54927-71-8Relevant academic research and scientific papers
Efficient and practical protocol for silylation of hydroxyl groups using reusable lithium perchlorate dispread in silica gel under neutral condition
Azizi, Najmedin,Yousefi, Rozbeh,Saidi, Mohammad R.
, p. 817 - 820 (2006)
A very efficient and mild procedure for the trimethylsilylation of a wide variety of alcohols, including primary, allylic, benzylic, secondary, hindered secondary, tertiary, and phenols with hexamethyldisilazane on the surface of silica gel dispersed with LiClO4 in room temperature at few minutes in excellent yields under neutral conditions is reported. This procedure also allows the excellent selectivity under LP-SiO2 system for silylation of alcohols in the presence of amine and phenolic hydroxy groups.
Phosphine-catalyzed reductions of alkyl silyl peroxides by titanium hydride reducing agents: Development of the method and mechanistic investigations
Harris, Jason R.,Haynes, M. Taylor,Thomas, Andrew M.,Woerpel
experimental part, p. 5083 - 5091 (2010/10/19)
(Figure presented) A method that allows for the reduction of protected hydroperoxides by employing catalytic amounts of phosphine is presented. The combination of a titanium(IV) alkoxide and a siloxane allowed for the chemoselective reduction of phosphine oxides in the presence of alkyl silyl peroxides. Subsequent reduction of the peroxide moiety by phosphine provided the corresponding silylated alcohols in useful yields. Mechanistic experiments, including crossover experiments, support a mechanism in which the peroxide group was reduced and the silyl group was transferred in a concerted step. Labeling studies with 17O-labeled peroxides demonstrate that the oxygen atom adjacent to the silicon atom is removed from the silyl peroxide.
An expeditious, efficient green methodology for the Boc protection of amines and silyl protection of alcohols over tungstophosphoric acid-doped mesoporous silica
Karmakar, Bikash,Banerji, Julie
experimental part, p. 3855 - 3858 (2010/08/20)
An efficient, chemoselective and eco-friendly protocol for the protection of amines as N-tert-butylcarbamate using (Boc)2O and protection of alcohols as silyl ether using HMDS over tungstophosphoric acid/SBA15 has been developed. Solventless condition, easy work-up, short reaction time, excellent yields and reusability of the catalyst are the striking features of this methodology which can be considered to be one of the better methods for the protection of amines and alcohols.
Unsuccessful attempts to add alcohols to transient 2-amino-2-siloxy- silenes-leading to a new benign route for base-free alcohol protection
Guliashvili, Tamaz,Tibbelin, Julius,Ryu, Jiyeon,Ottosson, Henrik
supporting information; experimental part, p. 9379 - 9385 (2011/01/07)
Thermolytic formation of transient 1,1-bis(trimethylsilyl)-2-dimethylamino- 2-trimethylsiloxysilene (2) from N,N-dimethyl(tris(trimethylsilyl)silyl) methaneamide (1) in presence of a series of alcohols was investigated. The products are, however, not the expected alcohol-silene addition adducts but silylethers formed in nearly quantitative yields. Thermolysis of 1 in the presence of both alcohols (MeOH or iPrOH) and 1,3-dienes (1,3-butadiene or 2,3-dimethyl-1,3-butadiene) gives alkyl-tris(trimethylsilyl)silylethers and the [4+2] cycloadducts between the silene and diene, which confirms the presence of 2 and that it is unreactive towards alcohols. The observed silylethers are substitution adducts where the amide group of the silylamide is replaced by an alkoxy group, and the reaction time is reflected in the steric bulk of the alcohol. Indeed, the formation of silylethers from the reaction of alcohols with silylamide represents a new base-free method for protection of alcohols. The protection reactions using 1 progresses at elevated temperatures, or alternatively, under acid catalysis at ambient temperature, and similar protections can be carried out with N-cyclohexyl(triphenylsilyl)methaneamide and N,N-dimethyl(trimethylsilyl)methaneamide. The latter silylamide can be used under neutral conditions at room temperature. The only by-products are formamides (N,N-dimethylformamide (DMF) or N-cyclohexylformamide), and the reactions can be performed without solvent. In addition to alcohols we also examined the method for protection of diols, thiols and carboxylic acids, and also these reactions proceeded in high yields and with good selectivities. The Royal Society of Chemistry.
Lanthanum trichloride: An efficient catalyst for the silylation of hydroxyl groups by activating hexamethyldisilazane (HMDS)
Narsaiah, Akkirala Venkat
, p. 3614 - 3618 (2008/02/08)
A variety of hydroxy functional groups was protected as their corresponding trimethylsilyl ethers using HMDS in the presence of lanthanum trichloride. The catalyst LaCl3 activates the HMDS and accelerates the reaction under mild reaction conditions at room temperature to afford the corresponding silylated products in excellent yields.
InCl3-catalyzed cross-coupling of alkyl trimethylsilyl ethers and allylsilanes via an in situ derived combined lewis acid of InCl3 and Me3SiI
Saito, Takahiro,Nishimoto, Yoshihiro,Yasuda, Makoto,Baba, Akio
, p. 8588 - 8590 (2008/02/12)
(Chemical Equation Presented) Direct Csp3-Csp3 coupling of various aliphatic trimethylsilyl ethers and allylsilanes is effectively catalyzed by InCl3 and I2. The transformation is thought to involve an in situ-derived combined Lewis acid of InCl3 and Me3SiI. The reaction can be used for the construction of quaternary-quaternary and quaternary-tertiary carbon-carbon bonds. This system enabled a highly chemoselective coupling to be conducted with a trimethylsilyl ether including an aryl halide moiety. Furthermore, couplings were possible using an alkynyltri-methylsilane and a trimethylsilyl ketene acetal.
Indium tribromide: An efficient catalyst for the silylation of hydroxy groups by the activation of hexamethyldisilazane
Yadav,Reddy,Basak,Baishya,Venkat Narsaiah
, p. 3831 - 3834 (2008/02/10)
A variety of substrates containing hydroxy groups have been protected as their corresponding trimethylsilyl ethers using 1,1,1,3,3,3-hexamethyldisilazane in the presence of indium tribromide. The catalyst indium tribromide activates the 1,1,1,3,3,3-hexamethyldisilazane and accelerates the reaction under mild reaction conditions at room temperature. Georg Thieme Verlag Stuttgart.
Facile O-silylation of tertiary alcohols in the presence of Mg-metal
Nishiguchi, Ikuzo,Kita, Yoshio,Watanabe, Masamitsu,Ishino, Yoshio,Ohno, Toshinobu,Maekawa, Hirofumi
, p. 1025 - 1027 (2007/10/03)
Treatment of aliphatic alcohols with trimethylsilyl chloride (TMSCl) in N,N-dimethylformamide (DMF) containing Mg-turning at room temperature brought about facile and efficient O-silylation to give the corresponding trimethylsilyl ethers in good to excellent yields. This method can be also available for sterically hindered tert-alcohols and alcohols having a variety of substituents which may be labile under the basic conditions used in the conventional O-silylation.
