Ligand-Controlled Regiodivergent Hydrosilylation of Conjugated Dienes Catalyzed by Mono(phosphine)palladium(0) Complexes

Article abstract of DOI:10.1021/acs.organomet.0c00597

Mono(phosphine)palladium(0) complexes, [Pd(2:2-C6H10O)(PR3)] (1), catalyze hydrosilylation of electron-deficient conjugated dienes with HSiPh3. Hydrosilylation of methyl penta-2,4-dienoate with HSiPh3 catalyzed by [Pd(2:2-C6H10O)(PR3)] (R = Me (1a), Et (1b), OEt (1d), OiPr (1e)) proceeds to give the 1,2-E product in quantitative yield with exclusive Markovnikov selectivity. In contrast, their triphenylphosphine and -phosphite analogues, [Pd(2:2-C6H10O)(PR3)] (R = Ph (1f), OPh (1g)), mainly produce the 1,4-Z product (1,2-E/1,4-Z = 3/7). The regioselectivity in the hydrosilylation of methyl 2,4-pentadienoate is also controlled by organosilanes. Mechanistic studies suggest that the reaction using a compact and basic mono-phosphorus complex proceeds by the Chalk-Harrod mechanism involving the reductive elimination from an (3-allyl)(silyl)palladium(II). A poor electron-donating mono-phosphorus ligand such as P(OPh)3 destabilizes a Pd(II) species and promotes direct reductive elimination to give the 1,4-Z product. On the other hand, a compact and electron-donating phosphorus ligand, such as PMe3, PEt3, and P(OMe)3, favors to give the more stable (3-allyl)(silyl)palladium(II) intermediate by the allyl rotation, followed by reductive elimination to give the 1,2-E product.

Full text of DOI:10.1021/acs.organomet.0c00597

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Ligand-Controlled Regiodivergent Hydrosilylation of Conjugated
Dienes Catalyzed by Mono(phosphine)palladium(0) Complexes
Nobuyuki Komine,* Tatsuo Mitsui, Shu Kikuchi, and Masafumi Hirano
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ABSTRACT: Mono(phosphine)palladium(0) complexes, [Pd(η2:η2-
C6H10O)(PR3)] (1), catalyze hydrosilylation of electron-deficient con-
jugated dienes with HSiPh3. Hydrosilylation of methyl penta-2,4-dienoate
with HSiPh3 catalyzed by [Pd(η2:η2-C6H10O)(PR3)] (R = Me (1a), Et
(1b), OEt (1d), OiPr (1e)) proceeds to give the 1,2-E product in
quantitative yield with exclusive Markovnikov selectivity. In contrast, their
triphenylphosphine and -phosphite analogues, [Pd(η2:η2-C6H10O)(PR3)]
(R = Ph (1f), OPh (1g)), mainly produce the 1,4-Z product (1,2-E/1,4-Z = 3/7). The regioselectivity in the hydrosilylation of
methyl 2,4-pentadienoate is also controlled by organosilanes. Mechanistic studies suggest that the reaction using a compact and basic
mono-phosphorus complex proceeds by the Chalk−Harrod mechanism involving the reductive elimination from an (η3-
allyl)(silyl)palladium(II). A poor electron-donating mono-phosphorus ligand such as P(OPh)3 destabilizes a Pd(II) species and
promotes direct reductive elimination to give the 1,4-Z product. On the other hand, a compact and electron-donating phosphorus
ligand, such as PMe3, PEt3, and P(OMe)3, favors to give the more stable (η3-allyl)(silyl)palladium(II) intermediate by the allyl
rotation, followed by reductive elimination to give the 1,2-E product.
INTRODUCTION
■
Hydrosilylation is undoubtedly an important reaction in
organic synthesis.1 The main difficulty of this reaction using
unsymmetric conjugated dienes is in the control of regio- and
stereoselectivities (eq 1).2,3 The 1,4-selective addition of
phosphine ligand prevents the η4-coordination of a conjugated
diene that leads to an η3-allyl intermediate (Figure 1).
Similarly, the 1,2- and anti-Markovnikov-selective hydro-
silylation of conjugated dienes catalyzed by an in situ generated
cobalt catalyst was reported by RajanBabu and co-workers (eq
3).5 The reaction of [CoCl2(i‑PrPDI)] with 2 equiv of
triorganosilanes to conjugated dienes can be achieved with
known catalysts. In these catalytic reactions, the formation of
an η3-allyl intermediate is proposed (Scheme 1).
Scheme 1. Mechanism of Hydrosilylation of Conjugated
Dienes Catalyzed by Pd(0)
Figure 1. A possible intermediate of hydrosilylation of 1,3-butadiene.
In contrast, the 1,2-selective addition of silanes to
conjugated dienes is still rare. Recently, Ritter and co-workers
Received: September 9, 2020
reported a Pt(II) catalyst bearing a cyclometalated phosphine
ligand to catalyze the 1,2- and anti-Markovnikov-selective
hydrosilylation of conjugated diene (eq 2).4 The key for the
1,2-selective hydrosilylation is believed to be that a
hexacoordinate Pt(IV) intermediate with a hemilabile
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Scheme 3. Mechanism of Hydrosilylation of Conjugated
Dienes Catalyzed by Co(acac)2/Phosphine Ligand
NaEt3BH generates an efficient catalyst for selective anti-
Markovnikov hydrosilylation of the terminal double bond in
conjugated dienes. Primary and secondary silanes such as
H3SiPh, H2SiPh, and H2SiMePh react with a wide range of
terminal dienes without affecting the configuration of the other
double bond. The reduction of the [CoCl2(i‑PrPDI)] with
NaEt3BH afforded the corresponding cobalt hydride species,
[CoH(i‑PrPDI)], that reacted with the Co center coordinated
with a bulky tridentate ligand added to the terminal carbon in a
less-hindered double bond of the conjugated diene to give an
(η1-homoallyl)cobalt species (Scheme 2). This cobalt species
reacted with the silane to give the linear hydrosilylation
product, regenerating the cobalt-hydride.
dinitrogen ligand such as a quinolineoxazoline was also
reported by Huang and co-workers (eq 6).7 The catalyst
system is effective for a wide array of conjugated dienes,
including mono- and 1,2-disubstituted dienes with aryl and/or
alkyl substituents. From the result of a deuterium-labeling
experiment, they suggested that the hydrosilylation most likely
proceeded through a modified Chalk−Harrod mechanism
involving the 1,2-insertion of a Co−Si bond into the terminal
double bond of the diene to form primary Co species for
avoiding steric repulsion (Scheme 4). Similarly, the iron
Scheme 2. Mechanism of Hydrosilylation of Conjugated
Dienes Catalyzed by [CoCl2(i‑PrPDI)]/NaEt3BH
Scheme 4. Mechanism of Hydrosilylation of Conjugated
Dienes Catalyzed by CoCl2/QuinOx Ligand
On the other hand, Ge and co-workers reported the 1,2- and
Markovnikov-selective hydrosilylation of conjugated dienes
using catalysts generated from Co(acac)2 and a phosphine
ligand (eqs 4 and 5).6 They proposed a hydrometalation
pathway with a Co(I)−H formed by the reaction of Co(II)
species with hydrosilane for this hydrosilylation of conjugated
dienes. In contrast to the [CoCl2(i‑PrPDI)]/NaEt3BH system,
the 2,1-addition of Co−H species into conjugated diene forms
an allylcobalt intermediate, which reacts with H3SiPh to give
the allylsilane product and regenerate the Co−H species. This
regioselectivity of the addition of Co−H species into
conjugated diene was controlled by the ligand (Scheme 3).
catalysts with 2,9-diaryl-1,10-phenanthroline ligands produced
1,2-addition products of 1-substituted and 1,1-disubstituted
buta-1,3-dienes with Markovnikov selectivity.8
Palladium-catalyzed hydrosilylation is an important strategy
for the synthesis of organosilanes, and recently several
progresses of palladium-catalyzed hydrosilylation of various
alkenes were reported.9 On the other hand, although Pd
complexes having phosphine ligands have long been known as
a catalyst for Markovnikov-selective hydrosilylations,10 the low
catalytic activity has been a problem. Sumida, Hosoya, and co-
workers pioneeringly documented efficient hydrosilylations of
electron-deficient alkynes by [Pd(dba)2]/PCy3.11 We found
mono(phosphine)palladium(0) complexes having a diallyl
ether ligand to be efficient catalysts for Markovnikov-selective
hydrosilylation of electron-deficient alkenes (eq 7).12
In the course of our study, we came across that the
hydrosilylation of conjugated dienes catalyzed by a mono-
(phosphine)palladium(0) complex gives the 1,2-E and 1,4-Z
products depending on the phosphorus ligand used and the
nature of silanes (eq 8). In this contribution, we disclose
regiodivergent hydrosilylation of conjugated diene catalyzed by
the mono(phosphine)palladium(0) complexes.13
Furthermore, asymmetric hydrosilylation of (E)-1-aryl-1,3-
diene derivatives catalyzed by the Co(acac)2/(R)-difluorphos
system was also reported to give chiral allylsilanes (eq 5).
The asymmetric 1,2-Markovnikov hydrosilylation of con-
jugated dienes catalyzed by a cobalt complex containing a
B
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As an alternative method to form a mono-phosphine
complex of Pd(0), we also evaluated the hydrosilylation
catalyzed by [Pd(dba)2] in the presence of 1 equiv of the
phosphorus ligand (Table 2). First of all, no catalytic activity
was observed in the presence of [Pd(dba)2] without addition
of the phosphorus ligand (entry 1). Hydrosilylation catalyzed
by bis(dibenzylideneacetone)palladium(0) with PMe3 pro-
ceeded with similar selectivity as the reaction catalyzed by 1a
(entry 2), although 1a showed higher catalytic activity than
[Pd(dba)2]/PMe3. With the PPh3 ligand, the 1,4-Z product
also dominated as shown in the reaction catalyzed by 1f (entry
9). According to these results, both catalytic systems probably
generate the same active species and the product selectivity
depends on the phosphorus ligand used. The reactions with
PMe2Ph, PMePh2, PPh2Cy, and P(OMe)3 gave 1,2-E selective
hydrosilylation (entries 4−7). Interestingly, a para-substituted
triaryl phosphine such as P(C6H4OMe-4)3 and P(C6H4F-4)3
shows 1,2-E or 1,4-Z selectivity, respectively. The steric
property of para-substituted triaryl phosphine is similar to
that of PPh3. Therefore, the higher electron-donating property
of P(C6H4OMe-4)3 than PPh3 provided the 1,2-E product. In
contrast, when an electron-withdrawing triaryl phosphine such
as P(C6H4F-4)3 was used, the 1,4-Z product was formed in
high selectivity. The reaction rate diminished by the addition
of 1 equiv of PMe3 and was completely hampered in the
presence of 2 equiv of PMe3 (Figure 2). These results suggest
the active catalyst is a mono(phosphine)palladium complex
and this catalysis does not depend on the substrate
concentrations.
RESULTS AND DISCUSSION
■
Reaction of Methyl Penta-2,4-dienoate with Triphe-
nylsilane Catalyzed by Mono(phosphine)palladium(0).
A series of palladium(0) complexes having a diallyl ether ligand
and an ancillary phosphorus ligand (1) were screened in
hydrosilylation of methyl penta-2,4-dienoate with HSiPh3
(Table 1). The reaction catalyzed by 5 mol % of 1a (PR3 =
PMe3) at 30 °C exclusively gave the 1,2-E product in
quantitative yield with perfect Markovnikov selectivity (Table
1, entry 1). With 10 mol % of 1b, 1d, and 1e, the reaction also
proceeded with 1,2-E and Markovnikov selectivity in high yield
(entries 2, 4, 5). When 5 mol % of 1c was used, a 78/22
mixture of 1,2-E/1,4-Z products was obtained (entry 3).
Interestingly, the catalysts 1f and 1g mainly produced the 1,4-Z
product (entries 6, 7). The catalyst 1f (10 mol %) gave
preferentially the 1,4-Z product in moderate yield. The
P(OPh)3 derivative 1g showed the lower catalytic activity.
When the reaction was carried out at 50 °C for 48 h in the
presence of 10 mol % of 1g, the hydrosilylation product was
formed in 62% yield.
Scope of Silanes. With these results in hand, we turned
our attention to the nature of silanes. We evaluated the
electronic effect of silanes on the hydrosilylations products by
use of 4-substituted triarylsilanes. Complexes 1a and 1f were
used as the catalysts in this reaction (Table 3). The
regioselectivity in these reactions is highly dependent on the
a
Table 1. Hydrosilylation of Methyl Penta-2,4-dienoate with Triphenylsilane Catalyzed by [Pd(η2:η2-diallyl ether)(PR3)] (1)
selectivity/%
entry
Pd cat (mol %)
time/h
yield/%
(E)-4aa
(Z)-5aa
1
2
3
4
5
1a (5)
1b (10)
1c (5)
1d (10)
1e (10)
1f (10)
1g (10)
8
12
16
24
26
72
48
99
83
84
92
81
60
62
100
100
78
100
100
28
0
0
22
0
0
72
74
b
b
b
6
7
bc
,
26
a
b
Conditions: [PhSiH]0 = 0.1 M, [methyl penta-2,4-dienoate]0 = 0.1 M, [1] = 0.005, 0.010 M, solvent: C6D6, temperature: 30 °C. [1] = 0.010 M.
c
50 °C.
C
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a
Table 2. Hydrosilylation of Methyl Penta-2,4-dienoate with Triphenylsilane Catalyzed by Pd(dba)2 in the Presence of PR3
selectivity/%
entry
PR3
time/h
yield/%
(E)-4aa
(Z)-5aa
1
2
3
4
5
6
7
8
9
10
11
none
PMe3
PMe3
PMe2Ph
PMePh2
48
24
24
21
46
7
24
40
63
40
15
0
79
0
100
0
b
82
84
34
77
60
50
32
41
98
89
78
100
77
28
2
11
22
0
23
72
90
82
PPh2Cy
P(OMe)3
P(C6H4OMe-4)3
PPh3
P(C6H4F-4)3
P(CH2Ph)3
10
18
a
Conditions: [HSiPh3]0 = 0.10 M, [methyl penta-2,4-dienoate]0 = 0.10 M, [Pd(dba)2] = 0.005 M, [PMe3] = 0.005 M, solvent: C6D6, temperature:
b
30 °C. [Pd(dba)2] = 0 M, [PMe3] = 0.005 M.
(entries 6, 7). When the reaction of HSi(C6H4Cl-4)3 or
HSi(C6H4CF3-4)3 with 1f was carried out, the corresponding
hydrosilylation product was obtained with completely 1,4-Z
selectivity (entries 9, 10). These results suggest the electron-
rich silanes to favor the 1,2-E products, and formation of the
1,4-Z product is encouraged by 1f.
