Catalytic Hydrosilylation of Hydrofluoroolefins (HFOs): Synthesis of New Fluorinated Silanes and Diversity of their Synthetic Character

Article abstract of DOI:10.1002/ejoc.202000853

New polyfluorinated silanes were synthesized via the Pt, Rh and Pd catalyzed hydrosilylation of commercially available hydrofluoroolefins (HFOs) in moderate to excellent yields. HFO-1234yf (2,3,3,3-tetrafluoropropene-1) and –1234ze (1,3,3,3-tetrafluoropropene-1) were reactive with Pt catalyst to form tetrafluoropropylsilanes along with defluorosilylation products. The Z- and E-isomers of HFO-1336mzz (1,1,1,4,4,4-hexafluorobut-2-ene) gave the desired silanes with Pd catalysis in good to excellent yields, while with Pt catalyst only the dehydrofluorination product CF₂=CHCH₂CF₃ (HFO-1345czf, 1,1,4,4,4-pentafluorobut-1-ene) was obtained. Synthetic applications of the new polyfluorinated silanes were illustrated by conversion of dichloro(hexafluorobutyl)(methyl)silane to the cyclic trisiloxane, which can serve as a monomer for the preparation of polysiloxanes. In addition, the hexafluorobutylsilanes showed defluorinative reactivity with lithium reagents, thereby demonstrating their synthetic utility as valuable building blocks for further transformations via C–F and C-Si bond activation.

Full text of DOI:10.1002/ejoc.202000853

European Journal of Organic Chemistry
Accepted Article
Accepted Article
Title: Catalytic Hydrosilylation of Hydrofluoroolefins (HFOs): Synthesis
of New Fluorinated Silanes and Diversity of Their Synthetic
Character
Authors: Natalia V. Pavlenko, Sheng Peng, Viacheslav Petrov, Andrew
Jackson, Xuehui Sun, Lee Sprague, and Yurii L. Yagupolskii
This manuscript has been accepted after peer review and appears as an
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of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
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the VoR from the journal website shown below when it is published
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content of this Accepted Article.
To be cited as: Eur. J. Org. Chem. 10.1002/ejoc.202000853
Link to VoR: https://doi.org/10.1002/ejoc.202000853
01/2020

10.1002/ejoc.202000853
European Journal of Organic Chemistry
: June 17, 2020
DOI: 10.1002/ejoc.202000853
F u l l P a p e r
Catalytic Hydrosilylation of Hydrofluoroolefins (HFOs): Synthesis
of New Fluorinated Silanes and Diversity of their Synthetic
Character
Natalia V. Pavlenko,[a] Sheng Peng,*[b] Viacheslav Petrov,[b] Andrew
Jackson,[b] Xuehui Sun,[b] Lee Sprague,[b] and Yurii L. Yagupolskii 0000-0002-
5179-4096*[a]
N. V. Pavlenko, S. Peng,* V. Petrov, A. Jackson, X. Sun, L. Sprague, Yu. L. Yagupolskii*
N. V. Pavlenko,[a] S. Peng,[b] V. Petrov,[b] A. Jackson,[b] X. Sun,[b] L. Sprague,[b] Prof.§ Yu. L. Yagupolskii[a]
We present here the hydrosilylation of commercially available hydrofloroolefins catalyzed by Pt, Pd, and Rh complexes as an
efficient route toward a family of new polyfluorinated silanes <?oas [jy[nt?>as well as their use as versatile building blocks for
subsequent functionalization based on C–F and C-Si bond activation.
Hydrosilylation of Fluoroolefins
[a] <orgDiv/>
<orgDiv/>Institute of Organic Chemistry, <orgName/>National Academy of Sciences of
Ukraine,
<street/>Murmanska St. 5, <city/>Kiev <postCode/>02660, <country/>Ukraine
E-mail: Yagupolskii@ioch.kiev.ua
[b] <orgName/>The Chemours Company, Experimental<Station,
<street/>Bldg. 262, Wilmington, De <postCode/>19880, <country/>USA
E-mail: Sheng.Peng@chemours.com
<pictid> Supporting information and ORCID(s) from the author(s) for this article are available on the WWW under
<url href="https://doi.org/10.1002/ejoc.202000853">https://doi.org/10.1002/ejoc.202000853</url>.
Keywords: Homogeneous catalysis / Defluorination / Desilylation / Hydrofluoroolefins /
Hydrosilylation / Silanes
New polyfluorinated silanes were synthesized via the Pt, Rh and Pd catalyzed hydrosilylation of
commercially available hydrofluoroolefins (HFOs) in moderate to excellent yields. HFO-1234yf
(2,3,3,3-tetrafluoropropene-1) and <?oas [mlbreak(off)] ?>–1234<?oas [mlbreak(on)] ?>ze
(1,3,3,3-tetrafluoropropene-1) were reactive with Pt catalyst to form <?oas
[jy?>tetrafluoropropylsilanes along with defluorosilylation products. The Z- and E-isomers of
HFO-1336mzz (1,1,1,4,4,4-hexafluorobut-2-ene) gave the desired silanes with Pd catalysis in
good to excellent yields, while with Pt catalyst only the dehydrofluorin<?oas [vo"-"][jy?>ation
product CF2=CHCH2CF3 (HFO-1345czf, 1,1,4,4,4-penta<?oas [vo"-"][jy?>fluorobut-1-ene) was
obtained. Synthetic applications of the new polyfluorinated silanes were illustrated by conversion
of dichloro(hexafluorobutyl)(methyl)silane to the cyclic trisiloxane, which can serve as a
monomer for the preparation of polysiloxanes. In addition, the hexafluorobutylsilanes showed
defluor<?oas [vo"-"][jy?>inative reactivity with lithium reagents, thereby demonstrating their
synthetic utility as valuable building blocks for further transformations via C–F and C-Si bond
activation.
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
Introduction
The hydrosilylation of alkenes to produce functionalized silanes represents one of the most
economically important reactions in silicon chemistry. These silanes are widely used in silicon
industry as versatile synthetic building blocks.[1] Fluoroalkylsilanes have shown remarkable
chemical and thermal stabilities for many applications. Their surface activity has been intensively
investigated in connection with the commercial production of “fluorosilicones”.[2] Furthermore,
fluorinated silanes such as the Ruppert–Prakash reagent[3] have been used as a powerful tool for
the introduction of fluorine containing moieties in organic molecules. A straightforward synthetic
approach to fluorinated silanes is the hydrosilylation of fluoroolefins, which are ideal starting
materials as they represent economic organofluorine feedstocks.[4] However, this approach
remains insufficiently explored thus far. Previously it has been shown that the hydrosilylation of
fluorinated olefins can be promoted by photoirradiation,[5] radical initiators[6] and transition metal
complexes.[7,8] Although high yields have been achieved via UV-light promotion,[5] most research
has focused on the reactions with Speier’s catalyst.[2i,7] Ojima et al. have also shown the
hydrosilylation of polyfluorinated olefins with Ir, Rh and Pd catalysts.[8] It should be pointed out,
that in all above mentioned reactions, only terminal 1H,1H,2H-olefins were used. Taking into
account that HFOs are ideal starting materials, and our interest in the expansion of their synthetic
potential, we chose some HFOs to study their hydrosilylation reactions; these are presented
below:
<forr1>
To date the transition metal catalyzed hydrosilylation of olefins has been thoroughly
investigated and reviewed.[1,9] Generally, alkene hydrosilylation has been dominated by the use of
platinum catalysts.[10] Rhodium complex has been successfully explored in the hydrosilylation of
trifluoropropene.[8] Palladium catalysts have been generally regarded as weakly active for
hydrosilylation reactions, however, in several instances they gave products of high regio- and
stereoselectivity that are not available using other catalysts.[8,11] So, Ojima showed by the
example of the transition metals catalyzed hydrosilylation of 3,3,3-trifluoropropene-1 that, in
contrast to platinum or rhodium <?oas [jy?>catalysis, which mainly form β-adducts, palladium
catalysis exclusively led to the formation of α-adducts.[8] For testing experiments on the
hydrosilylation of HFOs 1–4 we chose three commercially available catalysts, namely
H2PtCl6·6H2O (Speier’s catalyst), (Ph3P)3RhCl (Wilkinson’s catalyst) and (Ph3P)2PdCl2.
Herein, we describe our study on the platinum-, rhodium-, and palladium-catalyzed
reactions between HFOs and hydro<?oas [vo"-"][jy?>silanes. These studies have revealed some
considerable effects of the catalyst, as well as the nature of hydrosilanes and olefins, on the
outcome of the reaction.
Results and Discussion
The Reactions of Hydrosilanes with HFO-1234yf (1) and HFO-1234ze(E) (2)
It was reported in 1975 that tetrafluoropropenes 1 and 2 were underwent hydrosilylation
with trichlorosilane promoted by UV light.[12] Recently, hydrosilylation of the same HFOs with
triethylsilane under activation by aluminum chlorofluoride has been studied.[13] In the first case,
the Haszeldine group worked with mixtures of olefins 1 and 2 to obtain complex mixtures,
containing the desired silanes along with defluorination products. In the case of ACF-catalyzed
activation, both olefins gave mixtures, containing products of hydrodefluorination without the
desired silanes formation.
First we studied the Pt, Rh and Pd-catalyzed reactions of <?oas [jy?>tetrafluoropropene 1
with triethylsilane, dichloro(methyl)silane, and trichlorosilane at 80–120 °C in a closed system
without solvent. These results are summarized in Table 1<tabr1>.
