in
a Schlenk flask or reaction vial (entries 2 and 3). While the
product yield was still satisfactory with a lower loading of the
catalyst (entry 4), the efficiency turned out to be more
sensitive to the reaction time (entry 5), and solvents other
than chloroform were less effective (entries 6 and 7). Signifi-
cantly, the silylative reduction of cinnamonitrile was more
efficient when diethylsilane (Et2SiH2) was employed to give
the b-diethylsilyl-N,N-diethylsilylamine product, even under
shorter reaction times (93%, 30 min; entry 8), whereas the
use of phenylmethylsilane resulted in moderate product yield
(entry 9). Since these b-diethylsilyl and b-phenylmethylsilyl
products were found to be less stable than the corresponding
b-diphenylsilyl analogues, the silylative reduction of conju-
gated nitriles was carried out with diphenylsilane in most
cases. In addition, the reaction was less effective when
different types of silanes (e.g. mono- or trihydrosilanes)
were employed as the reducing reagent (entries 10–12).
With the optimal reaction conditions in hand, we sub-
sequently investigated the scope with respect to the a,b-
unsaturated nitriles (Table 2). As described above, cinnamo-
nitrile reacted efficiently with either diphenylsilane or
diethylsilane to afford the corresponding products in good
yields (1 and 2, respectively). While the former product was
isolated as a hydrochloride salt, the latter one was converted
in situ into its N-(p-toluenesulfonyl) derivative. It needs to be
mentioned that the moderate yield of 2 (45%) was mainly the
result of the low efficiency of the conversion of the crude
reaction mixture into its sulfonamide. The structure of 2 was
confirmed by an X-ray crystallographic analysis.
Cinnamonitrile compounds having substituents on the
phenyl moiety were converted into the corresponding prod-
ucts in high yields irrespective of their electronic properties.
For instance, substrates bearing ethyl, tert-butyl, and phenyl
substituents at the para position underwent the silylative
reduction in satisfactory yields (3–5; Table 2). In contrast, the
position of the substituents influenced the reaction efficiency
to some extent, as seen in the formation of the products 6–8.
In the case of sterically demanding substrates, such as ortho-
methylcinnamonitrile, the reaction with diphenylsilane
(Ph2SiH2) was carried out at 658C to obtain a reasonable
yield of 7. Interestingly, the use of diethylsilane instead of
diphenylsilane allowed the reaction of ortho-phenylcinnamo-
nitrile to proceed at room temperature, thus giving an
analogous product (8) in good yield. The present reaction
conditions were compatible with a range of functional groups
such as phenoxy and halides (9–13).[8c,13] Cinnamonitriles
having multiple substituents also reacted smoothly to give the
desired products in moderate to good yields (14–16). Again,
the moderate yields of the isolated products were mainly
a result of the subsequent conversion of the initially generated
b-silyl-N,N-disilylamines into the corresponding N-sulfona-
mides. In contrast, reactions of disubstituted substrates such
as b-methylcinnamonitrile were observed to be negligible
under the optimized reaction conditions.
Table 2: Substrate scope in the silylative reduction of conjugated nitriles.[a]
[a] Substrate (0.5 mmol), silane (4 equiv), and B(C6F5)3 (5 mol%). Yield of isolated product given and value within parentheses is the yield of the
initially formed b-silyl-N,N-disilylamine using 1,1,2,2-tetrachloroethane as an internal standard. [b] B(C6F5)3 (7 mol%).
2
www.angewandte.org
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
These are not the final page numbers!

Angewandte
Chemie
The scope of more challenging substrates, including
conjugated aliphatic nitriles, was next examined. We were
pleased to observe that acrylonitrile was efficiently reacted
with diphenylsilane at 258C to give 2-silyl-1-propylamine,
which was isolated as the HCl salt in good yield (17; Table 2).
Likewise, additional derivatives bearing longer aliphatic
chains also underwent the desired reaction with high effi-
ciency (18–19). Phenyl-substituted conjugated aliphatic
nitriles displayed high reactivity at room temperature, thus
leading to the corresponding sulfonamide products in excel-
lent yields (20–21).
without detection at the b-position (Scheme 3a). This result
=
suggests that a hydrosilylation on the conjugated C C bond
does not occur under the standard reaction conditions.