Then we also evaluated a series of triorganosilanes in this
hydrosilylation. When 1a was used as the catalyst, the 1,2-E
products were exclusively formed (Table 4, entries 1−4). In
contrast, the regioselectivity in these reactions catalyzed by 1f
was highly dependent on the structure of the silane. The
hydrosilylation reaction using HSiMePh2 and HSiMe2Ph
produced both the 1,2-E and 1,4-Z products in a roughly 1/
1 ratio (entries 5, 6). This suggests that the regioselectivity of
the hydrosilylation of methyl 2,4-pentadienoate catalyzed by
the mono(phosphine)palladium(0) complex is controlled by
the phosphine ligand as well as the silane.
The hydrosilylation of methyl penta-2,4-dienoate with
primary and secondary silanes such as phenyl and diphenyl
silanes was investigated (Table 5). Similar to triphenyl silane,
the hydrosilylation of methyl penta-2,4-dienoate with diphenyl
silane (2k) in the presence of 1a or 1f gave the corresponding
hydrosilylation products in 1,2-E or 1,4-Z selective, respec-
tively (entries 1, 3). In contrast, no hydrosilylation product
with phenyl silane (2l) was detected and gave unidentified
silylated mixtures (entries 2, 4). Note that RajanBabu and co-
workers reported the Co-catalyzed reactions of (E)-dodeca-
1,3-diene with HSiPh3 dominantly gave the reduction product,
(E)-3-dodecene, and those with H2SiPh2 and H3SiPh gave a
1,2-E-anti-Markovnikov selective product, (E)-1-silyldodec-3-
ene.5 Formation of a silylene species has been reported in the
Ru-,14 Ir-,15 and Fe-catalyzed16 hydrosilylation using a primary
silane, and the present catalyst may have reacted with a
primary silane and changed the course of the reaction.
Figure 2. Effect of added PMe3 on hydrosilylation of methyl penta-
2,4-dienoate (3a) with triphenylsilane (2a) catalyzed by the
mono(trimethylphosphine)palladium(0) complex [Pd(η2:η2-
○
●
C6H10O)(PMe3)] (1a): [PMe3] = 0 ( ), 0.0055 ( ), 0.010 M
△
(
). Conditions: [2a]0 = 0.10 M, [3a]0 = 0.10 M, [1a] = 0.005 M,
solvent: C6D6, temperature: 30 °C.
electric property of the triarylsilane. Namely, when HSi-
(C6H4OMe-4)3 and HSi(C6H4Me-4)3 were treated with
methyl penta-2,4-dienoate in the presence of 5 mol % of 1a
at 30 °C, 1,2-selective hydrosilylation also took place to give
the corresponding 1,2-E products (entries 1, 2). However, in
the similar reactions using HSi(C6H4Cl-4)3 or HSi(C6H4CF3-
4)3, the 1,2-E selectivity was decreased (entries 4, 5). After
treatment of HSi(C6H4OMe-4)3 or HSi(C6H4Me-4)3 with
methyl penta-2,4-dienoate in the presence of 1f (10 mol %) at
30 °C, a mixture of 1,2-E and 1,4-Z-allylsilane was formed
Scope of Conjugated Dienes. The scope of dienes in the
hydrosilylation with HSiPh3 catalyzed by 1 is given in Table 6.
The hydrosilylation of methyl (2E,4E)-hexa-2,4-dienoate
proceeded to give the corresponding allylsilane with complete
1,2-E selectivity in 90% yield for 19 h in the presence of 1 mol
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Table 3. Hydrosilylation of Methyl Penta-2,4-dienoate with Triarylsilane Catalyzed by Pd(η2:η2-diallyl ether)(PR3) (R = Me,
a
Ph)
selectivity/%
entry
Pd cat. (mol %)
HSiAr3
time/h
yield/%
(E)-4
(Z)-5
1
2
3
4
5
6
7
8
9
1a (5)
1a (5)
1a (5)
1a (5)
1a (5)
1f (10)
1f (10)
1f (10)
1f (10)
1f (10)
HSi(C6H4OMe-4)3 (2b)
HSi(C6H4Me-4)3 (2c)
HSiPh3 (2a)
HSi(C6H4Cl-4)3 (2d)
HSi(C6H4CF3-4)3 (2e)
HSi(C6H4OMe-4)3 (2b)
HSi(C6H4Me-4)3 (2c)
HSiPh3 (2a)
22
22
8
4
7
24
24
72
4.5
0.5
82
100
99
100
86
42
56
60
62
100
100
100
96
82
66
50
28
0
0
0
0
4
18
34
50
72
100
b
b
b
b
HSi(C6H4Cl-4)3 (2d)
HSi(C6H4CF3-4)3 (2e)
b
10
97
0
100
a
b
Conditions: [HSi(C6H4X-4)3]0 = 0.10 M, [methyl penta-2,4-dienoate]0 = 0.10 M, [1a] = 0.005 M, solvent: C6D6, temperature: 30 °C. [1f] =
0.010 M.
a
Table 4. Hydrosilylation of Methyl Penta-2,4-dienoate with HSiR3 Catalyzed by Pd(η2:η2-diallyl ether)(PR3) (R = Me, Ph)
selectivity/%
entry
Pd cat.
HSiR3
time/h
yield/%
(E)-4
(Z)-5
1
2
3
4
5
6
7
1a
1a
1a
1a
1a
1f
HSiMePh2 (2f)
HSiMe2Ph (2g)
HSi(OEt)3 (2h)
HSiBnMe2 (2i)
HSiEt3 (2j)
24
150
20
120
8
78
52
83
30
62
27
35
100
100
100
100
100
50
0
0
0
0
0
HSiMePh2 (2f)
HSiMe2Ph (2g)
42
42
50
52
1f
48
a
Conditions: [HSiR3]0 = 0.10 M, [methyl penta-2,4-dienoate]0 = 0.10 M, [1] = 0.020 M, solvent: C6D6, temperature: 30 °C.
% of 1a (entry 2). Similarly, 1,2-E selective hydrosilylation of
methyl (2E)-2-methylpenta-2,4-dienate and ethyl (2E)-3-
methylpenta-2,4-dienate with HSiPh3 also took place (entries
4, 5). In contrast, 1,4-Z selective hydrosilylation took place for
methyl (2E)-4-methylpenta-2,4-dienate (entry 3). The hydro-
silylation of methyl (2E,4E)-4-methylhexa-2,4-dienoate gave a
mixture of methyl (Z)-4-methyl-2-(triphenylsilyl)hex-3-enoate
and methyl (E)-4-methyl-2-(triphenylsilyl)hex-4-enoate (entry
6). No hydrosilylation product was formed in the reaction of
methyl (2E)-5-methylhexa-2,4-dienoate (entry 7). This result
suggests that the reaction proceeds with the prior coordination
of the CC bond to the palladium center. Hydrosilylation of
1-phenyl-1,3-butadiene derivatives with triphenylsilane was
also performed (entries 8−17). The reaction of phenyl-
butadiene catalyzed by 1a yielded a 4:6 mixture of 1,2-E and
1,4-Z product (entry 12). The hydrosilylation of 1-(4-
nitrophenyl)-1,3-butadiene catalyzed by 1a proceeded with
complete 1,2-E selectivity (entry 8). On the other hand, 1f
catalyzed 1,4-Z selective hydrosilylation of 1-phenyl-1,3-
butadiene derivatives (entries 9, 11, 13, 15, 17). The
hydrosilylation of 1,3-butadine, isoprene, and β-myrcene
catalyzed by 1a and 1f took place to give the corresponding
hydrosilylation product with 1,4-Z selectivity (entries 18−26).
In the case of (E)-1,3-pentadiene, it is not clear whether the
1,2- or 1,4 product is produced as it is (entry 20). However, as
noted in the next section, we concluded that the reaction did
E
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Table 5. Hydrosilylation of Methyl Penta-2,4-dienoate with Phenyl and Diphenyl Silane Catalyzed by Pd(η2:η2-diallyl
a
ether)(PR3) (R = Me, Ph)
selectivity/%
entry
Pd cat. (mol %)
silane
time/h
yield/%
(E)-4
(Z)-5
1
2
1a (5)
1a (5)
1f (10)
1f (10)
H2SiPh2
H3SiPh
H2SiPh2
H3SiPh
2
24
3
79
0
58
0
95
5
b
3
b
13
87
4
24
a
b
Conditions: [H2SiR2]0 = 0.10 M, [methyl penta-2,4-dienoate]0 = 0.10 M, [1a] = 0.005 M, solvent: C6D6, temperature: 30 °C. [1f] = 0.010 M.
a
Table 6. Hydrosilylation of Conjugated Dienes Catalyzed by [Pd(η2,η2-diallyl ether)(PMe3)] (1)
diene
selectivity/%
entry
R1
R2
R3
R4
R5
R6
cat.
time/h
yield/%
(E)-4
(Z)-5
1
2
3
CO2Me
CO2Me
CO2Me
CO2Me
CO2Et
CO2Me
CO2Me
C6H4NO2-4
C6H4NO2-4
C6H4CF3-4
C6H4CF3-4
Ph
H
H
H
Me
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
H
H
H
H
Me
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
Me
R
H
H
Me
H
H
Me
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
H
H
H
Me
Me
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
Me
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
H
(3a)
(3b)
(3c)
(3d)
(3e)
(3f)
(3g)
(3h)
(3h)
(3i)
(3i)
(3j)
(3j)
(3k)
(3k)
(3l)
1a
1a
1a
1a
1a
1a
1a
1a
1f
1a
1f
1a
1f
1a
1f
1a
1f
1a
1f
1a
1f
8.3
19
10
75
5
120
120
2
24
30
35
4
72
4.5
124
9
72
0.6
96
168
96
2
96
2
96
18
99
90
82
94
86
45
0
89
81
60
27
99
19
97
80
51
14
93
57
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9
100
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0
100
b
c
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de
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6
7
8
bf
,
g
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42
fg
9 ,
g
h
10
11
gi
,
fg
12 ,
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13 ,
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fg
14 ,
j
C6H4OMe-4
C6H4OMe-4
C6H4NMe2-4
C6H4NMe2-4
H
H
Me
Me
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H
Me
Me
Me
fg
15 ,
fg
16 ,
k
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17 ,
(3l)
100
91
93
lm
18 ,
(3m)
(3m)
(3n)
(3n)
(3o)
(3o)
(3p)
(3p)
(3q)
lm
19 ,
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20
87
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100
100
100
100
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26
1a
0
a
b
c
Conditions: [HSiPh3]0 = 0.1 M, [conjugated diene]0 = 0.1 M, [1] = 0.005 M, solvent: C6D6, temperature: 30 °C. Temperature: 50 °C. E/Z =
d
e
f
g
h
82/18. [HSiPh3]0 = 0.3 M. Methyl (E)-4-methyl-2-(triphenylsilyl)hex-4-enoate (6af) was formed (21%). [HSiPh3]0 = 0.4 M. [1] = 0.01 M. E/
Z = 6/94. [HSiPh3]0 = 0.2 M. E/Z = 14/86. E/Z = 24/76. [HSiPh3]0 = 0.6 M. [1] = 0.02 M. R = CH2CH2CHCMe2.
i
j
k
l
m
n
proceed in a 1,4-Z addition manner by use of DSiPh3. No
hydrosilylation took place for CH2CHCHCMe2 (entry
26).
Deuterium-Labeling Experiments in the Hydrosilyla-
tion of Dienes by Mono(phosphine)palladium(0) Cata-
lyst. In order to obtain further insight into the reaction
mechanism of the catalytic reaction, the reaction with DSiPh3
F
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Article
was carried out. At first, the reaction of methyl penta-2,4-
dienoate with DSiPh3 (99 atom % D) in the presence of a
catalytic amount of Pd(η2:η2-diallyl ether)(PMe3) (1a) was
carried out. The deuterium atom was exclusively incorporated
in the methyl group of the product (eq 9). The reaction
in the hydrosilylation product. This fact suggests the
hydrosilylation being proceeded with 1,4-selectivity.
Possible Catalytic Cycle. The catalytic cycle for hydro-
silylation was proposed as shown in Scheme 5. Initially, the
reaction of conjugated diene and silane to the mono-
(phosphine)palladium(0) species (A) gave the palladium
complex (B). In the presence of PMe3, the active species A
would give bis(phosphine)palladium(0), which is the resting
state in this catalytic system. In the complex B, the terminal
CC double bond of cisoid-1,3-diene coordinates at the
palladium center. Migratory insertion of the Pd−H bond to the
terminal CC bond in the diene takes place via addition to
the terminal diene carbon to produce the η1-allyl complex (C).
The isotope experiment suggests this step being the turnover-
limiting step. The coordination of the substituted CC bond
in C results in the formation of the syn-η3-allyl intermediate
(D) in which the silyl group is located in the cis of the R3
group and reductive elimination from D gives the 1,4-Z
product. The 1,2-E product is produced by reductive
elimination from the allyl palladium complex (E), which
formed by apparent allyl rotation of complex D. Three possible
pathways for apparent allyl rotation in the η3-allyl palladium
complex have been proposed, i.e., (1) dissociative mechanism,
(2) associative mechanism, and (3) sequential η3-to-η1
isomerization/C−Pd bond rotation/η1-to-η3 isomerization.21
Probably, a compact and electron-donating phosphine, such as
PMe3, PEt3, and a compact and weaker electron-withdrawing
phosphine, such as P(OMe)3 (cone angle < 140°), can
promote allyl rotation by the associative mechanism via
formation of an 18e species. Therefore, in these cases, allyl
rotation smoothly proceeds to give complex E, following
reductive elimination to give the 1,2-E product. On the other
hand, a strong electron-withdrawing phosphorus ligand such as
P(C6H4F-4)3 promotes reductive elimination from D. As is
well-known, sterically bulky phosphines such as P(CH2Ph)3
and PCy3 inhibit the allylic rotation and the electron-
withdrawing phosphine promotes reductive elimination.
Therefore, the hydrosilylation product was formed with 1,4-
Z-selectivity or lower 1,2-E-selectivity.
profiles using HSiPh3 and DSiPh3 catalyzed by 1a are shown in
Figure 3. It is worthwhile to note that this process is a zero-
Figure 3. Time−yield curves for hydrosilylation of methyl penta-2,4-
dienoate (3a) with H(or D)SiPh3 catalyzed by Pd(η2:η2-C6H10O)-
○
(PMe3) (1a): reaction with HSiPh3 (100% H) ( ) or DSiPh3 (99%
●
D) ( ). Conditions: [2a]0 = 0.10 M, [3a]0 = 0.10 M, [1a] = 0.005 M,
solvent: C6D6, temperature: 30 °C.
