5888-66-4Relevant articles and documents
Phosphines as Silylium Ion Carriers for Controlled C-O Deoxygenation: Catalyst Speciation and Turnover Mechanisms
Gudz, Anton,Payne, Philippa R.,Gagné, Michel R.
, p. 4047 - 4053 (2017)
We report studies delineating the speciation, kinetics, and deoxygenation catalysis of phosphine-modified mixtures of B(C6F5)3 (BCF) and R3SiH. Combinations of BCF, a tertiary silane, and PAr3 generat
Light-Promoted Transfer of an Iridium Hydride in Alkyl Ether Cleavage
Fast, Caleb D.,Schley, Nathan D.
supporting information, p. 3291 - 3297 (2021/10/12)
A catalytic, light-promoted hydrosilylative cleavage reaction of alkyl ethers is reported. Initial studies are consistent with a mechanism involving heterolytic silane activation followed by delivery of a photohydride equivalent to a silyloxonium ion generated in situ. The catalyst resting state is a mixture of Cp*Ir(ppy)H (ppy = 2-phenylpyridine-κC,N) and a related hydride-bridged dimer. Trends in selectivity in substrate reduction are consistent with nonradical mechanisms for C-O bond scission. Irradiation of Cp*Ir(ppy)H with blue light is found to increase the rate of hydride delivery to an oxonium ion in a stoichiometric test. A comparable rate enhancement is found in carbonyl hydrosilylation catalysis, which operates through a related mechanism also involving Cp*Ir(ppy)H as the resting state.
Metal-Free Catalytic Reductive Cleavage of Enol Ethers
Chulsky, Karina,Dobrovetsky, Roman
supporting information, p. 6804 - 6807 (2018/11/02)
In contrast to the well-known reductive cleavage of the alkyl-O bond, the cleavage of the alkenyl-O bond is much more challenging especially using metal-free approaches. Unexpectedly, alkenyl-O bonds were reductively cleaved when enol ethers were reacted with Et3SiH and a catalytic amount of B(C6F5)3. Supposedly, this reaction is the result of a B(C6F5)3-catalyzed tandem hydrosilylation reaction and a silicon-assisted β-elimination. A mechanism for this cleavage reaction is proposed based on experiments and density functional theory (DFT) calculations.
Electrophilic phosphonium cations (EPCs) with perchlorinated-aryl substituents: Towards air-stable phosphorus-based Lewis acid catalysts
Postle, Shawn,Podgorny, Vitali,Stephan, Douglas W.
, p. 14651 - 14657 (2016/10/03)
A series of phosphines incorporating (C6Cl5) substituents, Ph2P(C6Cl5) 1, PhP(C6Cl5)22, P(C6Cl5)33 and (C6F5)P(C6Cl5)24 were prepared. In the case of 1, 2 and 4, these were converted to the corresponding aryl-difluorophosphoranes 5-7via reaction with XeF2, whereas reaction of 3 with XeF2 afforded only an inseparable mixture of products. The compounds 5-7 were converted to the fluorophosphonium cations 8-10, whereas the reaction of 3 with Selectfluor afforded (C6Cl5)2POF and (C6Cl5)2. The fluorophosphonium salts showed evidence of improved air stability as well as Lewis acid catalytic activity in hydrodefluorination, hydrosilylation, deoxygenation and dehydrocoupling chemistry.
Pyridinium-phosphonium dications: Highly electrophilic phosphorus-based Lewis acid catalysts
Bayne, Julia M.,Holthausen, Michael H.,Stephan, Douglas W.
, p. 5949 - 5957 (2016/04/26)
Using commercially available 2-pyridyldiphenylphosphine (o-NC5H4)PPh2, a family of electrophilic phosphonium cations [(o-NC5H4)PFPh2]+ (2) and dications [(o-MeNC5H4)PRPh2]2+ (R = F (4); Me (5)) were prepared. The Lewis acidity of these pyridinium-phosphonium dications was probed in Friedel-Crafts dimerization, hydrodefluorination, hydrosilylation, dehydrocoupling and hydrodeoxygenation reactions. The influence of the counterion on the catalytic activity of the electrophilic phosphonium cations is also discussed.
