RSC Advances
Paper
the basis of the GC/MS and 1H NMR spectra of the reaction added in the amount of 2.2 ꢀ 10ꢁ6 mol. The reaction mixture
mixture.
was stirred and heated in an oil bath at 35 ꢂC until full
See Table 3, entry 1–19: A 5 mL glass reactor was charged conversion of Si–H was detected (GC analysis). Then the second
with toluene (3 mL), disubstituted silane (0.23 mmol, 1 equiv.), type of terminal alkyne (1.1 mmol) was added and the catalytic
ꢂ
terminal alkyne (0.46 mmol, 2 equiv.) and internal standard system was le for night at 60 C. Then the solvent was evapo-
(decane or dodecane, 20 mL). Then 4.6 ꢀ 10ꢁ7 mol platinum rated under vacuum and the resulting product was puried by
catalyst I was added. The reaction mixture was stirred and column chromatography (silica gel 60, n-hexane or n-hexane/
heated in an oil bath at 35 ꢂC until full conversion of Si–H was DCM ¼ 10/1). Evaporation of the solvent gave an analytically
detected. Conversion of the substrates was monitored by gas pure sample.
chromatography. Reaction yields and selectivities were calcu-
lated on the basis of the GC/MS and 1H NMR spectra of the
reaction mixture.
Conclusions
See Table 4, entry 1–9: A 5 mL glass reactor was charged with We found that a platinum(0) complex I bearing bulky N-
toluene (3 mL), silane (0.19 mmol, 1 equiv.), terminal alkyne heterocyclic carbene ligand effects hydrosilylation of alkynes
(0.19 mmol, 1 equiv.) and internal standard (decane or dodecane, with secondary silanes to produce b-E-alkenylsilanes with high
20 mL). Then 3.8 ꢀ 10ꢁ7 mol platinum catalyst I was added. The yield and excellent stereoselectivity. A broad range of terminal
ꢂ
reaction mixture was stirred and heated in an oil bath at 35 C acetylenes and secondary silanes undergo this reaction to afford
until full conversion of Si–H was detected (GC analysis). Then the
a lot of symmetrical and unsymmetrical organosilicon
second type of terminal alkyne (0.19 mmol, 1 equiv.) was added compounds which can be used as liquid crystals,12 solid poly-
and the catalytic system was le for the night at 60 C. Conver- meric electrolytes,13 coupling agents14 or monomers for UV
ꢂ
sion of the substrates was monitored by gas chromatography. induced polymerization.15 We established the conditions for
Reaction yields and selectivities were calculated on the basis of fully selective synthesis of mono- as well as dialkenylsubstituted
the GC/MS and 1H NMR spectra of the reaction mixture.
b-E-adducts. Additionally, sequential hydrosilylation of two
different terminal alkynes with disubstituted silane was also
achieved in the presence of the same catalyst. This one-pot
method is atom economical and allows construction of valu-
able organosilicon compounds from relatively simple and
General procedures for the synthesis of hydrosilylation
products
Products 3–20 (Table 2): A 25 mL glass reactor equipped with readily available starting materials.
a reux condenser and connected to gas and vacuum line was
charged under argon with toluene (10 mL), disubstituted silane
Conflicts of interest
(1.1 mmol) and terminal alkyne (1 mmol). The mixture was
heated to 35 ꢂC in an oil bath and platinum catalyst I was added There are no conicts to declare.
in the amount of 10ꢁ6 mol or 5 ꢀ 10ꢁ6 mol for reaction with 1-
ethynylnaphthalene and 9-ethynylphenanthrene. The reaction
Acknowledgements
mixture was stirred and heated in an oil bath at 35 ꢂC until full
conversion of Si–H was detected (GC analysis). Then the solvent The authors gratefully acknowledge the nancial support from
was evaporated under vacuum and the resulting product was the National Science Centre (Poland) (SONATA Project No.
puried by column chromatography (silica gel 60, n-hexane or UMO-2016/23/D/ST5/00417).
n-hexane/DCM ¼ 10/1). Evaporation of the solvent gave an
analytically pure sample.
Notes and references
Products 21–39 (Table 3): A 25 mL glass reactor equipped
with a reux condenser and connected to gas and vacuum line
was charged under argon with toluene (10 mL), disubstituted
silane (1.1 mmol)ꢂand terminal alkyne (2.2 mmol). The mixture
was heated to 35 C in an oil bath and platinum catalyst I was
added in the amount of 2.2 ꢀ 10ꢁ6 mol. The reaction mixture
was stirred and heated in an oil bath at 35 ꢂC until full
conversion of Si–H was detected (GC analysis). Then the solvent
was evaporated under vacuum and the resulting product was
puried by column chromatography (silica gel 60, n-hexane or
n-hexane/DCM ¼ 10/1). Evaporation of the solvent gave an
analytically pure sample.
1 (a) B. Marciniec, J. Gulinski, W. Urbaniak and
Z. W. Kornetka, Comprehensive Handbook on
Hydrosilylation, ed. B. Marciniec, Pergamon Press, Oxford,
1992; (b) B. M. Trost and Z. T. Ball, Synthesis, 2005, 115,
853–887; (c) B. Marciniec, H. Maciejewski, C. Pietraszuk
´
and P. Pawluc, Hydrosilylation: A Comprehensive Review on
Recent Advances, ed. B. Marciniec, Springer, 2009; (d)
D. Troegel and J. Stohrer, Coord. Chem. Rev., 2011, 255,
1440–1459; (e) D. Lim and E. Anderson, Synthesis, 2012, 7,
983–1010; (f) Y. Nakajima and S. Shimada, RSC Adv., 2015,
5, 20603–20616; (g) C. Cheng and J. F. Hartwig, Chem. Rev.,
2015, 115, 8946–8975; (h) M. Zaranek, B. Marciniec and
Products 40–48 (Table 4): A 25 mL glass reactor equipped
with a reux condenser and connected to gas and vacuum line
was charged under argon with toluene (10 mL), disubstituted
silane (1.1 mmol) and terminal alkyne (1.1 mmol). The mixture
´
P. Pawluc, Org. Chem. Front., 2016, 3, 1337–1344; (i) J. Sun
and L. Deng, ACS Catal., 2016, 6, 290–300.
2 (a) A. Hosomi, M. Endo and H. Sakurai, Chem. Lett., 1975, 5,
941–942; (b) W. P. Weber, Silicon Reagents for Organic
ꢂ
was heated to 35 C in an oil bath and platinum catalyst I was
40020 | RSC Adv., 2018, 8, 40016–40021
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