SUMMARY
■
order reaction for both silane and diene concentrations. The
rates for the reaction of HSiPh3 and DSiPh3 (99% D) were
calculated as (8.42 0.11) × 10−6 M s−1 and (1.87 0.03) ×
10−6 M s−1, respectively. The KIE value (kH/kD) estimated by
using these initial rates based on these independent reactions
was 4.51. The KIE is primary and indicates the rate-
determining step (rds) in this catalysis to involve the Si−H
or Pd−H cleavage step.17−20 No dependence of the reaction
rate on substrate concentrations suggests that the rds is an
intramolecular step such as the migratory insertion of the Pd−
H bond to the CC bond.
There is a long-standing discussion regarding regio- and
stereochemistry of hydrosilylation of conjugated dienes. The
present study shows isolated mono(trimethylphosphine)-
palladium(0) complexes, Pd(η2:η2-C6H10O)(PR3) (1), cata-
lyzed hydrosilylation of electron-deficient conjugated dienes
with HSiPh3. The hydrosilylation of methyl penta-2,4-dienoate
with HSiPh3 by 5 mol % of Pd(η2:η2-C6H10O)(PR3) (R = Me
(1a), Et (1b), OEt (1d), OiPr (1e)) proceeds to give the 1,2-E
product in quantitative yield with perfect Markovnikov
selectivity. In contrast, Pd(η2:η2-C6H10O)(PR3) (R = Ph
(1f), OPh (1g)) mainly produced the 1,4-Z product (1,2-E/
1,4-Z = 3/7). The regioselectivity of the hydrosilylation of
methyl 2,4-pentadienoate catalyzed by the mono(phosphine)-
palladium(0) complex is also controlled by the silane. The
reaction is proceeding by a Chalk−Harrod mechanism with the
reductive elimination of an (η3-allyl)(silyl)palladium(II). The
migratory insertion to the terminal CC bond in the diene,
followed by the coordination of the substituted CC bond,
takes place to produce the η3-allyl complex. A strong electron-
withdrawing phosphine such as P(OPh)3 destabilizes the
Pd(II) species and promotes direct reductive elimination to
give the 1,4-Z product. On the other hand, a compact and
The reaction of DSiPh3 with 1,3-pentadiene was also carried
out (eq 10). Note that only the methyl group in the α-position
of the SiPh3 fragment was deuterated and no incorporation of
the D atom was observed in the methyl group in the β-position
G
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Scheme 5. A Possible Mechanism
solution of HSiPh3 (2a) (0.061 mmol), methyl penta-2,4-dienoate
(3a) (0.067 mmol), and hexamethyldisiloxane (0.0031 mmol). After
the addition of a C6D6 solution of Pd{η2:η2-(CH2CHCH2)2O}-
(PMe3) (1a; 0.0668 M, 45 μL, 0.0030 mmol) to form a 0.1 M
solution of HSiPh3 (2a) and methyl penta-2,4-dienoate (3a), the
electron-donating phosphine, such as PMe3, PEt3, and a
compact and weaker electron-withdrawing phosphine, such as
P(OMe)3, promotes allyl rotation smoothly to give the
regioisomeric η3-allyl complex, following reductive elimination
to give the 1,2-E product.
1
reaction was monitored by H NMR at 30 °C, and the yields were
1
periodically estimated by H NMR. The final yield of methyl (E)-4-
EXPERIMENTAL SECTION
■
(triphenylsilyl)pent-2-enoate (4aa) was 99%. (b) In an NMR tube
containing 20.2 mg of HSiPh3 (2a) (0.0776 mmol) were placed 400
μL of C6D6 and 10.0 μL of methyl penta-2,4-dienoate (3a) (0.0866
mmol). To this was added hexamethyldisiloxane (0.4 μL, 0.0006
mmol) as an internal standard. After the addition of a C6D6 solution
of Pd{η2:η2-(CH2CHCH2)2O}{P(OPh)3} (1g; 0.0345 M, 200 μL,
0.0034 mmol) to form a 0.1 M solution of methyl penta-2,4-dienoate
All procedures described in this paper were carried out under a
nitrogen or argon atmosphere by use of Schlenk and vacuum line
techniques. Benzene-d6 was dried over sodium wire and purified by
vacuum distillation prior to use. HSiPh3, HSiPh2Me, HSiPhMe2,
HSiBnMe2, HSi(OEt)3, HSiEt3, diallyl ether, and dienes 3a, 3b, 3m,
3n, 3o, and 3p were purchased from TCI or Aldrich. The
mono(phosphine)palladium(0) complexes Pd{η2:η2-(CH2
CHCH2)2O}(PR3) (R = Me (1a), Et (1b), Cy (1c), OEt (1d),
OiPr (1e), Ph (1f), OPh (1g)),20,22 DSiPh3 (2a-d),23 HSiAr3 (Ar =
C6H4OMe-4 (2b), C6H4Me-4 (2c), C6H4Cl-4 (2d), C6H4CF3-4
(2e)),24 and dienes 3c,25 3d,26 3e,25 3f,27 3g,25 3h,28 3i, 3j,29 3k,30
3l,29 and 3q31 were prepared by literature procedures with
1
and HSiPh3, the reaction was monitored by H NMR at 30 °C, and
the yields were periodically estimated by 1H NMR. The final yield of
methyl (E)-4-(triphenylsilyl)pent-2-enoate (4aa) and methyl (Z)-2-
(triphenylsilyl)pent-3-enoate (5aa) were 15% and 42%, respectively.
The products were isolated by PTLC (hexane/Et2O = 5/1) as a
colorless powder. Methyl (E)-4-(triphenylsilyl)pent-2-enoate (4aa):
1H NMR (C6D6, rt): δ 1.15 (d, JHH = 7.0 Hz, 3H, CH3), 2.55 (dqd,
JHH = 7.3, 7.0, 1.6 Hz, 1H, CH3CH(SiPh3)), 3.35 (s, 3H, CO2CH3),
5.82 (dd, JHH = 15.6, 1.7 Hz, 1H, CHCHCO2CH3), 7.09−7.19 (m,
9H, m,p-Ph), 7.54−7.59 (m, 6H, o-Ph), 7.59 (dd, JHH = 15.6, 7.3 Hz,
1H, CHCHCO2CH3). 13C{1H} NMR (C6D6, rt): 13.81 (CH3),
25.91 (CHSi), 50.81 (CO2CH3), 118.78 (CHCHCO2CH3), 130.02
(aromatic CH), 133.24 (ipso-C), 136.34 (aromatic CH), 152.45
1
2
modification. H, H, and 13C{1H} NMR spectra were measured on
a 400 MHz (for 1H) NMR spectrometer. GC and GC-MS were
performed on Shimadzu GC-2014 (FID) and Shimadzu GCMS-2010
(EI) instruments, respectively, equipped with a TC-1 column (0.25
mm i.d. × 30 m). HRMS (APCI) analysis was performed on a Bruker
Daltonics micrOTOF-QII instrument.
Hydrosilylation of Electron-Deficient Conjugated Dienes
Catalyzed by Mono(phosphine)palladium(0) Complexes. As a
typical procedure, the hydrosilylation of methyl penta-2,4-dienoate
(2a) with triphenylsilane (3a) is given. (a) In an NMR tube
containing 355 μL of C6D6 were placed 205 μL of a 0.296 M C6D6
1
(CHCHCO2CH3), 166.68 (CO2CH3). H NMR (CDCl3, rt): δ
1.29 (d, JHH = 6.9 Hz, 3H, CH3), 2.82 (dqd, JHH = 7.3, 6.9, 1.7 Hz,
1H, CH3CH(SiPh3)), 3.65 (s, 3H, CO2CH3), 5.61 (dd, JHH = 15.6,
H
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1.7 Hz, 1H, CHCHCO2CH3), 7.30 (dd, JHH = 15.6, 7.3 Hz, 1H,
CHCHCO2CH3), 7.33−7.45 (m, 9H, m,p-Ph), 7.48−7.58 (m, 6H,
o-Ph). 13C{1H} NMR (CDCl3, rt): δ 13.71 (CH3), 25.91 (CHSi),
51.28 (CO2CH3), 118.04 (CHCHCO2CH3), 127.97 (m-C of
SiPh3), 129.80 (p-C of SiPh3), 132.73 (ipso-C of SiPh3), 135.99 (o-C
of SiPh3), 152.78 (CHCHCO2CH3), 167.23 (CO2CH3). HRMS
(APCI): m/z calcd for C24H24O2Si + H+: 373.1618 [M + H]+; found:
373.1605. Methyl (Z)-2-(triphenylsilyl)pent-3-enoate (5aa): 1H
NMR (C6D6, rt): δ 1.25 (dd, JHH = 6.8, 1.8 Hz, 3H, CH3), 3.10 (s,
3H, CO2CH3), 4.22 (d, JHH = 11.3 Hz, 1H, CH(SiPh3)(CO2CH3)),
7.03 (m, 6H, C6H4CH3-4), 7.59 (m, 1H, CHCHCO2CH3), 7.61
(m, 6H, C6H4CH3-4). 1H NMR (CDCl3, rt): δ 1.26 (d, JHH = 6.9 Hz,
3H, CH3), 2.76 (dtd, JHH = 7.2, 6.9, 1.7 Hz, 1H, CHSi(C6H4CH3-
4)3), 2.34 (s, 3H, C6H4CH3-4), 3.65 (s, 3H, CO2CH3), 5.59 (dd, JHH
= 15.8, 1.7 Hz, 1H, CHCHCO2CH3), 7.16 (m, 6H, C6H4CH3-4),
7.29 (dd, JHH = 15.8, 7.2 Hz, 1H, CHCHCO2CH3), 7.40 (m, 6H,
C6H4CH3-4). 13C{1H} NMR (CDCl3, rt): 13.70 (CH3CHSi), 21.53
(C6H4CH3-4), 26.19 (CHSi), 51.24 (CO2CH3), 117.70 (CH
CHCO2CH3), 128.76 (3-C of C6H4CH3-4), 129.47 (1-C of
C6H4CH3-4), 136.00 (2-C of C6H4CH3-4), 139.61 (4-C of
C6H4CH3-4), 153.31 (CHCHCO2CH3), 167.31 (CO2CH3).
HRMS (APCI): m/z calcd for C27H30O2Si + H+: 415.2088 [M +
H]+; found: 415.2077.
5.34 (dq, JHH = 10.7, 6.8 Hz, 1H, CHCHCH3), 6.18 (tq, JHH
=
11.0, 1.8 Hz, 1H, CHCHCH3), 7.10−7.22 (m, 9H, m,p-Ph), 7.72−
7.85 (m, 6H, o-Ph). 13C{1H} NMR (C6D6, rt): δ 13.01 (CH3), 37.65
(CHSi), 50.81 (CO2CH3), 124.74 (CH3CHCH), 125.48
(CH3CHCH), 128.34 (p-C of SiPh3), 130.15 (m-C of SiPh3),
133.11 (ipso-C of SiPh3), 136.85 (o-C of SiPh3), 172.88 (CO2CH3).
1H NMR (CDCl3, rt): δ 1.37 (dd, JHH = 6.9, 1.9 Hz, 3H, CH3), 3.32
(s, 3H, CO2CH3), 4.02 (dd, JHH = 11.2, 0.8 Hz, 1H, CH(SiPh3)-
(CO2CH3)), 5.45 (dqd, JHH = 10.7, 6.8, 0.8 Hz, 1H, CHCHCH3),
5.78 (tq, JHH = 11.1, 1.8 Hz, 1H, CHCHCH3), 7.35 (m, 6H, m-
Ph), 7.42 (m, 3H, p-Ph), 7.59 (m, 6H, o-Ph). 13C{1H} NMR (CDCl3,
rt): δ 13.00 (CH3), 37.06 (C(SiPh3)(CO2CH3)), 51.20 (CO2CH3),
124.44 (CH3CHCH), 124.92 (CH3CHCH), 127.74 (m-C of
SiPh3), 129.88 (p-C of SiPh3), 132.39 (ipso-C of SiPh3), 136.31 (o-C
of SiPh3), 173.33 (CO2CH3). HRMS (APCI): m/z calcd for
C24H24O2Si + H+: 373.1618 [M + H]+; found: 373.1620.
Methyl (Z)-2-(Tri-p-tolylsilyl)pent-3-enoate (5ca). Yield: 28%
1
(NMR), 28% (isolated). Colorless powder. H NMR (C6D6, rt): δ
1.33 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 2.09 (s, 9H, C6H4CH3-4), 3.18
(s, 3H, CO2CH3), 4.27 (dd, JHH = 11.3, 0.8 Hz, 1H, CHSi(C6H4CH3-
4)3(CO2CH3)), 5.38 (dqd, JHH = 10.7, 6.9, 0.8 Hz, 1H, CH
CHCH3), 5.75 (ddq, JHH = 11.3, 10.7, 1.8 Hz, 1H, CHCHCH3),
7.03 (m, 6H, C6H4CH3-4), 7.60 (m, 6H, C6H4CH3-4). 1H NMR
(CDCl3, rt): δ 1.37 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 2.35 (s, 3H,
C6H4CH3-4), 3.33 (s, 3H, CO2CH3), 3.97 (d, JHH = 11.6 Hz, 1H,
CHSi(C6H4CH3-4)3(CO2CH3)), 5.42 (dq, JHH = 10.8, 6.9 Hz, 1H,
CHCHCH3), 5.75 (ddq, JHH = 11.6, 10.8, 1.8 Hz, 1H, CH
CHCH3), 7.15 (m, 6H, C6H4CH3-4), 7.462 (m, 6H, C6H4CH3-4).
13C{1H} NMR (CDCl3, rt): δ 13.06 (CH3), 21.56 (C6H4CH3-4),
37.17 (CHSi)), 51.16 (CO2CH3), 123.53 (CH3CHCH), 124.71
(CH3CHCH), 128.51 (3-C of C6H4CH3-4), 129.08 (1-C of
C6H4CH3-4), 136.27 (2-C of C6H4CH3-4), 139.67 (4-C of
C6H4CH3-4), 173.49 (CO2CH3). HRMS (APCI): m/z calcd for
C27H30O2Si + H+: 415.2067 [M + H]+; found: 415.2077.
Methyl (E)-4-(Tris(4-chlorophenyl)silyl)pent-2-enoate (4da).
