Ruthenium Hydride Catalyzed Silylvinylation of Internal Alkynes Using Ethylene as an Additive

Article abstract of DOI:10.1021/acs.joc.5b01374

An efficient synthetic strategy for the regiospecific silylvinylation of internal alkynes is described. This transformation is catalyzed by RuHCl(CO)(SIMes)PPh₃ and provides a net 5-exo-dig trans-silylvinylation of internal alkynes. Ethylene wa

Full text of DOI:10.1021/acs.joc.5b01374

Page 1 of 31
The Journal of Organic Chemistry
Ruthenium Hydride Catalyzed Silylvinylation of Internal
Alkynes Using Ethylene as an Additive
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Robert J. Wilson, Lauren Kaminsky, Ijaz Ahmed and Daniel A. Clark*
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Department of Chemistry, 1-014 Center for Science and Technology, Syracuse University, Syracuse,
New York 13244
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Daclar01@syr.edu
Abstract:
An efficient synthetic strategy for the regiospecific silylvinylation of internal alkynes is described. This
transformation is catalyzed by RuHCl(CO)(SIMes)PPh3 and provides a net 5ꢀexo-dig transꢀ
silylvinylation of internal alkynes. Ethylene was used to decrease reaction times and displayed altered
selectivity at increased pressure. Furthermore, alkyl substituted alkynes were acceptable substrates at 80
psi of ethylene.
Introduction:
Alkenes are one of the most useful functional groups because they are incredibly versatile and known
to undergo a variety of transformations.1 Ethylene is the simplest alkene that is made in enormous
quantities with nearly 150 million lbs produced daily.2 It is an economical resource ideal for vinylation
chemistry as only one hydrogen atom is lost during the process.1 Ethylene has been utilized in numerous
organic transformations including Mizoroki–Heck reactions,3, 4 enyne metathesis5 and hydrovinylation.6ꢀ
8
However, ethylene has not been thoroughly investigated for the silylvinylation of alkynes. A regioꢀ
and stereospecific silylvinylation of internal alkynes delivers a wellꢀdefined tetraꢀsubstituted olefin, a
new vinyl group and vinylsilane of significantly increased complexity which functions as a useful
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handle.9 Vinyl silicon species are of particular interest due to their use in carbonꢀcarbon bond forming
reactions10, 11 allowing for further elaboration.
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Recently, we reported that ruthenium hydrides catalyze the silylvinylation of internal alkynes via
intermolecular insertion of acrylates12 and vinyl boronate esters.13 These reactions both produce highly
substituted dienes that possess unusual isomeric patterns formed through formal trans-5ꢀexo-dig
addition across the alkyne moiety. While screening catalysts for these transformations, we unearthed an
intramolecular14 vinylation of internal alkynes using RuHCl(CO)(SIMes)PPh3 (complex 1), which we
refer to as “ethylene transposition”. As observed previously, a formal trans-5ꢀexo-dig cyclization
occurred; however, the vinyl group (ethylene) was transferred across the alkyne instead of being
released as in the intermolecular coupling (Figure 1). In addition, we observed cycloisomerization
(isomer B) of the starting enyne as a minor byproduct of this process when aryl substituted alkynes were
employed in these reactions.15 Interestingly, when alkyl substituted alkynes were examined under
analogous conditions, only cycloisomerization products B were obtained using this protocol. Mori and
coꢀworkers have observed similar reactivity of enynes in the presence of ruthenium hydrides.16 An
improved procedure for the formation of dienes B has recently been reported which relies on ruthenium
complex Cp*RuCl(COD) and is compatible with both arylꢀ and alkylꢀsubstituted alkynes.15 Our main
goal for this study was to improve the ethylene insertion process and to expand our repertoire of alkynes
to include alkyl substituted substrates. Secondary goals included eradication of cycloisomerization
byproducts B, reduction of catalyst loading and decreasing reaction times.
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Figure 1. Silylvinylation of internal alkynes: discovery, previous work with methylvinylketone (MVK),
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and current work with ethylene.
Results and Discussion:
Based on the product formation observed previously, we suggest a mechanism which can
illustrate the formation of diene A (Figure 2). Phosphine dissociation from complex 1 provides
ruthenium complex 1a which undergoes olefin insertion to provide alkylꢀruthenium 1b. Silane 1b
extrudes ethylene and silicon is transferred to ruthenium to give silylꢀruthenium intermediate 1c. Our
mechanistic proposal suggests that cisꢀmetallation (1c to 1d) is followed by isomerization (1d to 1e) and
is supported by empirical data.12, 14, 17 Although we do not favor a direct transꢀaddition across the alkyne
piꢀsystem, Trost,18 Denmark,19 and Chang20 have observed antiꢀhydrosilylation products using various
ruthenium catalysts. Direct transꢀaddition across alkynes has also been observed by Fu21 and Mori22
using rhodium, and Murakami23 using gold. Subsequent insertion of ethylene into vinyl ruthenium 1e
and betaꢀhydride elimination of 1f liberates the product and regenerates ruthenium hydride 1a to
complete the catalytic cycle. We anticipated that the addition of ethylene to the reaction would increase
the production of diene A in preference to the undesired formation of diene B. Additionally, the use of
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ethylene could provide some understanding of the mechanism of this reaction; our hypothesis being that
increasing the amount of ethylene in the reaction would trap proposed “cisꢀsiomer” 1d prior to
isomerization to “transꢀisomer” 1e; the stability of these proposed intermediates is currently not known.
Using ethyleneꢀd4 we observed incorporation of exogenous ethylene into the product (Scheme 1). This
outcome affirms that the ethylene being added to the system can be incorporated into the product.
Another aspect of this study was to obtain silylvinylation of internal alkyl substituted alkynes.
Previously, ethylene transposition of these alkynes provided solely cycloisomerization isomer B
presumably through intermediates 1g and 1h (Figure 2).14
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Si
O
Si
O
Si
O
R1
R1
R
R
R
β-hydride
Ru
β-hydride elimination
R1
1f
A
R1
elimination
B
+ethylene
Si
O
Ru
O
Si
tion
Isomeriza
R
H
H
H
R
1h R1
+PPh3
-PPh3
+PPh3
-PPh3
Cl
SIMes
CO
Cl
SIMes
CO
Cl
SIMes
CO
1e
Ru
Ru
Ru
Ru
Ph3P
O
Si
1
yl-
rans sil
t
1a
1a
olefin
Ru
nation
ruthe
R
insertion
= open coordination site
1d
R1
Si
Si
Si
O
Ru
O
O
R1
β-silyl transfer
R1
R1
Si
-
cis silyl
ation
O
Ru
ruthen
R
Ru
R
R
1c
Si
R
alkene
hydroruthenation
alkyne
hydroruthenation
O
R1
H
1g
R1
R
- ethylene
1b
Figure 2. Mechanistic hypothesis.
Scheme 1. Isotopic Labeling Experiment
5 mol % complex 1
C2D4(g) (balloon)
O
Si
Si
O
Ph
Ph
H (52% 2H)
H (52% 2H)
Me
Me
DCE 80 °C 0.5 h
2b*
2a
H
(56% 2H)
Table 1. Catalyst Screen
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entry catalyst time (h) Conversion A:B:C
yield A (%)a
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100
89
18:1:2
55:4:1
1:0:0
6:1:0
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1
2*
3*
4*
5*
Ru-2
Ru-3
Ru-4
Ru-5
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29
aYield determined by 1H NMR vs mesitylene internal standard. *5 mol % catalyst was used.
Based on our previous observations, we began our investigation with alkyne 2a using ruthenium
hydride 1 (1 mol %) under an atmosphere (balloon) of ethylene in 1,2ꢀdichloroethane (DCE) at 80 °C.14
We observed a rapid (1 h) reaction that produced silylvinylation product 2b as a 9:1 mixture of E and Z
isomers. This corroborates our assertion that synꢀmetallation (i.e. formation of 1d) followed by
isomerization occurs to give 1e which proceeds to the silylvinylation products observed. Further
examination of catalysts revealed that complex 1 was the optimum ruthenium hydride catalyst and in
many cases 1 mol % was sufficient to provide the desired products (Table 1). However, the use of
ruthenium complexes that bear two bulky phosphine moieties (Ru-2 through Ru-5) do give some of the
desired product. It was observed that the more electron rich complexes afforded higher conversion and
larger quantities of AꢀC (Table 1). Presumably complex 1 is superior due to the greater donating ability
of the NHC24 and the enhanced lability of the less basic PPh3 ligand.25 Other solvents such as toluene
and 1,4ꢀdioxane were also found to be suitable for this reaction at 80 °C.
We examined the substrate scope using this protocol (Scheme 2) by keeping the aryl group
constant and altering groups at the homoꢀpropargyl and propargyl positions. The reaction tolerated
methyl and cyclohexyl groups at the homoꢀpropargyl position and gave 2b and 3b in 80% and 70%
yield, respectively. Aryl groups were also well tolerated and 4b was formed in 65% yield. Multiple
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substitutions at the homopropargyl position afforded 5b in 69% and 6b in 76% yield. Previously only
partial conversion to diene 7b was observed;14 here 7b was rapidly produced in 67% yield. Products 8b
(78%) and 9b (70%) demonstrate that the reaction works well with substitution in the syn or anti
relationship at the propargyl and homopropargyl locants. Next, variation of the aryl moiety at the alkyne
terminus was examined. As anticipated, paraꢀsubstitution was well tolerated with the 4ꢀfluorophenyl
providing 10b in 69% yield as essentially a single isomer. Chlorines were also amenable to these
reaction conditions giving 11b in 70% yield.
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Scheme 2. Substrate Scope
1
aRatios determined by H NMR using mesitylene as an internal standard. Products were isolated as a
mixture of Z/E isomers (A:C).
The bulk of the chlorine did not hamper the efficiency of the reaction, nor did other orthoꢀsubstituted
groups like 1ꢀnaphthyl which gave 12b in 71% yield. The 3,5ꢀxylyl moiety afforded 13b in 74% yield
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without difficulty. Electronics of the aryl group was also examined using 4ꢀanisole and 4ꢀacetophenone
derivatives which provided 14b in 73% yield and 15b in 64% yield. Interestingly, although the yields
are comparable, the ratio of isomers was substantially different in these cases. We posit that the electron
donating methoxyꢀgroup in 14b helps stabilize charge buildꢀup in the isomerization pathway.
Conversely, the electron withdrawing acetyl functionality destabilizes charge buildꢀup in the same step.
It has been reported previously that such isomerization events can occur through either zwitterionic or
carbene type intermediates.26 Finally, six membered oxasilacycle 16b was formed in 82% yield under
these conditions.
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The aryl substrates provided excellent selectivity for silylvinylation versus cycloisomerization (≥20:1)
compared to previous results (5ꢀ8:1).14 With these results we envisioned that higher concentration of
ethylene (increased pressure) would further reduce or eliminate isomer B. Using alkyne 2a the amount
of ethylene was systematically increased by 20 psi; we observed increased amounts of isomer C as a
function of pressure. Additionally, no undesired cycloisomerization product was observed over the
pressure range studied (Table 2). To ascertain whether the pressure or concentration was influencing the
outcome, a control experiment with increased argon pressure was conducted. At 80 psi of argon the
reaction was retarded and approximately 23% conversion with only 11% of isomer A was observed by
1H NMR. This supports the hypothesis that increased ethylene concentration increases the amount of
synꢀsilylvinylation product. To the best of our knowledge increased ethylene pressure has not been
shown to overcome inherent selectivity of a substrate for stereocontrol.
