Visible Light-Driven Radical trans-Hydrosilylation of Electron-Neutral and -Rich Alkenes with Tertiary and Secondary Hydrosilanes

Article abstract of DOI:10.1021/acs.joc.8b02409

A visible light-driven radical hydrosilylation of electron-neutral and -rich alkenes has been investigated on the basis of a newly developed catalytic reaction system composed of eosin Y, thiol, and base additives. A variety of linear and cyclic alkenes with different substitution patterns were found to undergo such metal-free hydrosilylation with tertiary and secondary hydrosilanes in a chemo-, regio-, and stereoselective manner. Comparison of the reactivity of diene compounds and late-stage hydrosilylation of steroid drugs were also explored. Deuterium labeling experiments reveal that a stepwise formation of C-Si and C-H bonds with a trans stereochemistry is preferred, in which the thiol may behave as a hydrogen atom transfer agent.

Full text of DOI:10.1021/acs.joc.8b02409

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Article
Visible Light-Driven Radical trans-Hydrosilylation of Electron-
Neutral and -Rich Alkenes with Tertiary- and Secondary Hydrosilanes
Jing Zhu, Wei-Chen Cui, Shaozhong Wang, and Zhu-Jun Yao
J. Org. Chem., Just Accepted Manuscript • DOI: 10.1021/acs.joc.8b02409 • Publication Date (Web): 31 Oct 2018
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Visible Light-Driven Radical trans-Hydrosilylation of
Electron-Neutral and -Rich Alkenes with Tertiary- and
Secondary Hydrosilanes
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Jing Zhu, Wei-Chen Cui, Shaozhong Wang*, Zhu-Jun Yao*
State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of
Advanced Organic Materials, School of Chemistry and Chemical Engineering,
Nanjing University, 163 Xianlin Avenue, Nanjing, Jiangsu 210023, China
E-mail: wangsz@nju.edu.cn; yaoz@nju.edu.cn
GRAPHIC ABSTRACT
ABSTRACT
A visible light-driven radical hydrosilylation of electron-neutral and -rich alkenes has
been investigated based on a newly-developed catalytic reaction system composed of
eosin Y, thiol and base additives. A variety of linear and cyclic alkenes with different
substitution patterns were found to undergo such metal-free hydrosilylation with
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tertiary and secondary hydrosilanes in a chemo-, regio- and stereoselective manner.
Comparison of reactivity of diene compounds, and late-stage hydrosilylation of
steroid drugs were also explored. Deuterium labelling experiments reveal that a
stepwise formation of C-Si and C-H bonds with a trans stereochemistry is preferred,
in which the thiol may behave as a hydrogen atom transfer agent.
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INTRODUCTION
Radical hydrosilylation of alkenes involves an anti-Markovnikov-type addition of a
silyl radical across a carbon-carbon double bond and the straightforward formation of
a carbon-silicon bond.1 Although certain applications of this highly atom-economic
transformation were found in synthetic chemistry2 and material chemistry3, in which
various silicon-containing groups and alkyl fragments derived from alkenes were
jointed together, the issues including the scope of alkenes and hydrosilanes, functional
group compatibility are still encountered.
At early stage, a type of radical-chain hydrosilylation of alkene was thoroughly
investigated (Scheme 1a).2a-d Twice hydrogen atom transfer (HAT) among a
hydrosilane, an extra electrophilic radical species (Me·, F3C·, Cl3C·, PhC(O)O· and
tBuO·) and a silylated carbon-centered radical were supposed.4 To make sure the HAT
from the hydrosilane to the radical adduct, labile trichlorosilane or bulky
tris(trimethylsilyl)silane with a weaker Si-H bond was preferred rather over normal
tertiary and secondary ones.5 Later, Roberts advanced a polarity-reversal catalysis to
nicely solve the mismatch between the nucleophilic silylated carbon-centered radical
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and the hydridic hydrosilane.2e,2f The introduction of thiol as a hydrogen transfer
agent significantly put forward the radical hydrosilylation of alkenes.6,7 Furthermore,
a combination of polarity-reversal catalysis and photocatalysis invented by Wu and
coworkers enabled a hydrosilylation of mono-substituted electron-rich alkenes with a
variety of hydrosilanes (Scheme 1b).2k Our recent experience in radical
hydrosilylation of alkynes encouraged us to reinvestigate the alkene hydrosilylation
by using a commercially available organic dye as photocatalyst,8,9 with an aim to
extend the scope from terminal alkenes to multi-substituted alkenes, to discriminate
the relative reactivity between terminal alkenes and internal alkenes, as well as to
attempt late-stage hydrosilylation of alkene-containing pharmaceutically relevant
molecules (Scheme 1c).
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Scheme 1. Radical Hydrosilylation of Electron-Neutral and -Rich Alkenes
R1
R1
Cl3SiH
radical initiators
+
(a)
(b)
or
SiR3
(TMS)3SiH
R = Cl, TMS
1 mol% 4CzIPN
5 mol% iPr3SiSH
5 mol% DIPEA
EDG
EDG
+
Me2PhSiH
dioxane
blue LEDs
SiPhMe2
1 mol% EY
5 mol% iPr3SiSH
5 mol% K2CO3
R3
R3
H
H
H
(c)
Ph2RSiH
+
R2
R2
Ph2RSi
dioxane/H2O
(100/1 v/v)
white LEDs
R1
R1
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RESULTS AND DISSCUSSION
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Initially, we chose 4-pentenyl acetate and triphenylsilane as model compounds to
study the hydrosilylation. A few commercially available organic dyes including
rhodamine 6G (Rh 6G), rhodamine B (Rh B), eosin Y (EY) and rose bengal (RB)
were selected as photocatalysts (PC) (Table 1, entries 1-4). Under the irradiation of a
10 W white LEDs and the assistance of base and thiol additives, the expected
hydrosilylation occurred in a mixed solvent of dioxane and water (50/1, v/v). A
combination of eosin Y (2 mol%), potassium carbonate (20 mol%) and
triisopropylsilanethiol10 (20 mol%) gave anti-Markovnikov adduct 1 in 99% yield.
Other thiol additives such as 2-methylpropane-2-thiol, ethyl 2-mercaptopropanoate
resulted in lower yields (Table 1, entries 5-6).11,12 No adduct was captured by using
2,4,6-triisopropylbenzenethiol (Table 1, entry 7). A slightly reduced yield was
observed when K2HPO4 or Na2CO3 was used instead of K2CO3 (Table 1, entries 8-9).
In the absence of base additives, incomplete conversion was found (Table 1, entry 10).
The reaction worked perfectly even when the loadings of eosin Y, potassium
carbonate and thiol I were reduced (Table 1, entry 11). Control experiments (see
supporting information (SI)) revealed that: (1) the ratio between triphenylsilane and
the alkene is essential for a complete conversion. (2) No adduct was detected in the
absence of either photocatalyst or thiol additive. (3) No reaction took place without
the irradiation.