Yield: 96% (NMR), 75% (isolated). Colorless powder. 1H NMR
(C6D6, rt): δ 0.97 (d, JHH = 7.0 Hz, 3H, CH3CHSi(C6H4Cl-4)3), 2.75
(dtd, JHH = 7.5, 7.0, 1.7 Hz, 1H, CHSi(C6H4Cl-4)3), 3.37 (s, 3H,
CO2CH3), 5.77 (dd, JHH = 15.6, 1.7 Hz, 1H, CHCHCO2CH3),
7.18 (dd, JHH = 15.6, 7.5 Hz, 1H, CHCHCO2CH3), 7.10−7.13 (m,
12H, C6H4Cl-4). 1H NMR (CDCl3, rt): δ 1.26 (d, JHH = 7.0 Hz, 3H,
CH3CHSi(C6H4Cl-4)3), 2.75 (dtd, JHH = 7.3, 7.0, 1.7 Hz, 1H,
CHSi(C6H4Cl-4)3), 3.67 (s, 3H, CO2CH3), 5.61 (dd, JHH = 15.6, 1.7
Hz, 1H, CHCHCO2CH3), 7.18 (dd, JHH = 15.6, 7.3 Hz, 1H, CH
CHCO2CH3), 7.33−7.41 (m, 12H, C6H4Cl-4). 13C{1H} NMR
(CDCl3, rt): 13.62 (CH3CHSi), 25.43 (CHSi), 51.44 (CO2CH3),
118.80 (CHCHCO2CH3), 128.57 (3-C of C6H4Cl-4), 130.15 (4-C
of C6H4Cl-4), 136.79 (2-C of C6H4Cl-4), 137.11 (ipso-C of C6H4Cl-
4), 151.36 (CHCHCO2CH3), 166.95 (CO2CH3). HRMS (APCI):
m/z calcd for C24H21Cl3O2Si + H+: 475.0449 [M + H]+; found:
475.0428.
Methyl (E)-4-(Tris(4-methoxyphenyl)silyl)pent-2-enoate (4ba).
Yield: 82% (NMR), 71% (isolated). Colorless powder. 1H NMR
(C6D6, rt): δ 1.21 (d, JHH = 6.9 Hz, 3H, CH3), 2.56 (dtd, JHH = 7.2,
6.9, 1.4 Hz, 1H, CHSi(C6H4OCH3-4)3), 3.23 (s, 9H, C6H4OCH3-4),
3.32 (s, 3H, CO2CH3), 5.84 (dd, JHH = 15.6, 1.4 Hz, 1H, CH
CHCO2CH3), 6.76 (m, 6H, C6H4OCH3-4), 7.52 (m, 6H,
C6H4OCH3-4), 7.64 (dd, JHH = 15.6, 7.2 Hz, 1H, CH
1
CHCO2CH3). H NMR (CDCl3, rt): δ 1.26 (d, JHH = 6.9 Hz, 3H,
CH3CHSi(C6H4O-4)3), 2.71 (dtd, JHH = 7.2, 6.9, 1.6 Hz, 1H,
CHSi(C6H4OCH3-4)3), 3.66 (s, 3H, CO2CH3), 3.80 (s, 9H,
C6H4OCH3-4), 5.59 (dd, JHH = 15.6, 1.7 Hz, 1H, CH
CHCO2CH3), 6.90 (m, 6H, C6H4OCH3-4), 7.30 (dd, JHH = 15.6,
7.2 Hz, 1H, CHCHCO2CH3), 7.42 (m, 6H, C6H4OCH3-4).
13C{1H} NMR (CDCl3, rt): δ 13.69 (CH3CHSi), 26.63 (CHSi),
51.25 (CO2CH3), 55.00 (C6H4OCH3-4), 113.67 (3-C of C6H4OCH3-
4), 117.55 (CHCHCO2CH3), 124.12 (1-C of C6H4OCH3-4),
137.44 (2-C of C6H4OCH3-4), 153.48 (CHCHCO2CH3), 160.77
(4-C of C6H4OCH3-4), 167.34 (CO2CH3). This was characterized by
spectroscopic methods. HRMS (APCI): m/z calcd for C27H30O5Si +
H+: 463.1935 [M + H]+; found: 463.1924.
Methyl (Z)-2-(Tris(4-methoxyphenyl)silyl)pent-3-enoate (5ba).
Yield: 14% (NMR), 4% (isolated). Colorless powder. 1H NMR
(C6D6, rt): δ 1.35 (dd, JHH = 6.6, 1.7 Hz, 3H, CH3), 3.19 (s, 3H,
CO2CH3), 3.28 (s, 9H, C6H4OCH3-4), 4.29 (d, JHH = 11.5 Hz, 1H,
CH(Si(C6H4OCH3-4)3)(CO2CH3)), 5.43 (dq, JHH = 11.2, 6.6 Hz,
1H, CHCHCH3), 6.29 (tq, JHH = 11.2, 1.7 Hz, 1H, CH
CHCH3), 6.86 (m, 6H, C6H4OCH3-4), 7.81 (m, 6H, C6H4OCH3-4).
1H NMR (CDCl3. rt): δ 1.34 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 3.33
(s, 3H, CO2CH3), 3.80 (s, 9H, C6H4OCH3-4), 3.93 (dd, JHH = 11.3,
Methyl (Z)-2-(Tris(4-chlorophenyl)silyl)pent-3-enoate (5da).
Yield: 62% (NMR), 62% (isolated). Colorless powder. 1H NMR
(C6D6, rt): δ 1.16 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 3.04 (s, 3H,
CO2CH3), 3.96 (dd, JHH = 11.0, 0.8 Hz, 1H, CH(Si(C6H4Cl-
4)3)(CO2CH3)), 5.34 (dqd, JHH = 11.0, 6.9, 0.8 Hz, 1H, CH
CHCH3), 5.85 (tq, JHH = 11.0, 1.8 Hz, 1H, CHCHCH3), 7.15 (m,
1
6H, C6H4Cl-4), 7.38 (m, 6H, C6H4Cl-4). H NMR (CDCl3, rt): δ
0.7 Hz, 1H, CH(Si(C6H4OCH3-4)3)(CO2CH3)), 5.42 (dqd, JHH
=
1.38 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 3.38 (s, 3H, CO2CH3), 3.96
(d, JHH = 11.2 Hz, 1H, CH(Si(C6H4Cl-4)3)(CO2CH3)), 5.49 (dq,
JHH = 10.8, 6.9 Hz, 1H, CHCHCH3), 5.70 (ddq, JHH = 11.2, 10.8,
1.8 Hz, 1H, CHCHCH3), 7.36 (m, 6H, C6H4Cl-4), 7.47 (m, 6H,
C6H4Cl-4). 13C{1H} NMR (CDCl3, rt): δ 13.12 (CH3), 36.61
(CHSi)), 51.50 (CO2CH3), 123.57 (CH3CHCH), 125.72
(CH3CHCH), 128.31 (2-C of C6H4Cl-4), 129.82 (1-C of
C6H4Cl-4), 136.90 (4-C of C6H4Cl-4), 137.43 (3-C of C6H4Cl-4),
172.82 (CO2CH3). HRMS (APCI): m/z calcd for C24H21Cl3O2Si +
H+: 475.0449 [M + H]+; found: 475.0444.
Methyl (E)-4-(Tris(4-(trifluoromethyl)phenyl)silyl)pent-2-enoate
(4ea). Yield: 71% (NMR), 46% (isolated). Colorless powder. 1H
NMR (C6D6, rt): δ 0.94 (d, JHH = 7.1 Hz, 3H, CH3CHSi(C6H4CF3-
4)3), 2.34 (dtd, JHH = 7.5, 7.1, 1.6 Hz, 1H, CHSi(C6H4CF3-4)3), 3.37
(s, 3H, CO2CH3), 5.72 (dd, JHH = 15.6, 1.6 Hz, 1H, CH
10.8, 6.9, 0.7 Hz, 1H, CHCHCH3), 5.75 (ddq, JHH = 11.3, 10.8, 1.8
Hz, 1H, CHCHCH3), 6.88 (m, 6H, 3-CH of C6H4OCH3-4), 7.49
(m, 6H, 2-CH of C6H4OCH3-4). 13C{1H} NMR (CDCl3, rt): δ 13.05
(CH3), 37.54 (CHSi)), 51.19 (CO2CH3), 54.99 (C6H4OCH3-4),
113.41 (3-C of C6H4OCH3-4), 123.77 (1-C of C6H4OCH3-4), 124.38
(CH3CHCH), 124.81 (CH3CHCH), 137.77 (2-C of
C6H4OCH3-4), 160.87 (4-C of C6H4OCH3-4), 173.59 (CO2CH3).
HRMS (APCI): m/z calcd for C27H30O5Si + H+: 463.1935 [M + H]+;
found: 463.1922.
Methyl (E)-4-(Tri-p-tolylsilyl)pent-2-enoate (4ca). Yield: 100%
1
(NMR), 78% (isolated). Colorless powder. H NMR (C6D6, rt): δ
1.25 (d, JHH = 6.9 Hz, 3H, CH3), 2.76 (dtd, JHH = 7.2, 6.9, 1.6 Hz, 1H,
CHSi(C6H4CH3-4)3), 2.34 (s, 9H, C6H4CH3-4), 3.36 (s, 3H,
CO2CH3), 5.59 (dd, JHH = 15.7, 1.6 Hz, 1H, CHCHCO2CH3),
I
https://dx.doi.org/10.1021/acs.organomet.0c00597
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
CHCO2CH3), 7.23 (m, 6H, C6H4CF3-4), 7.28 (dd, JHH = 15.6, 7.5
(ipso-C of Ph), 134.95 (o-C of Ph), 173.35 (CO2CH3). This was
characterized by spectroscopic methods.
1
Hz, 1H, CHCHCO2CH3), 7.34 (m, 6H, C6H4CF3-4). H NMR
Methyl (E)-4-(Dimethyl(phenyl)silyl)pent-2-enoate (4ga). Yield:
(CDCl3, rt): δ 1.31 (d, JHH = 7.0 Hz, 3H, CH3CHSi(C6H4CF3-4)3),
2.891 (dtd, JHH = 7.3, 7.0, 1.7 Hz, 1H, CHSi(C6H4CF3-4)3), 3.67 (s,
3H, CO2CH3), 5.67 (dd, JHH = 15.6, 1.7 Hz, 1H, CHCHCO2CH3),
7.19 (dd, JHH = 15.6, 7.3 Hz, 1H, CHCHCO2CH3), 7.62 (m, 6H,
C6H4CF3-4), 7.65 (m, 6H, C6H4CF3-4). 13C{1H} NMR (CDCl3, rt):
δ 13.61 (CH3CHSi), 24.83 (CHSi), 51.51 (CO2CH3), 119.50 (CH
CHCO2CH3), 123.81 (q, JCF = 272.5 Hz, CF3), 124.95 (q, JCF = 3.8
Hz, 3-C of C6H4CF3-4), 132.41 (q, JCF = 32.6 Hz, 4-C of C6H4CF3-4),
136.04 (1-C of C6H4CF3-4), 136.12 (2-C of C6H4CF3-4), 150.31
(CHCHCO2CH3), 166.77 (CO2CH3). 19F{1H} NMR (CDCl3, rt):
δ −63.06. HRMS (APCI): m/z calcd for C27H21F9O2Si + H+:
577.1240 [M + H]+; found: 577.1221.
1
52% (NMR), 43% (isolated). Colorless oil. H NMR (C6D6, rt): δ
0.08 (s, 3H, SiCH3), 0.09 (s, 3H, SiCH3), 0.86 (d, JHH = 6.9 Hz, 3H,
CH3CHSi(CH3)2Ph), 1.72 (dqd, JHH = 7.7, 6.9, 1.7 Hz, 1H,
CHSi(CH3)2Ph), 3.45 (s, 3H, CO2CH3), 5.76 (dd, JHH = 15.6, 1.7
Hz, 1H, CHCHCO2CH3), 7.13−7.19 (m, 3H, m,p-Ph), 7.30−7.34
(m, 2H, o-Ph), 7.32 (dd, JHH = 15.6, 7.7 Hz, 1H, CHCHCO2CH3).
13C{1H} NMR (C6D6, rt): δ −5.64 (CH3), −4.90 (CH3), 12.72
(CH3CHSi), 28.01 (CHSi), 50.81 (CO2CH3), 117.27 (CH
CHCO2CH3), 128.09 (p-C of Ph), 129.60 (m-C of Ph), 134.15 (o-
C of Ph), 136.45 (ipso-C of Ph), 153.23 (CHCHCO2CH3), 166.89
1
(CO2CH3). H NMR (CDCl3, rt): δ 0.308 (s, 3H, SiCH3), 0.312 (s,
3H, SiCH3), 1.10 (d, JHH = 6.9 Hz, 3H, CH3CHSi(CH3)2Ph), 2.09
(dqd, JHH = 7.5, 6.9, 1.7 Hz, 1H, CHSi(CH3)2Ph), 3.71 (s, 3H,
CO2CH3), 5.60 (dd, JHH = 15.6, 1.7 Hz, 1H, CHCHCO2CH3),
7.14 (dd, JHH = 15.7, 7.5 Hz, 1H, CHCO2CH3), 7.33−7.40 (m, 3H,
m,p-Ph), 7.45−7.50 (m, 2H, o-Ph). 13C{1H} NMR (CDCl3, rt): δ
−5.41 (SiCH3), −4.79 (SiCH3), 12.75 (CH3CHSi), 28.13 (CHSi),
51.24 (CO2CH3), 116.50 (CHCHCO2CH3), 127.83 (m-C of Ph),
129.39 (p-C of Ph), 133.86 (o-C of Ph), 136.32 (ipso-C of Ph), 153.69
(CHCHCO2CH3), 167.45 (CO2CH3). HRMS (APCI): m/z calcd
for C14H20O2Si + H+: 249.1305 (M + H)+; found: 249.1302.