Room temperature organocatalyzed reductive depolymerization of waste polyethers, polyesters, and polycarbonates
Feghali, Elias,Cantat, Thibault
, p. 980 - 984 (2015/03/30)
The reductive depolymerization of a variety of polymeric materials based on polyethers, polyesters, and polycarbonates is described using hydrosilanes as reductants and metal-free catalysts. This strategy enables the selective depolymerization of waste polymers as well as bio-based polyesters to functional chemicals such as alcohols and phenols at room temperature. Commercially available B(C6F5)3 and [Ph3C+,B(C6F5)4-] catalysts are active hydrosilylation catalysts in this procedure and they are compatible with the use of inexpensive and air-stable polymethylhydrosiloxane and tetramethyldisiloxane as reductants. A significant advantage of this recycling method is derived from its tolerance to the additives present in waste plastics and its ability to selectively depolymerize mixtures of polymers. Silanes pitted against waste: The reductive depolymerization of a variety of polymeric materials based on polyethers, polyesters, and polycarbonates is described, using hydrosilanes as reductants and metal-free catalysts. This strategy enables the selective depolymerization of waste polymers as well as bio-based polyesters to functional chemicals such as alcohols and phenols at room temperature.
Preparation of nano silica supported sodium hydrogen sulfate: As an efficient catalyst for the trimethyl, triethyl and t-butyldimethyl silylations of aliphatic and aromatic alcohols in solution and under solvent-free conditions
Abri, Abdolreza,Ranjdar, Somayeh
, p. 929 - 934 (2014/10/16)
Nano silica supported sodium hydrogen sulfate has been prepared by mixing NaHSO4 with activated Nano silicagel. We wish to report a new method for the synthesis of trimethyl (TMS), triethyl (TES) and t-butyldimethyl silyl (TBS) ethers from benzylic, allylic, propargylic alcohols, phenols, naphtholes and some of phenolic drugs in the solution and under solvent-free conditions.
The synergistic effect of nanoporous AuPd alloy catalysts on highly chemoselective 1,4-hydrosilylation of conjugated cyclic enones
Chen, Qiang,Tanaka, Shinya,Fujita, Takeshi,Chen, Luyang,Minato, Taketoshi,Ishikawa, Yoshifumi,Chen, Mingwei,Asao, Naoki,Yamamoto, Yoshinori,Jin, Tienan
, p. 3344 - 3346 (2014/03/21)
The nanoporous AuPd (AuPdNPore) alloy catalyst showed superior chemoselectivity and high catalytic activity for the direct 1,4-hydrosilylation of the conjugated cyclic enones with hydrosilane in comparison with the monometallic nanoporous Au and Pd catalysts. The enhanced catalytic properties of AuPdNPore arise mainly from the nanoporous structure and the synergistic effect of the AuPd alloy. The Royal Society of Chemistry 2014.
Unprecedented organocatalytic reduction of lignin model compounds to phenols and primary alcohols using hydrosilanes
Feghali, Elias,Cantat, Thibault
supporting information, p. 862 - 865 (2014/01/06)
The first metal-free reduction of lignin model compounds is described. Using inexpensive Et3SiH, PMHS and TMDS hydrosilanes as reductants, α-O-4 and β-O-4 linkages are reduced to primary alcohols and phenols under mild conditions using B(C6F5)3 as an efficient catalyst. The Royal Society of Chemistry.
A mild and highly efficient method for the preparation of silyl ethers using Fe(HSO4)3/Et3N by chlorosilanes
Abri, Abdolreza,Assadi, Mohammad Galeh,Pourreza, Samira
, p. 1449 - 1454 (2013/03/13)
Avery efficient and mild procedure for preparation of silyl ethers from benzylic, allylic, propargilic alcohols, phenols, naphtoles and some of phenolic drugs with trimethylsilylchloride (TMSCl), triethylsilylchloride (TESCl) and t-buthyldimethylsilyl chloride (TDSCl) ethers in the presence of Fe(HSO 4)3/Et3N in roomtemperature in excellent yields is reported. This procedure also allows the excellent selectivity for silylation of alcohols and phenols.
