Highly Selective Synthesis of Hydrosiloxanes by Au-Catalyzed Dehydrogenative Cross-Coupling Reaction of Silanols with Hydrosilanes

Article abstract of DOI:10.1021/acscatal.6b03560

We report a highly selective synthesis of siloxane building blocks containing SiH₂ or SiH functionalities. AuCl(PPh₃)/PPh₃ or AuCl(PPh₃)/PⁿBu₃ system catalyzed the reaction of trihydrosilanes with silanols giving SiH₂-containing siloxanes exclusively. On the other hand, a highly selective reaction of dihydrosilanes with silanols to afford SiH-containing siloxanes was achieved by simply changing the phosphine ligand to a bidentate one, xantphos. Usefulness of SiH₂-containing siloxanes was demonstrated by the synthesis of a trisiloxane, Et₃SiOSi(Ph)(H)OSi^tBuMe₂, and a pentasiloxane, Ph₂Si(OSiHPhOSiEt₃)₂, bearing SiH functionalities.

Full text of DOI:10.1021/acscatal.6b03560

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Letter
Highly Selective Synthesis of Hydrosiloxanes by Au-Catalyzed
Dehydrogenative Cross-Coupling Reaction of Silanols with Hydrosilanes
Yasushi Satoh, Masayasu Igarashi, Kazuhiko Sato, and Shigeru Shimada
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.6b03560 • Publication Date (Web): 27 Jan 2017
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Page 1 of 13
ACS Catalysis
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Highly Selective Synthesis of Hydrosiloxanes by Au-Catalyzed De-
hydrogenative Cross-Coupling Reaction of Silanols with Hy-
drosilanes
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Yasushi Satoh, Masayasu Igarashi, Kazuhiko Sato, and Shigeru Shimada*
Interdisciplinary Research Center for Catalytic Chemistry, National Institute of Advanced Industrial Science and
Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
ABSTRACT: We report a highly selective synthesis of siloxane building blocks containing SiH2 or SiH functionalities.
AuCl(PPh3)/PPh3 or AuCl(PPh3)/PnBu3 system catalyzed the reaction of trihydrosilanes with silanols giving SiH2-
containing siloxanes exclusively. On the other hand, a highly selective reaction of dihydrosilanes with silanols to afford
SiH-containing siloxanes was achieved by simply changing the phosphine ligand to a bidentate one, xantphos. Usefulness
of SiH2-containing siloxanes was demonstrated by the synthesis of a trisiloxane, Et3SiOSi(Ph)(H)OSitBuMe2, and a penta-
siloxane, Ph2Si(OSiHPhOSiEt3)2, bearing SiH functionalities.
KEYWORDS : Hydrosiloxanes, Hydrosilanes, Silanols, Au-Catalyst, Cross-Coupling
Siloxane materials (silicones) have a number of excellent
properties including high thermal stability, light stability
and transparency, high gas permeability, electrical insula-
tion property, and constancy of properties over a wide
temperature range.1,2 Therefore, oligo- and polysiloxanes
are used as irreplaceable materials in a wide range of
fields. For the further development of high performance
siloxane materials, precise structural control of oligo- and
polysiloxanes is indispensable. However, synthetic meth-
ods for siloxane compounds are surprisingly unexplored,
and it is difficult to synthesize siloxane materials with
well-defined structures by the conventional methods,
hydrolytic condensation reaction of chlorosilanes or
alkoxysilanes (sol-gel process) and base- or acid-catalyzed
ring-opening polymerization of cyclic oligosiloxanes.3
Although some new synthetic methods for siloxane com-
pounds have recently been developed, accessible struc-
tures are still very limited.4-12
lowering the melting points of triarylamines, and increas-
ing the solubility of carbon nanotubes.16 Among hy-
drosiloxanes, those containing SiH2 moiety (dihydrosilox-
anes) would be particularly useful for the construction of
linear and branched oligo- and polysiloxanes with well-
defined structures by the stepwise transformation of the