Methyl (Z)-2-(Tris(4-(trifluoromethyl)phenyl)silyl)pent-3-enoate
(5ea). Yield: 97% (NMR), 35% (isolated). Colorless powder. 1H
NMR (C6D6, rt): δ 1.23 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3), 3.01 (s,
3H, CO2CH3), 3.98 (dd, JHH = 11.2, 0.8 Hz, 1H, CH(Si(C6H4CF3-
4)3)(CO2CH3)), 5.34 (dqd, JHH = 10.8, 6.9, 0.8 Hz, 1H, CH
CHCH3), 5.85 (ddq, JHH = 11.2, 10.8, 1.8 Hz, 1H, CHCHCH3),
7.31 (m, 6H, C6H4CF3-4), 7.47 (m, 6H, C6H4CF3-4). 1H NMR
(CDCl3, rt): δ 1.40 (dd, JHH = 6.8, 1.7 Hz, 3H, CH3), 3.39 (s, 3H,
CO2CH3), 4.06 (dd, JHH = 11.2, 0.8 Hz, 1H, CH(Si(C6H4CF3-
4)3)(CO2CH3)), 5.55 (dqd, JHH = 10.9, 6.8, 0.8 Hz, 1H, CH
CHCH3), 5.78 (tq, JHH = 10.9, 1.7 Hz, 1H, CHCHCH3), 7.64 (m,
6H, C6H4CF3-4), 7.69 (m, 6H, C6H4CF3-4). 13C{1H} NMR (CDCl3,
Methyl (Z)-2-(Dimethyl(phenyl)silyl)pent-3-enoate (5ga). Yield:
18% (NMR). 1H NMR (CDCl3, rt): δ 0.37 (s, 6H, SiCH3), 1.31 (dd,
JHH = 6.9, 1.7 Hz, 3H, CH3CH), 3.38 (d, JHH = 11.0 Hz, 1H,
rt): δ 13.15 (CH3), 36.16 (CHSi)), 51.66 (CO2CH3), 123.86 (q, JCF
=
CH(SiPh2CH3)(CO2CH3)), 3.51 (s, 3H, OCH3), 5.39 (dq, JHH
=
272.2 Hz, CF3), 124.67 (q, JCF = 3.8 Hz, 3-C of C6H4CF3-4), 122.95
(CH3CHCH), 126.53 (CH3CHCH), 132.45 (q, JCF = 32.6 Hz,
4-C of C6H4CF3-4), 135.74 (CSi), 136.448 (2-C of C6H4CF3-4),
172.45 (CO2CH3). 19F NMR (CDCl3, rt): δ −63.06. HRMS (APCI):
m/z calcd for C27H21F9O2Si + H+: 577.1240 [M + H]+; found:
577.1238.
11.0, 6.9 Hz, 1H, CH3CH), 6.06 (tq, JHH = 11.0, 1.7 Hz, CH
CHCH3), 7.10−7.19 (m, 3H, m,p-Ph), 7.45−7.51 (m, 2H, o-Ph). This
was characterized by spectroscopic methods.
Methyl (E)-4-(Triethoxysilyl)pent-2-enoate (4ha). Yield: 83%
(NMR). 1H NMR (C6D6, rt): δ 1.08 (t, JHH = 7.2 Hz, 3H,
CH3CH2OSi), 1.17 (d, JHH = 7.2 Hz, 3H, CH3CHSi(OCH2CH3)3),
1.91 (dtd, JHH = 7.5, 7.2, 1.7 Hz, 1H, CH3CHSi(OCH2CH3)3), 3.42
(s, 3H, CO2CH3), 3.69 (q, JHH = 7.2 Hz, 1H, CH3CH2OSi), 5.98 (dd,
Methyl (E)-4-(Methyldiphenylsilyl)pent-2-enoate (4fa). Yield:
1
78% (NMR), 83% (isolated). Colorless oil. H NMR (C6D6, rt): δ
0.29 (s, 3H, SiCH3), 0.96 (d, JHH = 7.0 Hz, 3H, CH3CHSiCH3Ph2),
2.19 (dqd, JHH = 7.5, 7.0, 1.6 Hz, 1H, CHSiCH3Ph2), 3.40 (s, 3H,
CO2CH3), 5.78 (dd, JHH = 15.6, 1.6 Hz, 1H, CHCHCO2CH3),
7.10−7.19 (m, 6H, m,p-Ph), 7.39−7.45 (m, 4H, o-Ph), 7.410 (dd, JHH
= 15.6, 7.5 Hz, 1H, CHCHCO2CH3). 13C{1H} NMR (C6D6, rt): δ
−6.40 (CH3), 13.11 (CH3), 26.49 (CHSi), 50.80 (CO2CH3), 117.98
(CHCHCO2CH3), 128.22 (m-C) (overlapped with carbon of
C6D6), 129.79 (p-C of Ph), 129.84 (p-C of Ph), 134.77 (ipso-C of Ph),
134.85 (ipso-C of Ph), 135.08 (o-C of Ph), 135.10 (o-C of Ph), 152.27
J
HH = 15.8, 1.7 Hz, 1H, CHCHCO2CH3), 7.55 (dd, JHH = 15.8, 7.5
Hz, 1H, CHCHCO2CH3). 13C{1H} NMR (C6D6, rt): δ 12.40
(CH3CHSi), 18.37 (CH3CH2O), 24.95 (CHSi), 50.82 (CO2CH3),
59.05 (CH3CH2O), 118.15 (CHCHCO2CH3), 151.91 (CH
CHCO2CH3), 166.89 (CO2CH3). This was characterized by
spectroscopic methods.
Methyl (E)-4-(Benzyldimethylsilyl)pent-2-enoate (4ia). Yield:
1
30% (NMR). H NMR (C6D6, rt): δ −0.24 (s, 3H, SiCH3), −0.22
(s, 3H, SiCH3), 0.84 (d, JHH = 7.0 Hz, 3H, CH3CHSi), 1.54 (dqd, JHH
= 7.6, 7.0, 1.6 Hz, 1H, CH3CHSi), 1.85 (s, 2H, CH2Ph), 3.47 (s, 3H,
OCH3), 5.78 (dd, JHH = 15.6, 1.6 Hz, 1H, CHCHCO2CH3), 6.82
(m, 2H, o-Ph), 6.98 (m, 1H, p-Ph), 7.10 (m, 2H, m-Ph), 7.30 (dd, JHH
1
(CHCHCO2CH3), 166.77 (CO2CH3). H NMR (CDCl3, rt): δ
0.55 (s, 3H, SiCH3), 1.17 (d, JHH = 6.9 Hz, 3H, CH3CHSiCH3Ph2),
2.51 (dqd, JHH = 7.3, 6.9, 1.7 Hz, 1H, CHSiPh3), 3.68 (s, 3H,
CO2CH3), 5.62 (dd, JHH = 15.6, 1.7 Hz, 1H, CHCHCO2CH3),
7.19 (dd, JHH = 15.6, 7.3 Hz, 1H, = CHCO2CH3), 7.32−7.43 (m, 6H,
m,p-Ph), 7.48−7.53 (m, 4H, o-Ph). 13C{1H} NMR (CDCl3, rt): δ
−6.44 (SiCH3), 13.08 (CH3CHSi), 26.55 (CHSi), 51.25 (CO2CH3),
117.22 (CHCHCO2CH3), 127.93 (m-C of Ph), 129.62 (p-C of
Ph), 134.45 (o-C of Ph), 134.74 (ipso-C of Ph), 153.15 (CH
CHCO2CH3), 167.31 (CO2CH3). This compound was characterized
by spectroscopic methods.
1
= 15.6, 7.6 Hz, 1H, CHCHCO2CH3). H NMR (CDCl3, rt): δ
−0.04 (s, 3H, SiCH3), −0.03 (s, 3H, SiCH3), 1.13 (d, JHH = 6.9 Hz,
3H, CH3CHSi), 1.92 (dqd, JHH = 7.7, 6.9, 1.7 Hz, 1H, CH3CHSi),
2.11 (s, 2H, CH2Ph), 3.71 (s, 3H, OCH3), 5.63 (dd, JHH = 15.6, 1.7
Hz, 1H, CHCHCO2CH3), 6.98 (dm, JHH = 7.0, 2H, o-Ph), 7.07 (t,
m, JHH = 7.37 Hz, 1H, p-Ph), 7.14 (dd, JHH = 15.6, 7.7 Hz, 1H, CH
CHCO2CH3), 7.20 (t, m, JHH = 7.37−7.73 Hz, 2H, m-Ph). 13C{1H}
NMR (CDCl3, rt): δ −5.43 (CH3Si), −5.26 (CH3Si), 12.66
(CH3CHSi), 23.60 (CH2Ph), 27.06 (CHSi), 51.29 (OCH3), 116.42
(CHCHCO2CH3), 124.27 (p-C of Ph), 128.16 (o or m-C of Ph),
128.32 (o or m-C of Ph), 139.16 (ipso-C of Ph), 153.68 (CH
CHCO2CH3), 167.47 (CO2CH3). This was characterized by
spectroscopic methods.
Methyl (Z)-2-(Methyldiphenylsilyl)pent-3-enoate (5fa). Yield:
14% (NMR). 1H NMR (C6D6, rt): δ 0.66 (s, 3H, SiCH3), 1.14
(dd, JHH = 6.9, 1.8 Hz, 3H, CH3CH), 3.16 (s, 3H, CO2CH3), 3.88
(dd, JHH = 11.1, 0.9 Hz, 1H, CH(SiPh2CH3)(CO2CH3)), 5.30 (dqd,
J
HH = 10.9, 6.9, 0.9 Hz, 1H, CH3CH), 6.06 (ddq, JHH = 11.1, 10.9,
1.8 Hz, 1H, CHCHCH3), 7.10−7.19 (m, 6H, m,p-Ph), 7.42−7.47
Methyl (E)-4-(Triethylsilyl)pent-2-enoate (4ja). Yield: 62%
1
1
(m, 4H, o-Ph). H NMR (CDCl3, rt): δ 0.66 (s, 3H, SiCH3), 1.27
(NMR), 48% (isolated). Colorless oil. H NMR (C6D6, rt): δ 0.39
(dd, JHH = 6.9, 1.8 Hz, 3H, CH3CH), 3.39 (s, 3H, CO2CH3), 3.88
(q, JHH = 8.0 Hz, 6H, CH3CH2Si), 0.89 (t, JHH = 8.0 Hz, 9H,
(dd, JHH = 11.0, 0.8 Hz, 1H, CH(SiPh2CH3)(CO2CH3)), 5.39 (dqd,
CH3CH2Si), 0.91 (d, JHH = 7.0 Hz, 3H, CH3CHSi), 1.70 (dqd, JHH
7.6, 7.0, 1.7 Hz, 1H, CH3CHSi), 3.47 (s, 3H, OCH3), 5.82 (dd, JHH
=
=
J
HH = 11.0, 6.9, 0.8 Hz, 1H, CH3CH), 5.71 (tq, JHH = 11.0, 1.8 Hz,
1H, CHCHCH3), 7.30−7.41 (m, 6H, m,p-Ph), 7.57 (m, 4H, o-Ph).
13C{1H} NMR (CDCl3, rt): δ −5.32 (CH3Si), 12.97 (CH3), 37.63
(CHSiPh3), 51.19 (CO2CH3), 123.79 (CH3CHCH), 124.09
(CH3CHCH), 127.73 (m-C of Ph), 129.71 (p-C of Ph), 134.91
15.6, 1.7 Hz, 1H, CHCHCO2CH3), 7.30 (dd, JHH = 15.6, 7.6 Hz,
1H, CHCHCO2CH3). 13C{1H} NMR (C6D6, rt): δ 2.29
(CH3CH2Si), 7.56 (CH3CH2Si), 12.83 (CH3CHSi), 25.61
(CH3CHSi), 50.81 (CO2CH3), 116.49 (CHCHCO2CH3), 154.10
J
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Article
(CHCHCO2CH3), 167.03 (CO2CH3). HRMS (APCI): m/z calcd
for C12H24O2Si + H+: 229.1618 (M + H)+; found: 229.1612.
Methyl (E)-4-(Diphenylsilyl)pent-2-enoate (4ka). Yield: 79%
δ 12.62 (CH3), 15.75 (CH3), 25.91 (CHSi), 51.63 (CO2CH3), 125.10
(CHCCH3CO2CH3), 127.86 (m-C of SiPh3), 129.66 (p-C of
SiPh3), 133.10 (ipso-C of SiPh3), 136.06 (o-C of SiPh3), 145.46
(CHCCH3CO2CH3), 168.69 (CO2CH3). This was characterized
by spectroscopic methods.
1
(NMR). H NMR (C6D6, rt): δ 1.02 (d, JHH = 7.0 Hz, 3H, CH3),
2.20 (dqdd, JHH = 7.5, 7.0, 2.9, 1.6 Hz, 1H, CH3CH(SiPh3)), 3.38 (s,
3H, CO2CH3), 4.85 (d, JHH = 2.9 Hz, 1H, SiH), 5.77 (dd, JHH = 15.6,
1.6 Hz, 1H, CHCHCO2CH3), 7.07−7.18 (m, 6H, m,p-Ph), 7.59
(dd, JHH = 15.6, 7.5 Hz, CHCHCO2CH3), 7.44−7.52 (m, 4H, o-
Ph). 13C{1H} NMR (C6D6, rt): δ 13.66 (CH3), 25.27 (CHSi), 50.84
(CO2CH3), 118.38 (CHCHCO2CH3), 128.37 (m-C of SiPh2H),
128.39 (m-C of SiPh2H), 130.24 (p-C of SiPh2H), 130.29 (p-C of
SiPh2H), 131.98 (ipso C), 132.17 (ipso C), 135.71 (o-C of SiPh2H),
135.81 (o-C of SiPh2H), 152.07 (CHCHCO2CH3), 166.65
(CO2CH3). This was characterized by spectroscopic methods.
Methyl (Z)-2-(Diphenylsilyl)pent-3-enoate (5ka). Yield: 50%
Methyl (Z)-2-Methyl-4-(triphenylsilyl)pent-2-enoate ((Z)-4ad).
1
Yield: 17% (NMR). H NMR (CDCl3, rt): δ 1.24 (d, JHH = 7.1
Hz, 3H, CH3CHSiPh3), 1.80 (d, JHH = 1.1 Hz, 3H, C(CH3)), 3.48
(s, 3H, CO2CH3), 4.05 (dq, JHH = 11.8, 7.1 Hz, 1H, CH3CH(SiPh3)),
6.84 (dq, JHH = 11.8, 1.3 Hz, 1H, CHCHCO2CH3), 7.30−7.35 (m,
6H, m -Ph), 7.35−7.41 (m, 3H, p-Ph), 7.49−7.55 (m, 6H, o-Ph).
13C{1H} NMR (CDCl3, rt): δ 16.11 (CH3), 20.94 (CH3), 22.78
(CHSi), 50.90 (CO2CH3), 124.30 (CHCCH3CO2CH3), 127.68
(m-C of SiPh3), 129.41 (p-C of SiPh3), 133.54 (ipso-C of SiPh3),
136.11 (o-C of SiPh3), 146.97 (CHCCH3CO2CH3), 168.27
(CO2CH3). This was characterized by spectroscopic methods.