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Table 1. Optimization of the Radical Hydrosilylationa
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Entry
PC
Rh 6G
Rh B
RB
Base
K2CO3
K2CO3
K2CO3`
K2CO3
K2CO3
K2CO3
K2CO3
K2HPO4
Na2CO3
-----
Thiol
Time (h) Yield (%)b
1
2
8
8
37
60
92
99
81
24
0
I
I
3
8
I
4
EY
8
I
5
EY
8
II
III
IV
I
6
EY
8
7
EY
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EY
8
88
84
56
99
9
EY
8
I
10
11c
EY
24
10
I
EY
K2CO3
I
aReaction conditions: 0.3 mmol alkene, 0.36 mmol hydrosilane, 5 mol% PC, 20 mol%
thiol, 20 mol% base, 3.0 mL degassed dioxane/H2O (50/1, v/v), 10 W white LEDs,
b
c
32-34 ℃. NMR yield using 1,3,5-trimethoxybenzene as an internal standard. 1
mol% EY, 5 mol% thiol I and 5 mol% K2CO3 were used.
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With optimized conditions in hand, we next sought to examine the scope of the visible
light-driven hydrosilylation. As illustrated in Table 2, a set of mono-substituted and
1,1’-disubstituted electron-neutral alkenes containing cyclohexyl, alkoxyl and
tert-butyl substituents reacted with triphenylsilane smoothly, giving adducts 2-4 in
moderate to excellent yields. Electron-rich alkenes including vinyl sulfane, vinyl
phosphine and vinyl ethers proved to be competent partners for the hydrosilylation
protocol, delivering adducts 5-10 in yields from 55% to 96%. The variation of yield
suggested that the nature of heteroatoms and the steric effect of the attached alkyl
substituents may affect the transformation. Under the identical condition, vinyl acetate
was converted to 11 in 91% yield. Parallel experiments revealed that a series of
tertiary hydrosilanes including Ph2MeSiH, PhMe2SiH, Et3SiH, (TMS)3SiH reacted
with vinyl acetate to afford 12-15. The yield varied depending on the bond
dissociation energy of Si-H in different hydrosilanes.13 Both the arylated hydrosilanes
and (TMS)3SiH are favorable for the conversion. Poor yield was obtained in the case
of Et3SiH. Except for the tertiary hydrosilanes, the secondary hydrosilane Ph2SiH2
may engage in the hydrosilylation, affording adducts 16 and 17 bearing a Si-H bond.
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Table 2. Radical Hydrosilylation of Terminal Alkenesa
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OTMS
H
SiPh3
tBu
10
, 55% (60 h)
OTBS
H
SiHPh2
MeO
b
17
, 67% (60 h)
aReaction conditions: 0.3 mmol alkene, 0.36 mmol hydrosilane, 1 mol% EY, 5 mol%
thiol I, 5 mol% K2CO3, 3.0 mL degassed dioxane/H2O (50/1, v/v), 10 W white LEDs,
32-34 ℃. b50 W white LEDs, 3.0 mL degassed dioxane/H2O (100/1, v/v) instead.
The hydrosilylation of internal alkenes were further explored, which was viewed more
challengeable than that of terminal alkenes. The increasing steric effect may cause a
slower silyl radical addition to the carbon-carbon double bond.14,15 An array of
symmetrical cyclic alkenes with different ring sizes were first attempted to react with
a secondary hydrosilane (Ph2SiH2) (Table 3). To our delight, the cycloalkylated
silanes 18-23 were obtained in yields ranging from 31% to 91% under an improved
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condition. As compared with normal cyclic alkenes (cyclopentene, cyclohexene,
cycloheptene), middle-sized cyclooctene and bicyclic norbornene with higher ring
tension displayed better reactivity. The cyclic enol ether and enol acetate containing
an electron-rich double bond participated in the hydrosilylation in a similar manner,
giving adducts 24-25 in which a silyl group locates at the -position toward oxygen
atom. The protocol was applicable for the linear alkenes. However, the configuration
of the double bond is critical. As evidenced by the reaction outcomes of hex-3-enes,
the (Z)-isomer gave 26 in a yield higher than that of the (E)-isomer. Furthermore,
when β-citronellol, an unsymmetrical trisubstituted internal alkene, was examined,
adduct 27 was isolated in 59% yield. Although the diasteroselectivity of 27 was poor,
excellent regioselectivity was indeed obtained and no other regioisomer was captured.
To our disappointment, fully substituted alkenes failed in the hydrosilylation at this
stage.
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Table 3. Radical Hydrosilylation of Internal Alkenes.a
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aReaction conditions: 0.3 mmol alkene, 0.36 mmol hydrosilane, 1 mol% EY, 5 mol%
thiol I, 5 mol% K2CO3, 3.0 mL degassed dioxane/H2O (100/1, v/v), 50 W white
LEDs, 36-38 ℃.
To probe the relative reactivity between a terminal alkene and an internal alkene, an
array of diene substrates containing at least one terminal alkene were attempted (Table
4). Although a detectable hydrosilylation of cyclic alkene in limoeonene was found,
the hydrosilylation of exocyclic 1,1’-disubitituted terminal alkene was more favorable
than that of trisubstituted cyclohexene (Table 4, entry 1). Similar regioselectivity was
observed in the case of nootkatone (Table 4, entry 2). Adducts 29 and 30 were isolated
as major products with 1/1 diastereoselectivity. No hydrosilylation of
1,2-disubstituted cyclic alkene was detected when a vinyl substituted cyclohexene
was attempted, leading to the formation of adduct 31 in 44% yield (Table 4, entry 3).
The hydrosilylation of (E)-1,2-disubstituted linear alkene also did not compete with
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that of a mono-substituted one, giving 33 exclusively in 62% yield (Table 4, entry 4).
A comparable reactivity of a 1,1-disubstituted alkene and a mon-substituted alkene
was found, providing three possible adducts 33-35 (Table 4, entry 5).
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Table 4. Radical Hydrosilylation of Dienesa
Entry
1b
Diene
Adduct
Yield
53%
(d. r. =
1:1)
42%
(d. r. =
1:1)
2
3
44%
62%
4c
5c
43%
(33/34,
1.87/1)
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20% (35)
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aReaction conditions: 0.3 mmol alkene, 0.3 mmol hydrosilane, 1 mol% EY, 5 mol%
thiol I, 5 mol% K2CO3, 3.0 mL degassed dioxane/H2O (100/1, v/v), 50 W white
LEDs, 36-38 ℃. bAdduct 29 is contaminated with an inseparable minor product,
SiHPh2
H
whose structure was supposed as
(50/1, v/v) instead, 32-34 ℃.
. c10 W white LEDs, dioxane/H2O
To detail the mechanism of the hydrosilylation, a series of deuterium-labelling
experiments were performed based on the reaction of triphenylsilane and a terminal
alkene (Scheme 2a). Less than 1% deuterium atom was detected in adduct 36 when
1,4-dioxane-D8 was applied as solvent, which excluded the possibility that the solvent
attended the reaction as the hydrogen source (Scheme 2b). About 15% incorporation
of deuterium was detected when Ph3SiD was utilized (Scheme 2c). Almost the same
deuterium content was found when D2O was used in place of water (Scheme 2d).