Table 2. Sequential Increase of Ethylene Pressurea
entry pressure
ratio (A:C)b
1
2
balloon
20 psi
9:1
6:1
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3
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40 psi
60 psi
80 psi
2.5:1
1:1.4
1:1.7
1
2
3
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8
80 psi (Ar(g)) 1:0c
9
b
1
c
aReactions were pressurized at room temperature prior to heating. Determined by H NMR. 23%
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conversion and 11% A observed.
The silylvinylation pressure study also unearthed an interesting electronic effect. The E:Z ratio of
silylvinylation products was influenced by the electronics of the alkyne (Table 3). Alkynes substituted
with electronically neutral and weakly withdrawing groups gave ~1:2 ratio of A:C (entry 1 and 2
respectively). Electron rich alkynes (entry 3) provide isomer A as the major product, while electron
deficient alkynes provide major isomer C (entry 4). Increasing the ring size from five to six surprisingly
yielded a 25:1 ratio of A:C (entry 5). These preliminary results warrant further examination i.e. higher
pressures and increased reaction times, to determine the intrinsic electronic preference.
Table 3. Electronic Differentiation of Alkyne Terminus at 80 psi Ethylene
entry substrate
time (h) conv. (%) ratio (A:C)yield%a
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2
3
4
5
Ar = Ph
4
100
100
100
100
100
1:1.7
1:1.3
3:1
(99)
85
Ar = 4ꢀF
Ar=4ꢀOMe
Ar = 4ꢀAc
4
6
91
24
1:7
86
Ar = Ph, n= 2 24
25:1
72
aYield in parenthesis determined by 1H NMR with mesitylene as an internal standard.
We continued by examining substrates that had previously formed isomer B preferentially (i.e.
alkylꢀsubstituted alkynes) or were aberrant at lower ethylene pressure.14 To our delight, excellent results
were obtained when alkylꢀsubstituted alkynes were employed in this reaction (Figure 3). Methyl
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substituted dienes 17b and 18b were formed in 84% yield, both favoring isomer C as the major product.
Increasing the alkyl chain by one carbon to ethyl gave 19b in 79% yield; adding three carbons gave n-
butyl 20b in 69% yield, and further extension to n-hexyl provided 21b in 83% yield. In the later three
cases, isomer A was the predominant product formed. Given the similar steric environment presented by
these alkyl groups, we suggest that the observed product ratios are due to the subtle electronic changes
in these substrates. We assume that the increased concentration of ethylene prevents unwanted
hydroruthenation of the alkyne and thus inhibits the formation of isomer B.
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Figure 3. Reactions of internal alkyl alkynes at 80 psi. Ratio in parenthesis is isomers A to C
determined by 1H NMR and confirmed by nOe or NOESY experiments.
The synthetic utility of these systems was also explored. Fleming–Tamao oxidation27, 28 under neutral
conditions provided no oxidation products and slow decomposition of diene 4b was observed. Utilizing
basic conditions (Scheme 3, eq. 1) afforded α,βꢀepoxy ketone 22 in 70% yield. It was presumed that the
excess basic peroxide facilitates a Michaelꢀaddition into the newly formed α,βꢀunsaturated ketone (i.e.
23). To avoid this undesired Michael addition acidic conditions were used. These conditions utilized
propionic anhydride and enone 23 was obtained in 85% isolated yield as a single isomer (eq. 2). These
complementary methods provided access to β′ꢀhydroxyꢀketones in good yield. It was discovered that
Heck product 24 was formed while attempting to utilize the silicon moiety of diene 4b as a coupling
partner in Hiyama–Denmark29 chemistry. Using [(C3H5)PdCl]2, CuI, KF·2H2O, and 4ꢀiodotoluene in
DMF at room temperature gave Heck product 24 in low yield. After some experimentation the reaction
ο
of diene 4b with Pd(OAc)2, K2CO3, and 4ꢀiodotoluene in DMF at 80 C afforded 24 in 64% yield (eq.
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3). We are currently exploring conditions that will selectively couple the silicon to directly access all
carbon tetrasubstituted olefins. Additionally, Tamao oxidation was particularly useful with compound
17b which was successfully converted into enone 25 (eq. 4). Apparently, introducing a mixture of
isomers into the reaction was irrelevant as compound 25 was isolated in 73% yield as a single double
bond isomer.
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Scheme 3. Synthetic Elaboration of Dienes
Conclusion:
In summary, we report that the use of ethylene gas can be successfully utilized in the ruthenium
hydride catalyzed silylvinylation of internal alkynes. It was demonstrated that this protocol was useful
for the synthesis of highly substituted conjugated dienes. When the reaction was conducted at increased
pressure of ethylene (80 psi) competing cycloisomerization of the starting enyne was not observed.
Additionally, it was demonstrated that alkyl substituted alkynes produced silylvinylation products in
excellent yield. The resulting dienes were elaborated to epoxyꢀketones and enones using complementary
oxidation conditions. Finally, a regioꢀ and stereoselective Heck coupling was reported which further
enhances the scope of this chemistry beyond simple vinyl moieties. Future efforts in manipulating these
dienes for complex molecule synthesis will be reported in due course.
Experimental Section:
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General Procedures: Unless otherwise indicated, all reactions were conducted in oven (140 °C) or
flameꢀdried glassware using distilled and degassed solvents under a positive pressure of dry argon with
standard Schlenk techniques. All airꢀsensitive reagents were stored in a glovebox containing dry argon
gas. Dry tetrahydrofuran (THF), toluene, acetonitrile (CH3CN), and methylene chloride (DCM) were
obtained by passing commercially available preꢀdried, oxygenꢀfree formulations through two activated
alumina columns. Stainless steel syringes or cannulae that had been ovenꢀdried (140 °C) and cooled
under an argon atmosphere or in a desiccator were used to transfer airꢀ and moistureꢀsensitive liquids.
Yields refer to chromatographically and spectroscopically (1H NMR) homogeneous materials, unless
otherwise stated. Reactions were monitored by thinꢀlayer chromatography (TLC) carried out on
precoated glass plates of silica gel (0.25 mm) using the indicated solvent system. Visualization was
accomplished with ultraviolet light (254 nm) or by treatment with one of the following solutions and
carefully heating with a hotꢀair gun (450 °C): 10% phosphomolybdic acid in ethanol, 1% potassium
permanganate/7% potassium carbonate/0.5% sodium hydroxide aqueous solution, or anisaldehyde in
ethanol with 10% sulfuric acid. Flash column chromatography was performed using silica gel (40−63
ꢁm). All workup and purification procedures were carried out with reagent grade solvents in air.
Reagents were purchased and used without further purification, unless otherwise stated.
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Silicon-Tethered Alkynes: Alkynes 2a, 3a, 4a, 5a, 6a, 8a, 10a, 11a, 14a, 16a, 17a were prepared
following the literature protocol.12 Alkynes 9a, 12a, 13a, 15a, 18a were prepared following the
literature protocol.14 Dienes 2b-6b and 8b-16b were previously prepared as the Z isomer by our group.14
Ruthenium Hydride Ru-3 was prepared according to literature procedure.13
Dimethyl((2-methyl-4-phenylbut-3-yn-1-yl)oxy)(vinyl)silane (7a):To a flame dried 50 mL round
bottom flask with a magnetic stir bar was added alcohol S530 (1.08 g, 6.75 mmol), DCM (20 mL),
DMAP (165 mg, 1.35 mmol) and imidazole (919 mg, 13.5 mmol). Vinyldimethylchlorosilane was
added dropwise (1.39 mL, 10.13 mmol) to the resulting solution and the reaction stirred at RT for 2 h.
The reaction mixture was poured into sat. NH4Cl(aq.) (30 mL), extracted with DCM (2 x 20 mL), dried
over MgSO4, filtered and concentrated in vacuo to give a yellow residue. The yellow residue was
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purified via flash column chromatography (1% diethyl ether/hexanes) to yield 7a as a clear oil (1.37 g,
1
2
3
1
84%). Rf = 0.72 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.40ꢀ7.38 (m, 2H),
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7
8
7.28ꢀ7.25 (m, 3H), 6.15 (dd, J = 20.0, 15.0 Hz, 1H), 6.03 (dd, J = 14.8, 4.0 Hz, 1H), 5.81 (dd, J =20.0,
4.2 Hz, 1H), 3.76 (dd, J = 9.8, 6.0 Hz, 1H), 3.53 (dd, J = 9.8, 7.6 Hz, 1H), 2.81 (sext., J = 6.8 Hz, 1H),
9
13
1.25 (d, J = 6.8 Hz, 3H), 0.22 (s, 6H); C NMR (100 MHz, CDCl3): δ = 137.4, 133.5, 131.7, 128.3,
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127.7, 123.8, 92.1, 81.6, 67.1, 29.7, 17.5, ꢀ1.9; IR (film): v = 3053, 2967, 2909, 1596, 1490, 1253, 1086,
837 cmꢀ1; Anal. calcd. for C15H20OSi: C 73.71, H 8.25; found: C 73.83, H 8.19
Dimethyl((1-phenylhex-3-yn-1-yl)oxy)(vinyl)silane (19a): To a flame dried 250 mL 3ꢀneck round
bottom flask equipped with a pressure equalizing addition funnel, large magnetic stir bar and freshly
prepared propargyl magnesium bromide (0.63M in Et2O, 145 mmol) at ꢀ40 oC was added benzaldehyde
(9.9 mL, 97 mmol) dropwise. The reaction stirred at RT for 4 h, then poured into 1M HCl (200 mL).
The layers were separated and the organics were dried over MgSO4, filtered and concentrated in vacuo
to give a yellow oil (13.7 g). To a flame dried 500 mL round bottom flask with magnetic stir bar was
added the resulting crude alcohol (13.7 g, 94 mmol), DCM (235 mL) and PPTS (2.36 g, 9.39 mmol).