Ethyl (E)-3-Methyl-4-(triphenylsilyl)pent-2-enoate (4ae). Yield:
86% (NMR), 53% (isolated). Yellow powder. 1H NMR (C6D6, rt): δ
0.98 (t, JHH = 7.2 Hz, 3H, CO2CH2CH3), 1.23 (d, JHH = 7.4 Hz, 3H,
CH3CHSiPh3), 2.19 (d, JHH = 1.2 Hz, 3H, C(CH3)), 1.55 (qd, JHH
= 7.4, 0.6 Hz, 1H, CH3CHSiPh3), 4.01 (dt, JHH = 10.0, 7.2 Hz, 2H,
1
(NMR). H NMR (C6D6, rt): δ 1.19 (dd, JHH = 6.9, 1.8 Hz, 3H,
CH3), 3.20 (s, 3H, CO2CH3), 3.92 (dd, JHH = 10.8, 2.9 Hz, 1H,
CH(SiPh2H)(CO2CH3)), 5.18 (d, JHH = 2.9 Hz, 1H, SiH), 5.33 (dqd,
JHH = 10.8, 6.9, 1.0 Hz, 1H, CHCHCH3), 6.11 (tqd, 10.8, 1.8, 0.4
Hz, 1H, CHCHCH3), 7.07−7.20 (m, 6H, m,p-Ph), 7.63−7.71 (m,
4H, o-Ph). 13C{1H} NMR (C6D6, rt): δ 12.98 (CH3), 36.69
(CHSiPh3), 51.00 (CO2CH3), 123.93 (CH3CHCH), 124.91
(CH3CHCH), 128.22 (m-C of Ph), 128.24 (m-C of Ph), 130.32
(p-C of Ph), 130.36 (p-C of Ph), 131.96 (ipso-C of Ph), 132.17 (ipso-
C of Ph), 135.92 (o-C of Ph), 136.02 (o-C of Ph), 172.36 (CO2CH3).
This was characterized by spectroscopic methods.
CO2CH2CH3), 5.76 (qd, JHH
=
1.2, 0.6 Hz, 1H,

CH(CO2CH2CH3)), 7.10−7.20 (m, 9H, m,p-Ph), 7.57−7.62 (m,
6H, o-Ph). 13C{1H} NMR (C6D6, rt): δ 14.43 (CO2CH2CH3), 15.92
(CH3CHSiPh3), 20.76 (C(CH3)), 34.03 (CH3CHSiPh3), 59.21
(CO2CH2CH3), 116.09 (CH(CO2CH2CH3)), 128.17 (p-C of
SiPh3), 129.94 (m-C of SiPh3), 133.68 (ipso-C of SiPh3), 136.62 (o-
C of SiPh3), 163.46 (C(CH3){CH(SiPh3)(CH3)}, 166.53
(CO2CH2CH3). HRMS (APCI): m/z calcd for C26H28O2Si + H+:
401.1931 (M + H)+; found: 401.1916.
Methyl (E)-4-(Triphenylsilyl)hex-2-enoate (4ab). Yield: 90%
1
(NMR), 64% (isolated). Colorless powder. H NMR (C6D6, rt): δ
0.78 (t, JHH = 7.5 Hz, 3H, CH3), 1.47 (dq, JHH = 11.1, 7.5 Hz, 1H,
CHHCH(SiPh3)), 1.82 (qd, JHH = 7.5, 2.3 Hz, 1H, CHHCH(SiPh3)),
2.45 (dddd, JHH = 11.1, 9.7, 2.3, 1.2 Hz, 1H, CH2CH(SiPh3)), 3.33 (s,
3H, CO2CH3), 5.81 (dd, JHH = 15.9, 1.2 Hz, 1H, CHCHCO2CH3),
7.13−7.17 (m, 9H, m,p-Ph), 7.31 (dd, JHH = 15.9, 9.7 Hz, 1H, CH
Methyl (Z)-4-Methyl-2-(triphenylsilyl)hex-3-enoate (5af). Yield:
45% (NMR), 25% (isolated). Colorless powder. 1H NMR (C6D6, rt):
δ 0.69 (dd, JHH = 7.6 Hz, 3H, CH2CH3), 1.62 (d, JHH = 1.2 Hz, 3H,
CCH3), 1.654 (dq, JHH = 14.2, 7.6 Hz, 1H, CHHCH3), 1.88 (dqd, JHH
= 14.2, 7.6, 0.8 Hz, 1H, CHHCH3), 3.12 (s, 3H, OCH3), 4.16 (d, JHH
= 11.2 Hz, 1H, CH(SiPh3)(CO2CH3)), 5.90 (dq, JHH = 11.2, 1.2 Hz,
1H, CH), 7.17 (m, 6H, m-Ph), 7.76 (m, 3H, p-Ph), 7.80 (m, 6H, o-
Ph). 13C{1H} NMR (C6D6, rt): δ 12.17 (CH3CH2C), 22.81
(CH3C), 25.16 (CH3CH2C), 37.96 (CSiPh3), 50.87 (OCH3),
118.88 (CH), 130.08 (m-C of Ph), 133.29 (ipso-C of Ph), 136.62
(p-C of Ph), 136.85 (o-C of Ph), 138.33 (C), 173.21 (CO2CH3).
1H NMR (CDCl3, rt): δ 0.74 (dd, JHH = 7.7, 7.5 Hz, 3H, CH2CH3),
1.62 (d, JHH = 1.2 Hz, 3H, CCH3), 1.67 (dq, JHH = 13.7, 7.5 Hz, 1H,
CHHCH3), 1.89 (dq, JHH = 13.7, 7.7 Hz, 1H, CHHCH3), 3.32 (s, 3H,
OCH3), 3.91 (d, JHH = 11.2 Hz, 1H, CH(SiPh3)(CO2CH3)), 5.47 (d,
1
CHCO2CH3), 7.56−7.59 (m, 6H, o-Ph). H NMR (CDCl3, rt): δ
0.91 (t, JHH = 7.5 Hz, 3H, CH3), 1.58 (ddq, JHH = 14.2, 10.0, 7.5 Hz,
1H, CHHCH(SiPh3)), 1.89 (dqd, JHH = 14.2, 7.5, 2.3 Hz, 1H,
CHHCH(SiPh3)), 2.59 (ddd, JHH = 10.0, 9.7, 2.3 Hz, 1H,
CH2CH(SiPh3)), 3.65 (s, 3H, CO2CH3), 5.63 (dd, JHH = 15.6, 0.9
Hz, 1H, CHCHCO2CH3), 7.03 (dd, JHH = 15.6, 9.7 Hz, 1H, CH
CHCO2CH3), 7.352 (m, 3H, m-Ph), 7.41 (m, 3H, p-Ph), 7.52 (m,
6H, o-Ph). 13C{1H} NMR (CDCl3, rt): δ 14.52 (CH3), 22.42 (CH2),
34.90 (CHSi), 51.24 (CO2CH3), 119.92 (CHCHCO2CH3), 127.94
(m-C of SiPh3), 129.74 (p-C of SiPh3), 132.95 (ipso-C of SiPh3),
136.01 (o-C of SiPh3), 151.15 (CHCHCO2CH3), 166.98
(CO2CH3). HRMS (APCI): m/z calcd for C25H26O2Si + H+:
387.1775 (M + H)+; found: 387.1781.
J
HH = 11.2 Hz, 1H, CH), 7.34 (m, 6H, m-Ph), 7.41 (m, 3H, p-Ph),
Methyl 4-Methyl-2-(triphenylsilyl)pent-3-enoate (5ac). Yield:
7.57 (m, 6H, o-Ph). 13C{1H} NMR (CDCl3, rt): δ 11.96
(CH3CH2C), 22.86 (CH3C), 24.81 (CH3CH2C), 37.34
(CSiPh3), 51.16 (OCH3), 117.58 (CH), 127.66 (m-C of Ph),
129.77 (p-C of Ph), 132.54 (ipso-C of Ph), 136.31 (o-C of Ph), 138.59
(C), 173.77 (CO2CH3). This was characterized by spectroscopic
methods.
1
82% (NMR), 59% (isolated). Colorless powder. H NMR (C6D6,
rt): δ 1.23 (d, JHH = 1.2 Hz, 3H, CH3), 1.45 (d, JHH = 1.4 Hz, 3H,
CH3), 3.12 (s, 3H, CO2CH3), 4.07 (d, JHH = 11.2 Hz, 1H, CH
CH(SiPh3)(CO2CH3)), 5.86 (d, JHH = 11.2 Hz, 1H, (CH3)21CCH),
7.11−7.18 (m, 9H, m, p-Ph), 7.53−7.60 (m, 6H, o-Ph). H NMR
(CDCl3, rt): δ 1.30 (d, JHH = 1.4 Hz, 3H, CH3), 1.61 (d, JHH = 1.3 Hz,
3H, CH3), 3.32 (s, 3H, CO2CH3), 3.87 (d, JHH = 11.2 Hz, 1H, CH
CH(SiPh3)(CO2Me)), 5.50 (dqq, JHH = 11.2, 1.4, 1.3 Hz, 1H,
(CH3)2CCH), 7.34 (m, 6H, m-Ph), 7.41 (m, p-Ph, 3H), 7.57 (m, o-
Ph, 6H). 13C{1H} NMR (CDCl3, rt): δ 17.98 (CH3, cis to CHSi),
25.81 (CH3, trans to CHSi), 37.87 (CH(SiPh3)(CO2Me)), 51.13
(CO2CH3), 118.16 ((CH3)2CHCH), 127.67 (m-C of SiPh3),
129.76 (p-C of SiPh3), 132.62 (ipso-C of SiPh3), 132.95
((CH3)2CHCH), 136.29 (o-C of SiPh3), 173.70 (CO2CH3).
HRMS (APCI): m/z calcd for C25H26O2Si + H+: 387.1775 (M +
H)+; found: 387.1786.
Methyl (E)-2-Methyl-4-(triphenylsilyl)pent-2-enoate ((E)-4ad).
Yield: 77% (NMR), 46% (isolated). Colorless oil. 1H NMR
(CDCl3, rt): δ 1.29 (d, JHH = 7.1 Hz, 3H, CH3CHSiPh3), 1.53 (d,
JHH = 1.4 Hz, 3H, C(CH3)), 2.86 (dq, JHH = 12.0, 7.1 Hz, 1H,
CH3CH(SiPh3)), 3.68 (s, 3H, CO2CH3), 6.84 (dq, JHH = 12.0, 1.4
Hz, 1H, CHCHCO2CH3), 7.32−7.38 (m, 6H, m -Ph), 7.38−7.44
(m, 3H, p-Ph), 7.51−7.56 (m, 6H, o-Ph). 13C{1H} NMR (CDCl3, rt):
Methyl (E)-4-Methyl-2-(triphenylsilyl)hex-4-enoate (6af). Yield:
21% (NMR), 14% (isolated). Colorless powder. 1H NMR (C6D6, rt):
δ 1.45 (dq, JHH = 6.7, 1.0 Hz, 3H, CHCH3), 1.53 (dd, JHH = 1.2,
1.0 Hz, 3H, C(CH2)(CH3)), 2.48 (dd, JHH = 14.6, 1.6 Hz, 1H,
CHH), 3.04 (dd, JHH = 14.6, 12.2 Hz, 1H, CHH), 3.11 (s, 3H,
OCH3), 3.34 (dd, JHH = 12.2, 1.6 Hz, 1H, CH(SiPh3)(CO2CH3)),
5.38 (qq, JHH = 6.7, 1.2 Hz, 1H, CHCH3), 7.34 (m, 6H, m-Ph),
7.41 (m, 3H, p-Ph), 7.57 (m, 6H, o-Ph). 13C {1H} NMR (C6D6, rt): δ
13.50 (CHCH3), 15.57 (C(CH2)(CH3)), 35.15 (CH(SiPh3)-
(CO2CH3)), 38.82 (C(CH2)(CH3)), 50.73 (OCH3), 119.48 (
C(CH2)(CH3)), 130.08 (m-C of Ph), 133.29 (ipso-C of Ph), 136.62
(p-C of Ph), 135.27 (C), 136.85 (o-C of Ph), 174.91 (CO2CH3).
1H NMR (CDCl3, rt): δ 1.52 (d, JHH = 6.6 Hz, 3H, CHCH3), 1.55
(d, JHH = 1.2 Hz, 3H, C(CH2)(CH3)), 2.27 (dd, JHH = 14.9, 2.0
Hz, 1H, CHH), 2.65 (dd, JHH = 14.9, 12.1 Hz, 1H, CHH), 3.10 (dd,
J
HH = 12.1, 2.0 Hz, 1H, CH(SiPh3)(CO2CH3)), 3.27 (s, 3H, OCH3),
5.20 (qq, JHH = 6.6, 1.2 Hz, 1H, CH), 7.34 (m, 6H, m-Ph), 7.41 (m,
3H, p-Ph), 7.57 (m, 6H, o-Ph). 13C{1H} NMR (CDCl3, rt): δ 13.39
K
https://dx.doi.org/10.1021/acs.organomet.0c00597
Organometallics XXXX, XXX, XXX−XXX

Organometallics
pubs.acs.org/Organometallics
Article
(CHCH3), 15.52 (C(CH2)(CH3)), 34.62 (CH(SiPh3)-
(CO2CH3)), 38.10(C(CH2)(CH3)), 50.94 (OCH3), 119.11 (
C(CH2)(CH3)), 127.80 (m-C of Ph), 129.81 (p-C of Ph), 132.58
(ipso-C of Ph), 135.14 (C(CH2)(CH3)), 136.10 (o-C of Ph),
175.23 (CO2CH3). HRMS (APCI): m/z calcd for C26H28O2Si + H+:
401.1931 (M + H)+; found: 401.1921.
C6H4CF3-4), 7.56−7.60 (m, 6H, o-Ph). 1H NMR (CDCl3, rt): δ 1.51
(dd, JHH = 6.9, 1.9 Hz, 3H, CH3CH), 4.17 (d, JHH = 11.2 Hz, 1H,
CH(C6H4CF3-4)(SiPh3)), 5.52 (dqd, JHH = 10.6, 6.9, 0.9 Hz, 1H,
CH3CH), 5.89 (ddq, JHH = 11.2, 10.6, 1.9 Hz, 1H, CH3CHCH),
6.95 (d, JHH = 8.2 Hz, 2H, 2-CH of C6H4CF3-4), 7.27−7.35 (m, 6H,
m-Ph), 7.321 (d, JHH = 8.2 Hz, 2H, 3-CH of C6H4CF3-4), 7.37−7.43
(m, 9H, o,p-Ph). 13C{1H} NMR (CDCl3, rt): 13.15 (CH3), 35.02
(E)-(4-(4-Nitrophenyl)but-3-en-2-yl)triphenylsilane (4ah). Yield:
89% (NMR), 65% (isolated). Yellow powder. 1H NMR (C6D6, rt): δ
1.32 (d, JHH = 7.5 Hz, 3H, CH3), 2.65 (qui.d, JHH = 7.5, 1.7 Hz, 1H,
CH(SiPh3)(CO2CH3)), 5.96 (dd, JHH = 16.2, 1.7 Hz, 1H, 
CHC6H4NO2-4), 6.46 (dd, JHH = 16.2, 7.5 Hz, 1H, CHCH
C6H4NO2-4), 6.67 (m, 2H, C6H4NO2-4), 7.17−7.21 (m, 9H, m,p-
1
(CH(C6H4CF3-4)(SiPh3)), 124.39 (q, JCF = 272 Hz, CF3), 124.85
(CH3CH), 124.90 (3-C of C6H4CF3-4), 127.15 (q, 2JCF = 33 Hz, 4-
C of C6H4CF3-4), 127.88 (m-C of SiPh3), 128.73 (2-C of C6H4CF3-
4), 129.84 (CH3CHC), 129.7262 (p-C of SiPh3), 132.89 (ipso-C of
SiPh3), 136.48 (o-C of SiPh3), 146.55 (1-C of C6H4CF3-4). 19F NMR
(CDCl3, rt): −62.01. This was characterized by spectroscopic
methods.