Meanwhile, a hydrogen/deuterium exchange between the deuterated hydrosilane and
water was encountered in the investigation (see SI),16 which made us hypothesize that
the new hydrogen in the adduct may originate from water. The hypothesis was further
supported by the fact that up to 81% deuterium atom was incorporated when the
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amount of D2O was improved significantly, even though the isotope effect made the
yield drop to 19% (Scheme 2e-f). To identify the relative stereochemistry of the
hydrogen and the silyl group in the adduct, a diester-substituted cyclopentene and
diphenylhydrosilane were subjected to a reaction system containing excess D2O as
shown in Scheme 2e, the adduct was eventually isolated with 77% deuterium
incorporation after 48-hour irradiation of 50 W white LEDs (Scheme 2g). The NMR
analyses confirmed undoubtedly that the deuterium atom locates at an axial position
which is away from the equatorial silyl group, highlighting a possible stepwise
trans-hydrosilylation of alkenes.
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Scheme 2. Mechanistic Studies
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1 mol% EY
5 mol% iPr3SiSH,
5 mol% K2CO3
Ph
Ph
Ph
a)
+
Ph3SiH
Ph3Si
dioxane/H2O 50/1 v/v
10 W white LEDs
32-34 ºC, 24 h
89%
H
0.36 mmol
0.3 mmol
36
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as equation a
D8-dioxane instead
Ph
Ph
Ph3Si
Ph3Si
b)
c)
+
+
Ph3SiH
Ph3SiD
85%
H/D (<1% D)
Ph
as equation a
79%
H/D (15% D)
as equation a
D2O instead of H2O
Ph
d)
Ph
Ph3Si
+
Ph3SiH
81%
H/D (16% D)
as equation a
dioxane/D2O (2/1 v/v)
36 h instead
Ph
Ph
Ph
Ph3Si
Ph3Si
e)
f)
+
+
Ph3SiH
Ph3SiD
20%
D/H (78% D)
as equation a
D8-dioxane/D2O (2/1 v/v)
48 h instead
Ph
19%
D/H (81% D)
1 mol% EY
5 mol% iPr3SiSH
5 mol% K2CO3
(77% D)
COOMe
H
H/D
COOMe
COOMe
H
COOMe
Ph2SiH2
+
g)
H
H
H
dioxane/D2O 2/1 v/v
50 W white LEDs
36-38 oC, 48 h
6%
Ph2HSi
H
A proposed catalytic cycle was outlined in scheme 3. The excited state EY* is
generated from EY by irradiation of visible light. Under the assistance of the base
additive, a proton-coupled electron transfer (PCET) process [E1/2(*EY/EY -) = +0.83 V
vs saturated calomel electrode (SCE), thiol I E1/2 = +0.28 V vs SCE]2k,17,18 may
ox
happen to deliver a thiyl radical and radical anion EY.-. A subsequent hydrogen atom
transfer (HAT) from the hydrosilane to the electrophilic thiyl radical will result in the
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formation of a silyl radical [the BDE value of Si-H bond in Ph3SiH is about 86.4
kcal/mol, and the BDE value of S-H bond in thiol I is 88.2 kcal/mol].13 The silyl
radical further reacts with an alkene to generate a silicon-stabilized carbon-centered
radical. Another HAT from the thiol to the nucleophilic carbon-centered radical will
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red
deliver the hydrosilylation adduct and the thiyl radical (E1/2 = -0.82 V vs SCE in
MeCN),2k which is easily reduced by radical anion EY.- [E1/2(EY/EY-) = -1.06 V vs
SCE in MeCN],18 and combined by a proton to regenerate the thiol. The thiol plays
dual roles in the transformation as both a hydrogen abstractor at the radical-initiation
step and a hydrogen donor at the radical-quenching step. As evidenced by the
deuterium-labelling experiment, the thiol is prone to approach to the silylated
carbon-centered radical in an energetically beneficial manner due to the steric
interference, which makes the newly-formed C-H bond locate at the trans-position of
the C-Si bond.
Scheme 3. Proposed Mechanism
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To demonstrate the synthetic utility of the transformation, two clinical drugs,
pregnenolone acetate and stigmasterol, containing a multi-substituted cyclohexene
ring were assessed (Scheme 4). As shown, both of them underwent the visible
light-driven hydrosilylation to give adducts 37 and 38 in a highly chemo-, regio- and
diastereoselective manner. A range of functional groups such as ester, ketone, free
hydroxy and exocyclic 1,2-disubstituted alkene remained undisturbed. The
stereochemistry of the newly-formed C-Si and C-H bonds was established by NMR
experiments. This late-stage hydrosilylation is supposed to provide a potential way for
the rapid generation of silicon-containing medicinally relevant molecules.
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Scheme 4. Radical Hydrosilylation of Steroid Drugs.
1.2 equiv Ph2SiH2
O
O
1 mol% EY
5 mol% iPr3SiSH
5 mol% K2CO3
H
H
H
H
dioxane/H2O
(100/1, v/v)
50 W white LEDs
36-38 ºC, 72 h
H
H
AcO
AcO
H
SiHPh2
Pregnenolone acetate
37
, 66%
1.0 equiv Ph2SiH2
1 mol% EY
5 mol% iPr3SiSH
5 mol% K2CO3
H
H
H
H
H
H
dioxane/H2O
(100/1, v/v)
50 W white LEDs
36-38 ºC, 72 h
H
H
HO
H
HO
SiHPh2
Stigmasterol
38
, 36%
CONCLUSION
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A mild visible light-driven radical hydrosilylation of alkenes has been achieved using
catalytic amounts of eosin Y as the photocatalyst, thiol and base as additives. A
variety of mono-, di- and trisubstituted linear and cyclic electron-neutral and -rich
alkenes have been examined and found to undergo the chemo-, regio- and
stereoselective hydrosilylation with either tertiary or secondary hydrosilanes. The
relative reactivity especially between a terminal alkene and an internal alkene,
together with the late-stage hydrosilylation of two steroid drugs were explored.
Deuterium labelling experiments further suggested that a stepwise formation of C-Si
bond and C-H bond with a trans-stereochemistry is preferred, in which the thiol acts
as a polarity reversal agent. Further applications of the radical hydrosilylation of
alkenes are expected.
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EXPERMENT SCETION
1
General Information. All melting points were determined without correction. H
13
NMR spectra were obtained at 400 MHz, and C NMR spectra were obtained at 101
MHz. Spectra were recorded in CDCl3 solution using the residual protonated solvent
as the internal standard, J values were given in hertz. High-resolution mass spectral
analyses (HRMS) were determined on a Q-TOF-MS spectrometer. The 10 W LEDs
(model: 12 V 5050) with maximum emission at about 582 nm were purchased from
Greenthink Co., Ltd (China). The 50 White LEDs (model: 10E 60P 50W PW) with
maximum emission at about 475 nm were purchased from Qiyiguo Photoelectric Co.,
Ltd (China). For the emission spectra of LEDs, see SI.