Instead, it is more reasonable to assume that 1,4-hydro-
silylation across conjugated nitriles is operative in the initial
stage. When the in situ generated enamine 23 was treated
with Et2SiH2 (1 equiv), the (b-diethylsilyl)amino species 24
was obtained quantitatively, and thus indicated that the new
3
À
C(sp ) Si bond forms at a late stage via an enamine
intermediate (Scheme 3b). Additionally, it suggests that the
new C(sp ) Si bond formation does not occur through an
intramolecular migration of the N-silyl group of 23 to the b-
3
À
The present silylative reduction procedure was convenient
to carry out on a gram scale (Scheme 2). When 1-cyano-1-
butene (10 mmol) was reacted with diphenylsilane under the
position.
1
The reaction progress was monitored by H NMR spec-
troscopy and time-resolved IR (Figure 1). When cinnamoni-
Scheme 2. Synthetic applications.
optimal reaction conditions, 2-silyl-1-pentylamine was
obtained as the HCl salt in 81% yield (19; 2.47 g) using
3 mol% of the B(C6F5)3 catalyst at 258C in chloroform. The
reaction was also facile under neat conditions (85%, 2.59 g).
The obtained amine salt was converted into its sulfonamide
derivative, which was subsequently oxidized under the Tamao
conditions[14] to deliver the b-hydroxy N-sulfonamide 22 in
good yield (90% in two steps). It should be mentioned that
the two post reactions could be performed in one pot without
isolating a tosylated intermediate.
This silylative reduction of conjugated nitriles to b-
silylamines obviously involves three hydrosilylations across
the olefinic double and cyano triple bond. A series of
mechanistic experiments was performed to shed light on the
mechanistic considerations (Scheme 3). When 2 equivalents
of diphenylsilane were reacted with cinnamonitrile, a partially
reduced compound (N,N-disilylenamine; 23) was obtained in
high yield, and characterized by NMR spectrosocopy (1H and
29Si) and mass analyses. Moreover, with the employment of
Ph2SiD2, deuterium was observed to be incorporated
(> 95%) at the a- and g-position of enamine [D4]-23, but
Figure 1. Monitoring of the reaction progress by a) 1H NMR spectros-
copy and b) time-resolved IR spectroscopy.
trile (I) was treated with diethylsilane (3.3 equiv) in the
presence of the B(C6F5)3 catalyst, the triple hydrosilylation
was found to proceed cleanly through an enamine intermedi-
ate (II), thus eventually leading to the b-silyl-N,N-disilyl-
amine product III. I was consumed completely within
10 minutes at 258C with concomitant accumulation of II.
Interestingly, however, conversion of II into the final product
III was not observed during this period of intermediate
formation. Only after a full consumption of cinnamonitrile
did the final hydrosilylation of II start to proceed (Figure 1a),
thus suggesting that the formation of an enamine is fast while
the hydrosilylation on this intermediate is much slower. A
similar observation was also made by time-resolved IR
À1
ꢀ
(Figure 1b). A new cyano (C N) peak at 2316 cm was
monitored during the reaction progress and it was distinct
Scheme 3. Sequential reduction with silanes.
from the free cinnamonitrile peak (2226 cmÀ1) in the absence
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

.
Angewandte
Communications
of B(C6F5)3. In accordance with the literature,[15] the peak of
2316 cmÀ1 was assigned to a nitrile–borane complex which is
believed to be a resting species.
(2.3 equiv) in the presence of B(C6F5)3 catalyst (5 mol%), the
N,N-disilylenamine 25 was isolated in 92% yield. Likewise,
para-substituted derivatives of cinnamonitrile underwent
partial reduction to afford the corresponding enamines,
albeit in moderate yields (26 and 27). Substrates bearing
substituents at either the ortho or meta position also under-
went the reaction with high efficiency (28–33). Moreover, this
approach was readily extended to conjugated aliphatic nitriles
having a b-substituent to afford the corresponding 3-substi-
tuted enamine (34). However, reaction of substrates having
ketone or ester groups did not afford the desired products
under the present reaction conditions.