1
Ph), 7.59−7.62 (m, 6H, o-Ph), 7.72 (m, 2H, C6H4NO2-4). H NMR
(CDCl3, rt): δ 1.37 (d, JHH = 7.1 Hz, 3H, CH3), 2.85 (dq, JHH = 7.5,
7.1 Hz, 1H, CH(SiPh3)(CO2CH3)), 6.19 (d JHH = 16.1 Hz, 1H, 
CHC6H4NO2-4), 6.60 (dd, JHH = 16.1, 7.5 Hz, 1H, CHCH
C6H4NO2-4), 7.23 (m, 2H, C6H4NO2-4), 7.35 (m, 6H, m-Ph), 7.42
(m, 3H, p-Ph), 7.55 (m, 6H, o-Ph), 8.08 (m, 2H, C6H4NO2-4).
13C{1H} NMR (CDCl3, rt): δ 14.39 (CH3CHSiPh3), 25.66
(CH3CHSiPh3), 124.02 (2-C of C6H4NO2-4), 125.81 (
CHC6H4NO2-4), 125.92 (3-C of C6H4NO2-4), 127.93 (m-C of Ph),
129.74 (p-C of Ph), 133.20, (ipso-C of Ph), 136.04 (o-C of Ph),
139.21 (CHCHC6H4NO2-4), 144.74 (4-C of C6H4NO2-4), 146.02
(ipso-C of C6H4NO2-4). HRMS (APCI): m/z calcd for C28H26NO2Si
+ H+: 436.1727 (M + H)+; found: 436.1721.
(E)-Triphenyl(4-phenylbut-3-en-2-yl)silane (4aj). Yield: 40%
1
(NMR), 13% (isolated). Colorless oil. H NMR (C6D6, rt): δ 1.39
(d, JHH = 7.3 Hz, 3H, CH3), 2.71 (dqd, JHH = 7.7, 7.3, 1.3 Hz, 1H,
CHPh(SiPh3)), 6.29 (dd, JHH = 15.9, 1.3 Hz, 1H, CHCHPh), 5.53
(tq, JHH = 15.9, 7.7 Hz, 1H, CHCHPh), 7.10−7.21 (m, 14H, m,p-
Ph in SiPh3 and Ph), 7.55−7.62 (m, 6H, o-Ph in SiPh3). HRMS
(APCI): m/z calcd for C28H26Si + H+: 391.1877 (M + H)+; found:
391.1859.
(Z)-Triphenyl(1-phenylbut-2-en-1-yl)silane (5aj). Yield: 59%
1
(NMR), 45% (isolated). Colorless powder. H NMR (C6D6, rt): δ
1.45 (dd, JHH = 6.8, 1.9 Hz, 3H, CH3), 4.23 (dd, JHH = 11.3, 0.9 Hz,
1H, CHPh(SiPh3)), 5.44 (dqd, JHH = 10.7, 6.8, 0.9 Hz, 1H, CH
CHCH3), 6.11 (ddq, JHH = 11.3, 10.7, 1.9 Hz, 1H, CHCHCH3),
7.10−7.21 (m, 14H, m,p-Ph in SiPh3 and Ph), 7.55−7.62 (m, 6H, o-
Ph in SiPh3). 1H NMR (CDCl3, rt): δ 1.50 (dd, JHH = 6.7, 1.7 Hz, 3H,
(Z)-(1-(4-Nitrophenyl)but-2-en-1-yl)triphenylsilane (5ah). Yield:
1
31% (NMR), 20% (isolated). Light yellow powder. H NMR (C6D6,
rt): δ 1.37 (dd, JHH = 6.8, 1.8 Hz, 3H, CHCH3), 4.07 (d, JHH = 10.9
Hz, 1H, CH(C6H4NO2-4)(SiPh3)), 5.411 (dq, JHH = 10.9, 6.8 Hz,
1H, CHCH3), 5.86 (tq, JHH = 10.9, 1.8 Hz, 1H, CHCHCH3),
6.62 (m, 2H, 3-CH of C6H4NO2-4), 7.10 (m, 6H, m-Ph), 7.17 (m,
3H, p-Ph), 7.46 (m, 6H, o-Ph), 7.69 (m, 2H, 2-CH of C6H4NO2-4).
13C{1H} NMR (C6D6, rt): δ 13.17 (CH3), 35.84 (CHSiPh3), 123.33
(2-C of C6H4NO2-4), 125.56 (CHCHCH3), 128.12 (m-C of Ph),
128.82 (CHCHCH3), 129.22 (3-C of C6H4NO2-4), 130.18 (p-C
ofPh), 133.02 (ipso-C of Ph), 136.80 (o-C of Ph), 145.97 (4-C of
C6H4NO2-4), 150.23 (ipso-C6H4NO2-4). 1H NMR (CDCl3, rt): δ
1.52 (dd, JHH = 6.9, 1.6 Hz, 3H, CHCH3), 4.24 (d, JHH = 11.0 Hz,
1H, CH(C6H4NO2-4)(SiPh3)), 5.57 (dq, JHH = 10.6, 6.9 Hz, 1H, 
CHCH3), 5.88 (ddq, JHH = 11.0, 10.6, 1.6 Hz, 1H, CHCHCH3),
6.96 (m, 2H, 3-CH of C6H4NO2-4), 7.32 (t, JHH = 7.2 Hz, 6H, m-Ph),
7.40 (d, JHH = 7.2 Hz, 6H, o-Ph), 7.41 (m, 3H, p-Ph), 7.93 (m, 2H, 2-
CH of C6H4NO2-4). 13C{1H} NMR (CDCl3, rt): δ 13.23 (CH3),
35.57 (CHSiPh3), 123.72 (2-C of C6H4NO2-4), 125.80 (CH
CHCH3), 127.82 (m-C of Ph), 128.00 (CHCHCH3), 129.01 (3-C
of C6H4NO2-4), 129.93 (p-C of Ph), 132.34 (ipso-C of Ph), 136.40
(o-C of Ph), 145.28 (4-C of C6H4NO2-4), 150.78 (ipso-C of
C6H4NO2-4). HRMS (APCI): m/z calcd for C28H26NO2Si + H+:
436.1727 (M + H)+; found: 436.1724.
CH3), 4.12 (d, JHH = 11.5 Hz, 1H, CHPh(SiPh3)), 5.47 (dq, JHH
=
10.7, 6.8 Hz, 1H, CHCHCH3), 5.91 (tq, JHH = 11.0, 1.7 Hz, 1H,
CHCHCH3), 6.89 (m, 2H, o-Ph), 7.04−7.12 (m, 3H, m,p-Ph), 7.29
(m, 6H, m-Ph in SiPh3, 6H), 7.35−7.45 (m, 9H, o,p-Ph in SiPh3).
13C{1H} NMR (CDCl3, rt): δ 13.12 (CH3), 34.83 (CHPh(SiPh3)),
125.01 (p-C of Ph), 127.53 (m-C of SiPh3), 128.10 (m-C of Ph),
128.66 (o-C of Ph), 129.45 (p-C of SiPh3), 129.87 (CH
CHPh(SiPh3)), 133.54 (ipso-C of SiPh3), 136.57 (o-C of SiPh3),
142.00 (ipso-C of Ph). HRMS (APCI): m/z calcd for C28H26Si + H+:
391.1877 (M + H)+; found: 391.1877.
(E)-(4-(4-Methoxyphenyl)but-3-en-2-yl)triphenylsilane ((E)-4ak).
1
Yield: 42% (NMR), 19% (isolated). Colorless oil. H NMR (C6D6,
rt): δ 1.42 (d, JHH = 7.2 Hz, 3H, CH3CH(SiPh3)), 2.72 (dqd, JHH
=
7.5, 7.2, 1.2 Hz, 1H, CH3CH(SiPh3)), 3.26 (s, 3H, OCH3), 6.29 (d,
J
HH = 16.0 Hz, 1H, CHCH(C6H4OCH3-4)), 6.42 (dd, JHH = 16.0,
7.5 Hz, 1H, CHCH(C6H4OCH3-4)), 6.67 (m, 2H, 3-CH of
C6H4OCH3-4), 7.12 (m, 2H, 2-CH of C6H4OCH3-4), 7.10−7.21 (m,
9H, m,p-Ph in SiPh3), 7.55−7.62 (m, 6H, o-Ph in SiPh3). HRMS
(APCI): m/z calcd for C29H28OSi + H+: 421.1982 (M + H)+; found:
421.1978.
(Z)-(1-(4-Methoxyphenyl)but-2-en-1-yl)triphenylsilane ((Z)-5ak).
(E)-Triphenyl(4-(4-(trifluoromethyl)phenyl)but-3-en-2-yl)silane
1
1
Yield: 37% (NMR), 25% (isolated). Colorless oil. H NMR (C6D6,
(4ai). Yield: 30% (NMR), 12% (isolated). Colorless oil. H NMR
rt): δ 1.46 (dd, JHH = 6.8, 1.8 Hz, 3H, CH3), 3.23 (s, 3H, OCH3),
4.20 (d, JHH = 11.3 Hz, 1H, CH(C6H4OCH3-4)(SiPh3)), 5.44 (dqd,
JHH = 10.3, 6.8, 0.8 Hz, 1H, CHCHCH3), 6.10 (ddq, JHH = 11.3,
10.3, 1.8 Hz, 1H, CHCHCH3), 6.64 (m, 2H, 3-CH of C6H4OCH3-
4), 6.95 (m, 2H, 2-CH of C6H4OCH3-4), 7.10−7.21 (m, 9H, m,p-Ph
in SiPh3), 7.55−7.62 (m, 6H, o-Ph in SiPh3). 1H NMR (CDCl3, rt): δ
1.51 (dd, JHH = 6.7, 1.8 Hz, 1H, CH3CHCH), 3.74 (s, 3H, OCH3),
(C6D6, rt): δ 1.36 (d, JHH = 7.2 Hz, 3H, CH3), 2.69 (dqd, JHH = 7.6,
7.2, 1.4 Hz, 1H, CH(C6H4CF3-4)(SiPh3)), 6.10 (dd, JHH = 15.9, 1.4
Hz, 1H, CHC6H4CF3-4), 6.50 (dd, JHH = 15.9, 7.6 Hz, 1H, CH
CHC6H4CF3-4), 6.92 (m, 2H, 3-CH of C6H4CF3-4), 7.09−7.21 (m,
9H, m,p-Ph), 7.22 (m, 2H, 2-CH of C6H4CF3-4), 7.56−7.60 (m, 6H,
o-Ph). 1H NMR (CDCl3, rt): δ 1.37 (d, JHH = 7.2 Hz, 3H, CH3), 2.82
(dq JHH = 7.7, 7.2 Hz, 1H, CH(C6H4CF3-4)(SiPh3)), 6.19 (d, JHH
=
4.08 (d, JHH = 11.2 Hz, 1H, CH(CO2CH3)(SiPh3)), 5.46 (dqd, JHH
=
16.0 Hz, 1H, CHC6H4CF3-4), 6.49 (dd, JHH = 16.0, 7.7 Hz, 1H,
CHCHC6H4CF3-4), 7.23 (m, 2H, 3-CH of C6H4CF3-4), 7.30−7.45
(m, 9H, m,p-Ph), 7.45 (m, 2H, 2-CH of C6H4CF3-4), 7.54−7.59 (m,
6H, o-Ph). 19F NMR (CDCl3, rt): δ −62.20. HRMS (APCI): m/z
calcd for C29H26F3Si + H+: 459.1750 (M + H)+; found: 459.1741.
(Z)-Triphenyl(1-(4-(trifluoromethyl)phenyl)but-2-en-1-yl)silane
10.7, 6.7, 0.7 Hz, 1H, CH3CHCH), 5.87 (ddq, JHH = 11.2, 10.7, 1.8
Hz, 1H, CH3CHCH), 6.67 (m, 2H, C6H4OCH3-4), 6.82 (n, 2H,
C6H4OCH3-4), 7.31 (m, 6H, m-Ph), 7.34 (m, 3H, p-Ph), 7.43 (m,
6H, o-Ph). HRMS (APCI): m/z calcd for C29H28OSi + H+: 421.1982
(M + H)+; found: 421.1899.
(E)-(1-(4-Methoxyphenyl)but-2-en-1-yl)triphenylsilane ((E)-5ak).
Yield: 6% (NMR). 1H NMR (C6D6, rt): δ 1.49 (dd, JHH = 6.4, 1.5 Hz,
3H, CH3), 3.26 (s, 3H, OCH3), 3.88 (d, JHH = 7.7 Hz, 1H,
CH(C6H4OCH3-4)(SiPh3)), 5.36 (dqd, JHH = 15.2, 6.4, 1.5 Hz, 1H,
CHCHCH3), 6.03 (ddq, JHH = 15.2, 7.7, 1.5 Hz, 1H, CH
CHCH3), 6.67 (m, 2H, 3-CH of C6H4OCH3-4), 6.99 (m, 2H, 2-CH
1
(5ai). Yield: 27% (NMR), 13% (isolated). Colorless oil. H NMR
(C6D6, rt): δ 1.41 (dd, JHH = 6.9, 1.8 Hz, 3H, CH3CH), 4.15 (dd,
JHH = 10.8, 0.9 Hz, 1H, CH(C6H4CF3-4)(SiPh3)), 5.44 (dqd, JHH
=
10.8, 6.9, 0.9 Hz, 1H, CH3CH), 5.97 (tq, JHH = 10.8, 1.8 Hz, 1H,
CH3CHCH), 6.85 (d, JHH = 8.2 Hz, 2H, 2-CH of C6H4CF3-4),
7.09−7.21 (m, 9H, m,p-Ph), 7.28 (d, JHH = 8.2 Hz, 2H, 3-CH of
L
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of C6H4OCH3-4), 7.10−7.21 (m, 9H, m,p-Ph in SiPh3), 7.55−7.62
(m, 6H, o-Ph in SiPh3). This was characterized by spectroscopic
methods.