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General Procedure for the Radical Hydrosilylation of Alkenes. Under nitrogen
atmosphere, to a dry 10 mL glass tube containing eosin Y (2 mg, 0.003 mmol) and
K2CO3 (2 mg, 0.015 mmol) was added successively a tertiary or secondary
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i
hydrosilane (0.36 mmol or 0.3 mmol), alkene (0.3 mmol), Pr3SiSH (2.8 mg, 0.015
mmol) and degassed 1,4-dioxane/H2O (3 mL, 50/1 or 100/1 v/v) at room temperature.
The reaction was stirred and irradiated by white LEDs (10 W or 50 W) at a distance of
5 cm. Upon completion (monitored by TLC), the solution was concentrated under
vacuum. The residue was further purified by silica gel column chromatography (PE
for 2, 4-6, 10, 15, 17, 19-23, 26, 29, 31 and 36; PE/EA = 100/1 for 1, 7-9, 11-14, 16,
24 and 32-35; PE/EA = 10/1 for 3, 18, 25, 27, 30, 37 and 38).
o
5-(Triphenylsilyl)pentyl acetate (1). White solid, 114 mg, 99% yield; mp 52-53 C;
1H NMR (400 MHz, CDCl3) δ 7.60 – 7.53 (m, 6H), 7.46 – 7.34 (m, 9H), 4.04 (t, J =
6.7 Hz, 2H), 2.04 (s, 3H), 1.69 – 1.62 (m, 2H), 1.59 – 1.51 (m, 2H), 1.50 – 1.39 (m,
4H); 13C{1H} NMR (101 MHz, CDCl3) δ 171.2, 135.7, 135.2, 129.5, 127.9, 64.6, 30.1,
28.3, 23.8, 21.0, 13.3; IR (KBr) vmax 2923, 1738, 1258, 1012, 791, 699 cm-1; HRMS
(ESI) m/z calcd for C25H28NaO2Si 411.1751 [M+Na]+, found 411.1746.
(2-Cyclohexylethyl)triphenylsilane (2).19 White solid, 86 mg, 78% yield; mp 54-56
oC; H NMR (400 MHz, CDCl3) δ 7.61 – 7.50 (m, 6H), 7.47 – 7.31 (m, 9H), 1.85 –
1
1.73 (m, 2H), 1.74 – 1.59 (m, 3H), 1.40 (s, 2H), 1.39 (s, 2H), 1.30 – 1.06 (m, 4H),
0.98 – 0.76 (m, 2H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.8, 135.6, 129.4, 127.9,
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41.0, 33.0, 31.4, 26.9, 26.6, 10.4; IR (KBr) vmax 2920, 1259, 1109, 797, 697 cm-1;
HRMS (ESI) m/z calcd for C26H31Si 371.2190 [M+H]+, found 371.2202.
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3-Methyl-4-(triphenylsilyl)butan-1-ol (3). Colorless oil, 101 mg, 98% yield; 1H NMR
(400 MHz, CDCl3) δ 7.75 – 7.54 (m, 6H), 7.53 – 7.31 (m, 9H), 3.67 – 3.49 (m, 2H),
2.07 – 1.92 (m, 1H), 1.66 – 1.53 (m, 2H), 1.52 – 1.44 (m, 1H), 1.44 – 1.36 (m, 1H),
13
0.93 (d, J = 6.6 Hz, 3H); C{1H} NMR (101 MHz, CDCl3) δ 135.8, 129.5, 128.0,
61.0, 43.4, 26.0, 23.4, 21.7; IR (KBr) vmax 2922, 1427, 1107, 698 cm-1; HRMS (ESI)
m/z calcd for C23H26NaOSi 369.1645 [M+Na]+, found 369.1644.
1
Triphenyl(2,3,3-trimethylbutyl)silane (4). Colorless oil, 55 mg, 52% yield; H NMR
(400 MHz, CDCl3) δ 7.66 – 7.56 (m, 6H), 7.49 – 7.34 (m, 9H), 1.70 (d, J = 14.8 Hz,
1H), 1.66 – 1.55 (m, 1H), 1.22 – 1.11 (m, 1H), 0.89 (d, J = 0.4 Hz, 9H), 0.73 (d, J =
6.8 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 136.0, 129.4, 127.9, 38.9, 34.3, 29.0,
27.2, 17.7, 15.9; IR (KBr) vmax 2958, 1485, 1107, 696 cm-1; HRMS (ESI) m/z calcd
for C25H31Si 359.2190 [M+H]+, found 359.2189.
Triphenyl(2-(phenylthio)ethyl)silane (5).20 White solid, 67 mg, 57% yield; mp 98-99
1
oC; H NMR (400 MHz, CDCl3) δ 7.61 – 7.53 (m, 6H), 7.51 – 7.38 (m, 9H), 7.33 –
7.26 (m, 4H), 7.24 – 7.17 (m, 1H), 3.16 – 3.10 (m, 2H), 1.88 – 1.82 (m, 2H); 13C{1H}
NMR (101 MHz, CDCl3) δ 135.7, 134.1, 129.9, 129.4, 129.0, 128.2, 126.0, 29.4, 14.1;
IR (KBr) vmax 2922, 1427, 1110, 697 cm-1; HRMS (ESI) m/z calcd for C26H24NaSSi
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419.1260 [M+Na]+, found 419.1255.
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Diphenyl(2-(triphenylsilyl)ethyl)phosphane (6).21 White solid, 120 mg, 85% yield;
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o
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mp 134-135 C; H NMR (400 MHz, CDCl3) δ 7.55 – 7.50 (m, 6H), 7.48 – 7.30 (m,
19H), 2.23 – 2.16 (m, 2H), 1.55 – 1.44 (m, 2H); C{1H} NMR (101 MHz, CDCl3) δ
13
138.6, 138.4, 135.7, 134.6, 133.1, 132.9, 129.7, 128.7, 128.5, 128.5, 128.1, 21.7, 21.6,
8.9, 8.8; IR (KBr) vmax 2922, 1427, 1109, 696 cm-1; HRMS (ESI) m/z calcd for
C32H29NaPSi 495.1668 [M+Na]+, found 495.1671.
o
1
(2-Ethoxyethyl)triphenylsilane (7). White solid, 95 mg, 96% yield; mp 53-54 C; H
NMR (400 MHz, CDCl3) δ 7.67 – 7.52 (m, 6H), 7.51 – 7.34 (m, 9H), 3.71 – 3.60 (m,
2H), 3.42 (q, J = 7.0 Hz, 2H), 1.97 – 1.82 (m, 2H), 1.18 (t, J = 7.0 Hz, 3H); 13C{1H}
NMR (101 MHz, CDCl3) δ 135.7, 134.8, 129.6, 128.0, 67.3, 65.7, 15.4, 15.4; IR (KBr)
vmax 2922, 1258, 1093, 1012, 792, 697 cm-1; HRMS (ESI) m/z calcd for C22H24NaOSi
355.1489 [M+Na]+, found 355.1481.
o
(2-Methoxypropyl)triphenylsilane (8). White solid, 85 mg, 85% yield; mp 58-59 C;
1H NMR (400 MHz, CDCl3) δ 7.66 – 7.54 (m, 6H), 7.49 – 7.33 (m, 9H), 3.56 – 3.45
(m, 1H), 3.08 (s, 3H), 1.95 (dd, J1 = 14.8, J2 = 7.2 Hz, 1H), 1.62 (dd, J1 = 14.9, J2 =
6.6 Hz, 1H), 1.15 (d, J = 6.0 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.9,
129.4, 127.9, 74.4, 55.5, 22.8, 22.2; IR (KBr) vmax 2923, 1427, 1108, 697 cm-1;
HRMS (ESI) m/z calcd for C22H24NaOSi 355.1489 [M+Na]+, found 355.1497.