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The yellow solution was cooled to 0 C (ice/H2O bath) and DHP (17.1 mL, 188 mmol) was added
dropwise. The reaction mixture stirred at RT for 4 h and then was quenched by sat. NaHCO3(aq) (100
mL). The layers were separated and the organics were dried over MgSO4, filtered and concentrated in
vacuo to give a yellow oil (22.4 g). To a flame dried 500 mL 3ꢀneck round bottom flask equipped with a
pressure equalizing addition funnel and large magnetic stir bar was added the resulting crude alkyne (5.0
g, 21.7 mmol) and THF (130 mL). The yellow solution was cooled to ꢀ78 oC (dry ice/acetone bath) and
nBuLi (10.4 mL, 2.5M, 26.0 mmol) was added dropwise. After stirring for 1 h, bromoethane (7.3 mL,
98 mmol) was added dropwise then the solution was warmed to RT and stirred overnight. The reaction
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mixture was quenched by the addition of sat. NH4Cl(aq) (100 mL) at ꢀ78 C (dry ice/acetone bath). The
layers were separated and the aqueous was extracted with Et2O (2 x 50 mL). The combined organics
were dried over MgSO4, filtered and concentrated in vacuo to give a orange oil (5.36 g). To an oven
dried 100 mL round bottom flask with magnetic stir bar was added the resulting orange oil (5.36 g, 21
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The Journal of Organic Chemistry
o
mmol), EtOH (50 mL) and PPTS (1.56 g, 6.2 mmol). The orange solution stirred at 50 C for 4 h, then
was cooled to RT and concentrated in vacuo. The residue was dissolved in DCM and washed with brine
(2 x 50 mL). The organics were dried over MgSO4, filtered and concentrated in vacuo to give a brown
oil. Purification via flash column chromatography (gradient elution with 5ꢀ10% EtOAc/hexanes) gave
alcohol S6 as a yellow oil (1.48 g, 41% over 3 steps). To an oven dried 100 mL round bottom flask with
magnetic stir bar was added S6 (1.48 g, 8.5 mmol), DCM (45 mL), imidazole (1.16 g, 17 mmol) and
DMAP (208 mg, 1.7 mmol). The solution was cooled to 0 oC (ice/H2O bath) and
vinyldimethylchlorosilane (1.8 mL, 12.7 mmol) was added dropwise. The resulting yellow suspension
stirred at RT overnight. The reaction was quenched with sat. NH4Cl(aq) (50 mL) and the organics were
dried over Na2SO4, filtered and concentrated in vacuo to give a yellow residue. Purification via flash
column chromatography (gradient elution with 1ꢀ3% diethyl ether/hexanes) gave alkyne 19a as a pale
yellow oil (1.39 g, 63%). Rf = 0.59 (10% diethyl ether/hexanes); 1H NMR (400 MHz, CDCl3): δ = 7.30
(m, 5H), 6.09 (dd, J = 20.0, 14.8 Hz, 1H), 5.97 (dd, J = 4.0, 14.8 Hz, 1H), 5.74 (dd, J = 4.0, 20.0 Hz,
1H), 4.78 (dd, J = 6.0, 7.6 Hz, 1H), 2.51 (m, 2H), 2.14 (qt, J = 10.0, 2.4 Hz, 2H), 1.09 (t, J = 7.6 Hz,
3H), 0.17 (s, 3H), 0.12 (s, 3H); 13C NMR (100 MHz, CDCl3): δ = 144.2, 137.9, 133.3, 128.2, 127.5,
126.2, 83.7, 76.8, 74.5, 31.2, 14.3, 12.7, ꢀ1.3, ꢀ1.4; IR (film): v = 3051, 2973, 2373, 1438, 1252, 1070
cmꢀ1; Anal. calcd. for C16H22OSi: C 74.36, H 8.58; found: C 74.31, H 8.58
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Dimethyl((1-phenyloct-3-yn-1-yl)oxy)(vinyl)silane (20a): To a flame dried 250 mL 3ꢀneck round
bottom flask with a pressure equalizing addition funnel and magnetic stir bar was added 1ꢀhexyne (4.1
g, 49.9 mmol) and THF (50 mL). The solution was cooled to ꢀ78 oC (dry ice/acetone bath) and nBuLi
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(30 mL, 1.66M, 49.9 mmol) was added dropwise via addition funnel. After stirring at ꢀ78 C for 1 h, a
solution of styrene oxide (5 g, 41.6 mmol) in HMPA (10.9 mL, 62.4 mmol) was added dropwise via
addition funnel. After 10 min, the reaction mixture was allowed to warm to RT. The reaction was
poured into 100 mL water and extracted with diethyl ether. The organic layer was washed with 1M HCl
and brine, dried over MgSO4, filtered and concentrated in vacuo to afford a yellow oil (1.57 g, 18%). To
a flameꢀdried 250 mL round bottom flask with stir bar was added the crude alcohol (1.57 g, 7.76 mmol)
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and DCM (50 mL). To the yellow solution was sequentially added imidazole (1.06 g, 15.52 mmol, ) and
DMAP (0.2 equiv). The resulting mixture was cooled to 0 oC (ice/H2O bath) and
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vinyldimethylchlorosilane was added dropwise. After stirring at 0 C for 10 min, the resulting
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suspension was allowed to warm to RT. After 4 h, the reaction was quenched with sat. NH4Cl(aq) (30
mL) and extracted with DCM (3 x 30 mL). The combined organics were washed with brine (2 x 50
mL), dried with MgSO4(s), filtered and concentrated to yield a yellow oil. The oil was purified via flash
column chromatography (2% diethyl ether/hexanes) to yield 20a as a clear oil (1.73 g, 78%). Rf = 0.64
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(10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.35ꢀ7.22 (m, 5H), 6.08 (dd, 1H, J =
20.0, 14.8 Hz), 5.96 (dd, 1H, J = 14.8, 4.2 Hz), 5.74 (dd, 1H, J = 20.0, 4.2 Hz), 4.77 (t, 1H, J = 6.3 Hz),
2.61ꢀ2.44 (m, 2H), 2.12 (tt, 2H, J = 9.2, 6.8, 2.4 Hz), 1.47ꢀ1.32 (m, 4H), 0.88 (t, 3H, J = 7.2 Hz), 0.16
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(s, 3H), 0.11 (s, 3H); C NMR (100 MHz, CDCl3): δ = 144.1, 137.8, 133.2, 128.1, 127.4, 126.1, 82.2,
74.4, 31.1, 31.1, 22.0, 18.6, 13.8, ꢀ1.3, ꢀ1.5; IR (film): v = 3030, 2957, 2931, 2871 cmꢀ1; Anal. calcd.
for C18H26OSi: C 75.46, H 9.15; found: C 75.29, H 9.05
Dimethyl((1-phenyldec-3-yn-1-yl)oxy)(vinyl)silane (21a): Prepared following the procedure for 20a:
1ꢀoctyne (3.5 mL, 24 mmol), nBuLi (9.6 mL, 2.5M, 24 mmol), styrene oxide (2.28 mL, 20 mmol) in
HMPA (5.2 mL, 30 mmol). The reaction was poured into 100 mL water and extracted with diethyl
ether. The organic layer was washed with 1M HCl and brine, dried over MgSO4, filtered and
concentrated in vacuo to afford a yellow oil (2.74g, 59%). To a flame dried 100 mL round bottom flask
was added the crude alcohol (1.39 g, 6.04 mmol), DCM (20 mL), DMAP (147 mg, 1.21 mmol) and
imidazole (822 mg, 12.08 mmol). Vinyldimethylchlorosilane (1.25 mL, 9.06 mmol) was added
dropwise to the yellow solution and the resulting suspension stirred overnight. The reaction mixture was
poured into sat. NH4Cl(aq.) (30 mL), extracted with DCM (2 x 20 mL), dried with MgSO4, filtered and
concentrated in vacuo to give a yellow residue. Purification via column chromatography (1% diethyl
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ether/hexanes) gave alkyne 20a as a clear oil (1.21 g, 64%). Rf = 0.37 (2% diethyl ether/hexanes); H
NMR (400 MHz, CDCl3): δ = 7.35ꢀ7.28 (m, 3H), 7.25ꢀ7.22 (m, 2H), 6.08 (dd, J = 20.0, 15.2 Hz, 1H),
5.96 (dd, J = 14.8, 4.4 Hz, 1H), 5.81 (dd, J = 20.2, 4.2 Hz, 1H), 4.77 (t, J = 6.5 Hz, 1H), 2.60ꢀ2.44 (m,
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2H), 2.13ꢀ2.08 (m, 2H), 1.47ꢀ1.23 (m, 8H), 0.89 (t, J = 6.6 Hz, 3H), 0.16 (s, 3H), 0.11 (s, 3H); 13C
NMR (100 MHz, CDCl3): δ = 144.1, 137.7, 133.2, 128.1, 127.4, 126.1, 82.2, 74.3, 31.5, 31.1, 29.0,
28.7, 22.7, 18.2, 14.2, ꢀ1.3, ꢀ1.5; IR (film): v = 2932, 2859, 1594, 1454, 1252, 1090, 836 cmꢀ1;Anal.
calcd. for C20H30OSi: C 76.37, H 9.61; found: C 76.21, H 9.56
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General procedure for Silylvinylation at 1 atmosphere ethylene (A):An oven dried 50 mL Schlenk
tube equipped with a magnetic stir bar was brought into an argon filled glove box. To the Schlenk tube
was added RuHCl(CO)(SIMes)(PPh3) (1) (1ꢀ5 mol%) followed by the alkyne substrate (1.0 equivalent)
in 1,2ꢀdichloroethane or toluene (0.25M). The Schlenk tube was sealed and removed from the glove
box. The solution was purged with ethylene gas for 1ꢀ5 minutes via balloon and steel needle. The needle
was removed from the solution and placed 3ꢀ4 cm above the solvent, then the apparatus was immersed
in an 80 °C oil bath. The reaction was stirred until complete consumption of the starting material was
visualized by thin layer chromatography. Upon completion, the reaction was filtered through a short
plug of silica gel (eluted with dichloromethane) and concentrated in vacuo. A crude yield was obtained
by 1H NMR with mesitylene (0.33 equivalents) as an internal standard. The crude product was purified
via flash chromatography on silica gel.
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2,2,5-trimethyl-3-(1-phenylallylidene)-1,2-oxasilolane (2b): Following the general procedure (A),
RuH 1 (35 mg, 0.046 mmol) and alkyne 2a (1.12 g, 4.6 mmol) in toluene (4.6 mL) stirred under
ethylene (1 atm) at 80 °C for 1 h. Purification via flash column chromatography (2ꢀ3% diethyl
ether/hexanes) gave diene 2b as a clear oil (896 mg, 80% as a Z/E mixture). Crude ratio A:B:C =
1
10:1:1; Rf = 0.40 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.34ꢀ7.28 (m, 3H),
7.13ꢀ7.10 (m, 2H), 6.86 (dd, J = 17.4, 10.8 Hz, 1H), 5.23 (dd, J = 10.8, 1.5 Hz, 1H), 4.87 (dd, J = 17.4,
1.5 Hz, 1H), 4.24ꢀ4.16 (m, 1H), 2.96 (dd, J = 15.9, 5.1 Hz, 1H), 2.32 (dd, J = 15.9, 8.4 Hz, 1H), 1.32 (d,
J = 6.0 Hz, 3H), ꢀ0.07 (s, 3H), ꢀ0.20 (s, 3H). Minor isomer diagnostic peaks: δ = 6.52 (dd, J = 16.8,
10.8 Hz, 1H), 5.08 (d, J = 10.5 Hz, 1H), 4.75 (d, J = 16.8 Hz, 1H), 1.20 (d, J = 6.0 Hz, 3H), 0.42 (s,
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3H), 0.39 (s, 3H); C NMR (100 MHz, CDCl3): δ = 148.2, 147.2, 144.4, 143.5, 141.6, 139.8, 139.8,
135.9, 129.7, 128.9, 128.3, 127.9, 127.3, 126.9, 118.3, 116.4, 72.7, 72.5, 42.8, 40.7, 24.1, 23.8, 0.7, 0.6,
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0.3, ꢀ0.3; IR (film): ν = 3056, 2964, 2873, 1581, 1249, 1035, 832 cmꢀ1; Anal. calcd. for C15H20OSi: C
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73.71, H 8.25; found: C 73.71, H 8.34
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Isotopic Labeled Diene (2b*): Following the general procedure (A), RuH 1 (36 mg, 0.05 mmol) and
alkyne 2a (244 mg, 1.0 mmol) in DCE (4.0 mL) stirred under C2D4 (1 atm) at 80 °C for 30 min.