1.28 (dm, JHH = 6.7 Hz, 3H, CH3CHC(CH3)CH2SiPh3), 1.60 (qd,
JHH = 1.4, 1.2 Hz, 3H, CH3CHC(CH3)CH2SiPh3), 2.39 (s, 2H,
CH3CHC(CH3)CH2SiPh3), 5.10 (qq, JHH = 6.7, 1.2 Hz, 1H,
CH3CHC(CH3)CH2SiPh3), 7.12−7.19 (m, 9H, m,p-Ph), 7.59−
7.63 (m, 6H, o-Ph). 1H NMR (CDCl3, rt): δ 1.18 (dm, JHH = 6.7 Hz,
3H, CH3CHC(CH3)CH2SiPh3), 1.52 (qd, JHH = 1.4, 1.3 Hz, 3H,
CH3CHC(CH3)CH2SiPh3), 2.36 (s, 2H, CH3CHC(CH3)-
CH2SiPh3), 5.10 (qq, JHH = 6.7, 1.3 Hz, 1H, CH3CHC(CH3)-
CH2SiPh), 7.35 (m, m-Ph, 6H), 7.411 (m, p-Ph, 3H), 7.53 (m, o-Ph,
6H). 13C{1H} NMR (CDCl3, rt): 13.64 (CH3CHC(CH3)-
CH2SiPh3), 19.75 (CH3CHC(CH3)CH2SiPh3), 26.44
(CH3CHC(CH3)CH2SiPh3), 118.31 (CH3CHC(CH3)-
CH2SiPh3), 127.69 (m-C of Ph), 129.39 (p-C of Ph), 132.41
(CH3CHC(CH3)CH2SiPh3), 135.05 (ipso-C of Ph), 135.80 (o-C of
Ph). HRMS (APCI): m/z calcd for C23H24Si + H+: 329.1720 (M +
H)+; found: 329.1707.
(E)-N,N-Dimethyl-4-(3-(triphenylsilyl)but-1-en-1-yl)aniline ((E)-
1
4al). Yield: 30% (NMR). H NMR (C6D6, rt): δ 1.45 (d, JHH = 7.2
Hz, 3H, CH3), 2.47 (s, 3H, N(CH3)2), 2.76 (qd, JHH = 7.2, 6.9 Hz,
1H, CH3CH(SiPh3)), 6.38 (d, JHH = 15.7 Hz, 1H, CH
CHC6H4N(CH3)2-4), 6.45 (dd, JHH = 15.7, 6.9 Hz, 1H, CH
CHC6H4N(CH3)2-4), 6.49 (m, 2H, 3-CH in C6H4N(CH3)2-4), 7.23
(m, 2H, 2-CH in C6H4N(CH3)2-4), 7.16 (m, m,p-Ph, 9H), 7.72 (m,
o-Ph, 6H). HRMS (APCI): m/z calcd for C30H31NSi + H+: 434.2299
(M + H)+; found: 434.2295.
(Z)-N,N-Dimethyl-4-(1-(triphenylsilyl)but-2-en-1-yl)aniline ((Z)-
1
5al). Yield: 16% (NMR), 9% (isolated). Yellow powder. H NMR
(C6D6, rt): δ 1.48 (dd, JHH = 6.8, 1.8 Hz, 3H, CH3CHCH), 2.45 (s,
6H, N(CH3)2), 4.24 (d, JHH = 11.3 Hz, 1H, CH(C6H4N(CH3)2-
4)(SiPh3)), 5.45 (dqd, JHH = 10.7, 6.8, 0.8 Hz, 1H, CHCHCH3),
6.15 (ddq, JHH = 11.3, 10.7, 1.8 Hz, 1H, CHCHCH3), 6.49 (m, 2H,
3-CH in C6H4N(CH3)2-4), 7.04 (m, 2H, 2-CH in C6H4N(CH3)2-4),
(Z)-(2-Ethylidene-6-methylhept-5-en-1-yl)triphenylsilane (5ap).
Yield: 94% (NMR), 85% (isolated). Colorless powder. 1H NMR
(C6D6, rt): δ 1.29 (d, JHH = 6.9 Hz, 3H, CH3CH), 1.50 (s, 3H,
(CH3)2C), 1.62 (s, 3H, (CH3)2C), 1.99 (t, JHH = 7.7 Hz, 2H, 
CHCH2CH2), 2.15 (td, JHH = 7.7, 6.9 Hz, 2H, CHCH2CH2), 2.46
(s, 2H, CH2SiPh3), 5.10 (tm, JHH = 6.9 Hz, 1H, (CH3)2CCH), 5.25
(q, JHH = 6.9 Hz, 1H, CH3CH), 7.13−7.20 (m, 6H, m,p-Ph), 7.64
(m, 4H, o-Ph). 13C{1H} NMR (C6D6, rt): δ 13.94 (CH3CH), 17.74
((CH3)2C), 18.27 (CH2SiPh3), 25.82 ((CH3)2C), 27.27 (
CHCH2CH2), 39.50 (CHCH2CH2), 118.10 (CH3CH), 124.91
((CH3)2CCH), 128.08 (p-C of Ph), 129.73 (m-C of Ph), 130.97
((CH3)2CCH), 135.50 (ipso-C of Ph), 136.26 (o-C of Ph), 136.57
(CH3CHC). This was characterized by spectroscopic methods.
Methyl (E)-4-(Triphenylsilyl)pent-2-enoate-5-d (4aa-d). Yield:
1
7.16 (m, 9H, m,p-Ph), 7.67 (m, 6H, o-Ph). H NMR (CDCl3, rt): δ
1.48 (dd, JHH = 6.9, 1.7 Hz, 3H, CH3CHCH), 2.85 (s, 6H,
N(CH3)2), 4.04 (d, J = 11.7 Hz, 1H, CH(C6H4N(CH3)2-4)(SiPh3)),
5.41 (dq, JHH = 10.9, 6.9 Hz, 1H, CH3CHCH), 5.86 (ddq, J = 11.7,
10.9, 1.7 Hz, 1H, CH3CHCH), 6.54 (m, 2H, 3-CH in
C6H4N(CH3)2-4), 6.78 (m, 2H, 2-CH in C6H4N(CH3)2-4), 7.29
(m, 6H, m-Ph), 7.38 (m, 3H, p-Ph), 7.43 (m, 6H, o-Ph). 13C{1H}
NMR (CDCl3, rt): δ 13.06 (CH3CHCH), 33.25 (CHSiPh3), 40.92
(N(CH3)2), 113.05 (2-C in C6H4N(CH3)2-4), 122.85 (CH3CH
CH), 127.48 (m-C of SiPh3), 129.27 (3-C in C6H4N(CH3)2-4),
129.30 (p-C of SiPh3), 130.05 (1-C in C6H4N(CH3)2-4), 130.52
(CH3CHCH), 134.10 (ipso-C of SiPh3), 136.61 (o-C of SiPh3),
148.49 (4-C in C6H4N(CH3)2-4). HRMS (APCI): m/z calcd for
C30H31NSi + H+: 434.2299 (M + H)+; found: 434.2317.
1
92% (NMR), 73% (isolated). Colorless powder. H NMR (C6D6,
rt): δ1.14 (dm, JHH = 6.6 Hz, 2H, CH2D), 2.56 (dt, JHH = 7.5, 6.6 Hz,
1H, CH2DCHSiPh3), 5.80 (dd, JHH = 15.6, 1.6 Hz, 1H, CH
CHCO2CH3), 7.14 (m, 6H, m,p-Ph), 7.562 (m, 6H, o-Ph), 7.57 (dd,
JHH = 15.6, 7.5 Hz, 1H, CHCHCO2CH3). D NMR (C6H6, rt): δ
1.11 (CH2D). HRMS (APCI): m/z calcd for C24H23DO2Si + H+:
374.1681 (M + H)+; found: 374.1668.
(E)-N,N-Dimethyl-4-(1-(triphenylsilyl)but-2-en-1-yl)aniline ((E)-
1
5al). Yield: 5% (NMR). H NMR (C6D6, rt): δ 1.50 (dt, JHH = 6.5,
1.5 Hz, 3H, CH3), 2.47 (s, 6H, N(CH3)2), 3.92 (d, JHH = 7.5 Hz, 1H,
CH(C6H4N(CH3)2-4)(SiPh3)), 5.40 (dqd, JHH = 15.2, 6.5, 1.5 Hz,
1H, CHCHCH3), 6.09 (ddq, JHH = 15.2, 7.5, 1.5 Hz, 1H, CH
CHCH3), 6.47 (m, 2H, 3-CH in C6H4N(CH3)2-4), 7.07 (m, 2H, 2-
CH in C6H4N(CH3)2-4), 7.16 (m, 6H, m,p-Ph), 7.64 (m, 6H, o-Ph).
This was characterized by spectroscopic methods.
(Z)-(Pent-3-en-2-yl-5-d)triphenylsilane (5ah-d). Yield: 70%
(NMR). 1H NMR (C6D6, rt): δ 1.29 (d, JHH = 7.5 Hz, 3H,
CH(CH3)(SiPh3)), 1.42 (ddt, JHH = 6.7, 2.0 Hz, JDH = 2.0 Hz, 2H,
CH2DCH), 2.89 (dq, JHH = 10.9, 7.5 Hz, 1H, CHCH(CH3)-
(SiPh3)), 5.37 (dt, JHH = 10.9, 6.7 Hz, CH2DCH), 5.57 (tt, JHH
=
(Z)-But-2-en-1-yltriphenylsilane (5am). Yield: 79% (NMR), 23%
(isolated). Colorless powder. 1H NMR (C6D6, rt): δ 1.37 (ddt, JHH
=
10.9, 2.0 Hz, CHCH(CH3)(SiPh3)), 7.17 (m, 9H, m,p-Ph), 7.68
(m, 6H, o-Ph). D NMR (C6H6, rt): δ 1.41 (td, JDH = 2.2, 0.9 Hz,
CH2DCH). This was characterized by spectroscopic methods.
6.7, 1.8, 0.9 Hz, 3H, CH3CH), 2.33 (ddq, JHH = 8.2, 1.6, 0.9 Hz,
2H, CHCH2SiPh3), 5.39 (dqt, JHH = 10.7, 6.7, 1.6 Hz, 1H,
CH3CH), 5.67 (dtq, JHH = 10.7, 8.2, 1.8 Hz, 1H, CHCH2SiPh3),
7.13−7.20 (m, 9H, m,p-Ph), 7.58−7.62 (m, 6H, o-Ph). 1H NMR
(CDCl3. rt): δ 1.39 (dm, JHH = 6.7 Hz, 3H, CH3CH), 2.33 (dm,
JHH = 8.1 Hz, 2H, CHCH2SiPh3), 5.38 (dqt, J = 10.5, 6.7, 1.5 Hz,
1H, CH3CH), 5.56 (dtq, J = 10.5, 8.1, 1.5 Hz, 1H, 
CHCH2SiPh3), 7.35 (m, 6H, m-Ph), 7.40 (m, 3H, p-Ph), 7.53 (m,
6H, o-Ph). 13C{1H} NMR (CDCl3, rt): 12.65 (CH3CH), 14.50 (
CHCH2SiPh3), 123.46 (CH3CH), 124.84 (CHCH2SiPh3),
127.77 (m-C of Ph), 129.46 (p-C of Ph), 134.81 (ipso-C of Ph),
135.68 (o-C of Ph). This was characterized by spectroscopic methods.
ASSOCIATED CONTENT
* Supporting Information
The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.organomet.0c00597.
■
sı
NMR spectra of hydrosilylation products (PDF)
AUTHOR INFORMATION
Corresponding Author
■
(Z)-Pent-3-en-2-yltriphenylsilane (5an). Yield: 61% (NMR), 43%
1
(isolated). Colorless powder. H NMR (C6D6, rt): δ 1.29 (d, JHH
=
Nobuyuki Komine − Department of Applied Chemistry,
Graduate School of Engineering, Tokyo University of
Agriculture and Technology, Koganei, Tokyo 184-8588,
Japan; orcid.org/0000-0003-1744-695X;
Email: komine@cc.tuat.ac.jp
7.3 Hz, 3H, CH(CH3)(SiPh3)), 1.45 (dd, JHH = 6.7, 1.6 Hz, 3H,
CH3CH), 2.90 (dq, JHH = 11.3, 7.3 Hz, 1H, CHCH(CH3)-
(SiPh3)), 5.38 (dq, JHH = 10.7, 6.7 Hz, 1H, CH3CH), 5.57 (ddq,
JHH = 11.3, 10.7, 1.6 Hz, 1H, CHCH(CH3)), 7.17 (m, 9H, m,p-
Ph), 7.68 (m, 6H, o-Ph). 13C{1H} NMR (C6D6, rt): δ 13.16
(CH3CHCHCH(CH3)(SiPh3)), 16.90 (CH3CHCHCH(CH3)-
(SiPh3)), 19.89 (CH3CHCHCH(CH3)(SiPh3)), 122.39
(CH3CHCHCH(CH3)(SiPh3)), 128.09 (m-C of Ph), 129.65 (p-
C of Ph), 133.34 (CH3CHCHCH(CH3)(SiPh3)), 134.71 (ipso-C
of Ph), 136.56 (o-C of Ph). HRMS (APCI): m/z calcd for C23H24Si +
H+: 329.1720 (M + H)+; found: 329.1727.
Authors
Tatsuo Mitsui − Department of Applied Chemistry, Graduate
School of Engineering, Tokyo University of Agriculture and
Technology, Koganei, Tokyo 184-8588, Japan
Shu Kikuchi − Department of Applied Chemistry, Graduate
School of Engineering, Tokyo University of Agriculture and
Technology, Koganei, Tokyo 184-8588, Japan
(Z)-(2-Methylbut-2-en-1-yl)triphenylsilane (5ao). Yield: 93%
1
(NMR), 63% (isolated). Colorless powder. H NMR (C6D6, rt): δ
M
https://dx.doi.org/10.1021/acs.organomet.0c00597
Organometallics XXXX, XXX, XXX−XXX

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Catalyzed by Cationic Nickel(ii) Allyl Complexes: a Non-innocent
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Masafumi Hirano − Department of Applied Chemistry,
Graduate School of Engineering, Tokyo University of
Agriculture and Technology, Koganei, Tokyo 184-8588,
Japan; orcid.org/0000-0001-7835-1044
Complete contact information is available at:
https://pubs.acs.org/10.1021/acs.organomet.0c00597
Funding
Grant-in-Aid for Scientific Research (C) 20K05489.
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This paper is dedicated to Prof. P. H. Dixneuf for his
outstanding contribution to organometallic chemistry. We are
grateful to Dr. Sayori Kiyota for APCI. This work was
financially supported by the Japan Science and Technology
Agency and the Ministry of Education, Culture, Sports, Science
and Technology of Japan.
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Organometallics
pubs.acs.org/Organometallics
Article
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(20) We previously reported the hydrometalation of alkenes
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O
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Organometallics XXXX, XXX, XXX−XXX