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Trimethyl((1-(triphenylsilyl)propan-2-yl)oxy)silane (9). White solid, 99 mg, 85%
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yield; mp 46-47 C; H NMR (400 MHz, CDCl3) δ 7.66 – 7.55 (m, 6H), 7.49 – 7.34
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(m, 9H), 4.19 – 4.07 (m, 1H), 1.90 (dd, J1 = 14.8, J2 = 6.6 Hz, 1H), 1.75 (dd, J1 = 14.8,
13
J2 = 6.9 Hz, 1H), 1.18 (d, J = 6.0 Hz, 3H), -0.05 (s, 9H); C{1H} NMR (101 MHz,
CDCl3) δ 136.0, 135.5, 129.4, 127.9, 66.5, 27.3, 26.2, 0.3; IR (KBr) vmax 2958, 1427,
1249, 1108, 837, 697 cm-1; HRMS (ESI) m/z calcd for C24H30NaOSi2 413.1727
[M+Na]+, found 413.1715.
((3,3-Dimethyl-1-(triphenylsilyl)butan-2-yl)oxy)trimethylsilane (10). White solid, 71
o
1
mg, 55% yield; mp 107-109 C; H NMR (400 MHz, CDCl3) δ 7.64 – 7.58 (m, 6H),
7.43 – 7.34 (m, 9H), 3.75 (dd, J1 = 9.1, J2 = 3.6 Hz, 1H), 1.85 (dd, J1 = 15.4, J2 = 9.1
13
Hz, 1H), 1.70 (dd, J1 = 15.4, J2 = 3.7 Hz, 1H), 0.90 (s, 9H), -0.30 (s, 9H); C{1H}
NMR (101 MHz, CDCl3) δ 136.2, 129.4, 127.8, 78.4, 36.9, 26.6, 18.0, 1.0; IR (KBr)
vmax 2924, 1259, 1107, 799, 698 cm-1; HRMS (ESI) m/z calcd for C27H36NaOSi2
455.2197 [M+Na]+, found 455.2197.
1-(Triphenylsilyl)propan-2-yl acetate (11).2f White solid, 114 mg, 98% yield; mp
61-62 oC; 1H NMR (400 MHz, CDCl3) δ 7.62 (d, J = 6.4 Hz, 6H), 7.53 – 7.35 (m, 9H),
5.32 – 5.16 (m, 1H), 2.09 – 1.98 (m, 1H), 1.83 – 1.75 (m, 1H), 1.72 (s, 3H), 1.27 (d, J
= 6.1 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 170.4, 135.7, 134.7, 129.6, 128.0,
69.3, 23.6, 22.0, 21.1; IR (KBr) vmax 2937, 1732, 1220, 956, 697 cm-1; HRMS (ESI)
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m/z calcd for C23H24NaO2Si 383.1438 [M+Na]+, found 383.1432.
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1-(Methyldiphenylsilyl)propan-2-yl acetate (12). Colorless oil, 72 mg, 81% yield; H
NMR (400 MHz, CDCl3) δ 7.62 – 7.50 (m, 4H), 7.46 – 7.32 (m, 6H), 5.22 – 5.05 (m,
1H), 1.80 (s, 3H), 1.69 (dd, J1 = 14.6, J2 = 7.4 Hz, 1H), 1.46 (dd, J1 = 14.7, J2 = 6.9
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Hz, 1H), 1.23 (d, J = 6.2 Hz, 3H), 0.66 (s, 3H); C{1H} NMR (101 MHz, CDCl3) δ
13
170.5, 136.8, 136.7, 134.5, 134.5, 129.4, 128.0, 128.0, 69.5, 23.4, 23.0, 21.3, -3.7; IR
(KBr) vmax 2926, 1730, 1243, 1110, 697 cm-1; HRMS (ESI) m/z calcd for
C18H22NaO2Si 321.1281 [M+Na]+, found 321.1278.
1-(Dimethyl(phenyl)silyl)propan-2-yl acetate (13).7a Colorless oil, 52 mg, 74% yield;
1H NMR (400 MHz, CDCl3) δ 7.59 – 7.47 (m, 2H), 7.46 – 7.31 (m, 3H), 5.10 – 4.99
(m, 1H), 1.89 (s, 3H), 1.32 (dd, J1 = 14.5, J2 = 7.0 Hz, 1H), 1.21 (d, J = 6.2 Hz, 4H),
1.13 (dd, J1 = 14.5, J2 = 7.2 Hz, 1H), 0.34 (s, 3H), 0.33 (s, 3H); 13C{1H} NMR (101
MHz, CDCl3) δ 170.6, 138.8, 133.6, 129.1, 127.9, 69.8, 24.5, 23.3, 21.5, -2.2; IR
(KBr) vmax 2925, 1734, 1246, 1112, 1015, 833, 698 cm-1; HRMS (ESI) m/z calcd for
C13H20NaO2Si 259.1125 [M+Na]+, found 259.1121.
1-(Triethylsilyl)propan-2-yl acetate (14).22 Colorless oil, 26 mg, 41% yield; 1H NMR
(400 MHz, CDCl3) δ 5.02 (dd, J1 = 13.6, J2 = 6.8 Hz, 1H), 1.99 (s, 3H), 1.25 (d, J =
6.1 Hz, 3H), 1.05 (dd, J1 = 14.5, J2 = 6.9 Hz, 1H), 0.93 (t, J = 7.9 Hz, 9H), 0.86 (dd,
J1 = 14.5, J2 = 7.6 Hz, 1H), 0.53 (q, J = 7.9 Hz, 6H); 13C{1H} NMR (101 MHz,
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CDCl3) δ 170.7, 70.1, 23.4, 21.7, 20.1, 7.5, 3.9; IR (KBr) vmax 2923, 1738, 1258, 1010,
790 cm-1; HRMS (ESI) m/z calcd for C11H24NaO2Si 239.1438 [M+Na]+, found
239.1448.
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1-(1,1,1,3,3,3-Hexamethyl-2-(trimethylsilyl)trisilan-2-yl)propan-2-yl acetate (15).
1
Colorless oil, 86 mg, 82% yield; H NMR (400 MHz, CDCl3) δ 5.04 – 4.84 (m, 1H),
2.01 (s, 3H), 1.34 – 1.25 (m, 4H), 1.07 (dd, J = 13.9, 8.3 Hz, 1H), 0.17 (s, 27H);
13C{1H} NMR (101 MHz, CDCl3) δ 170.7, 72.3, 23.0, 21.9, 16.4, 1.3; IR (KBr) vmax
2958, 1738, 1258, 1012, 791 cm-1; HRMS (ESI) m/z calcd for C14H36NaO2Si4
371.1685 [M+Na]+, found 371.1674.