The initial experiment was conducted with a stoichiometric mixture of olefin 1 and
HSi(Me)Cl2 using 200 ppm of H2PtCl6 catalyst (Table 1<xtabr1>, entry 1). The results were
analyzed by 19F NMR spectroscopy (C6H5CF3 as an internal standard) to show a complex
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
mixture, in which the linear anti-Markovnikov adduct 5a and reduction product 6a[8] were
identified as major components. Performing this reaction under the same conditions, but with
400 ppm of H2PtCl6 led to the formation of a significant amount of reduction adduct 5a
(Table 1<xtabr1>, entry 2). Decreasing the temperature to 80 °C promoted the
hydrodefluorination (Table 1<xtabr1>, entries 5, 6). The hydrosilylation selectivity was almost
unchanged when two-fold excess of olefin 1 was used (Table 1<xtabr1>, entry 3), but 1.5
equivalents of hydrosilane considerably increased the yield of silane 5a (Table 1<xtabr1>, entry
4). The best result was observed when the reaction was carried out at 120 °C for 48 hours with
1.5-fold excess of starting silane and 200 ppm of catalyst (Table 1<xtabr1>, entry 7). The target
silane 5a was isolated in 63^% yield and fully characterized with 1H, 19F, 13C and 29Si NMR
spectroscopy.
Consistent with the trends observed for HSi(Me)Cl2, reaction of 1 with HSiCl3 under these
conditions (Table 1<xtabr1>, entry 11) afforded trichlorosilane 5b in 59^% yield. Unfortunately,
due to difficulties in separating from 6b and 7b, silane 5b was not isolated in pure state, but was
characterized in a mixture.
The next experiment was performed with HSiEt3, which as a rule exhibits high activity in
Pt-catalyzed hydrosilylation of terminal olefins. However, in the case of tetrafluoropropene 1, the
reaction under the optimized conditions (neat, 48 hours at 120 °C, 1.5-fold excess of silane)
afforded the desired silane 5c in only 28^% yield, while the product of hydrodefluorination 6c[8]
was formed in 47^% yield (Table 1<xtabr1>, entry 13). In addition, the reaction mixture
contained ca. 7^% of hydrodefluorinative branched Markovnikov adduct 7c.[8]
In a manner similar to the Pt-activated reactions, the Rh-catalyzed hydrosilylation of olefin
1 with HSi(Me)Cl2 and HSiCl3 was carried out (Table 1<xtabr1>, entries 8,12). In both cases, the
conversions were moderate, and the obtained reaction mixtures did not contain any of the desired
adducts 5a and 5b. Only dehydrofluorinated products 6a and 6b[8] were identified. This is
perhaps not surprising since the rhodium-catalyzed hydrodefluorination of vinyl fluorides is a
well-documented.[14]
Finally, an attempted reaction of olefin 1 with HSi(Me)Cl2, catalyzed by palladium under
the testing conditions, resulted in a low conversion and the formation of negligible amounts of
adducts 5a, 6a and 7a (Table 1<xtabr1>, entry 9).
As Table 1<xtabr1> shows, both the catalysts and the hydrosilanes used exert a remarkable
influence on the selectivity of the reaction. Classic Speier’s catalyst gave new polyfluorinated
chloro<?oas [vo"-"][jy?>silanes 5a,b in satisfactory yields, while Wilkinson’s catalyst promoted
the hydrosilylation in parallel with hydrodefluorination process. The palladium catalyst provided
low activity.
The hydrosilylation of isomeric tetrafluoropropene HFO-1234ze(E) 2 with HSiCl3,
catalyzed by Pt, Rh and Pd complexes, resulted in complex mixtures of defluorinated adducts,
which were identified on the basis of the published data on the photoinduced hydrosilylation of
3,3,3-trifluoroprop-1-ene[8] and acetylenes CF3C≡CH and CF3C≡CF.[15] Results are presented in
Table 2<tabr2>.
Table 2<xtabr2> shows, the hydrosilylation of propylene 2 proceeds with poor conversion
and regioselectivity as compared to isomer 1. Promoted by Pt and Rh catalysts the
hydrodefluorination reactions afforded negligible amounts of the accessible from
trifluoropropene linear adduct 6b (Table 2<xtabr2>, entries 1–4). Using (Ph3P)2PdCl2 complex,
this reaction occurred at 125 °C (Table 2<xtabr2>, entry 6) to give the mixture of linear and
branched silanes 6b and 7b along with small amounts of products 10, 11, 12, which are attributed
to the dehydrofluorinative hydrosilylation. The products were identified with NMR method on
the base of the published data.[8,15] NMR analysis of this mixture also showed adduct 9, which
was previously observed in the mixture, obtained under the UV-light promoted
hydrosilylation.[12] Although we failed to isolate this product by distillation, it was tentatively
identified in the mixture, based on the 1H and 19F NMR data. The 19F NMR spectrum showed two
signals with the integrated intensity ratio 3:1, a multiplet for a CF3 group at δ = <?oas
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
[mlbreak(off)] ?>–62<?oas [mlbreak(on)] ?>.3 ppm and the highly characteristic signal of a
CH2F group as a triplet of doublets of quartets at δ = <?oas [mlbreak(off)] ?>–219<?oas
[mlbreak(on)] ?>.7 ppm with coupling constants 2JFH = 46.4 Hz and 3JHF≈4JFF ≈ 11 Hz. In the 1H
NMR spectrum there are signals, attributed to CH2 protons at 5.0 ppm as a doublet of doublets
(2JHF = 46.4 Hz, 3JHH = 11.2 Hz) and a CH proton as a multiplet at 2.8 ppm and a 2:1 integration
ratio. These observations with Pd catalyst (Table 2<xtabr2>, entry 6) are promising and their
optimization requires further study.
The Reactions of Hydrosilanes with Hexafluorobutenes HFO-1336mzz(Z) (3) and HFO-
1336mzz(E) (4)
Based upon the experience in the hydrosilylation of tetrafluoropropenes we commenced a
study of the reactions between hydrosilanes and isomeric hexafluorobutenes 3 and 4, catalyzed by
H2PtCl6, (Ph3P)3RhCl and (Ph3P)2PdCl2. Initial experiments were conducted in a glass ampoule
with Teflon stop-cock in the solvent-free conditions with a stoichiometric mixture of components
at 120 °C for 24 hours. The results are summarized in Table 3<tabr3>.
First, the obtained results turned out rather unexpected. Table 3<xtabr3> demonstrates that
the course of these reactions is dramatically dependent on the catalyst used. The Pt catalyzed
hydrosilylation of Z-isomer 3 with all tested silanes gave only low yields of 13a-d. Instead of the
hydrosilylation, the formal hydrodefluorination of starting olefin 3 proceeded to afford
hydrofluoroolefin 14 with variable yields dependent on the hydrosilane employed
(Table 3<xtabr3>, entries 1, 4, 7, 10, 13). In all 19F and 1H NMR spectra of reaction mixtures the
main signals were attributed to butene 14 along with the signals of the appropriate fluorosilanes
in comparable intensities. Whereas Z-isomer 3 showed moderate to high activities, E-isomer 4
exhibited no activity with all silanes tested under catalysis with H2PtCl6. Table 3<xtabr3> also
presents an example of silicone polymer modification, where the hydrosilylation of
hexafluorobutene 3 with commercially available oligomeric siloxane Me3SiO[–HSi(Me)O–
]35SiMe3 was performed to produce oligomeric adduct 13e, containing the desired
CF3CH2CH(CF3) fragment with simultaneous substitution of Si–H to Si–F groups (ca. 15^%).
Meanwhile butene 14 was observed in 25^% yield (Scheme 1 and Table 3<xtabr3>, entry 13).
Screening of hydrosilanes under the same conditions using Wilkinson’s catalyst indicated
no activity with chlorosilanes (Table 3<xtabr3>, entries 2, 5, 8), but the reaction of Z-butene 3
with Et3SiH gave again the dehydrofluorinative product 14 in 63^% yield (Table 3<xtabr3>,
entry 11).
To the best of our knowledge, over the past decade considerable progress has been made in
the field of transition metal-mediated C–F bond activation and cleavage to establish new
synthetic methodologies.[16] However, allylic C(sp3)–F bond activation by transition metals
complexes remains elusive.[13,17] Scheme 2<schr2> below shows our attempt to interpret the
hydrodefluorination results, obtained under the Pt and Rh catalyzed hydrosilylation of HFO 3
(Table 3<xtabr3>).
In accordance with the Chalk–Harrod mechanism for Pt-catalyzed hydrosilylation
reactions, the proposal scheme first involves insertion of CF3CH=CHCF3 into the M–H bond of
adduct A, giving the intermediate B. Elimination FSiR3 from B gives hydride complex C and
subsequent reductive elimination afforded the final olefin 14, regenerating the active catalyst
species A.
<?oas [mv4]?>Surprisingly and at the same time gratifyingly, the Pd complex was efficient
for the hydrosilylation of both Z and E butenes with almost all hydrosilanes. In contrast to the
results with H2PtCl6, the CF3 groups remain untouched during the hydrosilylation, promoted by
(Ph3P)2PdCl2, and the reactions of butenes 3 and 4 with HSi(Me)Cl2 and HSiCl3 occurred to
afford the desired adducts 13a and 13c in quantitative yields (Table 3<xtabr3>, entries 3 and 9).