Purification via flash column chromatography (1.5 x 15 cm, 2% diethyl ether/hexanes) gave diene 2b*
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as a clear oil (155 mg, 63% as a Z/E mixture). % H incorporation: 56%, 52% and 52%; Crude ratio
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A:B:C = 12:1:1; Rf = 0.40 (10% diethyl ether/hexanes); H NMR (600 MHz, CDCl3): δ = 7.32ꢀ7.25
(m, 3H), 7.13ꢀ7.12 (m, 2H), 6.86 (dd, J = 17.4, 10.8 Hz, 1H), 5.22 (dd, J = 10.8, 1.5 Hz, 1H), 4.87 (dd, J
= 17.4, 1.5 Hz, 1H), 4.23ꢀ4.17 (m, 1H), 2.93 (dd, J = 15.9, 5.1 Hz, 1H), 2.32 (dd, J = 15.9, 8.4 Hz, 1H),
1.32 (d, J = 6.0 Hz, 3H), ꢀ0.08 (s, 3H), ꢀ0.20 (s, 3H); 2H NMR (92 MHz, CHCl3): δ = 6.87, 5.25, 4.87;
5-cyclohexyl-2,2-dimethyl-3-(1-phenylallylidene)-1,2-oxasilolane (3b): Following the general
procedure (A), RuH 1 (4 mg, 0.006 mmol) and alkyne 3a (78 mg, 0.25 mmol) in DCE (1.0 mL) stirred
under ethylene (1 atm) at 80 °C for 1 h. Purification via preparative TLC (1% diethyl ether/hexanes)
gave diene 3b as a clear oil (55 mg, 70% as a Z/E mixture). Crude ratio A:B:C = 16:2:1; Rf = 0.80
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(10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.34ꢀ7.27 (m, 3H), 7.14ꢀ7.11 (m, 2H),
6.89 (dd, J = 17.4, 10.5 Hz, 1H), 5.23 (dd, J = 10.5, 1.5 Hz, 1H), 4.87 (dd, J = 17.4, 1.5 Hz, 1H), 3.80ꢀ
3.75 (m, 1H), 2.87 (dd, J = 16.2, 5.5 Hz, 1H), 2.45 (dd, J = 16.2, 8.7 Hz, 1H), 1.96ꢀ1.92 (m, 1H), 1.78ꢀ
1.66 (m, 4H), 1.31ꢀ0.98 (m, 6H), ꢀ0.08 (s, 3H), ꢀ0.22 (s, 3H); minor isomer diagnostic peaks: δ = 6.52
(dd, J = 17.1, 10.8 Hz, 1H), 5.08 (d, J = 10.5 Hz, 1H), 4.75 ( d, J = 16.8 Hz, 1H), 0.40 (s, 3H), 0.39 (s,
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3H); C NMR (100 MHz, CDCl3): δ = 147.0, 143.7, 141.8, 135.9, 129.8, 127.9, 127.2, 118.2, 80.7,
44.8, 36.0, 29.3, 28.7, 26.3, 26.3, 0.4, ꢀ0.2; IR (film): ν = 2925, 2852, 1581, 1449, 1248, 1032 cmꢀ1;
Anal. calcd. for C20H28OSi: C 76.86, H 9.03; found: C 76.52, H 8.82
2,2-dimethyl-5-phenyl-3-(1-phenylallylidene)-1,2-oxasilolane (4b): Following the general procedure
(A), RuH 1 (2 mg, 0.0025 mmol) and alkyne 4a (77 mg, 0.25 mmol) in DCE (1.0 mL) stirred under
ethylene (1 atm) at 80 °C for 1 h. Purification via preparative TLC (1:200 diethyl ether/hexanes) gave
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diene 4b as a clear oil (50 mg, 65% as a Z/E mixture). Crude ratio A:B:C = 10:1:1; Rf = 0.20 (5%
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diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.44ꢀ7.28 (m, 8H), 7.19ꢀ7.16 (m, 2H), 6.87
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(dd, J = 17.1, 10.5 Hz, 1H), 5.26 (d, J = 10.5 Hz, 1H), 5.08 (dd, J = 9.5, 5.5 Hz, 1H), 4.92 (d, J = 17.1
Hz, 1H), 3.29 (dd, J = 16.3, 5.5 Hz, 1H), 2.61 (dd, J = 16.3, 9.5 Hz, 1H), ꢀ0.09 (s, 3H), ꢀ0.15 (s, 3H);
minor isomer diagnostic peaks: δ = 6.58 (dd, J = 17.1, 10.5 Hz, 1H), 5.14 (d, J = 10.5 Hz, 1H), 4.81
(d, J = 17.1 Hz, 1H), 0.52 (s, 3H), 0.51 (s, 3H); 13C NMR (100 MHz, CDCl3): δ = 147.4, 144.4, 142.9,
141.6, 135.8, 129.8, 128.5, 128.0, 127.4, 127.4, 125.6, 118.8, 77.9, 42.0, 0.5, ꢀ0.4; IR (film): ν = 3060,
2961, 2880, 1582, 1420, 1250, 781 cmꢀ1; Anal. calcd. for C20H22OSi: C 78.38, H 7.24; found: C 78.43,
H 7.02
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2,2,5-trimethyl-5-phenyl-3-(1-phenylallylidene)-1,2-oxasilolane (5b): Following the general
procedure (A), RuH 1 (2 mg, 0.0025 mmol) and alkyne 5a (80 mg, 0.25 mmol) in DCE (1.0 mL) stirred
under ethylene (1 atm) at 80 °C for 1 h. Purification via preparative TLC (2% diethyl ether/hexanes)
gave diene 5b as a clear oil (56 mg, 70% as a Z/E mixture). Crude ratio A:B:C = 16:2:1; Rf = 0.62
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(10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.52ꢀ7.49 (m, 2H), 7.38ꢀ7.30 (m, 5H),
7.27ꢀ7.22 (m, 1H), 7.16ꢀ7.12 (m, 2H), 6.92 (dd, J = 17.4, 10.8 Hz, 1H), 5.27 (dd, J = 10.8, 1.2 Hz, 1H),
4.91 (dd, J = 17.4, 1.2 Hz, 1H), 3.14 (d, J = 16.2 Hz, 1H), 3.03 (d, J = 16.2 Hz, 1H), 1.58 (s, 3H), ꢀ0.07
(s, 3H), ꢀ0.10 (s, 3H); minor isomer diagnostic peaks: δ = 6.55 (dd, J = 16.8, 10.8 Hz, 1H), 5.10 (dd, J
= 10.8, 0.9 Hz, 1H), 4.75 (d, J = 17.1 Hz, 1H), 2.72 (d, J = 16.5 Hz, 1H), 2.60 (d, J = 16.5 Hz, 1H),
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1.48 (s, 3H), 0.54 (s, 3H), 0.38 (s, 3H); C NMR (100 MHz, CDCl3): δ = 149.5, 147.6, 143.1, 141.7,
135.8, 129.8, 128.2, 128.0, 127.4, 126.5, 124.8, 118.6, 81.5, 46.5, 32.2, 1.0, 0.8; IR (film): ν = 3057,
2965, 2887, 1599, 1582, 1492, 1250, 962 cmꢀ1; Anal. calcd. for C21H24OSi: C 78.70, H 7.55; found: C
79.07, H 7.75
2,2-dimethyl-3-(1-phenylallylidene)-1-oxa-2-silaspiro[4.5]decane (6b): Following the general
procedure (A), RuH 1 (2 mg, 0.0025 mmol) and alkyne 6a (74 mg, 0.25 mmol) in DCE (1.0 mL) stirred
under ethylene (1 atm) at 80 °C for 3 h. Purification via flash column chromatography (1% diethyl
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ether/hexanes) gave diene 6b as a clear oil (56 mg, 76% as a Z/E mixture). Crude ratio A:B:C =
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16:2:1; Rf = 0.42 (5% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.34ꢀ7.25 (m, 3H),
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1.5 Hz, 1H), 2.65 (s, 2H), 1.70ꢀ1.41 (m, 10H), ꢀ0.16 (s, 6H); minor isomer diagnostic peaks: δ = 6.54
(dd, J = 16.8, 10.2 Hz, 1H), 5.06 (d, J = 10.8 Hz, 1H), 4.71 (d, J = 16.8 Hz, 1H), 2.22 (s, 3H), 0.40 (s,
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6H); C NMR (100 MHz, CDCl3): δ = 146.5, 143.0, 140.8, 134.9, 128.8, 126.9, 126.2, 117.0, 78.8,
42.7, 38.7, 24.7, 22.2, 0.1; IR (film): ν = 3055, 2931, 2857, 1582, 1443, 1249, 891 cmꢀ1; Anal. calcd.
for C19H26OSi: C 76.45, H 8.78; found: C 76.29, H 8.47
2,2,4-trimethyl-3-(1-phenylallylidene)-1,2-oxasilolane (7b): Following the general procedure (A),
RuH 1 (9.0 mg, 0.0125 mmol) and alkyne 7a (75 mg, 0.25 mmol) in DCE (1.0 mL) stirred under
ethylene (1 atm) at 80 °C for 1.5 h. Purification via flash column chromatography (1% diethyl
ether/hexanes) gave diene 7b as a clear oil (50 mg, 67% as a Z/E mixture). Crude ratio A:B:C =
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13:1:2; Rf = 0.36 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.33ꢀ7.25 (m, 3H),
7.14ꢀ7.10 (m, 2H), 6.90 (dd, J = 17.1, 10.5 Hz, 1H), 5.25 (dd, J = 10.5, 1.5 Hz, 1H), 4.87 (dd, J = 17.1,
1.5 Hz, 1H), 4.00 (dd, J = 9.3, 5.1 Hz, 1H), 3.85 (d, J = 9.6 Hz, 1H), 3.18ꢀ3.09 (m, 1H), 1.21 (d, J = 7.2
Hz, 3H), 0.14 (s, 3H), ꢀ0.41 (s, 3H); minor isomer diagnostic peaks: δ = 6.49 (dd, J = 17.1, 10.5 Hz,
1H), 5.09 (dd, J = 10.5, 0.9 Hz, 1H), 4.69 (dd, J = 17.1, 1.2 Hz, 1H), 2.60ꢀ2.52 (m, 1H), 0.85 (d, J = 7.2
Hz, 3H), 0.46 (s, 3H), 0.39 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 148.3, 147.0, 141.5, 135.3, 129.7,
127.9, 127.3, 118.7, 72.5, 38.2, 21.1, 1.6, ꢀ1.2; IR (film): ν = 3025, 2960, 2867, 1581, 1490, 1250, 842