two Si-H bonds. Selective transformation of one of the
two Si-H bonds in dihydrosilanes has been well estab-
lished.14 However, examples of dihydrosiloxanes are very
limited because of the lack of simple and reliable synthet-
ic procedures. Known examples are mostly symmetric
siloxanes with two SiH2 groups, (RH2Si)2O, which can be
synthesized by the hydrolytic condensation of RH2SiX (X
= Cl or Br).17
The dehydogenative coupling reaction of silanols
(R13SiOH) with trihydrosilanes (R2SiH3) would be a suita-
ble reaction for the synthesis of dihydrosiloxanes
R13SiOSiH2R2. However, there is no report for the selective
synthesis of dihydrosiloxanes by this reaction. Michalska
reported Rh complex-catalyzed reaction of silanols with
hydrosilanes, in which the reaction of a trihydrosilane,
For the construction of siloxanes with a well-defined
structure, usage of siloxane building blocks with appro-
priate functional groups would be promising. Si-H bonds
are among the most useful functional groups in silicon
chemistry. A wide range of reactions has been developed
for the transformation of the Si-H bonds.13,14 Therefore,
siloxane compounds containing Si-H bonds (hydrosilox-
anes) are highly useful building blocks for the synthesis of
various siloxane compounds. Furthermore, hydrosilox-
anes are useful for the incorporation of siloxane moieties
in organic and inorganic compounds using the reactivity
of the Si-H bonds.15,16 Recent reports showed that the in-
corporation of siloxane moiety improved the materials
properties such as a hole mobility of thin film transistors,
n
PhSiH3, with silanols R3SiOH (R = Et or Pr) gave a mix-
ture of dihydrosiloxanes PhSiH2OSiR3, monohydrosilox-
anes PhSiH(OSiR3)2, and PhSi(OSiR3)3 even when the re-
action was done with PhSiH3/R3SiOH = 1/1.4a
In this paper, we report a highly selective synthesis of
dihydrosiloxanes by dehydrogenative cross-coupling reac-
tion of silanols with hydrosilanes catalyzed by Au-
phosphine complexes. Selective synthesis of monohy-
drosiloxanes was also achieved by simply changing the
phosphine ligand.
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Page 2 of 13
Table 1. Screening of Catalysts and Reaction Conditions for the Cross-Coupling Reaction of Silanols 1 with
Phenylsilane 2aa
1
2
3
4
5
6
7
8
Catalyst (mol%)
Ligand (mol%)
H
Si
H
Ph
Si
H
H
O
Ph
O
O
O
R3Si
R3Si
SiR3
R3Si-OH
H Si Ph
+
+
+
R3Si
SiR3
Solvent
rt, 13 h
H
1a: R = Et
2a
3aa: R = Et
3ba: R = Me
4aa: R = Et
4ba: R = Me
5a: R = Et
1b: R = Me
5b: R = Me
Yield (%)b
9
entry
1c
2d ,e
3d
1
Catalyst (mol%)
RhCl(PPh3)3 (2.5)
Pt(tBu)2 (2.5)
Ligand (mol%)
none
Solvent
THF
3
4
5
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
1a
1a
1a
6
51
63
73
0
0
none
THF
11
7
0
[RuCl2(p-cymene)]2 (2.5)
none
THF
0
4f
1a BiCl3 (2.5)
none
THF
14
15
36
0
5
1a B(C6F5)3 (2.5)
none
THF
0
82
0
6
1a AuCl(PPh3) (2.5)
1a AuCl(PPh3) (2.5)
1a none
none
THF
0
7
PPh3 (2.5)
PPh3 (2.5)
PPh3 (2.5)
PnBu3 (2.5)
PnBu3 (7.5)
PnBu3 (7.5)
PnBu3 (7.5)
PnBu3 (7.5)
PnBu3 (7.5)
PnBu3 (0.5)
THF
97(84)
0
0
0
8 d
9g,
10 g,
11 g
12 g
13 g
14 g,
15 g
16 h
THF
0
0
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1b AuCl(PPh3) (2.5)
1a AuCl(PPh3) (0.025)
THF
83
0
17
15
3
THF
85
0
THF
91(76)
92
0
Toluene
CH2Cl2
DMAc
DMSO
THF
0
5
69
0
8
71
6
22
48
0
42
0
99
0
aReaction conditions: 1 (0.5 mmol), 2a (0.5 mmol), and catalyst (2.5 mol% based on 1) in THF (1 mL) at 25 ºC for 13 h under Ar.
bYields are based on 1 and were determined by integral values of 29Si NMR signals using PhSiMe3 as an internal standard. The
values in parentheses are isolated yields. Ph2SiH2 (14%), PhSi(OSiEt3)3 (4%), and Et3SiCl (2%) were also obtained. dReaction
c
time, 4 h. Ph2SiH2 (9%) was also obtained. fEt3SiCl (10%) was also obtained. 2a (1 mmol) was used. Reaction conditions: 1a (2
e
g
h
mmol) and 2a (2 mmol), AuCl(PPh3) (0.025 mol%), PnBu3 (0.5 mol%) in THF at 25 ºC for 48 h under Ar.
