Synthesis of arylsilanes
A zinc-catalyzed nucleophilic substitution reaction of chlorosilanes with organomagnesium reagents affords a broad range of functionalized tetraorganosilanes under mild reaction conditions. The reaction can be performed on large scale.
K. Murakami, H. Yorimitsu, K. Oshima, J. Org. Chem., 2009, 74, 1415-1417.
Various siletanes have been used as substrates for the oxidation of carbon-silicon bonds upon exposure to aqueous fluoride and peroxide. These tetraalkylsilanes offer a combination of stability and reactivity with many practical benefits, including compatibility with silicon protecting groups and electron-rich aromatic rings.
J. D. Sunderhaus, H. Lam, G. B. Dudley, Org. Lett., 2003, 8, 4571-4573.
Rapid, efficient methods enable the preparation of phenols from the oxidation of arylhydrosilanes. Electron-rich aromatics benefit from silane activation via oxidation to the methoxysilane using homogeneous or heterogeneous transition metal catalysis. A combination of these two oxidations into a streamlined flow procedure involves minimal processing of reaction intermediates.
E. J. Rayment, N. Summerhill, E. A. Anderson, J. Org. Chem., 2012, 77, 7052-7060.
A new palladium-catalyzed silylation of aryl chlorides affords desired product in good yield, is tolerant of various functional groups, and provides access to a wide variety of aryltrimethylsilanes from commercially available aryl chlorides. Additionally, a one-pot procedure that converts aryl chlorides into aryl iodides has been developed.
E. McNeill, T. E. Barder, S. L. Buchwald, Org. Lett., 2007, 9, 3785-3788.
A Ni/Cu-catalyzed silylation of unactivated C-O electrophiles derived from phenols or benzyl alcohols offers a wide scope and mild conditions and provides a direct access to synthetically versatile silylated compounds.
C. Zarate, R. Martin, J. Am. Chem. Soc., 2014, 136, 2236-2239.
An iron-catalyzed method for the silylation of (hetero)aromatic chlorides features high efficiency, a broad substrate scope, and excellent functional group compatibility. Moreover, this protocol enables the late-stage silylation of some pharmaceuticals.
J. Jia, X. Zeng, Z. Liu, L. Zhao, C.-Y. He, X.-F. Li, Z. Feng, Org. Lett., 2020, 22, 2816-2821.
A base-mediated borylsilylation of benzylic ammonium salts provides geminal silylboronates bearing benzylic proton under mild reaction conditions. Deaminative silylation of aryl ammonium salts was also achieved in the presence of LiOtBu. Both methods offer high efficiency, mild reaction conditions, and good functional group tolerance for late-stage functionalization of amines.
W.-Y. Qi, J.-S. Zhen, X.-h. Xu, X. Du, Y.-h. Li, H. Yuan, Y.-S. Guan, X. Wei, Z.-Y. Wang, G. Liang, Y. Luo, Org. Lett., 2021, 23, 5988-5992.
An efficient palladium-catalyzed silylation of activated aryl and alkenyl ketones offers high efficiency and broad substrate scope. Further applications in the late-stage diversification of biologically important molecules demonstrate the synthetic utility of this method.
X. Wang, Z.-Y. Wang, X. Zhang, H. Xu, H.-X. Dai, Org. Lett., 2022, 24, 7344-7349.
An unprecedented nickel-catalyzed decarbonylative silylation of silyl ketones provides structurally diverse arylsilanes under mild reaction conditions.
W. Srimontree, W. Lakornwong, M. Rueping, Org. Lett., 2019, 21, 9330-9333.
By treatment with s-BuLi/TMEDA at -78°C, unprotected 2-methoxybenzoic acid is deprotonated exclusively in the position ortho to the carboxylate. A reversal of regioselectivity is observed when the acid is treated with n-BuLi/t-BuOK.
T.-H. Nguyen, A.-S. Castanet, J. Mortier, Org. Lett., 2006, 8, 765-768.
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.