cmꢀ1; Anal. calcd. for C15H20OSi: C 73.71, H 8.25; found: C 73.97, H 8.35
2,2-dimethyl-3-(1-phenylallylidene)octahydrobenzo[d][1,2]oxasilole (8b): Following the general
procedure, RuH 1 (9.0 mg, 0.0125 mmol) and alkyne 8a (71 mg, 0.25 mmol) in DCE (1.0 mL) stirred
under ethylene (1 atm) at 80 °C for 1 h. Purification via flash column chromatography (2% diethyl
ether/hexanes) gave diene 8b as a clear oil (55 mg, 78% as a Z/E mixture). Crude ratio A:B:C =
1
34:1:3; Rf = 0.34 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.34ꢀ7.26 (m, 3H),
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7.14ꢀ7.10 (m, 2H), 6.89 (dd, J = 17.1, 10.5 Hz, H), 5.20 (dd, J = 10.5, 1.5 Hz, 1H), 4.85 (dd, J = 17.1,
1.5 Hz, 1H), 4.07ꢀ4.06 (m, 1H), 2.89ꢀ2.82 (m, 1H), 2.08ꢀ2.03 (m, 1H), 1.74ꢀ1.72 (m, 1H), 1.65ꢀ1.50 (m,
4H), 1.40ꢀ1.26 (m, 2H), 0.17 (s, H), ꢀ0.39 (s, 3H); minor isomer diagnostic peaks: δ = 6.47 (dd, J =
16.8, 10.5 Hz, 1H), 5.07 (dd, J = 10.8, 1.2 Hz, 1H), 4.65 (dd, J = 16.8, 1.5 Hz, 1H), 0.48 (s, 3H), 0.39
(s, 3H); 13C NMR (100 MHz, CDCl3): δ = 150.0, 146.3, 141.6, 135.5, 129.9, 128.0, 127.3, 118.3, 74.1,
44.3, 31.3, 28.4, 25.6, 19.7, 1.7, ꢀ1.1; IR (film): ν = 3054, 2931, 2851, 1582, 1491, 1441, 1249 cmꢀ1;
Anal. calcd. for C18H24OSi: C 76.00, H 8.56; found: C 75.94, H 8.79
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2,2,4,5-tetramethyl-3-(1-phenylallylidene)-1,2-oxasilolane (9b): Following the general procedure (A),
RuH 1 (2 mg, 0.005 mmol) and alkyne 9a (65 mg, 0.25 mmol) in DCE (1.0 mL) stirred under ethylene
(1 atm) at 80 °C for 1 h. Purification via flash column chromatography (1% diethyl ether/hexanes) gave
diene 9b as a clear oil (45 mg, 70% as a Z/E mixture). Crude ratio A:B:C = 18:2:1; Rf = 0.38 (10%
1
diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.33ꢀ7.27 (m, 3H), 7.15ꢀ7.12 (m, 2H), 6.88
(dd, J = 17.1, 10.5 Hz, 1H), 5.24 (dd, J = 10.5, 1.5 Hz, 1H), 4.88 (dd, J = 17.4, 1.8 Hz, 1H), 4.11ꢀ4.06
(m, 1H), 2.86ꢀ2.83 (m, 1H), 1.21 (d, J = 7.2 Hz, 3H), 1.17 (d, J = 6.6 Hz, 3H), 0.15 (s, 3H), ꢀ0.43 (s,
3H); minor isomer diagnostic peaks: δ = 6.52 (dd, J = 17.1, 10.5 Hz, 1H), 5.08 (dd, J = 10.2, 1.2 Hz,
1H), 4.67 (dd, J = 17.1, 1.2 Hz, 1H), 0.44 (s, 3H), 0.42 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 148.1,
148.1, 141.8, 135.4, 129.8, 127.9, 127.3, 118.7, 80.0, 44.3, 24.6, 21.3, 2.3, 0.7; IR (film): ν = 3025,
2960, 2867, 1581, 1490, 1250, 842 cmꢀ1; Anal. calcd. for C16H22OSi: C 74.36, H 8.58; found: C 74.34,
H 8.89
3-(1-(4-fluorophenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (10b): Following the general
procedure (A), RuH 1 (4 mg, 0.006 mmol) and alkyne 10a (79 mg, 0.3 mmol) in toluene (1.2 mL)
stirred under ethylene (1 atm) at 80 °C for 1 h. Purification via preparative TLC (1% diethyl
ether/hexanes) gave diene 10b as a clear oil (55 mg, 69% as a Z/E mixture). Crude ratio A:B:C =
1
23:3:1; Rf = 0.27 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): δ = 7.11ꢀ7.07 (m, 2H),
7.04ꢀ6.99 (m, 2H), 6.84 (dd, J = 17.1, 10.5 Hz, 1H), 5.23 (d, J = 10.5 Hz, 1H), 4.82 (dd, J = 17.4, 1.8
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Hz, 1H), 4.24ꢀ4.16 (m, 1H), 2.94 (dd, J = 16.1, 5.0 Hz, 1H), 2.31 (dd, J = 16.1, 8.2 Hz, 1H), 1.32 (d, J
= 6.0 Hz, 3H), ꢀ0.06 (s, 3H), ꢀ0.18 (s, 3H); minor isomer diagnostic peaks: δ = 6.50 (dd, J = 16.8, 10.5
Hz, 1H), 5.08 (d, J = 10.8 Hz, 1H), 4.73 (d, J = 17.1 Hz, 1H), 0.41 (s, 3H), 0.38 (s, 3H); 13C NMR (100
MHz, CDCl3): δ = 162.0 (d, JCꢀF = 249.7 Hz), 146.2, 144.3, 137.7 (d, JCꢀF = 3.4 Hz), 136.0, 131.5 (d, JCꢀ
F = 8.5 Hz), 118.4, 115.1 (d, JCꢀF = 22.1 Hz), 72.6, 40.8, 24.2, 0.7, ꢀ0.1; 19F NMR (376.4 MHz, CDCl3):
δ = (ꢀ115.2)ꢀ(ꢀ115.2)(m); (ꢀ115.6)ꢀ(ꢀ115.7)(m); IR (film): ν = 3044, 2928, 1507, 1452, 1256, 910 cmꢀ1;
Anal. calcd. for C15H19FOSi: C 68.66, H 7.30; found: C 68.82, H 7.26
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3-(1-(2-chlorophenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (11b): Following the general
procedure (A), RuH 1 (11.0 mg, 0.015 mmol) and alkyne 11a (84 mg, 0.30 mmol) in 1,4ꢀdioxane (1.2
mL) stirred under ethylene (1 atm) at 100 °C for 30 min. Purification via preparative TLC (1% diethyl
ether/hexanes) gave diene 11b as a clear oil (59 mg, 70% as a Z/E mixture). Crude ratio A:B:C =
1
12:1:3; Rf = 0.46 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3, mixture of rotamers): δ =
7.40ꢀ7.37 (m, 1H), 7.28ꢀ7.23 (m, 2H), 7.13ꢀ7.11 (m, 1H), 6.81 (ddd, J = 17.2, 10.5, 2.7 Hz, 1H), 5.20
(d, J = 7.9 Hz, 1H), 4.69 (d, J = 12.9 Hz, 1H) 4.33ꢀ4.25 (m, 0.5H), 4.25ꢀ4.17 (m, 0.5H), 3.05 (dd, J =
16.2, 5.2 Hz, 0.5H), 2.94 (dd, J = 16.2, 5.7 Hz, 0.5H), 2.47 (dd, J = 16.2, 7.1 Hz, 0.5H), 2.30 (dd, J =
16.1, 8.9 Hz, 0.5H), 1.35 (d, J = 6.1 Hz, 1.5H), 1.32 (d, J = 6.1 Hz, 1.5H), 0.00 (s, 1.5H), ꢀ0.08 (s,
1.5H), ꢀ0.16 (s, 1.5H), ꢀ0.25 (s, 1.5H); minor isomer diagnostic peaks: δ = 6.49 (dd, J = 16.8, 10.4 Hz,
1H), 5.07 (d, J = 10.5 Hz, 1H), 4.60 (d, J = 17.0 Hz, 1H), 4.15ꢀ4.12 (m, 1H), 0.44 (s, 3H), 0.41 (s, 3H);
13C NMR (75 MHz, CDCl3): δ = 144.8, 144.6, 144.2, 140.0, 140.0, 134.7, 134.6, 134.2, 134.1, 132.2,
129.8, 129.6, 129.5, 129.0, 128.6, 126.6, 126.5, 117.6, 117.6, 116.0, 72.8, 72.7, 40.8, 40.3, 24.2, 24.1,
23.9, 1.1, 0.4, ꢀ1.1, ꢀ1.9; IR (film): ν = 2966, 2926, 2876, 1584, 1471, 1436, 1250, 835 cmꢀ1; Anal.
calcd. for C15H19ClOSi: C 64.61, H 6.87; found: C 64.56, H 6.76
2,2,5-trimethyl-3-(1-(naphthalen-1-yl)allylidene)-1,2-oxasilolane (12b): Following the general
procedure (A), RuH 1 (11.0 mg, 0.015 mmol) and alkyne 12a (88 mg, 0.30 mmol) in 1,4ꢀdioxane (1.2
mL) stirred under ethylene (1 atm) at 100 °C for 1 h. Purification via flash column chromatography (2%
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diethyl ether/hexanes) gave diene 12b as a clear oil (62 mg, 71% as a Z/E mixture). Crude ratio A:B:C
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= 23:1:5; Rf = 0.44 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3) (mixture of rotamers): δ
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= 7.85ꢀ7.76 (m, 3H), 7.51ꢀ7.38 (m, 3H), 7.25 (d, J = 6.7 Hz, 1H), 7.01 (ddd, J = 17.2, 10.4, 2.4 Hz, 1H),
5.18 (d, J = 10.4 Hz, 1H), 4.67 (d, J = 17.2 Hz, 1H), 4.39ꢀ4.30 (m, 0.5H), 4.28ꢀ4.19 (m, 0.5H), 3.16 (dd,
J = 16.1, 5.1 Hz, 0.5H), 2.42 (dd, J = 16.5, 5.7 Hz, 0.5H), 1.39 (d, J = 6.1 Hz, 1.5H), 1.36 (d, J = 6.1 Hz,
0.5H), 0.00 (s, 1.5H), ꢀ0.1 (s, 1.5H), ꢀ0.7 (s, 1.5H), ꢀ0.8 (1.5H); minor isomer diagnostic peaks: δ =
6.70 (ddd, J = 16.6, 10.4, 2.4 Hz, 1H), 5.28 (d, J = 10.2 Hz, 1H), 4.90 (d, J = 17.2 Hz, 1H), 1.16 (d, J =
6.1 Hz, 3H), 1.13 (d, J = 6.1 Hz, 3H), ꢀ0.1 (s, 3H), ꢀ0.2 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 145.8,
145.6, 145.1, 144.7, 139.2, 139.0, 135.9, 135.8, 133.6, 133.5, 132.7, 132.7, 128.2, 127.9, 127.9, 127.8,
126.8, 126.7, 125.9, 125.9, 125.3, 125.2, 118.6, 118.6, 72.8, 72.6, 40.9, 40.5, 24.3, 24.2, 1.1, 0.4, ꢀ1.1, ꢀ
1.8; IR (film): v = 3046, 2966, 2927, 1585, 1507, 1395, 1376, 1249, 1104, 1037, 944, 781 cmꢀ1; Anal.