1-(Diphenylsilyl)propan-2-yl acetate (16). Colorless oil, 63 mg, 74% yield; 1H NMR
(400 MHz, CDCl3) δ 7.68 – 7.52 (m, 4H), 7.48 – 7.32 (m, 6H), 5.21 – 5.11 (m, 1H),
4.96 (t, J = 3.8 Hz, 1H), 1.84 (s, 3H), 1.77 – 1.68 (m, 1H), 1.57 (m, 1H), 1.31 (d, J =
13
6.2 Hz, 3H); C{1H} NMR (101 MHz, CDCl3) δ 170.6, 135.2, 135.1, 133.9, 133.6,
129.9, 129.8, 128.2, 128.2, 69.5, 22.7, 21.1; IR (KBr) vmax 2961,2127, 1732, 1257,
1013, 795, 698 cm-1; HRMS (ESI) m/z calcd for C17H20NaO2Si 307.1125 [M+Na]+,
found 307.1125.
tert-Butyl(2-(diphenylsilyl)-1-methoxyethoxy)dimethylsilane (17). Colorless oil, 75
1
mg, 67% yield; H NMR (400 MHz, CDCl3) δ 7.66 – 7.57 (m, 4H), 7.46 – 7.35 (m,
6H), 5.00 – 4.93 (m, 1H), 4.89 (dd, J = 7.0, 4.5 Hz, 1H), 3.24 (s, 3H), 1.79 – 1.71 (m,
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1H), 1.65 (dt, J1 = 14.7, J2 = 4.3 Hz, 1H), 0.90 (s, 9H), 0.09 (s, 3H), 0.05 (s, 3H);
13C{1H} NMR (101 MHz, CDCl3) δ 135.4, 135.3, 134.5 134.4, 129.6, 128.0, 97.8,
53.5, 25.9, 23.3, 18.2, -4.2, -4.4; IR (KBr) vmax 2926, 1428, 1116, 803, 696 cm-1;
HRMS (ESI) m/z calcd for C21H32NaO2Si2 395.1833 [M+Na]+, found 395.1829.
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Dimethyl 3-(diphenylsilyl)cyclopentane-1,1-dicarboxylate (18). Colorless oil, 70 mg,
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64% yield; H NMR (400 MHz, CDCl3) δ 7.63 – 7.53 (m, 4H), 7.45 – 7.33 (m, 6H),
4.81 (d, J = 3.8 Hz, 1H), 3.73 (s, 3H), 3.67 (s, 3H), 2.67 – 2.58 (m, 1H), 2.37 – 2.27
(m, 1H), 2.27 – 2.17 (m, 1H), 2.11 – 1.97 (m, 2H), 1.87 – 1.75 (m, 1H), 1.75 – 1.65
(m, 1H); 13C{1H} NMR (101 MHz, CDCl3) δ 173.1, 172.8, 135.4, 135.4, 133.6, 133.5,
129.8, 128.1, 128.1, 61.4, 52.8, 52.7, 38.0, 35.8, 29.0, 23.2; IR (KBr) vmax 2961, 1730,
1256, 698 cm-1; HRMS (ESI) m/z calcd for C21H24NaO4Si 391.1336 [M+Na]+, found
391.1339.
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Cyclopentyldiphenylsilane (19).23 Colorless oil, 32 mg, 43% yield; H NMR (400
MHz, CDCl3) δ 7.63 – 7.55 (m, 4H), 7.44 – 7.32 (m, 6H), 4.78 (d, J = 3.4 Hz, 1H),
1.95 – 1.89 (m, 2H), 1.61 – 1.48 (m, 7H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.6,
134.8, 129.5, 128.0, 29.3, 27.0, 22.7; IR (KBr) vmax 2947, 1427, 1108, 799, 695 cm-1;
HRMS (ESI) m/z calcd for C17H20NaSi 275.1226 [M+Na]+, found 275.1224.
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Cyclohexyldiphenylsilane (20).24 Colorless oil, 25 mg, 31% yield; H NMR (400
MHz, CDCl3) δ 7.62 – 7.54 (m, 4H), 7.43 – 7.33 (m, 6H), 4.68 (d, J = 2.8 Hz, 1H),
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1.83 – 1.78 (m, 2H), 1.75 – 1.67 (m, 3H), 1.34 – 1.23 (m, 6H); C{1H} NMR (101
MHz, CDCl3) δ 135.7, 134.0, 129.6, 128.0, 28.5, 28.0, 26.9, 23.5; IR (KBr) vmax 2918,
1427, 1112, 798, 695 cm-1; HRMS (ESI) m/z calcd for C18H23Si 267.1564 [M+H]+,
found 267.1567.
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Cycloheptyldiphenylsilane (21). Colorless oil, 52 mg, 62% yield; 1H NMR (400 MHz,
CDCl3) δ 7.65 – 7.52 (m, 4H), 7.47 – 7.31 (m, 6H), 4.75 (s, 1H), 1.96 – 1.87 (m, 2H),
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1.82 – 1.70 (m, 2H), 1.69 – 1.56 (m, 2H), 1.55 – 1.37 (m, 7H); C{1H} NMR (101
MHz, CDCl3) δ 135.7, 134.4, 129.5, 128.0, 30.0, 29.9, 28.4, 23.7; IR (KBr) vmax 2981,
1427, 1107, 797, 727, 696 cm-1; HRMS (ESI) m/z calcd for C19H25Si 281.1720
[M+H]+, found 281.1718.
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Cyclooctyldiphenylsilane (22). Colorless oil, 71 mg, 91% yield; H NMR (400 MHz,
CDCl3) δ 7.65 – 7.54 (m, 4H), 7.45 – 7.33 (m, 6H), 4.74 (d, J = 1.8 Hz, 1H), 1.93 –
1.83 (m, 2H), 1.73 – 1.47 (m, 13H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.7, 134.5,
129.5, 128.0, 28.6, 27.7, 27.3, 26.4, 21.0; IR (KBr) vmax 2916, 2109, 1427, 1107, 798,
727, 696 cm-1; HRMS (ESI) m/z calcd for C20H27Si 295.1877 [M+H]+, found
295.1866.
((1S,2S,4R)-Bicyclo[2.2.1]heptan-2-yl)diphenylsilane (23).25 Colorless oil, 68 mg,
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81% yield; H NMR (400 MHz, CDCl3) δ 7.68 – 7.50 (m, 4H), 7.49 – 7.27 (m, 6H),
4.74 (d, J = 5.3 Hz, 1H), 2.42 – 2.18 (m, 2H), 1.66 – 1.55 (m, 4H), 1.40 – 1.27 (m,
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4H), 1.20 – 1.13 (m, 1H); C{1H} NMR (101 MHz, CDCl3) δ 135.6, 135.5, 135.2,
134.4, 129.5, 128.0, 128.0, 38.6, 37.6, 37.4, 34.0, 33.7, 29.3, 25.8; IR (KBr) vmax 2946,
2110, 1727, 1111, 791, 727, 695 cm-1; HRMS (ESI) m/z calcd for C19H23Si 279.1564
[M+H]+, found 279.1574.