Both products were isolated by distillation and characterized. Surprisingly, HSiEt3 provided only
8^% conversion with the Z-isomer (Table 3<xtabr3>, entry 12), while HSi(Me)2Cl and
polysiloxane gave the target adducts 13b and 13e in moderate yields (Table 3<xtabr3>, entries 6
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
and 14 correspondingly). The results obtained indicate a significant electronic effect of
substituents in the hydrosilanes on conversions and yields of the desired products under catalysis
with Pd. It should be noted, that interpretation of such a sharp difference in the activity of Pt and
Pd catalysts requires further study.
Intrigued by this unexpected reactivity of hexafluorobutenes, we optimized the reaction
parameters for some hydrosilanes to obtain the preparative method for the synthesis of the new
polyfluorinated organosilicon compounds family and the unknown butene 14. All reactions
optimized were carried out with the more reactive Z-isomer 3; results are presented in
Table 4<tabr4>. Silane 13b, a potential and interesting precursor for subsequent transformations,
was obtained from HSi(Me)2Cl under prolong heating at 125 °C in good yield (Table 4<xtabr4>,
entry 1). However, HSiEt3 under the same conditions gave only 35^% conversion and a low yield
of the desired adduct 13d (Table 4<xtabr4>, entry 2). Use of a two-fold excess of starting
hydrosilane adversely affected the yield of target product 13d (Table 4<xtabr4>, entry 3).
Luckily, the desired compound was alternatively prepared via Grignard reaction on a standard
methodology in a high yield; trimethyl<?oas [vo"-"][jy?>silane 15 was similarly synthesized. The
reaction of compound 13b with PhMgBr under activation with CuI[18] gave the next
hydrolytically stable silane 16 (Scheme 3<schr3>).
Finally, we optimized the reaction of butene 3 with oligomeric hydrosilane under catalysis
with H2PtCl6. Before proceeding to the discussion on this optimization we would like to note, that
HFO 14 was not synthesized and characterized in pure state until now, though it has been
mentioned as a component of complex mixtures.[19]
It should be noted, that in all cases of the hydrosilylation with Pt and Rh catalysts
(Table 3<xtabr3>, entries 1, 4, 10, 11) we failed to isolate the pure product 14 from reaction
mixtures because of the small difference in boiling points and volatiles between the starting olefin
3 and the desired product 14. Therefore, the optimized hydrosilylation of olefin 3 by oligomeric
hydrosilane was carried out at 125 °C over a period of 48 hours and using two-fold excess of Si–
H component to give almost full conversion of starting butene (Table 4<xtabr4>, entry 4). This
procedure was effective on 5 grams at 85^% yield of pentafluorobutene 14 (HFO-1345czf) of
95^% purity, which was simply distilled from non-volatile oligomeric residue.
Synthesis of Modified with 3,3,3-Trifluoro-1-(trifluoro<?oas [vo"-"][jy?>methyl)propyl
Group Siloxanes on the Base of Silane 13a
It is well known that fluorinated polysiloxanes or silicones possess exclusive chemical and
thermal stability and are of great practical and scientific interest.[2] Having in hands
dichloromethylsilane 13a as a potent monomer for new fluorosilicones, we used the classic
scheme for silicones syntheses from di<?oas [vo"-"][jy?>chlorosilanes[2a–2c] and carried out
hydrolysis of 13a for the following oligosiloxane formation. For example, the hydrolysis of ether
solution of silane 13a by aqueous solution of NaOH (0 °C, 30 min) resulted in the formation of
dimeric siloxane 17, which was isolated as a colorless oil and fully characterized by the NMR
spectroscopy. (Scheme 4<schr4>). The same material 17 was also obtained by hydrolysis of 13a
using an excess of water at room temperature.
In accordance with patented methodology[2b] to obtain fluorinated silicones the crude
siloxane 17 was distilled under reduced pressure in the presence of about 1^% (weight) KOH to
afford the insoluble solid polymeric material along with a small amount of viscous liquid (b.p.
98–104 °C/0.4 Torr), which consisted predominantly of cyclic tetrasiloxane 19, as evidenced by
the 29Si NMR spectrum (Scheme 5<schr5>, route a). Cyclic siloxanes 18 and 19 in a ratio ca. 2:1
were obtained in 71^% yield, when a stoichiometric mixture of siloxane 17 and chlorosilane 13a
was heated neat at 100 °C until HCl gas evolution stopped (ca. 5 hours) (Scheme 5<xschr5>,
route b). Next, an one-step procedure for the transformation of dichlorosilanes to siloxanes was
tested.[2i,20] The reaction of chlorosilane 13a with DMSO in mild conditions (neat, at room
temperature overnight) afforded the mixture of 18, 17 and 19 in a ratio ca. 5:1:2 in ca. 83^% yield
(Scheme 5<xschr5>, route c).
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
It should be noted, that 29Si NMR spectroscopy is a very convenient tool for identification
and characterization of cyclosiloxanes.[21] The 29Si{H} NMR spectrum of the siloxanes 18 and 19
mixture, obtaining via route b is presented in Figure 1<figr1>.
As shown in Figure 1<xfigr1>, two groups of signals with an intensity ratio ca. 2:1 are
observed in this spectrum. According to the published data for signals of cyclic siloxanes[21a,b,d]
the downfield group (–15 to <?oas [mlbreak(off)] ?>–16<?oas [mlbreak(on)] ?> ppm)
corresponds to trisiloxane 18 and the less intense upfield lines (–25 to <?oas [mlbreak(off)] ?>–
27<?oas [mlbreak(on)] ?>) are due to tetrasiloxane 19.
For cyclic trisiloxane 18 there are two possible isomers I and II:
<forr6>
Evidently, structure I should give a single resonance, whereas II is expected to give two
signals with a 2:1 intensity ratio. Both isomers are present in this spectrum in a ratio 1:24; the
minor structure I as a multiplet at <?oas [mlbreak(off)] ?>–15<?oas [mlbreak(on)] ?>.2 ppm and
the major structure II as a high field shifted group of quartets. In both cases spectral lines possess
3JSiF couplings of 6 Hz due to fluorine atoms of the β-CF3 group. The sum of the intensities of
two quartets at <?oas [mlbreak(off)] ?>–15<?oas [mlbreak(on)] ?>.5 and <?oas [mlbreak(off)]
?>–15<?oas [mlbreak(on)] ?>.7 ppm is related to the sum of the intensities of quartets at <?oas
[mlbreak(off)] ?>–16<?oas [mlbreak(on)] ?>.1 ppm as 1:2, that is typical of structure II. We
suggest that the signals doubling in both structures I and II is due to the presence of a chiral
center in the hexafluorobutyl substituent. The more complex resonances attributable to the
tetrasiloxanes were not analyzed. Pure siloxanes 18 and 19 were isolated by continuous
rectification from the reaction mixtures and characterized.
Perspectives of Synthetic Applications for 3,3,3-Trifuoro-1-trifluoromethylpropylsilanes
Fluorinated organosilanes are valuable building blocks for <?oas [jy?>fluoroorganic
synthesis from the point of view of organosilicon chemistry versatility.[22] Therefore, we became
interested in exploring the synthetic potential of silanes 13d, 15 and 16, which are stable, easy to
handle and can be readily prepared in the laboratory on the 20 g scale. Fluoroalkylsilanes have
been used for a broad variety of perfluoroalkylation reactions that has been extensively
reviewed.[3,22] To the best of our knowledge, during the last decades selective C–F bond
activation by fluoride-ion have become current subject of active investigation to synthesize
building blocks, which are unavailable via traditional fluorination methods. We began our
research on the reactivity of hexafluorobutylsilanes, performing the fluoride-ion catalyzed
reactions of the hydrolytically stable silanes 13d, 15 and 16 with aromatic aldehydes as the most
successful substrates. It turns out that elimination fluorosilane was the most favorable process
(under variety of conditions), leading to the high yield formation of butene 14
(Scheme 6<schr6>).
It should be noted, that the desilylative defluorination of compound 16 in diglyme at the
room temperature by the promotion with 5 molar^% CsF gave HFO 14 of a high purity in the
almost quantitative yield in 10 g scale.
It is known, that until now the simplest trifluoroethyl carbanion has not been successfully
generated. From this viewpoint hexafluorobutylsilanes 13d, 15 and 19 are unsuitable for
synthetic purposes in cases where they would involve the intermediate formation of α-
CF3carbanions. However, gem-difluoroalkene 14 could serve as a synthon for the introduction of
vinyl moiety with trifluoroethyl group in organic molecules. Thus, reactions of compound 16
with organolithium reagents gave vinyl fluorides with the preservation of silicon function
(Scheme 7<schr7>).
Lithiation of silane 16 resulted in the formation of the carbanion A and after subsequent
defluorination yielded the intermediate gem-difluoroalkene B. The last is itself reactive towards
RLi and was immediately transformed to the final products 20a,b through an addition/elimination
process.[23] Notably, treatment of silane 16 with one mol equivalent of PhLi or BuLi did not result
in the desired vinyl fluoride B, but produced a mixture of starting compound and vinylsilanes 20a
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
or 20b. These products were isolated by column chromatography on SiO2 in 86^% yield for 20a
and 72^% yield for 20b. NMR analysis showed the mixtures of Z and E isomers in both cases
with the ratio Z/E ca. 4:1 for 20a and Z/E ca. 5:1 for 20b. The configuration of the isomers was
determined by the 5JFFcis coupling constant in the 19F{H} NMR spectrum (ca. 0 Hz for (Z)-isomer
and 5.0 Hz for (E)-isomer).