A model reaction between triethylsilanol (1a) and
phenylsilane (2a) was examined with 1a/2a = 1/1 ratio us-
ing various catalysts in THF at room temperature. Repre-
sentative results are shown in Table 1. As reported,
RhCl(PPh3)34a catalyzed the reaction unselectively giving
tion and alcohol silylation reaction with hydrosilanes.19,20
This chemistry was also perused by other researchers.21
Fortunately we found that AuCl(PPh3) selectively gave 3aa
in 36% yield without any by-product (Table 1, entry 6).
Significant improvement of the yield was attained by the
addition of PPh3 (1 equiv to AuCl(PPh3)) resulting in the
exclusive formation of 3aa in 97% yield (Table 1, entry
7).22 PPh3 alone without AuCl(PPh3) did not catalyze the
reaction at all (Table 1, entry 8). On the other hand, the
reaction of 2a with Me3SiOH (1b), which is less sterically
bulky and easier to self-condense than 1a, afforded not
only the desired product 3ba but also 17% of hexamethyl-
disiloxane (5b) even with 2 equiv of 2a (Table 1, entry 9).
Therefore, further optimization of the catalyst was per-
formed; the addition of trialkylphosphines such as PnBu3
instead of PPh3 slightly improved the selectivity for 3ba
over 5b (Table1, entry 10), and increasing the amount of
PnBu3 to 3 equiv (to Au) further improved the yield of 3ba
to 91% with only 3% of 5b (Table 1, entry 11). Reaction sol-
vents significantly affected the selectivity between 3ba
and 5b; THF and toluene gave almost similar results (Ta-
ble 1, entries 11, 12), while other solvents such as CH2Cl2,
PhSiH2OSiEt3
(3aa),
PhSiH(OSiEt3)2
(4aa)
and
PhSi(OSiEt3)3 as well as a redistribution product of 2a,
Ph2SiH2, and Et3SiCl (Table 1, entry 1). Other late transi-
tion metal complexes Pt(tBu)2 and [RuCl2(p-cymene)]2,
the latter is active for the dehydrogenative silylation of
alcohols and carboxylic acids with hydrosilanes,18 similar-
ly catalyzed the reaction to give 4aa as a major product
together with 3aa as a minor product (Table 1, entries 2-
3). In the case of Pt(tBu)2, a small amount of Ph2SiH2 was
also produced. BiCl3 also catalyzed this reaction to give
3aa in a low yield together with Et3SiCl as a side product
(Table 1, entry 4). B(C6F5)3, which is known to catalyze the
dehydrogenative coupling of silanols with hydrosilanes,6
mainly catalyzed the self-condensation of 1a to give 5a in
82% yield (Table 1, entry 5).
Then we examined Au complexes; Ito and co-workers
first reported the Au/phosphine catalysis for hydrosilyla-
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ACS Catalysis
phenylenebis(dimethylsilanol) (1g) and diphenylsilanedi-
N,N-dimethylacetamide (DMAc), and dimethylsulfoxide
1
2
3
4
5
6
7
8
(DMSO) considerably decreased the yield of 3ba with
increased amounts of 5a (Table 1, entries 13-15). PnBu3 is
also effective for the reaction of 1a with 2a; with 20 equiv
(to Au) of PnBu3, the catalyst loading could be reduced to
0.025 mol% giving 3aa almost quantitatively after 48 h,
and the TON reached ca. 4000 (Table 1, entry 16). The
increase of PnBu3/Au ratio probably prevents the catalyst
decomposition and metal aggregation.19,21c,22
ol (1h) were cleanly silylated respectively with cyclopen-
tylsilane (2c) and 2b giving 3gc and 3hb in high yields.