In summary, the B(C6F5)3-catalyzed chemoselective and
mild silylative reduction of conjugated nitriles has been
developed to afford synthetically valuable b-silyl amines.
Mechanistic details were elucidated to reveal that it proceeds
by rapid double hydrosilylation of conjugated nitriles to an
Based on the above observations and literature precedent
indicating a stepwise process of multiple hydrosilylation of
enones,[8e,10a,12,13c,16] we propose a mechanistic pathway of the
borane-catalyzed silylative reduction of conjugated nitriles
(Scheme 4).[12,17] The first hydrosilylation of the conjugated
nitrile is assumed to proceed through either a [1,2]- or [1,4]-
addition manner, thus leading to the vinylimine C[18] and N-
silyl ketene imine D,[19] respectively, with the former being
energetically more favorable according to DFT calculations
(see the Supporting Information for details). It is noteworthy
that the second hydrosilylation affords an isolable N,N-
disilylenamine intermediate E irrespective of whether it starts
from C or D. The final silylative reduction of E is believed to
be slowest in the proposed catalytic cycle, thus delivering the
desired product with the concomitant regeneration of B-
(C6F5)3 catalyst.
The above mechanistic understanding led us to envision
that synthetically valuable enamine compounds[20] can be
obtained presumably by tuning the stoichiometry and steric
bulkiness of silanes. Indeed, we were delighted to find that the
use of bulky triphenylsilane as a reducing reagent resulted in
the chemoselective reduction to stop at the enamine stage
(Scheme 5). When cinnamonitrile was treated with Ph3SiH
enamine intermediate, which is subsequently reduced to a b-
3
À
silyl amine, thus forming a new C(sp ) Si bond. Based on this
mechanistic understanding, a preparative route to enamines
was also established using bulky silanes.
Keywords: boron · conjugation · hydrosilylation · reduction ·
synthetic methods
[1] a) E. Colvin, Silicon in Organic Synthesis II, Butterworth,
Oxford, 1981, p. 325; b) E. Langkopf, D. Schinzer, Chem. Rev.
1995, 95, 1375; c) I. Fleming, A. Barbero, D. Walter, Chem. Rev.
1997, 97, 2063; d) Y. Nagai, Org. Prep. Proced. Int. 1980, 12, 13;
e) C. Cheng, J. F. Hartwig, Chem. Rev. 2015, DOI: 10.1021/
cr5006414.
[2] a) J. Wang, C. Ma, Y. Wu, R. A. Lamb, L. H. Pinto, W. F.
DeGrado, J. Am. Chem. Soc. 2011, 133, 13844; b) A. K. Franz,
P. D. Dreyfuss, S. L. Schreiber, J. Am. Chem. Soc. 2007, 129,
1020; c) A. K. Franz, S. O. Wilson, J. Med. Chem. 2013, 56, 388;
d) S. Gately, R. West, Drug Dev. Res. 2007, 68, 156.
[3] a) A. M. Tondreau, C. C. H. Atienza, K. J. Weller, S. A. Nye,
K. M. Lewis, J. G. P. Delis, P. J. Chirik, Science 2012, 335, 567;
b) I. Ojima, The Chemistry of Organic Silicon Compounds (Eds.:
S. Patai, Z. Rappoport), Wiley Interscience, New York, 1989,
p. 1479.
Scheme 4. Mechanistic proposal for the borane-catalyzed silylative
reduction of conjugated nitriles.
[4] a) B. Marciniec, J. Gulinski, W. Urbaniak, Z. W. Kornetka,
Comprehensive Handbook on Hydrosilylation (Ed.: B. Marci-
niec), Pergamon, Oxford, 2002, p. 3; b) B. Marciniec, Coord.
Chem. Rev. 2005, 249, 2374.
[5] a) M. Rubin, T. Schwier, V. Gevorgyan, J. Org. Chem. 2002, 67,
1936; b) E. M. Simmons, J. F. Hartwig, Nature 2012, 483, 70;
c) A. Simonneau, M. Oestreich, Angew. Chem. Int. Ed. 2013, 52,
11905; Angew. Chem. 2013, 125, 12121.