The isomeric mixture 20a was then subjected to the hydro<?oas [vo"-"][jy?>desilylation by
action of two mol equivalent TBAF in THF at room temperature for 12 h to afford the mixture of
the expected (E)-styrene 21 as the main product and acetylene 22 as the product of (E)-isomer
20a desilylative defluorination (Scheme 8<schr8>).
Chromatographic purification of the reaction mixture gave a difficult-to-separate mixture of
styrene 21 and acetylene 22 in a ratio ca. 4:1. The last was described previously,[24] and recorded
1H, 19F and 13C NMR spectra were in full agreement with the published data. The (E)-
configuration of the styrene 21 was determined by its 3JHFcis coupling constant in the 1H and 19F
NMR spectra. In turn one can use compound 21 as a multivariate synthon to achieve the
trifluoroethyl group containing polyfunctional molecules, exploiting C–F bond activation
methods for further transformations.
Finally, we investigated the oxidative desilylation of silane 19 via Fleming two-step
procedure.[25] Fleming postulated the phenyldimethylsilyl group as a masked hydroxy group, and
we tested his method to afford alcohol 24 (Scheme 9<schr9>).
In the first stage crude silane 23 was characterized with 19F and 29Si NMR spectra and
entered in the reaction with oxidant without isolation. Work-up of the obtained mixture and
subsequent distillation gave target alcohol 24 in 22^% unoptimized yield after two steps. The
structure of compound 24 was confirmed by comparing the boiling point and the NMR data with
the previously reported values.[26]
Conclusions
The study Pt, Rh, and Pd complexes catalyzed hydrosilylation of HFOs 1, 3, 4 led to the
formation of a new polyfluorinated organosilicon compounds series in the moderate to excellent
yields. Dramatic differences in the catalytic action of Pt and Pd on the course of reactions with
hexafluorobutene 3 was observed; unlike the Pd catalyzed high yielding hydrosilylation, Pt
promoted a rare allylic C–F bond cleavage to afford previously unreported HFO-1345czf 14. The
fluoride-ion activation of hydrolytically stable silanes resulted in the formation of the same
olefin. Several examples of the new silanes synthetic utility were described. Notably,
dichloromethylsilane 13a was used to synthesize trisiloxane 18 as a monomer for new fluorinated
<?oas [jy?>silicones. Dehydrofluorination of the stable silane 16 by lithium reagents
demonstrated the ability of this compound to serve as a value building block for further
transformations via C–F and C-Si bonds activation.
Experimental Section
1H, 13C, 19F and 29Si NMR spectra were recorded on a Bruker 170 AVANCE 500 spectrometer (at 500 MHz for 1H
NMR, 125 MHz for 13C NMR, 470 MHz for 19F NMR and 99 MHz for 29Si NMR) or on Varian UNITY Plus 400
spectrometer (at 400 MHz for 1H NMR, 100 MHz for 13C NMR and 376 MHz for 19F NMR). Chemical shifts are
given in ppm relative to Me4Si and CCl3F as internal standards. Mass spectra were registered on an Agilent 5890
Series II 5972 GC-MS instrument (EI 70 eV). Flash chromatography was performed using Kieselgel Merck 60 (230–
400 mesh). Elemental analyses were performed at the Analytical Laboratory of the Institute of Organic Chemistry,
NAS of Ukraine, Kyiv.
Typical hydrosilylation procedure. A glass ampoule with Teflon stop-cock was charged with catalyst, silane and
PhCF3 as an internal standard, and the mixture was degassed. Then olefin was condensed, and the corresponding
reaction conditions were applied. The crude reaction mixtures were cooled till <?oas [mlbreak(off)] ?>–20<?oas
[mlbreak(on)] ?> °C, samples were dissolved in CDCl3 and then analyzed by 1H and 19F NMR. The conversion of
substrates was determined on the base of NMR data by integration of products resonances vs. the standard. The
products were purified by fractional distillation under vacuum and characterized.
Dichloro(methyl)(2,3,3,3-tetrafluoropropyl)silane (5a) was obtained according to the general procedure at 125 °C
for 48 h from HFO 1 (6.06 g, 53.2 mmol) and HSi(Me)Cl2 (9.2 g, 79.7 mmol) as a volatile liquid (7.67 g, 63^%); b.p.
This article is protected by copyright. All rights reserved.

10.1002/ejoc.202000853
European Journal of Organic Chemistry
92–94 °C (750 Torr). 1HNMR (500 MHz, CDCl3): δ = 4.99 (dm, 2JHF = 45.3 Hz, 1H), 1.86 (ddd, 3JHF = 19.0 Hz, JAB
= 15.4 Hz, 3JHH = 9.5 Hz, 1H), 1.66 (ddd, 3JHF = 45.6 Hz, JAB = 15.4 Hz, 3JHH = 2.5 Hz, 1H), 0.92 (d, 4JHH = 1.0 Hz,
3H); <?oas [jy?>19F NMR (470 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–81<?oas [mlbreak(on)] ?>.23 (dd, 3JFF
=
11.2 Hz, 3JFH = 9.5 Hz, 3F), <?oas [mlbreak(off)] ?>–192<?oas [mlbreak(on)] ?>.24 (dddq, 2JFH ≈ 3JFH ≈ 45 Hz, 3JFH
≈ 20 Hz, 3JFF ≈ 11 Hz, 1F); 19F{H} NMR (470 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–82<?oas [mlbreak(on)]
?>.14 (d, 3JFF = 11.2 Hz, 3F), <?oas [mlbreak(off)] ?>–192<?oas [mlbreak(on)] ?>.28 (q, 3JFF = 11.2 Hz, 1F); 13C{H}
NMR (125 MHz, CDCl3): δ = 122.49 (qd, 1JCF = 280.6 Hz, 2JCF = 27.1 Hz), 85.69 (dq, 1JCF = 182.7 Hz, 2JCF
=
36.1 Hz), 21.75 (d, 2JCF = 24.6 Hz), 6.12–6.02 (m); 29Si{H} NMR (99 MHz, CDCl3): δ = 27.68 (d, 3JSiF = 8.9 Hz);
elemental analysis calcd. (%) for C4H6Cl2F4Si: C 20.97, H 2.64, Cl 30.95; found C 20.74, H 2.80, Cl 30.78.
Trichloro(2,3,3,3-tetrafluoropropyl)silane (5b) was obtained according to the general procedure at 125 °C for 48 h
from HFO 1 (4.0 g, 35.1 mmol) and HSiCl3 (7.13 g, 52.6 mmol) as a mixture with CF3CH2CH2SiCl3 (ca. 23 mol-%),
boiled at 102–103 °C (754 Torr), yield 6.68 g mixture (ca. 59^% of 5b). 1H NMR (500 MHz, CDCl3): <?oas [jy?>δ
= 5.03 (dm, 2JHF = 45.3 Hz, 1H), 2.21–2.10 (m, 1H), 1.91 (ddd, 3JHF = 42.0 Hz, JAB = 15.6 Hz, 3JHH = 3.1 Hz, 1H),
two multiplets at δ = 2.34 (0.61 H) and 1.65 (0.61 H) belong to CF3CH2CH2SiCl3;[8] <?oas [jy?>19F NMR (470 MHz,
CDCl3): δ = <?oas [mlbreak(off)] ?>–80<?oas [mlbreak(on)] ?>.50 to <?oas [mlbreak(off)] ?>–81<?oas
[mlbreak(on)] ?>.07 (m, 3F), <?oas [mlbreak(off)] ?>–192<?oas [mlbreak(on)] ?>.50 to <?oas [mlbreak(off)] ?>–
193<?oas [mlbreak(on)] ?>.16 (m, 1F), multiplet at δ = <?oas [mlbreak(off)] ?>–68<?oas [mlbreak(on)] ?>.24 ppm
(0.9 F) belongs to CF3CH2CH2SiCl3;[8] 13C{H} NMR (125 MHz, CDCl3): δ = 121.73 (qd, 1JCF = 281.2 Hz, 2JCF
=
26.4 Hz), 84.25 (dq, 1JCF = 186.5 Hz, 2JCF = 36.9 Hz), 23.74 (d, 2JCF = 23.9 Hz), signals at δ = 125.86 (q, 1JCF
=
281.6 Hz), 26.99 (q, 2JCF = 32.7 Hz), 16.26 belong to CF3CH2CH2SiCl3;[8] 29Si{H} NMR (99 MHz, CDCl3): δ = 6.81
(dm, 3JSiF = 8.7 Hz, 1Si), a signal at δ = 11.17 ppm (s, 0.3Si) belongs to CF3CH2CH2SiCl3; elemental analysis calcd.
(%) for C3H3Cl3F4Si: <?oas [jy?>Cl 42.63; found: Cl 43.28.