Furthermore, all three silanol groups in phenylsilanetriol
(1i) as well as in 1,3,5,7,9,11,14- heptaisobutyltricy-
clo[7.3.3.15,11]heptasiloxane-endo-3,7,14-triol (1j) were
successfully reacted with 2b and 2a, respectively, to give
the desired silylated products 3ib and 3ja in excellent
isolated yields. It is noteworthy that silanol 1k having (N-
tert-butoxycarbonylpyrrolyl) group was also participated
in this reaction, and the corresponding dihydrosiloxane
3ka was obtained in 75% isolated yield as a sole product.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Table 2. Substrate Scope of Au-Catalyzed Cross-
Coupling Reaction of Silanols with Trihydrosilanesa
We further investigated the potential of Au catalysts for
the selective transformation of dihydrosilanes to mono-
hydrosiloxanes. A model reaction of 1a with diphen-
ylsilane (6a) giving monohydrosiloxane 7aa was examined
using various phosphine ligands in the presence of
AuCl(PPh3). Representative results are summarized in
Table 3. As expected from the above results, in which fur-
ther reaction of dihydrosiloxanes 3 with silanols did not
proceed, the AuCl(PPh3)/PR3 catalyst system did not cata-
lyze the reaction of 1a with 6a (Table 3, entries 1-2).
Changing the phosphine ligand from a monodentate PR3
Au Complex
PPh3 or PnBu3
[Si](OH)n
n RSiH3
[Si](OSiH2R)n
+
THF, rt – 70oC, 13 h
1
2
3
n = 1-3
H
O
H
Si
H
H
H
Ph
O
Ph
O
Ph
O
Ph
Si
Si
Si
Si
Et3
Me3
iPr3
tBuMe2
Si
Si
Si
H
H
H
3bab
3aa
84%
3ca
76%
3da
85%
76%
H
Si
H
H
Si
H
H
Si
H
to
a
bidentate
ligand
such
(dppe)
as
or
1,2-
1,1’-
nHex
O
Ph
O
Ph
O
t
Si
Si
Si
Ph3
Ph3
( BuO)3
bis(diphenylphosphino)ethane
bis(diphenylphosphino)ferrocene (dppf) was not effective
at all (Table 3, entries 3-4). Ito and Sawamura reported
3ea
89%
3fa
80%
3eb
76%
that AuCl(xantphos) complex (xantphos
=
4,5-
H
Si
H
Ph
H
nHex
O
O
nHex
bis(diphenylphosphino)-9,9-dimethylxanthene) efficient-
ly catalyzed alcohol silylation with monohy-
drosilanes.20a,20b
Me
Si
Me
Si
Si
Si
H
Si
O
O
H
H
Ph
H
Si
Me
Me
3hbc
3gcc
H
90%
80%
Table 3. Screening of Catalysts and Reaction Condi-
tions for the Cross-Coupling Reaction of 1a with Di-
phenylsilane 6aa
Si
H2Ph
O
R
Si
H2Ph
O
H
nHex
R
R
O Si
O
O
Si
H
Si
R
Si
H
Ph
O
Si
H
O
H
nHex
O
O
nHex
Si
Me2
O
N
O
OSiH2Ph
H
Si
Si
Ph
Si
O
O
O
R
Si
O
Boc
Si
Si
H
H
Si
R
R
3ibd
3jad
3kae,f
R =
95%
93%
75%
yield (%)b
aReaction conditions: 1 (3 mmol), 2 (3 mmol), AuCl(PPh3)
or AuCl (1 - 2.5 mol% based on 1), and PPh3 or PnBu3 (2.5 - 7.5
mol% based on 1) in THF at 25 - 70 ºC for 13 h under Ar. De-
tailed reaction conditions are shown in the supporting in-
formation. b2 (6 mmol) was used. c1 (2 mmol) and 2 (12
mmol) were used. d1 (2 mmol) and 2 (20 mmol) were used. e1
entry
Au-Complex
AuCl(PPh3)
AuCl(PPh3)
AuCl(PPh3)
AuCl(PPh3)
AuCl(PPh3)
AuCl(PCy3)
AuCl
ligand
none
7aa
0
5a
0
1
2
3
4
5
6
7
PPh3
3
0
dppe
0
0
(2 mmol) and
butoxycarbonyl.