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Diphenyl(tetrahydrofuran-3-yl)silane (24). Colorless oil, 24 mg, 31% yield; 1H NMR
(400 MHz, CDCl3) δ 7.63 – 7.51 (m, 4H), 7.49 – 7.34 (m, 6H), 4.87 (d, J = 3.8 Hz,
1H), 4.14 (t, J = 8.4 Hz, 1H), 3.81 (td, J1 = 8.1, J2 = 3.4 Hz, 1H), 3.72 (td, J1 = 8.1, J2
= 6.6 Hz, 1H), 3.65 (dd, J1 = 10.7, J2 = 8.4 Hz, 1H), 2.20 – 2.12 (m, 1H), 2.06 – 1.92
(m, 1H), 1.90 – 1.79 (m, 1H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.4, 135.4, 133.2,
130.1, 130.0, 128.3, 70.9, 68.5, 29.6, 24.0; IR (KBr) vmax 2924, 1427, 1109, 798, 727,
695 cm-1; HRMS (ESI) m/z calcd for C16H18NaOSi 277.1119 [M+Na]+, found
277.1120.
Cis-(4S,5S)-4-(Diphenylsilyl)-5-methyldihydrofuran-2(3H)-one (cis-25). Colorless
oil, 24 mg, 28% yield; 1H NMR (400 MHz, CDCl3) δ 7.60 – 7.54 (m, 4H), 7.49 – 7.39
(m, 6H), 4.93 (d, J = 2.9 Hz, 1H), 4.62 – 4.52 (m, 1H), 2.70 (dd, J1 = 17.6, J2 = 8.9 Hz,
1H), 2.52 (dd, J1 = 17.6, J2 = 13.0 Hz, 1H), 2.10 – 1.97 (m, 1H), 1.32 (d, J = 6.1 Hz,
3H); 13C{1H} NMR (101 MHz, CDCl3) δ 176.9, 135.5, 135.4, 130.7, 128.6, 80.3, 33.1,
29.5, 21.2; IR (KBr) vmax 2922, 2126, 1774, 1050, 792, 730, 698 cm-1; HRMS (ESI)
m/z calcd for C17H18NaO2Si 305.0968 [M+Na]+, found 305.0967.
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Trans-(4R,5S)-4-(Diphenylsilyl)-5-methyldihydrofuran-2(3H)-one
(trans-25).
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Colorless oil, 18 mg, 22% yield; H NMR (400 MHz, CDCl3) δ 7.64 – 7.52 (m, 4H),
7.50 – 7.36 (m, 6H), 4.98 (d, J = 4.6 Hz, 1H), 4.96 – 4.90 (m, 1H), 2.66 – 2.59 (m,
2H), 2.58 – 2.51 (m, 1H), 1.32 (d, J = 6.6 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3)
δ 177.1, 135.1, 135.1, 132.0, 131.7, 130.6, 130.5, 128.7, 128.5, 79.5, 30.5, 26.12 19.2;
IR (KBr) vmax 2929, 2131, 1776, 1060, 743, 688 cm-1; HRMS (ESI) m/z calcd for
C17H18NaO2Si 305.0968 [M+Na]+, found 305.0966.
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Hexan-3-yldiphenylsilane (26). Colorless oil, 41 mg, 51% yield; 1H NMR (400 MHz,
CDCl3) δ 7.72 – 7.51 (m, 4H), 7.49 – 7.31 (m, 6H), 4.88 (d, J = 2.4 Hz, 1H), 1.71 –
1.58 (m, 1H), 1.57 – 1.40 (m, 4H), 1.39 – 1.27 (m, 2H), 0.96 (t, J = 7.4 Hz, 3H), 0.87
(t, J = 7.1 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.7, 134.5, 129.5, 128.0,
32.0, 24.9, 22.9, 22.0, 14.4, 13.6; IR (KBr) vmax 2956, 2116, 1259, 1014, 795, 696
cm-1; HRMS (ESI) m/z calcd for C18H25Si 269.1720 [M+H]+, found 269.1714.
(3S)-6-(Diphenylsilyl)-3,7-dimethyloctan-1-ol (27). Colorless oil containing two
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diastereomers with a ratio 1/1, 60 mg, 59% yield; H NMR (400 MHz, CDCl3) δ 7.66
– 7.55 (m, 8H), 7.48 – 7.29 (m, 12H), 4.91 (d, J = 3.3 Hz, 2H), 3.52 (t, J = 6.6 Hz,
4H), 2.03 – 2.00 (m, 2H), 1.59 – 1.45 (m, 4H), 1.45 – 1.42 (m, 1H), 1.42 – 1.38 (m,
2H), 1.36 (d, J = 3.2 Hz, 1H), 1.35 – 1.31 (m, 1H), 1.29 (d, J = 5.3 Hz, 1H), 1.28 –
1.24 (m, 3H), 1.24 – 1.17 (m, 2H), 1.16 – 1.10 (m, 2H), 1.08 – 1.00 (m, 1H), 0.97 (d,
J = 6.6 Hz, 6H), 0.96 – 0.93 (m, 6H), 0.77 – 0.74 (m, 6H); 13C{1H} NMR (101 MHz,
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CDCl3) δ 135.8, 135.5, 135.1, 129.4, 128.0, 128.0, 61.2, 39.9, 39.8, 37.6, 31.6, 31.6,
29.9, 29.8, 29.3, 29.2, 25.1, 25.0, 22.4, 22.3, 21.7, 21.6, 19.6, 19.6; IR (KBr) vmax
2923, 2118, 1428, 1259, 1012, 792, 698 cm-1; HRMS (ESI) m/z calcd for
C22H32NaOSi 363.2115 [M+Na]+, found 363.2110.
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(2-((S)-4-Methylcyclohex-3-en-1-yl)propyl)diphenylsilane (29). Colorless oil
containing two diastereomers with a ratio 1/1, 56 mg, 58% yield; 1H NMR (400 MHz,
Chloroform-d) δ 7.64 – 7.55 (m, 8H), 7.46 – 7.33 (m, 12H), 5.40 (s, 2H), 5.02 – 4.93
(m, 2H), 2.07 – 1.92 (m, 6H), 1.85 – 1.68 (m, 6H), 1.66 (s, 6H), 1.52 – 1.37 (m, 4H),
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1.33 – 1.22 (m, 2H), 1.10 – 1.00 (m, 2H), 0.96 (d, J = 6.7 Hz, 6H); C{1H} NMR
(101 MHz, CDCl3) δ 135.2, 135.1, 135.0, 134.0, 129.5, 129.4, 128.0, 128.0, 121.0,
120.9, 108.1, 40.9, 40.9, 34.0, 33.8, 30.9, 30.9, 28.8, 27.9, 26.7, 25.5, 23.5, 19.1, 18.8,
17.6, 17.1; IR (KBr) vmax 2921, 2119, 1428, 1115, 801, 696 cm-1; HRMS (ESI) m/z
calcd for C22H29Si 321.2033 [M+H]+, found 321.2040.