Dichloro(1,1,1,4,4,4-hexafluorobut-2-yl)(methyl)silane (13a) was obtained according to the general procedure at
120 °C for 10 h with (Ph3P)2PdCl2 catalysis from HFO 3 (8.0 g, 48.8 mmol) and HSi(Me)Cl2 (5.6 g, 48.8 mmol) as a
colorless liquid (13.4 g, 99^%); b.p. 68–70 °C (80 Torr). 1H NMR (400 MHz, CDCl3): δ = 2.50–2.72 (m, 2H), 2.34–
2.43 (m, 1H), 0.98 (s, 3H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–59<?oas [mlbreak(on)]
?>.95to <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.03 (m, 3F), <?oas [mlbreak(off)] ?>–66<?oas
[mlbreak(on)] ?>.35to <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.47 (m, 3F); 13C{H} NMR (100 MHz,
CDCl3): δ = 126.16 (q, 1JCF = 278.7 Hz), 125.41 (q, 1JCF = 277.7 Hz), 32.49 (qq, 2JCF = 31.5 Hz, 3JCF = 2.5 Hz), 28.87
(qq, 2JCF = 33.2 Hz, 3JCF = 4.1 Hz), 5.09 (s); 29Si{H} NMR (99 MHz, CDCl3): δ = 25.59 (q, 3JSiF = 6.9 Hz); elemental
analysis calcd. (%) for C5H6Cl2F6Si: C 24.42, H 3.42, Cl 24.03; found C 20.62, H 3.20, Cl 24.33.
Chloro(1,1,1,4,4,4-hexafluorobut-2-yl)dimethylsilane (13b) was obtained according to the general procedureat
125 °C for 48 h with (Ph3P)2PdCl2 catalysis from HFO 3 (16.4 g, 0.1 mol) and HSi(Me)2Cl (14.25 g, 0.15 mol) as a
colorless liquid (22.9 g, 88^%); b.p. 55–56 °C (60 Torr), 1H NMR (500 MHz, CDCl3): δ = 2.44–2.61 (m, 2H), 2.11–
2.21 (m, 1H), 0.61 (s, 3H), 0.59 (s, 3H); 19F NMR (470 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–59<?oas
[mlbreak(on)] ?>.64 to <?oas [mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.76 (m, 3F), <?oas [mlbreak(off)] ?>–
66<?oas [mlbreak(on)] ?>.02 to <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.14 (m, 3F); 13C{H} NMR
(125 MHz, CDCl3): δ = 127.29 (q, 1JCF = 277.8 Hz), 125.81 (q, 1JCF = 276.6 Hz), 30.00 (qq, 2JCF = 30.2 Hz, 3JCF
=
1.3 Hz), 28.97 (qq, 2JCF = 31.4 Hz, 3JCF = 2.5 Hz), 1.59 (s), 0.61 (s); 29Si{H} NMR (99 MHz, CDCl3): δ = 28.91 (q,
3JSiF = 6.0 Hz); elemental analysis calcd. (%) for C6H9ClF6Si: C 30.61, H 4.77, Cl 12.91; found C 30.76, H 4.98, Cl
12.47.
Trichloro(1,1,1,4,4,4-hexafluorobut-2-yl)silane (13c) was obtained according to the general procedure at 120 °C
for 24 h with (Ph3P)2PdCl2 catalysis from HFO 3 (6.56 g, 40.0 mmol) and HSiCl3 (5.42 g, 40.0 mmol) as a colorless
liquid (11.48 g, 97^%); b.p. <?oas [jy?>52–54 °C (60 Torr). 1H NMR (400 MHz, CDCl3): δ = 2.59–2.76 (m); 19
F
NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.95 (br s, 3F), <?oas [mlbreak(off)]
?>–66<?oas [mlbreak(on)] ?>.34 (br s, 3F); 19F{H} NMR (376.5 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–
60<?oas [mlbreak(on)] ?>.04 (q, 5JFF = 5.6 Hz, 3F), <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.44 (q, 5JFF
=
5.6 Hz, 3F); 13C{H} NMR (125 MHz, CDCl3): δ = 125.06 (q, 1JCF = 279.1 Hz), 124.95 (q, 1JCF = 276.6 Hz), 34.94 (q,
2JCF = 30.2Hz), 28.97 (q, 2JCF = 33.9 Hz); 29Si{H} NMR (99 MHz, CDCl3): δ = 3.14 (q, 3JSiF = 8.9 Hz); elemental
analysis calcd. (%) for C4H3Cl3F6Si: Cl 35.51; found: Cl 34.93.
Triethyl(1,1,1,4,4,4-hexafluorobut-2-yl)silane (13d). To 1.0 mol solution of EtMgBr in THF (110 mL, 110 mmol)
was added silane 13c (8.9 g, 29.7 mmol) in 50 mL of THF at the temperature ≤ 0 °C under cooling with an ice bath.
The reaction mixture was stirred for 12 hours at room temperature, boiled for 3 hours, hydrolyzed by pouring onto
cracked ice with following extraction by ether. The extract was dried with MgSO4, ether was evaporated, and the
residue was fractionated to give silane 15 as a colorless liquid (4.79 g, 58^%); b.p. 70–71 °C (10 Torr). 1H NMR
(400 MHz, CDCl3): δ = 2.36–2.52 (m, 1H), 2.18–2.32 (m, 1H), 1.90–2.04 (m, 1H), 0.99 (t, 3JHH = 8.0 Hz, 9H), 0.70
(m, 2H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.85 to <?oas
[mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.97 (m, 3F), <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.52 to
<?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.64 (m, 3F); 13C{H} NMR (125 MHz, CDCl3): δ = 128.14 (q, 1JCF
= 277.8 Hz), 125.68 (q, 1JCF = 276.5 Hz), 28.85 (qq, 2JCF = 28.3 Hz, 3JCF = 3.8 Hz), 24.16 (qq, 2JCF = 30.2 Hz, 3JCF
=
1.3 Hz), 6.23, 1.84; 29Si{H} NMR (99 MHz, CDCl3): δ = 10.50 (q, 3JSiF = 3.0 Hz); elemental analysis calcd. (%) for
C10H18F6Si: C 42.85, H 6.47; found C 42.76, H 6.69.
This article is protected by copyright. All rights reserved.

10.1002/ejoc.202000853
European Journal of Organic Chemistry
Trimethyl(1,1,1,4,4,4-hexafluorobut-2-yl)silane (15). According to the procedure for the synthesis of 13d the
reaction of 2.6 mol solution of MeMgCl in THF (66.5 mL, 173 mmol) with 13c (14.4 g, 48 mmol) gave silane 15 as
a colorless liquid (7.4 g, 65^%); b.p. 114–115 °C (750 Torr). 1H NMR (400 MHz,CDCl3): δ = 2.36–2.52 (m, 1H),
2.18–2.30 (m, 1H), 1.78–1.92 (m, 1H), 0.18 (s, 9H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–
60<?oas [mlbreak(on)] ?>.47 to <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.58 (m, 3F), <?oas [mlbreak(off)]
?>–66<?oas [mlbreak(on)] ?>.64 to <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.75 (m,3F); 13C{H} NMR
(125 MHz, CDCl3): δ = 128.52 (q, 1JCF = 277.8 Hz), 126.17 (q, 1JCF = 277.8 Hz), 29.22 (qm, 2JCF = 31.4 Hz), 27.44
(qm, 2JCF = 28.9 Hz), <?oas [mlbreak(off)] ?>–2<?oas [mlbreak(on)] ?>.49 to <?oas [mlbreak(off)] ?>–2<?oas
[mlbreak(on)] ?>.54 (m); 29Si{H} NMR (99 MHz, CDCl3): δ = 6.41 (q, 3JSiF = 3.9 Hz); elemental analysis calcd. (%)
for C7H12F6Si: <?oas [jy?>C 35.29, H 5.08; found C 35.03, H 4.76.
(1,1,1,4,4,4-Hexafluorobut-2-yl)dimethyl(phenyl)silane (16) (scaled experiment). Silane 13b (10.4 g, 40 mmol)
was added to a suspension of CuI (0.32 g, 2 mmol) in 75 mL of THF. Then 1.0 mol solution PhMgBr in THF
(60 mL, 60 mmol) was dropped under cooling with an ice bath. The mixture was stirred at room temperature
overnight, quenched with the aqueous solution of NH4Cl and extracted with ethyl acetate. Organic layer was dried
with MgSO4 and then fractionated under vacuum to give silane 16 as a colorless liquid (11.9 g, 99^%); b.p. 109–
110 °C (25 Torr). 1H NMR (400 MHz, CDCl3): δ = 7.30–7.52 (m, 5H), 2.42–2.26 (m, 1H), 2.23–2.00 (m, 2H), 0.47
(s, 6H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.52 to <?oas
[mlbreak(off)] ?>–59<?oas [mlbreak(on)] ?>.62 (m, 3F), <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.38 to
<?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.52 (m, 3F); 13C{H} NMR (100 MHz, CDCl3): δ = 134.12,
133.97, 130.21, 128.44 (q, 1JCF = 277.6 Hz), 128.24, 126.11 (q, 1JCF = 276.7 Hz), 29.48 (qq, 2JCF = 31.2 Hz, 3JCF
2.5 Hz), 27.70 (qq, 2JCF = 29.2 Hz, 3JCF = 1.0 Hz), <?oas [mlbreak(off)] ?>–3<?oas [mlbreak(on)] ?>.38, <?oas
[mlbreak(off)] ?>–4<?oas [mlbreak(on)] ?>.57; 29Si{H} NMR (99 MHz, CDCl3): δ = 0.58 (q, 3JSiF = 5.0 Hz);
elemental analysis calcd. (%) for C12H14F6Si: C 47.99, H 4.70, found: C 48.27, H 5.12.
1,1,4,4,4-Pentafluorobut-1-ene (14).