2 = tert-
(4 mmol) were used. fBoc
dppf
trace
97(82)
68
0
xantphos
xantphos
xantphos
3
The scope of the Au-catalyzed dehydrogenative cross-
coupling reaction of silanols 1 with trihydrosilanes 2 is
shown in Table 2. Various monosilanols, including trial-
12
4
57
i
t
kylsilanols 1a, 1b, Pr3SiOH 1c, and BuMe2SiOH 1d, tri-
arylsilanol Ph3SiOH 1e, and trialkoxysilanol (tBuO)3SiOH
1f, successfully reacted with 2a to give dihydrosiloxanes
3aa-3fa in 76-89% isolated yields. Hexylsilane (2b) also
reacted with 1e to give dihydrosiloxane 3eb in 76% isolat-
aReaction conditions: 1a (0.5 mmol), 6a (0.5 mmol),
AuCl(PPh3) (0.0125mmol), and a ligand (0.0125 mmol) in THF
(1 mL) at 25 ºC for 13 h under Ar. bYields were determined by
integral values of 29Si NMR signals using PhSiMe3 as an in-
ternal standard. The value in parentheses is an isolated yield.
ed
yield.
Two
silanol
groups
in
1,4-
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Page 4 of 13
We found that the AuCl(PPh3)/xantphos system is ac- perature for 8 h (Scheme 2, eq.2). Both compounds 8 and
1
2
3
4
5
6
7
8
tive for the reaction of 1a with 6a to selectively give 7aa
with a small amount of 5a (Table 3, entry 5). As the cata-
lyst precursor, usage of AuCl(PCy3) or AuCl instead of
AuCl(PPh3) considerably decreased the yield of 7aa (Table
3, entries 6-7).
9 possess SiH functionalities and are useful building
blocks for further transformations. So far there are very
limited examples for the selective synthesis of functional-
ized oligosiloxanes.11,23 As demonstrated by the synthesis
of 8 and 9, dihydrosiloxanes 3 are highly useful building
blocks for the synthesis of a variety of organosilicon com-
pounds including oligo- and polysiloxanes.24
Table 4 shows the scope of the AuCl(PPh3)/xantphos
system for the selective synthesis of monohydrosiloxanes.
Silanols 1c and 1d respectively reacted with diethylsilane
(6b) and methylphenylsilane (6c) to give monohy-
drosiloxanes 7cb and 7dc in high yields. Silanediol 1h and
triol 1i also efficiently reacted with 6b to selectively afford
7hb and 7ib in high yields.
Ito and co-workers reported a mechanistic study for the
AuCl(xantphos)-catalyzed silylation of alcohols, where
chlorosilanes produced by the reaction of AuCl(xantphos)
and hydrosilanes reacted with alcohols to form
alkoxysilanes.20b In order to confirm the possibility of the
similar mechanism in our system, we performed the reac-
tion of 2a with AuCl(PPh3)/PnBu3. However, almost no
reaction occurred and the formation of chloro-
phenylsilane was not observed at all by 29Si NMR. There-
fore, a different mechanism should be operated at least in
the AuCl(PPh3)/PnBu3-catalyzed reactions.
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
Table 4. Substrate Scope of the Au-Catalyzed Cross-
Coupling Reaction of Silanols with Dihydrosilanesa
Scheme 1. A gram-scale synthesis of dihydrosilane
3aa
Scheme 2. Synthesis of trisiloxane 8 and pentasilox-
ane 9 from dihydrosiloxane 3aa
aReaction conditions: 1 (3 mmol), 6 (3 mmol), AuCl(PPh3)
(2.5 mol% based on 1), and xantphos (2.5 mol% based on 1) in
THF at 25 - 60 ºC for 13 h under Ar. Detailed reaction condi-
tions are shown in the supporting information. b6b (6
mmol), AuCl(PPh3) (2 mol%), and xantphos (2 mol%) were
used. c1i (1.5 mmol), 6b (15 mmol), AuCl(PPh3) (4 mol%), and
xantphos (4 mol%) were used.