calcd. for C19H22OSi: C 77.50, H 7.53; found: C 77.48, H 7.48
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3-(1-(3,5-dimethylphenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (13b): Following the general
procedure (A), RuH 1 (2 mg, 0.0025 mmol) and alkyne 13a (68 mg, 0.25 mmol) in toluene (1.0 mL)
stirred under ethylene (1 atm) at 85 °C for 1 h. Purification via flash column chromatography (2%
diethyl ether/hexanes) gave diene 13b as a clear oil (50 mg, 74% as a Z/E mixture). Crude ratio A:B:C
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= 28:3:1; Rf = 0.29 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 6.92 (s, 1H), 6.84
(dd, J = 10.5, 17.2 Hz, 1H), 6.74 (s, 2H), 5.23 (dd, J = 1.4, 10.6 Hz, 1H), 4.95 (dd, J = 1.5, 17.2 Hz,
1H), 4.23ꢀ4.15 (m, 1H), 2.93 (dd, J = 5.4, 16.1 Hz, 1H), 2.33ꢀ2.30 (m, 1H), 2.30 (s, 3H), 2.30 (s, 3H),
1.32 (d, J = 6.08 Hz, 3H), ꢀ0.07 (s, 3H), ꢀ0.21 (s, 3H); minor isomer diagnostic peaks: δ = 6.50 (dd, J
= 10.4, 17.0 Hz, 1H), 5.07 (d, J = 10.1 Hz, 1H), 4.78 (d, J = 17.0 Hz, 1H), 0.41 (s, 3H), 0.39 (s, 3H); 13C
NMR (100 MHz, CDCl3): δ =147.6, 143.1, 141.6, 137.3, 135.8, 128.7, 127.5, 118.2, 72.6, 40.7, 24.1,
21.4, 0.7, ꢀ0.3; IR (film): v = 3012, 2925, 1601, 1248, 823 cmꢀ1; Anal. calcd. for C17H24OSi: C 74.94, H
8.88; found: C 74.85, H 8.64
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3-(1-(4-methoxyphenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (14b): Following the general
procedure (A), RuH 1 (4 mg, 0.005 mmol) and alkyne 14a (82 mg, 0.3 mmol) in DCE (1.2 mL) stirred
under ethylene (1 atm) at 80 °C for 1 h. Purification via preparative TLC (3% diethyl ether/hexanes)
gave diene 14b as a clear oil (60 mg, 73%). Crude ratio A:B:C = 44:3:1; Rf = 0.26 (10% diethyl
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ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.05ꢀ7.01 (m, 2H), 6.89ꢀ6.80 (m, 3H), 5.22 (dd, J =
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10.5, 1.5 Hz, 1H), 4.88 (dd, J = 17.1, 1.5 Hz, 1H), 4.25ꢀ4.14 (m, 1H), 3.82 (s, 3H), 2.93 (dd, J = 16.5,
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5.4 Hz, 1H), 2.30 (dd, J = 16.5, 8.4 Hz, 1H), 1.32 (d, J = 6.0 Hz, 3H), ꢀ0.05 (s, 3H), ꢀ0.18 (s, 3H); C
NMR (100 MHz, CDCl3): δ = 158.9, 146.8, 143.4, 136.1, 134.1, 130.8, 118.1, 113.2, 72.5, 55.3, 40.7,
24.1, 0.7, ꢀ0.1; IR (film): ν = 3087, 2968, 2835, 1608, 1508, 1458, 1246, 1036 cmꢀ1; Anal. calcd. for
C16H22O2Si: C 70.03, H 8.08; found: C 70.03, H 7.81
1-(4-(1-(2,2,5-trimethyl-1,2-oxasilolan-3-ylidene) allyl) phenyl) ethanone (15b): Following the
general procedure (A), RuH 1 (2 mg, 0.0025 mmol) and alkyne 15a (72 mg, 0.25 mmol) in DCE (1.0
mL) was stirred under ethylene (1 atm) at 80 °C for 3 h. Purification via flash column chromatography
(1% diethyl ether/hexanes) gave diene 15b as a clear oil (46 mg, 64% as a Z/E mixture). Crude ratio
1
A:B:C = 7:1:1; Rf = 0.20 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.92 (d, J =
8.4 Hz, 2H), 7.24 (d, J = 8.4 Hz, 2H), 6.85 (dd, J = 17.1, 10.5 Hz, 1H), 5.24 (d, J = 10.5 Hz, 1H), 4.79
(d, J = 18.0 Hz, 1H), 4.24ꢀ4.17 (m, 1H), 2.96 (dd, J = 16.2, 5.4 Hz, 1H), 2.62 (s, 3H), 2.34 (dd, J = 16.2,
8.2 Hz, 1H), 1.32 (d, J = 6.0 Hz, 3H), ꢀ0.07 (s, 3H), ꢀ0.19 (s, 3H); minor isomer diagnostic peaks: δ =
7.97 (d, J = 8.4 Hz, 2H), 7.22 (d, J = 8.4 Hz, 2H), 6.51 (dd, J = 16.8, 10.5 Hz, 1H), 5.11 (d, J = 10.5 Hz,
1H), 4.70 (d, J = 17.4 Hz, 1H), 4.11ꢀ4.04 (m, 1H), 1.20 (d, J = 6.0 Hz, 3H), 0.42 (s, 3H), 0.39 (s, 3H);
13C NMR (100 MHz, CDCl3): δ = 198.0, 198.0, 146.9, 146.9, 146.2, 145.5, 145.2, 144.5, 139.2, 136.2,
135.9, 135.6, 130.1, 129.3, 128.6, 128.2, 118.6, 116.8, 72.8, 72.5, 42.8, 41.0, 26.8, 26.8, 24.1, 23.8, 0.7,
0.3, ꢀ0.0; IR (film): ν = 3087, 2964, 2871, 1684, 1601, 1264, 944 cmꢀ1; Anal. calcd. for C17H22O2Si: C
71.28, H 7.74; found: C 70.99, H 7.75
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2,2,6-trimethyl-3-(1-phenylallylidene)-1,2-oxasilinane (16b): Following the general procedure (A),
RuH 1 (4 mg, 0.006 mmol) and alkyne 16a (77 mg, 0.3 mmol) in DCE (1.2 mL) stirred under ethylene
(1 atm) at 80 °C for 1 h. Purification via flash column chromatography (1% diethyl ether/hexanes) gave
diene 16b as a clear oil (63 mg, 82%). Crude ratio A:B:C = 14:1:1; Rf = 0.74 (10% diethyl
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ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.30ꢀ7.26 (m, 3H), 7.09ꢀ7.02 (m, 3H), 5.21 (dd, J =
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10.8, 1.8 Hz, 1H), 4.73 (dd, J = 17.1, 1.8 Hz, 1 H), 4.10ꢀ4.03 (m, 1H), 3.08 (ddd, J = 15.9, 5.4, 3.3 Hz,
1H), 2.47 (ddd, J = 15.9, 12.6, 3.3 Hz, 1H), 1.90ꢀ1.83 (m, 1H), 1.61ꢀ1.51 (m, 1H), 1.21 (d, J = 6.3 Hz,
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3H), ꢀ0.14 (s, 3H), ꢀ0.37 (s, 3H); C NMR (100 MHz, CDCl3): δ = 147.2, 141.6, 140.3, 134.3, 130.6,
127.9, 127.3, 118.7, 70.5, 36.1, 29.1, 24.7, 1.6, 0.2; IR (film): ν = 3080, 2965, 2846, 1558, 1490, 1248,
829 cmꢀ1; Anal. calcd. for C16H22OSi: C 74.36, H 8.58; found: C 74.39, H 8.69
General Procedure for high pressure reactions (B): An oven dried Fischer Porter bottle equipped
with a magnetic stir bar was brought into an argon filled glove box. To the Fischer Porter bottle was
added RuHCl(CO)(SIMes)PPh3 (1) and the alkyne in toluene. The bottle was plugged with a septum
and removed from the glove box. The septum was replaced with a Swagelok regulator and the system
was purged with ethylene (80 psi) and vented three times, then refilled to 80 psi and heated to 80 οC for
the allotted time. Upon completion by TLC, the reaction was filtered through a short plug of silica gel
(eluted with dichloromethane), concentrated in vacuo and a crude yield was obtained by 1H NMR with
mesitylene (0.33 equivalents) as an internal standard. The crude product was purified by flash
chromatography on silica gel.
3-(1-(4-fluorophenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (Diene Mixture 10b): Following the
general procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 10a (66 mg, 0.25 mmol) in toluene (1.0
mL) stirred under ethylene (80 psi) at 80 °C for 4 h. Purification via flash column chromatography (10%
diethyl ether/hexanes) gave the diene mixture 10b as a clear oil (56 mg, 85% as a Z/E mixture). Crude
ratio A:C = 1:1.3; Rf = 0.27 (10% diethyl ether/hexanes); 1H NMR (300 MHz, CDCl3): isomer A: δ =
7.12ꢀ6.99 (m, 4H), 6.85 (dd, J = 17.4, 10.8 Hz, 1H), 5.24 (dd, J = 10.8, 1.5 Hz, 1H), 4.82 (dd, J = 17.4,
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1.2 Hz, 1H), 4.24ꢀ4.17 (m, 1H), 2.95 (dd, J = 16.2, 5.4 Hz, 1H), 2.31 (dd, J = 16.2, 8.4 Hz, 1H), 1.32 (d,
J = 6.0 Hz, 3H), ꢀ0.05 (s, 3H), ꢀ0.17 (s, 3H); isomer C: δ = 7.12ꢀ6.99 (m, 4H), 6.51 (dd, J = 17.1, 10.5
Hz, 1H), 5.09 (dd, J = 10.8, 0.6 Hz, 1H), 4.74 (dd, J = 17.1, 0.6 Hz, 1H), 4.11ꢀ4.02 (m, 1H), 2.38 (dd, J
= 17.4, 5.1 Hz, 1H), 2.02 (dd, J = 16.8, 8.4 Hz, 1H), 1.21 (d, J = 6.0 Hz, 3H), 0.42 (s, 3H), 0.39 (s, 3H);
13C NMR (75 MHz, CDCl3): δ = 163.7, 163.4, 160.1, 146.9, 146.1, 145.0, 144.1, 139.7, 137.5, 137.5,
135.9, 135.6, 135.5, 131.3, 131.2, 130.5, 130.4, 118.3, 116.4, 115.4, 115.1, 115.0, 114.7, 72.7, 72.5,
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42.8, 40.7, 24.0, 23.7, 0.7, 0.6, 0.3, ꢀ0.2; F NMR (282.3 MHz, CDCl3): δ = (ꢀ115.6)ꢀ(ꢀ115.7)(m); δ =
(ꢀ116.1)ꢀ(ꢀ116.2)(m); IR (film): ν = 2966, 2927, 1601, 1506, 1252 cmꢀ1; Anal. calcd. for C15H19FOSi: C
68.66, H 7.30; found: C 68.52, H 7.12
3-(1-(4-methoxyphenyl)allylidene)-2,2,5-trimethyl-1,2-oxasilolane (Diene Mixture 14b): Following
the general procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 14a (72 mg, 0.25 mmol) in toluene
(1.0 mL) stirred under ethylene (80 psi) at 80 °C for 4 h. Purification via flash column chromatography
(10% diethyl ether/hexanes) gave the diene mixture 14b as a clear oil (66 mg, 91% as a Z/E mixture).