=
Procedure 1: The hydrosilylation of butene 3 with oligomeric hydrosilane Me3Si-[O-Si(H)Me-]35OSiMe3. A glass
ampoule with Teflon stop-cock (V 50 mL) was charged with silane (4.9 g, 76.4 mmol) and H2PtCl6·6H2O (39 mg,
0.076 mmol, 0.2 molar^%), and the mixture was degassed. Then butene 3 (6.3 g, 38.0 mmol) was condensed, the
ampoule was closed, and the mixture was stirred at 125 °C for 48 h. All volatile products were distilled off under
static vacuum in a cooled with dry-ice trap to give 14 of 95^% purity (4.8 g, ca. 85^%).
Procedure 2: Desilylative defluorination of silane 16 (scaled experiment). Silane 16 (20.0 g, 66.7 mmol) was
dissolved in dry diglyme (50 mL) and placed in an open system, equipped with the argon inlet and a cooled trap (–
78 °C) for the condensation of highly volatile products. CsF (500 mg, 3.3 mmol, 5 molar^%) was added to this
solution and the obtaining mixture was stirring under a slow argon flow through the system to collect the volatiles.
After the exothermic effect was observed, the reaction mixture was heated at 80 °C for 5 h to give in the trap HFO 14
as a volatile liquid of a high purity, (9.43 g, 97^%); b.p. 21–22 °C (750 Torr). 1H NMR (500 MHz, CDCl3): δ = 4.29
(dt, 3JHF = 23.5Hz, 3JHH = 8.0 Hz, 1H), 2.83–2.78 (m, 3JHH ≈ 8 Hz, 3JHF ≈ 10 Hz, 2H); 19F NMR (470 MHz, CDCl3): δ
= <?oas [mlbreak(off)] ?>–67<?oas [mlbreak(on)] ?>.77 (t, 3JFH = 10.8 Hz, 3F), <?oas [mlbreak(off)] ?>–85<?oas
[mlbreak(on)] ?>.66 (d, 2JFF = 36.9 Hz, 1F), <?oas [mlbreak(off)] ?>–88<?oas [mlbreak(on)] ?>.90 (dd, 2JFF
=
36.9 Hz, 3JFH = 23.5Hz, 1F); 13C{H} NMR (125 MHz, CDCl3): δ = 159.24 (d, 1JCF = 291.2 Hz), 156.95 (d, 1JCF
=
291.2 Hz), 125.31 (qm, 1JCF = 277.3 Hz), 90.50 (ddq, 2JCF = 30.9 Hz, 2JCF = 19.9 Hz, 3JCF = 4.0 Hz), 28.39 (qd, 2JCF
31.9 Hz, 3JCF = 5.5 Hz). GC/MS (70 eV): <?oas [mlbreak(off)] ?>m/z<?oas [mlbreak(on)] ?> (%): 147 [M + H]+
(17), 191 [M + C2H2F]+ (78), 177 [M + CFH]+ (98), 133 [M – CH]+ (96), 96 [M – CF2]+ (100), 78 [M – CF3 + H]+
(81).
=
<?oas [la999]?>1,3-Bis[(1,1,1,4,4,4-hexafluorobut-2-yl)methyl]disiloxane-1,3-diol (17). Water (10 mL) was added
dropwise with intensive stirring to a cooled silane 13a (8.9 g, 31.9 mmol) under cooling with an ice bath. The
mixture was stirred at room temperature for 3 hours and then extracted by ether. The organic layer was dried with
MgSO4, the solvent was evaporated, the residue was distilled to afford di<?oas [vo"-"][jy?>siloxane 17 as a colorless
viscous liquid (7.3 g, 98^%); b.p. 83–85 °C (0.6 Torr). 1H NMR (400 MHz, CDCl3): δ = 4.05–3.20 (br s, 1H), 2.54–
2.32 (m, 2H), 2.04–1.94 (m, 1H), 0.34 (brs, 3H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–60<?oas
[mlbreak(on)] ?>.58 to <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.82 (m, 3F), <?oas [mlbreak(off)] ?>–
66<?oas [mlbreak(on)] ?>.48 to <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.74 (m, 3F); 13C{H} NMR
(125 MHz, CDCl3): δ = 127.46 (q, 1JCF = 277.8 Hz), 126.03 (q, 1JCF = 275.3 Hz), 29.00–27.92 (m), <?oas
[mlbreak(off)] ?>–2<?oas [mlbreak(on)] ?>.22 to <?oas [mlbreak(off)] ?>–2<?oas [mlbreak(on)] ?>.56 (m); 29Si{H}
NMR (99 MHz, CDCl3): δ=-18.48 to <?oas [mlbreak(off)] ?>–19<?oas [mlbreak(on)] ?>.10 (m); elemental analysis
calcd. (%) for C10H14F12O3Si2: C 25.75, H 3.03; found C 25.18, H 3.49.
Formation of cyclic oligosiloxanes.
Route a. Disiloxane 17 (7.4 g, 15.8 mmol) was distilled from KOH (74 mg, 1^%) under reduced pressure to give
tetrakis[(1,1,1,4,4,4-hexafluorobut-2-yl)methyl]tetrasiloxane (19) as a colorless viscous liquid (2.1 g, 15^%); b.p.
98–104 °C (0.4 Torr). 1H NMR (400 MHz, CDCl3): δ = 2.50–2.30 (br s, 2H), 2.05–1.85 (br s, 1H), 0.40–0.15 (m,
3H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.80 to <?oas
[mlbreak(off)] ?>–61<?oas [mlbreak(on)] ?>.25 (m, 3F), <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.50 to
<?oas [mlbreak(off)] ?>–67<?oas [mlbreak(on)] ?>.15 (m, 3F); 13C{H} NMR (100 MHz, CDCl3): δ = 127.14 (q, 1JCF
= 276.7 Hz), 125.81 (q, 1JCF = 275.7 Hz), 29.20–27.40 (m), <?oas [mlbreak(off)] ?>–1<?oas [mlbreak(on)] ?>.80 to
This article is protected by copyright. All rights reserved.

10.1002/ejoc.202000853
European Journal of Organic Chemistry
<?oas [mlbreak(off)] ?>–6<?oas [mlbreak(on)] ?>.94 (the group of multiplets); 29Si{H} NMR (99 MHz, CDCl3): δ=-
25 to <?oas [mlbreak(off)] ?>–29<?oas [mlbreak(on)] ?> (the group of multiplets). The pot residue was obtained as a
colorless insoluble resin (5.1 g), and further identification was not done.
Route b. Dichlorosilane 13a (1.0 g, 3.6 mmol) and siloxane 17 (1.7 g, 3.6 mmol) were stirred at 100 °C until HCl gas
was evolved (ca. 5 hours). The obtaining mixture was dissolved in CH2Cl2 (25 mL), this solution was washed with
water, dried with MgSO4, solvent was evaporated and all volatiles products were distilled off from the residue under
reduced pressure to give the fraction (1.72 g, 71^%); b.p. 85–120 °C (0.6 Torr). Analysis of this fraction by the
29Si{H} NMR showed 65 molar^% of trisiloxane 18 and 35 molar^% of tetrasiloxane 19.
Route c. A solution of DMSO (6.6 g, 84 mmol) in 10 mL dry CHCl3 was dropped to a solution of silane 13a (11.7 g,
41.9 mmol) in 25 mL dry CHCl3 at room temperature, and the reaction was allowed to stir overnight. Obtaining
suspension was cooled to 0 °C and the solution was separated, the solvent was evaporated, and the residue (7.81 g)
was analyzed by the 29Si{H} NMR to show 66^% of trisiloxane 18, 12^% of disiloxane 17 and 22^% of tetrasiloxane
19. Repeated rectification of the reaction mixture gave pure tris[(1,1,1,4,4,4-hexafluorobut-2-yl)methyl]trisiloxane
(18) as a colorless liquid (3.20 g, 34^%); b.p. 55–56 °C (0.07 Torr). 1H NMR (400 MHz, CDCl3): δ = 2.54–2.32 (m,
2H), 2.08–1.88 (m, 1H), 0.42–0.32 (m, 3H); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–60<?oas
[mlbreak(on)] ?>.54 to <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.95 (the group of multiplets, 3F), <?oas
[mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.48 to <?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.94 (the group
of multiplets, 3F); 13C{H} NMR (125 MHz, CDCl3):the group of multiplets at 130.40–122.45 ppm; the most
intensive signals at δ = 127.05 (qm, 1JCF = 281.6 Hz), 125.75 (qm, 1JCF = 276.5 Hz), 29.20÷27.47 (m), <?oas
[mlbreak(off)] ?>–1<?oas [mlbreak(on)] ?>.89 to <?oas [mlbreak(off)] ?>–2<?oas [mlbreak(on)] ?>.61 (m); 29Si{H}
NMR (99 MHz, CDCl3): δ=-15.09 to <?oas [mlbreak(off)] ?>–15<?oas [mlbreak(on)] ?>.34 (m, 0.2 Si), <?oas
[mlbreak(off)] ?>–15<?oas [mlbreak(on)] ?>.46 (q, 3JSiF = 6.2 Hz, 0.5 Si), <?oas [mlbreak(off)] ?>–15<?oas
[mlbreak(on)] ?>.69 (q, 3JSiF = 6.2 Hz, 0.5Si), <?oas [mlbreak(off)] ?>–15<?oas [mlbreak(on)] ?>.94 to <?oas
[mlbreak(off)] ?>–16<?oas [mlbreak(on)] ?>.27 (m, 2Si); elemental analysis calcd. (%) for C15H18F18O3Si: C 26.79,
H 2.70; found C 26.34,H 3.14.