[6] a) S. C. Bergmeier, Tetrahedron 2000, 56, 2561; b) O. K. Karja-
lainen, A. M. P. Koskinen, Org. Biomol. Chem. 2012, 10, 4311;
c) D. J. Ager, I. Prakash, D. R. Schaad, Chem. Rev. 1996, 96, 835;
d) E. J. Corey, C. J. Helal, Angew. Chem. Int. Ed. 1998, 37, 1986;
Angew. Chem. 1998, 110, 2092.
[7] a) C. Bornschein, S. Werkmeister, B. Wendt, H. Jiao, E.
Alberico, W. Baumann, H. Junge, K. Junge, M. Beller, Nat.
Commun. 2014, 5, 4111; b) M. Perez, Z.-W. Qu, C. B. Caputo, V.
Podgorny, L. J. Hounjet, A. Hansen, R. Dobrovetsky, S.
Grimme, D. W. Stephan, Chem. Eur. J. 2015, DOI: 10.1002/
chem.201406356, and references therein.
Scheme 5. Partial reduction of conjugated nitriles to enamines. Reac-
tion conditions: substrate (0.5 mmol) and silane (2.3 equiv). Yield of
the isolated product is shown, with that of the product in the crude
reaction mixture given within parentheses (determined by 1H NMR
spectroscopy using 1,1,2,2-tetrachloroethane as an internal standard).
[a] B(C6F5)3 (10 mol%).
4
www.angewandte.org
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
These are not the final page numbers!

Angewandte
Chemie
[8] a) K. Ishihara, H. Yamamoto, Eur. J. Org. Chem. 1999, 527;
b) J. M. Blackwell, E. R. Sonmor, T. Scoccitti, W. E. Piers, Org.
Lett. 2000, 2, 3921; c) V. Gevorgyan, J.-X. Liu, M. Rubin, S.
Benson, Y. Yamamoto, Tetrahedron Lett. 1999, 40, 8919; d) M.
Tan, Y. Zhang, Tetrahedron Lett. 2009, 50, 4912; e) J. M.
Blackwell, D. J. Morrison, W. E. Piers, Tetrahedron 2002, 58,
8247; f) R. C. Chadwick, V. Kardelis, P. Lim, A. Adronov, J. Org.
Chem. 2014, 79, 7728; g) M. Oestreich, J. Hermeke, J. Mohr,
Chem. Soc. Rev. 2015, DOI: 10.1039/c4s00451e.
[9] a) P. Spies, S. Schwendemann, S. Lange, G. Kehr, R. Frçhlich, G.
Erker, Angew. Chem. Int. Ed. 2008, 47, 7543; Angew. Chem.
2008, 120, 7654; b) Y. Liu, H. Du, J. Am. Chem. Soc. 2013, 135,
12968; c) T. Mahdi, J. N. Castillo, D. W. Stephan, Organometal-
lics 2013, 32, 1971; d) T. A. Rokob, A. Hamza, A. Stirling, I.
Papai, J. Am. Chem. Soc. 2009, 131, 2029.
[10] a) P. A. Chase, G. C. Welch, T. Jurca, D. W. Stephan, Angew.
Chem. Int. Ed. 2007, 46, 8050; Angew. Chem. 2007, 119, 8196;
b) P. A. Chase, T. Jurca, D. W. Stephan, Chem. Commun. 2008,
1701.
[11] a) N. Komine, M. Abe, R. Suda, M. Hirano, Organometallics
2015, 34, 432; b) A. M. Caporusso, N. Panziera, P. Pertici, E.
Pitzalis, P. Salvadori, G. Vitulli, G. Martra, J. Mol. Catal. A 1999,
150, 275; c) H. Dong, Y. Jiang, H. Berke, J. Organomet. Chem.
2014, 750, 17; d) I. Ojima, M. Kumagai, J. Organomet. Chem.
1976, 111, 43; e) R. K. Dieter, K. Lu, S. E. Velu, J. Org. Chem.
2000, 65, 8715; f) T. Murai, T. Sakane, S. Kato, J. Org. Chem.
1990, 55, 449.
[14] a) K. Tamao, N. Ishida, T. Tanaka, M. Kumada, Organometallics
1983, 2, 1694; b) R. Shchepin, C. Xu, P. Dussault, Org. Lett. 2010,
12, 4772.