1
Crude ratio A:C = 3:1; Rf = 0.26 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): isomer
A: δ = 7.06ꢀ7.03 (m, 2H), 6.92ꢀ6.80 (m, 3H), 5.21 (d, J = 10.5 Hz, 1H), 4.87 (dd, J = 17.1, 1.5 Hz, 1H),
4.24ꢀ4.14 (m, 1H), 3.81 (s, 3H), 2.93 (dd, J = 16.2, 5.4 Hz, 1H), 2.29 (dd, J = 16.2, 8.4 Hz, 1H), 1.31 (d,
J = 6.0 Hz, 3H), ꢀ0.05 (s, 3H), ꢀ0.17 (s, 3H); isomer C: δ = 7.06ꢀ7.03 (m, 2H), 6.92ꢀ 6.80 (m, 2H), 6.51
(dd, J = 16.8, 10.5 Hz, 1H), 5.07 (d, J = 10.5 Hz, 1H), 4.79 (d, J = 17.1 Hz, 1H), 4.10ꢀ4.03 (m, 1H),
3.82 (s, 3H) 2.43 (dd, J = 16.8, 5.1 Hz, 1H), 2.06 (dd, J = 16.5, 8.4 Hz, 1H), 1.20 (d, J = 6.0 Hz, 3H),
0.41 (s, 3H), 0.38 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 158.7, 158.3, 147.4, 146.7, 143.3, 139.9,
136.0, 133.9, 130.7, 129.9, 118.0, 116.1, 113.5, 113.1, 72.6, 72.4, 55.2, 55.2, 42.8, 40.6, 24.0, 23.7, 0.7,
0.6, 0.2, ꢀ0.3; IR (film): ν = 2963, 2929, 1608, 1509, 1248 cmꢀ1; Anal. calcd. for C16H22O2Si: C 70.03,
H 8.08; found: C 70.41, H 7.80
1-(4-(1-(2,2,5-trimethyl-1,2-oxasilolan-3-ylidene)allyl)phenyl)ethanone (Diene Mixture 15b):
Following the general procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 15a (72 mg, 0.25 mmol)
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in toluene (1.0 mL) stirred under ethylene (80 psi) at 80 °C for 24 h. Purification via flash column
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chromatography (10% diethyl ether/hexanes) gave the diene mixture 15b as a clear oil (62 mg, 86% as a
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Z/E mixture). Crude ratio A:C = 1:7; Rf = 0.20 (10% diethyl ether/hexanes); H NMR (300 MHz,
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CDCl3): isomer A: δ = 7.92 (d, J = 8.4 Hz, 2H), 7.24 (d, J = 8.4 Hz, 2H), 6.85 (dd, J = 17.1, 10.5 Hz,
1H), 5.24 (d, J = 10.5 Hz, 1H), 4.79 (d, J = 18.0 Hz, 1H), 4.24ꢀ4.17 (m, 1H), 2.96 (dd, J = 16.2, 5.4 Hz,
1H), 2.62 (s, 3H), 1.32 (d, J = 6.0 Hz, 3H), ꢀ0.07 (s, 3H), ꢀ0.19 (s, 3H); isomer C: δ = 7.97 (d, J = 8.4
Hz, 2H), 7.22 (d, J = 8.4 Hz, 2H), 6.51 (dd, J = 16.8, 10.5 Hz, 1H), 5.11 (d, J = 10.5 Hz, 1H), 4.70 (d, J
= 17.4 Hz, 1H), 4.12ꢀ4.02 (m, 1H), 2.62 (s, 3H), 2.34 (dd, J = 16.8, 5.1 Hz, 1H), 2.00 (dd, J = 16.8, 5.4
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Hz, 1H), 1.19 (d, J = 6.0 Hz, 3H), 0.42 (s, 3H), 0.39 (s, 3H); C NMR (75 MHz, CDCl3): δ = 197.8,
145.8, 145.0, 139.0, 135.7, 129.1, 128.4, 116.6, 72.6, 42.7, 26.6, 23.6, 0.6, 0.1; IR (film): ν = 2964,
2925, 1684, 1264 cm ꢀ1; Anal. calcd. for C17H22O2Si: C 71.28, H 7.74; found: C 71.03, H 7.40
2,2,6-trimethyl-3-(1-phenylallylidene)-1,2-oxasilinane (Diene Mixture 16b): Following the general
procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 16a (57 mg, 0.22 mmol) in toluene (1.0 mL)
stirred under ethylene (80 psi) at 80 °C for 24 h. (25:1). Purification via flash column chromatography
(10% diethyl ether/hexanes) gave the diene mixture 16b as a clear oil (41 mg, 72%). Crude ratio A:C
= 25:1; 1H NMR (300 MHz, CDCl3): δ = 7.28ꢀ7.27 (m, 3H), 7.09ꢀ7.00 (m, 3H), 5.20 (dd, J = 10.5, 1.5
Hz, 1H), 4.72 (dd, J = 17.1, 1.5 Hz, 1H), 4.11ꢀ4.00 (m, 1H), 3.06 (ddd, J = 16.2, 5.1, 3.3 Hz, 1H), 2.45
(ddd, J = 15.9, 12.6, 3.3 Hz, 1H), 1.90ꢀ1.81 (m, 1H), 1.62ꢀ1.48 (m, 1H), 1.20 (d, J = 6.0 Hz, 3H), ꢀ0.15
(s, 3H), ꢀ0.38 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 147.1, 141.5, 140.2, 134.1, 130.4, 127.8, 127.2,
118.7, 70.4, 36.0, 29.0, 24.6, 1.5, 0.1;
3-(but-3-en-2-ylidene)-2,2-dimethyl-5-phenethyl-1,2-oxasilolane (Diene Mixture 17b): Following
the general procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 17a (68 mg, 0.25 mmol) in toluene
(1.0 mL) stirred under ethylene (80 psi) at 80 °C for 24 h. Purification via flash column chromatography
(2% diethyl ether/hexanes) gave the diene mixture 17b as a clear oil (57 mg, 84% as a Z/E mixture).
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Crude ratio A:C = 1:3; Rf = 0.64 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): major
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isomer C: δ = 7.32ꢀ7.16 (m, 5H), 6.35 (dd, J = 16.8, 10.2 Hz, 1H), 5.23 (d, J = 17.3 Hz, 1H), 5.06 (d, J
= 10.7 Hz, 1H), 4.12ꢀ4.02 (m, 1H), 2.88ꢀ2.67 (m, 4H), 2.27 (dd, J = 16.2, 7.6 Hz, 1H), 1.86 (s, 3H), 0.37
(s, 3H), 0.32 (s, 3H); minor isomer A: δ = 6.70 (dd, J = 17.3, 10.7 Hz, 1H), 5.28 (d, J = 16.8 Hz, 1H),
5.17 (d, J = 10.8 Hz, 1H), 1.91 (s, 3H), 0.36 (s, 3H), 0.32 (s, 3H); 13C NMR (75 MHz, CDCl3): δ=
142.8, 142.4, 141.7, 140.4, 140.1, 139.4, 136.1, 128.6, 128.4, 125.8, 114.4, 112.5, 76.0, 75.7, 40.2, 40.1,
39.9, 38.4, 32.3, 20.0, 15.3, 0.9, 0.5, 0.4, 0.0; IR (film): ν = 2957, 2931, 1585, 1453, 1250, 866 cmꢀ1;
Anal. calcd. for C17H24OSi: C 74.94, H 8.88; found C 74.88, H 8.99
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3-(but-3-en-2-ylidene)-2,2-dimethyl-5-phenyl-1,2-oxasilolane (Diene Mixture 18b): Following the
general procedure (B), RuH 1 (4 mg, 0.005 mmol) and alkyne 18a (80 mg, 0.32 mmol) in toluene (1.3
mL) stirred under ethylene (80 psi) at 80 °C for 24 h. Purification via flash column chromatography (1%
diethyl ether/hexanes) gave the diene mixture 18b as a clear oil (67 mg, 84% as a Z/E mixture). Crude
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ratio A:C = 1:2; Rf = 0.52 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): major isomer
C: δ = 7.39ꢀ7.32 (m, 4H), 7.27ꢀ7.23 (m, 1H), 6.36 (dd, J = 17.1, 10.8 Hz, 1H), 5.23 (d, J = 16.9 Hz,
1H), 5.06 (d, J = 11.0 Hz, 1H), 5.05ꢀ5.00 (m, 1H), 3.02 (dd, J = 16.8, 5.7 Hz, 1H), 2.50ꢀ2.44 (m, 1H),
1.86 (dd, J = 1.6, 0.7 Hz, 3H), 0.41 (s, 3H), 0.39 (s, 3H); minor isomer A: δ = 6.68 (dd, J = 17.3, 10.6
Hz, 1H), 5.28 (d, J = 17.3 Hz, 1H), 5.15 (d, J = 10.6 Hz, 1H) 3.13 (ddd, J = 16.2, 5.5, 1.0 Hz, 1H), 1.92
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(dd, J = 2.2, 1.0 Hz, 3H), 0.40 (s, 3H), 0.38 (s, 3H); C NMR (100 MHz, CDCl3): δ = 144.3, 144.2,
142.2, 141.3, 139.8, 139.6, 139.1, 135.5, 128.0, 126.9, 125.1, 114.3, 112.5, 77.7, 77.3, 42.5, 41.1, 19.6,
ꢀ1
14.9, 0.0, 0.0, ꢀ0.3, ꢀ0.4; IR (film): ν = 3088, 3029, 2956, 2877, 1588, 1251, 1036, 868 cm ; Anal.
calcd. for C15H20OSi: C 73.71, H 8.21; found C 73.43, H 8.20
2,2-dimethyl-3-(pent-1-en-3-ylidene)-5-phenyl-1,2-oxasilolane (Diene Mixture 19b): Following the
general procedure (B), RuH 1 (4 mg, 0.005 mmol) and alkyne 19a (77 mg, 0.3 mmol) in toluene (1.2
mL) stirred under ethylene (80 psi) at 80 °C for 1 h. Purification via flash column chromatography (1%
diethyl ether/hexanes) gave the diene mixture 19b as a clear oil (61 mg, 79% as a Z/E mixture). Crude
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ratio A:C = 5:1; Rf = 0.63 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): isomer A: δ =
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7.38ꢀ7.31 (m, 4H), 7.25ꢀ7.23 (m, 1H), 6.52 (dd, J = 17.7, 11.0 Hz, 1H), 5.29 (d, J = 17.7 Hz, 1H), 5.17
(d, J = 11.0 Hz, 1H), 5.00 (dd, J = 9.0, 5.5 Hz, 1H), 3.10 (dd, J = 16.1, 5.5 Hz, 1H), 2.49ꢀ2.41 (m, 1H),
2.38ꢀ2.24 (m, 2H), 1.10 (t, J = 7.8 Hz, 3H), 0.39 (s, 3H), 0.37 (s, 3H); isomer C: δ = 6.25 (dd, J = 17.3,
10.6 Hz, 1H), 5.25 (d, J = 17.3 Hz, 1H), 5.06 (d, J = 11.0 Hz, 1H), 3.01 (dd, J = 16.5, 5.5 Hz, 1H), 1.01
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(t, J = 7.8 Hz, 3H); C NMR (100 MHz, CDCl3): δ = 148.2, 146.2, 144.7, 144.7, 141.4, 139.2, 138.8,
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134.2, 128.4, 127.3, 125.5, 125.4, 114.9, 112.6, 78.0, 77.8, 42.2, 41.7, 28.2, 22.7, 14.9, 13.0, 0.4, 0.1;
ꢀ1
IR (film): ν = 3088, 2966, 2876, 1586, 1251, 1061, 907 cm ; Anal. calcd. for C16H22OSi: C 74.36, H
8.58; found: C 74.55, H 8.74
3-(hept-1-en-3-ylidene)-2,2-dimethyl-5-phenyl-1,2-oxasilolane (Diene Mixture 20b): Following the
general procedure (B), RuH 1 (4 mg, 0.005 mmol) and alkyne 20a (86 mg, 0.3 mmol) in toluene (1.2
mL) stirred under ethylene (80 psi) at 80 °C for 1 h. Purification via flash column chromatography (1%
diethyl ether/hexanes) gave the diene mixture 20b as a clear oil (59 mg, 69% as a Z/E mixture). Crude
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ratio A:C = 8:1; Rf = 0.36 (10% diethyl ether/hexanes); H NMR (400 MHz, CDCl3): isomer A: δ =
7.31ꢀ7.24 (m, 4H), 7.19ꢀ7.15 (m, 1H), 6.46 (dd, J = 17.6, 10.8 Hz, 1H), 5.21 (d, J = 17.6 Hz, 1H), 5.09