General procedure for the reactions with organolithium reagents. The organolithium reagent (2.2 mol^equiv.)
was added to a solution of 16 (1 mol^equiv.) in THF at <?oas [mlbreak(off)] ?>–78<?oas [mlbreak(on)] ?> °C over a
period of 30 min. The solution was stirred for 30 min, then warmed to room temperature and stirred overnight. The
reaction was quenched by the addition of saturated aqueous NH4Cl solution at 0 °C. The aqueous layer was extracted
with diethyl ether, the combined extracts were washed with water, dried with MgSO4 and concentrated under
vacuum affording crude products 20a,b, which were purified by column chromatography on SiO2.
Dimethyl(phenyl)(1,4,4,4-tetrafluoro-2-phenylbut-1-enyl)silane (20a) was obtained according to the general
procedure from 16 (2.5 g, 8.3 mmol) and 1.8 M solution PhLi in THF (10 mL, 18.0 mmol) with following
chromatography (pentane), as a mixture of isomers in a ratio E:Z ca. 1:7.5 (2.4 g, 86^%); Rf = 0.45 (pentane). 1H
NMR (400 MHz, CDCl3): δ = 7.54–7.36 (m, 11H, Z-is. +E-is.), 3.11 (q, 3JHF = 10.1 Hz, 0.26 H, E-is.), 2.93 (q, 3JHF
=
10.2 Hz, 2H, Z-is.), 0.58 (s, 6H, Z-is.), 0.23 (s, 0.78 H, E-is.); 19F NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)]
?>–57<?oas [mlbreak(on)] ?>.68 (m, 0.13 F, E-is.), <?oas [mlbreak(off)] ?>–60<?oas [mlbreak(on)] ?>.90 (br s, 1F,
Z-is.), <?oas [mlbreak(off)] ?>–64<?oas [mlbreak(on)] ?>.38 (t, 3JFH = 10.1 Hz, 3F, Z-is.), <?oas [mlbreak(off)] ?>–
64<?oas [mlbreak(on)] ?>.97 (m, 0.40 F, E-is.); 13C{H} NMR (100 MHz, CDCl3): δ = 168.26 (d, 1JCF = 249.8 Hz, Z-
is.), 166.78 (d, 1JCF = 279.1 Hz, E-is.), 137.85 (E-is.), 137.75 (Z-is.), 134.01 (Z-is.), 133.91 (E-is.), 133.68 (d, 2JCF
31.0 Hz, E-is.), 132.11 (d, 2JCF = 33.7 Hz, Z-is.), 130.18 (d, 3JCF = 2.2 Hz, E-is.), 129.94 (d, 3JCF = 1.8 Hz, Z-is.),
=
129.50 (Z-is.), 129.32 <?oas [jy?>(Z-is.), 129.25 (E-is.), 128.67 (Z-is.), 128.14 (E-is.), 127.97 (Z-is.), 126.42 (qd, 1JCF
= 277.7 Hz, 4JCF = 5.1 Hz, Z-is.), the signal of CF3 for E-is. was lost in noise, 104.89 (dq, 2JCF = 40.2 Hz, 3JCF
=
2.1 Hz, Z-is.), 102.95 (m, E-is.), 34.15 (qd, 2JCF = 30.2 Hz, 3JCF = 12.1 Hz, Z-is.), 32.36 (qd, 2JCF = 30.2 Hz, 3JCF
13.1 Hz, E-is.), <?oas [mlbreak(off)] ?>–1<?oas [mlbreak(on)] ?>.44 (s, E-is.), <?oas [mlbreak(off)] ?>–1<?oas
=
[mlbreak(on)] ?>.72 (s, <?oas [jy?>Z-is.); 29Si{H} NMR (99 MHz, CDCl3): δ=-7.00 (d, 3JSiF = 11.9 Hz, Z-is.), <?oas
[mlbreak(off)] ?>–7<?oas [mlbreak(on)] ?>.04 to <?oas [mlbreak(off)] ?>–7<?oas [mlbreak(on)] ?>.20 (m, E-is.);
elemental analysis calcd. (%) for C18H18F4Si: C 63.88, H 5.36; found C 64.24, H 5.12.
1-Fluoro-2-(2,2,2-trifluoroethyl)hex-1-enyl]dimethyl(phenyl)sil<?oas [vo"-"][jy?>ane (20b) was obtained
according to the general procedure from 16 (1.5 g, 5.0 mmol) and 2.4 M solution BuLi in THF (5.2 mL, 12.5 mmol)
with following distillation as a mixture of isomers in a ratio E:Z ca. 1:5 (1.15 g, 72^%); b.p. 90–91 °C (0.5 Torr). 1H
NMR (400 MHz, CDCl3): δ = 7.64–7.24 (m, 6 H, Z-is. +E-is.), 2.97 (q, 3JHF = 10.4 Hz, 0.4 H, E-is.), 2.75 (q, 3JHF
10.8 Hz, 2 H, Z-is.), 2.32 (dt, 3JHF = 22.4 Hz, 3JHH = 7.6 Hz, 2 H, Z-is.), 2.03 (dm, 3JHF = 22.8 Hz, 0.4 H, <?oas
=
[jy?>E-is.), 1.52 (quintet, 3JHH = 7.6 Hz, 2 H, Z-is.),1.38–1.22 (m, 2.4 H, Z-is. +E-is.), 1.08–1.02 (m, 0.4 H, E-is.),
0.91 (t, 3JHH = 7.6 Hz, 3 H, Z-is.), 0.72 (t, 3JHH = 7.6 Hz, 0.6 H, E-is.), 0.43 (m, 7.2 H, Z-is. +E-is.); <?oas [jy?>19F
NMR (376 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–65<?oas [mlbreak(on)] ?>.53 (q, 3JFH = 5JFF = 10.8 Hz, 0.6 F,
E-is.), <?oas [mlbreak(off)] ?>–65<?oas [mlbreak(on)] ?>.60 (t, 3JFH = 10.8 Hz, 3 F, Z-is.), <?oas [mlbreak(off)] ?>–
71<?oas [mlbreak(on)] ?>.96 to <?oas [mlbreak(off)] ?>–72<?oas [mlbreak(on)] ?>.11 (m, 0.2 F, E-is.), <?oas
[mlbreak(off)] ?>–72<?oas [mlbreak(on)] ?>.29 (t, 3JFH = 22.4 Hz, 1 F, Z-is.); 13C{H} NMR (125 MHz, CDCl3): δ =
172.30 (d, 1JCF = 252.6 Hz, Z-is.), 169.78 (d, 1JCF = 282.8 Hz, E-is.), 141.39, 138.13, 137.99, 133.89, 133.87, 129.40,
129.13, 128.83, 128.07, 127.83, 127.33, 127.23, 126.42 (qd, 1JCF = 277.8 Hz, 4JCF = 5.0 Hz, Z-is.), signal of CF3 for
E-is. lost in noise, 101.63 (d, 2JCF = 38.9 Hz, Z-is.), 98.55 (m, E-is.), 33.28 (qd, 2JCF = 30.2 Hz, 3JCF = 15.1 Hz, Z-is.),
32.60 (d, 2JCF = 30.2 Hz, E-is.), 31.38 (qd, 2JCF = 30.2 Hz, 3JCF = 15.1 Hz, E-is.), 29.39 (d, 2JCF = 31.4 Hz, Z-is.),
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
28.40 (s, E-is.), 28.20 (s, Z-is.), 22.38 (s, Z-is.), 22.30 (s, E-is.), 13.81 (s, Z-is.), 13.68 (s, E-is.), <?oas [mlbreak(off)]
?>–1<?oas [mlbreak(on)] ?>.61 (br s, E-is.), <?oas [mlbreak(off)] ?>–1<?oas [mlbreak(on)] ?>.94 (s, Z-is.), <?oas
[mlbreak(off)] ?>–1<?oas [mlbreak(on)] ?>.96 (s, Z-is.); 29Si{H} NMR (99 MHz, CDCl3): δ=-2.71 (d, 3JSiF
=
14.9 Hz, E-is.), <?oas [mlbreak(off)] ?>–3<?oas [mlbreak(on)] ?>.69 (d, 3JSiF = 13.9 Hz, Z-is.); elemental analysis
calcd. (%) for C16H22F4Si: C 60.35, H 6.96; found C 60.79, H 7.18.
