Categories: C-Si Bond Formation > Siloxanes
Synthesis of arylsiloxanes
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General reaction conditions for the synthesis of
aryl(trialkoxy)silanes from aryl Grignard and lithium reagents and tetraalkyl
orthosilicates (Si(OR)4) have been developed. Ortho-, meta-,
and
para-substituted bromoarenes underwent efficient metalation and
silylation at low temperature to provide aryl siloxanes.
A. S. Manoso, C. Ahn, A. Soheili, C. J. Handy, R. Correia, W. Seganish, P.
DeShong, J. Org. Chem.,
2004,
69, 8305-8314.
General reaction conditions for the synthesis of
aryl(trialkoxy)silanes from aryl Grignard and lithium reagents and tetraalkyl
orthosilicates (Si(OR)4) have been developed. Ortho-, meta-,
and
para-substituted bromoarenes underwent efficient metalation and
silylation at low temperature to provide aryl siloxanes.
A. S. Manoso, C. Ahn, A. Soheili, C. J. Handy, R. Correia, W. Seganish, P.
DeShong, J. Org. Chem.,
2004,
69, 8305-8314.
High yields were achieved by using [Rh(cod)(MeCN)2]BF4
as catalyst in a specific silylation of aryl iodides and bromides with
triethoxysilane in the presence of NEt3. This new reaction
tolerates different functional groups and therefore often eliminates the
need to use protective groups (compared to previous methods via Grignard
reagents).
M. Murata, M. Ishikura, M. Nagata, S. Watanabe, Y. Masuda, Org. Lett., 2002, 4, 1843-1845.
The silylation of various aryl iodides with 1,1,1,3,5,5,5-heptamethyltrisiloxane
was achieved using transition-metal catalysts, such as Pd(0), Pt(0), and Rh(I),
which offer a dramatically different substrate scope.
M. Murata, K. Ota, H. Yamasaki, S. Watanabe, Y. Masuda, Synlett, 2007,
1387-1390.
The use of palladium(0) dibenzylideneacetone activated with 2-(di-tert-butylphosphino)biphenyl
(Buchwald's ligand) enables the silylation of electron-rich para- and
meta-substituted aryl halides to form the corresponding aryltriethoxysilane in
good yield. However, ortho-substituted aryl halides failed to be
silylated.
A. S. Manoso, P. DeShong, J. Org. Chem., 2001,
66, 7449-7455.
An efficient rhodium-catalyzed method allows the preparation of
aryltriethoxysilanes from arenediazonium tosylate salts. A new method for
hydrodediazoniation has also been explored.
Z. Y. Tang, Y. Zhang, T. Wang, W. Wang, Synlett, 2010,
804-808.
Treatment of substituted arylbromides with tert-butyllithium in diethyl
ether at -78˚C, followed by the addition to dichlorodiethoxysilane, leads to the
quantitative formation of diaryldiethoxysilanes. Diaryldiethoxysilanes can be
reduced to the corresponding diarylsilanes by stirring with lithium aluminum
hydride in diethyl ether. This method avoids the handling of gaseous and
explosive dichlorosilane.
P. Gigier, W. A. Herrmann, F. E. Kühn, Synthesis, 2010,
1431-1432.