The developed Au-catalyzed cross-coupling reaction
could easily be performed on a gram-scale as demonstrat-
ed by the synthesis of 3aa (Scheme 1). In this case, PnOct3
was used instead of PnBu3 for easier separation of the
product 3aa from the phosphine ligand by vacuum distil-
lation. With 1 mol% Au-catalyst, 20 mmol of 1a was react-
ed with 2a to produce 4 g of 3aa.
In summary, Au-catalyzed dehydrogenative cross-
coupling reaction of silanols with hydrosilanes has been
developed to give dihydrosiloxanes as well as monohy-
drosiloxanes with excellent selectivities. The resulting
hydrosiloxanes are highly useful building blocks for the
synthesis of a variety of organosilicon compounds as
demonstrated by the synthesis of the functionalized
trisiloxane and pentasiloxane. Further investigation with
regard to the reaction mechanism and applications of this
reaction is currently in progress.
In order to demonstrate the usefulness of dihydrosilox-
ane products 3, synthesis of a trisiloxane 8 and a penta-
siloxane
9
from
3aa
was
examined
using
AuCl(PPh3)/xantphos- or B(C6F5)3-catalyzed reaction
(Scheme 2). Trisiloxane 8 was selectively obtained in 86%
yield by the reaction of 3aa (1 mmol) and 1d (1 mmol) in
the presence of AuCl(PPh3) (0.025 mmol) and xantphos
o
(0.025 mmol) in THF at 70 C (Scheme 2, eq. 1). On the
other hand, pentasiloxane 9 was obtained in 96% yield
through a selective mono-substitution of one of the two
Si-H bonds in two 3aa molecules by the reaction of 3aa (1
mmol) and dimethoxydiphenylsilane (0.5 mmol) in the
presence of B(C6F5)3 (0.05 mmol) in toluene at room tem-
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Buslov, I.; Becouse, J.; Mazza, S.; Montandon-Clerc, M.; Hu, X.
Procedures, characterization, and spectral data (PDF)
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Angew., Chem., Int. Ed. 2015, 54, 14523-14526. (g) Toutov, A. A.;
Liu, W. B.; Betz, K. N.; Fedorov, A.; Stoltz, B. M.; Grubbs, R. H.
Nature 2015, 518, 80-84. (h) Steiman, T. J.; Uyeda, C. J. Am.
Chem. Soc. 2015, 137, 6104-6110. (i) Jia, X. Q.; Huang, Z. Nat.
Chem. 2016, 8, 157-161. (j) Mathew, J.; Nakajima, Y.; Choe, Y. K.;
Urabe, Y.; Ando, W.; Sato, K.; Shimada, S. Chem. Commun. 2016,
52, 6723-6726.
AUTHOR INFORMATION
Corresponding Author
*E-mail for S.S.: s-shimada@aist.go.jp
ACKNOWLEDGMENT
(15) (a) Amro, K.; Clément, S.; Déjardin, P.; Douglas, W. E.; Gerb-
ier, P.; Janot, J. –M.; Thami, T. J. Mater. Chem. 2010, 20, 7100-
7103. (b) Cheng, C.; Simmons, E. M.; Hartwig, J. F. Angew., Chem.
Int. Ed. 2013, 52, 8984-8989. (c) Cheng, C.; Hartwig, J. F. Science
2014, 343, 853-857. (d) Cheng, C.; Hartwig, J. F. J. Am. Chem. Soc.
2015, 137, 592-595.
This work was supported by the "Development of Innovative
Catalytic Processes for Organosilicon Functional Materials"
project (PL: K.S.) from the New Energy and Industrial Tech-
nology Development Organization (NEDO).
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Table 1. Screening of Catalysts and Reaction Conditions for the Cross-Coupling Reaction of Silanols 1 with
Phenylsilane 2a
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Table 2. Substrate Scope of Au-Catalyzed Cross-Coupling Reaction of Silanols with Trihydrosilanes
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Table 3. Screening of Catalysts and Reaction Condi-tions for the Cross-Coupling Reaction of 1a with Di-
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Table 4. Substrate Scope of the Au-Catalyzed Cross-Coupling Reaction of Silanols with Dihydrosilanes
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Scheme 1. A gram-scale synthesis of dihydrosilane 3aa
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Scheme 2. Synthesis of trisiloxane 8 and pentasilox-ane 9 from dihydrosiloxane 3aa
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