[15] H. Jacobsen, H. Berke, S. Doring, G. Kehr, G. Erker, R. Frohlich,
O. Meyer, Organometallics 1999, 18, 1724.
[16] a) H. Wang, R. Frçhlich, G. Kehr, G. Erker, Chem. Commun.
2008, 5966; b) D. J. Parks, W. E. Piers, J. Am. Chem. Soc. 1996,
118, 9440; c) A. Y. Houghton, J. Hurmalainen, A. Mansikka-
mꢀki, W. E. Piers, H. M. Tuononen, Nat. Chem. 2014, 6, 983;
d) D. J. Parks, J. M. Blackwell, W. E. Piers, J. Org. Chem. 2000,
65, 3090; e) S. Rendler, M. Oestreich, Angew. Chem. Int. Ed.
2008, 47, 5997; Angew. Chem. 2008, 120, 6086.
[17] a) L. J. Hounjet, D. W. Stephan, Org. Process Res. Dev. 2014, 18,
385; b) M. Mewald, M. Oestreich, Chem. Eur. J. 2012, 18, 14079;
c) G. I. Nikonov, S. F. Vyboishchikov, O. G. Shirobokov, J. Am.
Chem. Soc. 2012, 134, 5488; d) K. Sakata, H. Fujimoto, J. Org.
Chem. 2013, 78, 12505; e) J. M. Blackwell, K. L. Foster, V. H.
Beck, W. E. Piers, J. Org. Chem. 1999, 64, 4887.
[18] a) D. V. Gutsulyak, A. Van der Est, G. I. Nikonov, Angew.
Chem. Int. Ed. 2011, 50, 1384; Angew. Chem. 2011, 123, 1420;
b) D. V. Gutsulyak, G. I. Nikonov, Angew. Chem. Int. Ed. 2010,
49, 7553; Angew. Chem. 2010, 122, 7715.
[19] S. E. Denmark, T. W. Wilson, Angew. Chem. Int. Ed. 2012, 51,
9980; Angew. Chem. 2012, 124, 10120.
[20] a) R. J. P. Corriu, J. J. E. Moreau, M. Pataud-Sat, J. Org. Chem.
1990, 55, 2878; b) J. Hermeke, H. F. T. Klare, M. Oestreich,
Chem. Eur. J. 2014, 20, 9250; c) J. Hermeke, M. Mewald, M.
Oestreich, J. Am. Chem. Soc. 2013, 135, 17537; d) S. J. Geier,
P. A. Chase, D. W. Stephan, Chem. Commun. 2010, 46, 4884.
[12] N. Gandhamsetty, J. Seewon, P. Sung-Woo, P. Sehoon, S. Chang,
J. Am. Chem. Soc. 2014, 136, 16780.
[13] a) V. Gevorgyan, M. Rubin, S. Benson, J.-X. Liu, Y. Yamamoto,
J. Org. Chem. 2000, 65, 6179; b) T. Robert, M. Oestreich, Angew.
Chem. Int. Ed. 2013, 52, 5216; Angew. Chem. 2013, 125, 5324;
c) M. Yasuda, Y. Onishi, M. Ueba, T. Miyai, A. Baba, J. Org.
Chem. 2001, 66, 7741.
Received: March 13, 2015
Revised: March 24, 2015
Published online: && &&, &&&&
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

.
Angewandte
Communications
Communications
Hydrosilylation
N. Gandhamsetty, J. Park, J. Jeong,
S.-W. Park, S. Park,
S. Chang*
&&&& — &&&&
Triple whammy: The B(C6F5)3-catalyzed
silylative reduction of conjugated nitriles
has been developed to afford synthetically
valuable b-silyl amines. Based on the
mechanistic understanding, a preparative
route to enamines was also established
using bulky silanes. The reaction is
chemoselective, has a broad scope, and
proceeds under mild reaction conditions.
The mechanism of the triple hydrosilyla-
tion is discussed.
Chemoselective Silylative Reduction of
Conjugated Nitriles under Metal-Free
Catalytic Conditions: b-Silyl Amines and
Enamines
6
www.angewandte.org
ꢀ 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2015, 54, 1 – 6
These are not the final page numbers!