(4R,4aS,6R)-6-(1-(Diphenylsilyl)propan-2-yl)-4,4a-dimethyl-4,4a,5,6,7,8-hexahydro
naphthalen-2(3H)-one (30). Colorless oil containing two diastereomers with a 1/1
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ratio, 51 mg, 42% yield; H NMR (400 MHz, CDCl3) δ 7.61 – 7.51 (m, 8H), 7.44 –
7.26 (m, 12H), 5.76 – 5.68 (m, 2H), 5.02 – 4.88 (m, 2H), 2.44 – 2.33 (m, 1H), 2.31 (td,
J = 5.2, 4.3, 2.6 Hz, 1H), 2.29 – 2.26 (m, 2H), 2.25 (d, J = 4.1 Hz, 1H), 2.23 – 2.20 (m,
2H), 2.17 (dt, J = 5.5, 4.1 Hz, 1H), 2.03 – 1.87 (m, 3H), 1.82 (dt, J = 12.9, 2.8 Hz,
1H), 1.78 (q, J = 2.7 Hz, 2H), 1.77 – 1.72 (m, 1H), 1.69 – 1.59 (m, 4H), 1.33 – 1.25
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(m, 2H), 1.21 – 1.14 (m, 1H), 1.14 – 1.08 (m, 2H), 1.07 – 1.01 (m, 2H), 0.99 (s, 3H),
0.97 (s, 3H), 0.95 – 0.93 (m, 6H), 0.92 – 0.90 (m, 6H); 13C{1H} NMR (101 MHz,
CDCl3) δ 199.9, 171.6, 135.2, 135.1, 134.7, 134.5, 129.7, 129.6, 128.1, 128.1, 124.5,
42.8, 42.2, 42.1, 41.1, 40.7, 40.6, 39.6, 39.4, 39.4, 39.3, 34.3, 34.2, 33.2, 33.1, 29.9,
28.3, 19.1, 18.8, 18.0, 17.4, 17.0, 15.1, 15.0; IR (KBr) vmax 2924, 2117, 1667, 1108,
801, 698 cm-1; HRMS (ESI) m/z calcd for C27H34NaOSi 425.2271 [M+Na]+, found
425.2269.
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(2-(Cyclohex-3-en-1-yl)ethyl)diphenylsilane (31).23 Colorless oil, 38 mg, 44% yield;
1H NMR (400 MHz, CDCl3) δ 7.68 – 7.53 (m, 4H), 7.48 – 7.32 (m, 6H), 5.67 (d, J =
2.4 Hz, 2H), 4.88 (t, J = 3.5 Hz, 1H), 2.21 – 2.10 (m, 1H), 2.09 – 1.99 (m, 2H), 1.78
(m, 1H), 1.73 – 1.64 (m, 1H), 1.63 – 1.56 (m, 1H), 1.49 – 1.42 (m, 2H), 1.25 – 1.14
(m, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.1, 134.6, 129.5, 128.0, 127.1, 126.6,
36.4, 31.6, 31.1, 28.5, 25.3, 9.3; IR (KBr) vmax 2927, 1720, 1260, 1097, 800 cm-1;
HRMS (ESI) m/z calcd for C20H25Si 293.1720 [M+H]+, found 293.1722.
(E)-(4-(Hex-3-en-1-yloxy)butyl)triphenylsilane (32). Colorless oil, 77 mg, 62% yield;
1H NMR (400 MHz, CDCl3) δ 7.60 – 7.54 (m, 6H), 7.45 – 7.35 (m, 9H), 5.63 – 5.53
(m, 1H), 5.49 – 5.39 (m, 1H), 3.47 – 3.39 (m, 4H), 2.35 – 2.25 (m, 2H), 2.11 – 1.99
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(m, 2H), 1.61 – 1.52 (m, 4H), 1.47 – 1.35 (m, 6H), 1.01 (t, J = 7.5 Hz, 3H); C{1H}
NMR (101 MHz, CDCl3) δ 135.7, 134.1, 129.4, 127.9, 125.3, 71.0 70.8, 33.7, 33.1,
29.7, 25.8, 25.7, 24.0, 13.9, 13.3; IR (KBr) vmax 2924, 1259, 1108, 796, 697 cm-1;
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HRMS (ESI) m/z calcd for C28H35OSi 415.2452 [M+H]+, found 415.2458.
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(6-((3-Methyl
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but-3-en-1-yl)oxy)hexyl)triphenylsilane (34). Colorless oil containing 33 and 34 in a
1.87/1 ratio, 55 mg, 43% yield; 1H NMR (500 MHz, CDCl3) δ 7.68 – 7.55 (m, 8.8H),
7.52 – 7.36 (m, 13.0H), 5.93 – 5.79 (m, 0.9H), 5.13 – 4.96 (m, 1.8H), 4.88 – 4.77 (m,
1H), 3.62 – 3.53 (m, 1.0H), 3.51 – 3.30 (m, 4.9H), 2.42 – 2.31 (m, 1.0H), 2.17 – 2.07
(m, 1.9H), 2.07 – 1.96 (m, 1.0H), 1.84 – 1.79 (m, 1.4H), 1.74 – 1.64 (m, 1.9H), 1.64 –
1.52 (m, 5.2H), 1.51 – 1.33 (m, 6.3H), 1.00 – 0.83 (m, 2.9H); 13C{1H} NMR (101
MHz, CDCl3) δ 135.8, 135.7, 129.4, 127.9, 114.6, 111.4, 71.1, 70.7, 69.4, 69.1, 40.4,
37.9, 33.7, 29.8, 29.4, 26.6, 25.8, 25.6, 24.0, 23.4, 22.9, 21.7, 13.4; IR (KBr) vmax
2923, 1427, 1259, 1108, 1016, 796, 698 cm-1; HRMS (ESI) m/z calcd for
C29H36NaOSi 451.2428 [M+Na]+, found 451.2430.
(2-Methyl-4-((6-(triphenylsilyl)hexyl)oxy)butyl)triphenylsilane (35). Colorless oil,
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41 mg, 20% yield; H NMR (400 MHz, CDCl3) δ 7.62 – 7.49 (m, 12H), 7.47 – 7.29
(m, 18H), 3.40 – 3.31 (m, 2H), 3.27 (t, J = 6.6 Hz, 2H), 2.00 – 1.90 (m, 1H), 1.67 –
1.58 (m, 2H), 1.57 – 1.44 (m, 6H), 1.42 – 1.35 (m, 4H), 1.33 – 1.27 (m, 2H), 0.85 (d,
J = 6.6 Hz, 3H); 13C{1H} NMR (101 MHz, CDCl3) δ 135.8, 135.8, 135.5, 129.5,
129.4, 128.0, 127.9, 71.0, 69.1, 40.4, 33.8, 29.9, 26.7, 25.9, 24.0, 23.4, 21.7, 13.4; IR
(KBr) vmax 2923, 1720, 1259, 1106, 726, 696 cm-1; HRMS (ESI) m/z calcd for
C47H52NaOSi2 711.3449 [M+Na]+, found 711.3434.
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