(d, J = 10.8 Hz, 1H), 4.93 (dd, J = 9.5, 5.4 Hz, 1H), 3.02 (dd, J = 16.2, 5.4 Hz, 1H), 2.37 (dd, J = 16.2,
5.4 Hz, 1H), 2.25ꢀ2.13 (m, 2H), 1.43ꢀ1.35 (m, 2H), 1.33ꢀ1.24 (m, 2H), 0.86 (t, J = 7.5 Hz, 3H), 0.32 (s,
3H), 0.30 (s, 3H); isomer C: δ = 6.19 (dd, J = 17.2, 10.4 Hz, 1H), 4.99 (d, J = 10.8 Hz, 1H), 2.93 (dd, J
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= 16.7, 5.4 Hz, 1H), 0.82 (t, J = 7.1 Hz, 3H), 0.33 (s, 3H), 0.31 (s, 3H); C NMR (100 MHz, CDCl3):
δ= 146.8, 145.1, 144.7, 142.0, 139.4, 139.2, 134.7, 128.4, 127.3, 127.3, 125.5, 114.8, 112.7, 78.0, 77.8,
42.5, 41.8, 35.3, 32.6, 30.8, 29.5, 23.3, 23.2, 14.1, 14.1, 0.4, 0.3; IR (film): ν = 3087, 2957, 2873, 1585,
1250, 1036, 867 cm ꢀ1; Anal. calcd. for C18H26OSi: C 75.46, H 9.15; found: C 75.65, H 9.26
2,2-dimethyl-3-(non-1-en-3-ylidene)-5-phenyl-1,2-oxasilolane (Diene Mixture 21b): Following the
general procedure (B), RuH 1 (2 mg, 0.0025 mmol) and alkyne 21a (78 mg, 0.25 mmol) in toluene (1.0
mL) stirred under ethylene (80 psi) at 80 °C for 24 h. Purification via flash column chromatography (1%
diethyl ether/hexanes) gave the diene mixture 21b as a clear oil (65 mg, 83% as a Z/E mixture). Crude
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1
ratio A:C = 7:1; Rf = 0.78 (10% diethyl ether/hexanes); H NMR (300 MHz, CDCl3): isomer A: δ =
7.40ꢀ7.31 (m, 5H), 6.54 (dd, J = 17.4, 10.9 Hz, 1H), 5.30 (d, J = 17.4 Hz, 1H), 5.17 (d, J = 10.9 Hz,
1H), 5.01 (dd, J = 9.6, 5.6 Hz, 1H), 3.11 (dd, J = 16.2, 5.3 Hz, 1H), 2.46 (dd, J = 16.2, 9.6 Hz, 1H),
2.32ꢀ2.23 (m, 2H), 1.53ꢀ1.43 (m, 2H), 1.40ꢀ1.26 (m, 7H), 0.93ꢀ0.87 (m, 3H), 0.40 (s, 3H), 0.38 (s, 3H);
isomer C: δ = 6.27 (dd, J = 17.4, 10.9 Hz, 1H), 5.07 (d, J = 10.9 Hz, 1H), 3.00 (dd, J = 16.8, 5.6 Hz,
1H), 0.41 (s, 3H), 0.39 (s, 3H); 13C NMR (75 MHz, CDCl3): δ = 145.2, 144.7, 139.4, 134.8, 128.5,
127.3, 125.5, 114.9, 78.0, 41.8, 35.7, 31.9, 30.5, 30.0, 22.8, 14.2, 0.3, 0.3; IR (film) ν = 2957, 2931,
1585, 1453, 1250, 866 cm ꢀ1; Anal. calcd. for C20H30OSi: C 76.37, H 9.61; found C 76.24, H 9.79
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3-hydroxy-1-(3-methyl-2-phenyloxiran-2-yl)-3-phenylpropan-1-one (22): To an oven dried 25 mL
round bottom flask equipped with a magnetic stir bar was added diene 4b (92 mg, 0.3 mmol) in THF
(1.3 mL). To the stirred solution was added sequentially MeOH (2.7 mL), KF·H2O (282 mg, 3.0 mmol),
KHCO3 (300 mg, 3.0 mmol), and H2O2 (2.5 mL, ~23 mmol) dropwise with vigorous stirring. After
stirring the cloudy white suspension for 4 h TLC indicated consumption of the starting diene. Na2S2O3(s)
(~1.0 g) was carefully added in small portions to consume remaining peroxides. The reaction was
diluted with EtOAc (20 mL) and washed with brine. The organics were dried over MgSO4, filtered and
concentrated in vacuo. The crude oil was purified via flash column chromatography (silica gel 2.5 x 15
cm, eluted with 10% EtOAc/hexanes) to give ketone 22 as a clear oil (59 mg, 70% as a mixture of
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diastereoisomers). Rf = 0.25 (20% EtOAc/hexanes); H NMR (400 MHz, CDCl3): δ = 7.45ꢀ7.32 (m,
10H), 5.15 (t, J = 3.7 Hz, 0.5H), 5.12 (t, J = 3.7 Hz, 1H), 3.50 (q, J = 5.2 Hz, 0.5H), 3.43 (q, J = 5.2 Hz,
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0.5H), 3.08ꢀ2.82 (m, 3H), 1.06 (d, J = 5.3 Hz, 3H); C NMR (100 MHz, CDCl3): δ = 207.8, 207.8,
142.7, 142.6, 131.8, 128.6, 128.6, 128.5, 128.3, 128.1, 128.1, 127.8, 127.8, 125.8, 125.7, 69.9, 69.7,
68.1, 59.1, 58.8, 46.3, 45.9, 14.5, 14.4; IR (film): ν = 3511, 3060, 2967, 2926, 1708, 1494, 1022 cm ꢀ1;
Anal. calcd. for C18H18O3: C 76.57, H 6.43; found: C 76.44, H 6.41
(E)-1-hydroxy-1,4-diphenylhex-4-en-3-one (23): To a flame dried 50 mL round bottom flask equipped
with a magnetic stir bar was added diene 4b (92 mg, 0.3 mmol, 10:1, Z:E), DMF (15 mL), KHF2 (71
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mg, 0.9 mmol), propionic anhydride (0.96 mL, 7.5 mmol) and H2O2 (0.85 mL, 7.5 mmol) sequentially.
The reaction was stirred at rt for 14 h then poured into water (15 mL), extracted with Et2O (3 x 15 mL)
washed with saturated NaHCO3(aq) (20 mL), dried over MgSO4, filtered and concentrated in vacuo. The
crude oil was purified via flash column chromatography (silica gel 1.5 x 12 cm, gradient elution with
10ꢀ20% EtOAc/hexanes) to afford ketone 23 as a clear oil (68 mg, 85%, 13:1 mixture of double bond
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isomers). Rf = 0.22 (20% EtOAc/hexanes); H NMR (400 MHz, CDCl3): δ = 7.41ꢀ7.28 (m, 8H), 7.09ꢀ
7.07 (m, 2H), 7.04 (q, J = 7.2 Hz, 1H), 5.18 (dd, J = 7.4, 4.8 Hz, 1H) 3.65 (s, 1H), 2.98 (s, 1H), 2.96 (d,
J = 3.3 Hz, 1H), 1.73 (d, J = 7.0 Hz, 3H); minor isomer diagnostic peaks δ = 5.53 (q, J = 7.4 Hz, 1H),
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1.82 (d, J = 7.2 Hz, 3H); C NMR (100 MHz, CDCl3): δ = 200.7, 143.7, 142.9, 140.2, 135.1, 129.6,
128.4, 128.4, 127.7, 127.5, 125.7, 70.2, 47.8, 15.7; IR (film): ν = 3412, 3058, 2912, 1773, 1670, 1597,
1137, 700 cmꢀ1; Anal. calcd. for C18H18O2: C 81.17, H 6.81; found: C 81.34, H 6.83
2,2-dimethyl-5-phenyl-3-((E)-1-phenyl-3-(p-tolyl)allylidene)-1,2-oxasilolane (24): To an oven dried
50 mL Schlenk tube equipped with magnetic stir bar was added 4ꢀiodotoluene (164 mg, 0.75 mmol),
K2CO3 (138 mg, 1.0 mmol), Pd(OAc)2 (6.0 mg, 0.025 mmol) and diene 4b (180 mg, 0.58 mmol) in
DMF (5.0 mL). The reaction mixture was evacuated and purged with argon(g) three times, then stirred at
80 °C for 8 h. Once cooled to rt, the solution was diluted with EtOAc (20 mL), washed with water (2 x
30 mL), dried over MgSO4, filtered and concentrated in vacuo. The crude oil was purified via flash
column chromatography (silica gel 2.5 x 12 cm; 3% EtOAc/hexanes) to afford diene 24 as a yellow oil
1
(126 mg, 64%). Rf = 0.51 (10% EtOAc/hexanes); H NMR (400 MHz, C6D6): δ = 7.44 (d, J = 8.2 Hz,
2H), 7.40ꢀ7.35 (m, 5H), 7.30ꢀ7.28 (m, 1H),7.25ꢀ7.21 (m, 5H), 7.08 (d, J = 7.8 Hz, 2H), 6.19 (d, J = 16.0
Hz, 1H), 5.11 (dd, J = 9.3, 5.3 Hz, 1H), 3.38 (dd, J = 16.3, 5.5 Hz, 1H), 2.69 (dd, J = 16.3, 9.5 Hz, 1H),
13
2.31 (s, 3H), 0.08 (s, 3H), ꢀ0.13 (s, 3H); C NMR (100 MHz, C6D6): δ = 147.3, 144.8, 142.8, 142.0,
137.9, 134.6, 133.4, 129.8, 129.4, 128.5, 128.1, 127.4, 127.4, 127.0, 126.7, 125.5, 77.9, 42.3, 21.3, 0.5,
0.3; IR (film): ν = 3027, 2958, 1583, 1249, 1031, 862 cmꢀ1; Anal. calcd. for C27H28OSi: C 81.77, H
7.12; found: C 81.52, H 7.18
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(E)-6-hydroxy-3-methyl-8-phenyloct-2-en-4-one (25): To a flame dried 50 mL round bottom flask
equipped with a magnetic stir bar was added diene 17b (105 mg, 0.39 mmol), DMF (15 mL), KHF2
(91.3 mg, 1.17 mmol), propionic anhydride (1.6 mL, 9.75 mmol) and H2O2 (1.1 mL, 9.75 mmol)
sequentially. The reaction was stirred at rt overnight then poured into water (25 mL), extracted with
Et2O (3 x 25 mL) washed with brine (25 mL), dried over MgSO4, filtered and concentrated in vacuo.
The crude oil was purified via flash column chromatography (silica gel 2.5 x 15 cm, gradient elution
with 15ꢀ30% diethyl ether/hexanes) to afford ketone 25 as a clear oil (66 mg, 73%). Rf = 0.12 (20%
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diethyl ether/hexanes); H NMR (400 MHz, CDCl3): δ = 7.30ꢀ7.16 (m, 5H), 6.75 (dq, J = 6.8, 1.6 Hz,
1H), 4.11ꢀ4.05 (m, 1H), 3.47 (br s, 1H), 2.88ꢀ2.81 (m, 2H), 2.75ꢀ2.67 (m, 2H), 1.91ꢀ1.82 (m, 4H), 1.77
13
(t, J = 1.2 Hz, 3H), 1.75ꢀ1.71 (m, 1H); C NMR (100 MHz, CDCl3): δ = 202.5, 142.3, 139.0, 138.7,
128.7, 128.6, 126.0, 67.5, 43.6, 38.4, 32.1, 15.1, 11.0; IR (film): ν = 3496, 3061, 3026, 2927, 2860,
1655, 1496, 1451, 1073, 700 cmꢀ1; Anal. calcd. for C15H20O2: C 77.55, H 8.68; found: C 77.71, H 8.54
Acknowledgement:
We are grateful to the donors of the ACS PRF (DNI 50787), the NSF (CAREER CHEꢀ1352432), and
Syracuse University for generous financial support. We thank Alexandre D.C. Dixon for the synthesis of
compounds 18a and 20a and Daniel D. Nguyen for the synthesis of 19a. We thank Prof. John Chisholm,
for critical reading of this manuscript.
Supporting Information Available
1H and 13C NMR spectra for all new compounds. This material is available free of charge via the
Internet at http://pubs.acs.org.
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