Hydrodesilylation of silane 20a. A solution of 20a (0.7 g, 2 mmol) in 10 mL THF and 1 M solution of TBAF in
THF (0.25 mL, 2.5 mmol) was stirred at room temperature overnight, worked up with water, extracted with diethyl
ether, dried with MgSO4, and the solvent was distilled off. The residue was then chromatographed on SiO2 with
pentane to give the mixture of (E)-(1,4,4,4-tetrafluorobut-1-enyl)benzene (21) and (4,4,4-trifluorobut-1-
ynyl)benzene (22) in a ratio ca. 4:1 according to the NMR and GC mass spectrometry; yield 0.2 g; Rf = 0.45
(pentane). 1H NMR (400 MHz, CDCl3): δ = 7.30–7.55 (m, 6.5 H), 5.42 (dt, 3JHFcis = 19.2 Hz, 3JHH = 8.0 Hz, 1H),
3.27 (q, 3JHF = 9.6 Hz, 0.6 H), 2.94 (dq, 3JHF = 10.4 Hz, 3JHH = 8.0 Hz, 2H); 19F (376 MHz, CDCl3): δ = <?oas
[mlbreak(off)] ?>–67<?oas [mlbreak(on)] ?>.02 (t, 3JFH ≈ 10 Hz, 0.9 F), <?oas [mlbreak(off)] ?>–67<?oas
[mlbreak(on)] ?>.04 (t, 3JFH = 10.4 Hz, 3F), <?oas [mlbreak(off)] ?>–91<?oas [mlbreak(on)] ?>.73 (d, 3JFHcis
19.2 Hz, 1F); 13C{H} NMR (125 MHz, CDCl3): δ = 161.23 (d, 1JCF = 253.9 Hz). 131.83, 130.54 (d, 2JCF = 28.9 Hz),
130.01 (d, 4JCF = 1.3 Hz), 128.68, 128.61, 128.30, 128.00 (d, 3JCF = 5.0 Hz), 125.78 (qd, 1JCF = 276.5 Hz, 4JCF
2.5 Hz), 124.28 (q, 1JCF = 276.5 Hz), 122.20, 96.95 (dq, 2JCF = 32.7 Hz, 3JCF = 3.8 Hz), 84.35, 77.47 (q,3JCF
=
=
=
5.0 Hz), 31.80 (qd, 2JCF = 30.2 Hz, 3JCF = 8.8 Hz), 26.76 (q, 2JCF = 35.1 Hz); GC-MS (70 eV):21 (79.62^%) <?oas
[mlbreak(off)] ?>m/z<?oas [mlbreak(on)] ?> (%): 204 [M] (91), 135 [M – CF3] (100), 115 [M – CF3 – HF] (98); 22
(20.38^%) <?oas [mlbreak(off)] ?>m/z<?oas [mlbreak(on)] ?> (%): 184.0 [M] (88), 165.0 [M – F] (12), 115.0 [M –
CF3] (100). Spectral data for acetylene 22 correspond to the previously reported literature values.[25]
Fleming oxidation of silane 16. Boron trifluoride-acetic acid complex (3.8 g, 2.8 mL, 20 mmol) was added to a
solution of 16 (1.5 g, 5 mmol) in 15 mL CH2Cl2. The reaction mixture was stirred for 48 h at room temperature, then
quenched with aqueous NaHCO3 and extracted with CH2Cl2. The combine extracts were dried with MgSO4 and
evaporated to give the crude fluoro(1,1,1,4,4,4-hexafluorobut-2-yl)dimethylsilane (23) (1.3 g), which was analyzed
by 19F and 29Si{H} NMR. Although spectroscopic data showed the presence of starting silane 16 (ca. 25 molar^%),
the target fluorosilane 23 was further used without purification. 19F NMR (470 MHz, CDCl3): δ = 60.82 (m, 3F),
<?oas [mlbreak(off)] ?>–66<?oas [mlbreak(on)] ?>.85 (m, 3F), <?oas [mlbreak(off)] ?>–163<?oas [mlbreak(on)]
?>.76 (s, 1F); 29Si{H} NMR (99 MHz, CDCl3): δ = 27.94 (dq, 1JSiF = 285 Hz, 3JSiF = 5.0 Hz, 1Si); <?oas [jy?>a
signal for silane 16 δ = 0.55 (q, 3JSiF = 5.0 Hz, 0.4Si).
The crude intermediate 23 was dissolved in diethyl ether (10 mL), and to the resulting solution m-CPBA (3.5 g,
20 mmol) following by NEt3 (0.85 mL, 6 mmol) was added at room temperature. The reaction mixture was stirred
overnight, quenched with aqueous Na2S2O3, extracted with diethyl ether, dried with MgSO4 and the solvent was
distilled off at atmospheric pressure. The obtained residue was dissolved in MeOH (15 mL) with few drops of conc.
HCl and this mixture was stirred for 30 minutes. The solvent was distilled off at atmospheric pressure, the residue
was extracted with pentane, the combined extracts were washed with aqueous NaHCO3, dried with MgSO4 and
fractionated with a short column at atmospheric pressure to give the close-cut fraction (b.p. 89–90 °C) as 1,1,1,4,4,4-
hexafluorobutan-2-ol (24) (0.20 g, 23^% for two steps). 1H NMR (400 MHz, CDCl3): δ = 4.25–4.37 (m, 1H), 3.46
(br s, 1H), 2.42–2.54 (m, 2H); 19F NMR (470 MHz, CDCl3): δ = <?oas [mlbreak(off)] ?>–64<?oas [mlbreak(on)]
?>.04 (t, 3JFH = 9.4 Hz, 3F), <?oas [mlbreak(off)] ?>–80<?oas [mlbreak(on)] ?>.68 (d, 3JFH = 4.78 Hz, 3F). Spectral
data correspond to the previously reported literature values.[26]<?oas [lx?>
Figure 1. 29Si{H} NMR spectrum of the siloxanes 18 and 19 mixture, obtained via route b.
Scheme 1. The hydrosilylation of butene 3 by oligomeric hydrosiloxane under catalysis with H2PtCl6.
<?oas [mv-4]?>Scheme 2. Possible reaction pathway for the formation of butene 14.
Scheme 3. Synthesis of hydrolytically stable silanes via Grignard reaction.
Scheme 4. Hydrolysis of chlorosilane 13a.
Scheme 5. Routes to the syntheses of cyclic siloxanes 18 and 19.
Scheme 6. The desilylative defluorination of silanes 13d, 15 and 16 under activation with catalytic amounts of
fluoride-ion.
Scheme 7. Lithiation of silane 16 by PhLi and BuLi.
Scheme 8. Desilylation of isomeric mixture 20a with TBAF.
Scheme 9. The oxidative desilylation of silane 16 via Fleming two-step procedure.
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10.1002/ejoc.202000853
European Journal of Organic Chemistry
Table 1. The hydrosilylation of 1 under catalysis with platinum, rhodium and palladium complexes.
<forr2>
<tnote>[a] Pt catalyst as hexahydrate 200 ppm; Rh catalyst 400 ppm; Pd catalyst 500 ppm.</tnote> <tnote>[b]
Experiments were performed in a glass ampoule with Teflon stop-cock in solvent-free conditions with an equimolar
mixture of reagents unless otherwise indicated.</tnote> <tnote>[c] Conversion of 1 was estimated by 19F NMR
spectroscopy using C6H5CF3 as an internal standard.</tnote> <tnote>[d] Yields given are determined by 19F NMR
spectroscopy using C6H5CF3 as an internal standard. Values in parentheses indicate yields for the isolated products in
weight^%.</tnote> <tnote>[e] 400 ppm of catalyst were used.</tnote> <tnote>[f] 2-Fold excess of 1 was
used.</tnote> <tnote>[g] 1.5 Equivalents of hydrosilane were used.</tnote> <tnote>[h] Silane 5b was obtained in a
mixture with the adducts CF3CH2CH2SiCl3 (ca. 23 mol-%) and CF3CH(CH3)SiCl3 (ca. 2 mol-%).</tnote>
Table 2. The hydrosilylation of 2 under catalysis with platinum, rhodium and palladium complexes.
<forr3>
<tnote>[a] Pt catalyst 200 ppp; Rh catalyst 400 ppm; Pd catalyst 500 ppm.</tnote> <tnote>[b] All experiments were
performed in a glass ampoule with Teflon stop-cock in solvent-free conditions with an equimolar mixture of
reagents.</tnote> <tnote>[c] Conversion of 2 was estimated by 19F NMR spectroscopy using C6H5CF3 as an internal
standard.</tnote> <tnote>[d] Yields given are determined by 19F NMR spectroscopy using C6H5CF3 as an internal
standard.</tnote>
<mc2>Table 3. The hydrosilylation of isomeric hexafluorobutenes 3 (Z-isomer) and 4 (E-isomer) under catalysis
with platinum, rhodium and palladium complexes.[a]
<forr4>
<tnote>[a] All experiments were performed in a glass ampoule with Teflon stop-cock in the solvent-free conditions
with an equimolar mixture of reagents at 120 °C for 24 hours.</tnote> <tnote>[b] Pt catalyst as hexahydrate
200 ppm; Rh catalyst 400 ppm; Pd catalyst 500 ppm.</tnote> <tnote>[c] Conversion was estimated by 19F NMR
spectroscopy using C6H5CF3 as an internal standard.</tnote> <tnote>[d] Yields given are for the isolated products.
Values in parentheses indicate yields determined by 19F NMR spectroscopy with C6H5CF3 as an internal
standard.</tnote> <tnote>[e] E-isomer was not investigated.</tnote>
Table 4. Optimization of butene 3 hydrosilylation.
<forr5>
<tnote>[a] Pt catalyst as hexahydrate 200 ppm; Rh catalyst 400 ppm; Pd catalyst 500 ppm.</tnote> <tnote>[b] All
experiments were performed in a glass ampoule with Teflon stop-cock in the solvent-free conditions at 125 °C for
48 h.</tnote> <tnote>[c] Conversion was estimated by 19F NMR spectroscopy using C6H5CF3 as an internal
standard.</tnote> <tnote>[d] Yields given are for the isolated products. Values in parentheses indicate yields
determined by 19F NMR spectroscopy with C6H5CF3 as an internal standard.</tnote>
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European Journal of Organic Chemistry
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