|
Silylation
Silylation is the introduction of one or more (usually) substituted silyl groups (R3Si) to a molecule. The process is the basis of organosilicon chemistry. Of organic compounds Alcohols, carboxylic acids, amines, thiols, and phosphates can be silylated. The process involves the replacement of a proton with a trialkylsilyl group, typically trimethylsilyl (-SiMe3). Generally the substrate is deprotonated with a suitable strong base followed by treatment with a silyl chloride (e.g. trimethylsilyl chloride). Often strong bases such butyl lithium or a Grignard reagent are used, as illustrated by the synthesis of a trimethylsilyl ethers as protecting groups from an alcohol: :ROH + BuLi → ROLi + BuH :ROLi + Me3SiCl → ROSiMe3 + LiCl Bis(trimethylsilyl)acetamide ("BSA", Me3SiNC(OSiMe3)Me is an efficient silylation agent used for the derivatisation of compounds. The reaction of BSA with alcohols gives the corresponding trimethylsilyl ether, together with N-(trimethylsilyl)acetamide as a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrosilylation
Hydrosilylation, also called catalytic hydrosilation, describes the addition of Si-H bonds across unsaturated bonds."Hydrosilylation A Comprehensive Review on Recent Advances" B. Marciniec (ed.), Advances in Silicon Science, Springer Science, 2009. Ordinarily the reaction is conducted catalytically and usually the substrates are unsaturated organic compounds. Alkenes and alkynes give alkyl and vinyl silanes; aldehydes and ketones give silyl ethers. Hydrosilylation has been called the "most important application of platinum in homogeneous catalysis." Scope and mechanism Hydrosilylation of alkenes represents a commercially important method for preparing organosilicon compounds. The process is mechanistically similar to the hydrogenation of alkenes. In fact, similar catalysts are sometimes employed for the two catalytic processes. The prevalent mechanism, called the Chalk-Harrod mechanism, assumes an intermediate metal complex that contains a hydride, a silyl ligand (R3Si), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrosilation
Hydrosilylation, also called catalytic hydrosilation, describes the addition of Si-H bonds across unsaturated bonds."Hydrosilylation A Comprehensive Review on Recent Advances" B. Marciniec (ed.), Advances in Silicon Science, Springer Science, 2009. Ordinarily the reaction is conducted catalytically and usually the substrates are unsaturated organic compounds. Alkenes and alkynes give alkyl and vinyl silanes; aldehydes and ketones give silyl ethers. Hydrosilylation has been called the "most important application of platinum in homogeneous catalysis." Scope and mechanism Hydrosilylation of alkenes represents a commercially important method for preparing organosilicon compounds. The process is mechanistically similar to the hydrogenation of alkenes. In fact, similar catalysts are sometimes employed for the two catalytic processes. The prevalent mechanism, called the Chalk-Harrod mechanism, assumes an intermediate metal complex that contains a hydride, a silyl ligand (R3Si), and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organosilicon Chemistry
Organosilicon compounds are organometallic compounds containing carbon–silicon chemical bond, bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an ''inorganic chemistry, inorganic'' compound. History In 1846 Von Ebelman's had synthesized Tetraethyl orthosilicate (Si(OC2H5)4). In 1863 Friedel and Crafts managed to make the first organosilieon compound with C-Si bonds which gone byound the syntheses of orthosilicic acid esters. The same year they also described a «polysilicic acid ether» in the preparation of Ethanol, ethyl- and methyl-o-silicic acid. The early extensive research in the field of organosilicon compounds was pioneerd in the beginning of 20th century by Frederic Kipping. He also had coined the term «silicone» (akin to ketones) in relation to these materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organosilicon Compound
Organosilicon compounds are organometallic compounds containing carbon–silicon chemical bond, bonds. Organosilicon chemistry is the corresponding science of their preparation and properties. Most organosilicon compounds are similar to the ordinary organic compounds, being colourless, flammable, hydrophobic, and stable to air. Silicon carbide is an ''inorganic chemistry, inorganic'' compound. History In 1846 Von Ebelman's had synthesized Tetraethyl orthosilicate (Si(OC2H5)4). In 1863 Friedel and Crafts managed to make the first organosilieon compound with C-Si bonds which gone byound the syntheses of orthosilicic acid esters. The same year they also described a «polysilicic acid ether» in the preparation of Ethanol, ethyl- and methyl-o-silicic acid. The early extensive research in the field of organosilicon compounds was pioneerd in the beginning of 20th century by Frederic Kipping. He also had coined the term «silicone» (akin to ketones) in relation to these materials ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silyl Ether
Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry. Common silyl ethers are: trimethylsilyl (TMS), ''tert''-butyldiphenylsilyl (TBDPS), ''tert''-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions. Common silyl ethers Formation Commonly silylation of alcohols requires a silyl chloride and an amine base. One reliable and rapid procedure is the Corey protocol in which the alcohol is reacted with a silyl chlori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silyl Ether
Silyl ethers are a group of chemical compounds which contain a silicon atom covalently bonded to an alkoxy group. The general structure is R1R2R3Si−O−R4 where R4 is an alkyl group or an aryl group. Silyl ethers are usually used as protecting groups for alcohols in organic synthesis. Since R1R2R3 can be combinations of differing groups which can be varied in order to provide a number of silyl ethers, this group of chemical compounds provides a wide spectrum of selectivity for protecting group chemistry. Common silyl ethers are: trimethylsilyl (TMS), ''tert''-butyldiphenylsilyl (TBDPS), ''tert''-butyldimethylsilyl (TBS/TBDMS) and triisopropylsilyl (TIPS). They are particularly useful because they can be installed and removed very selectively under mild conditions. Common silyl ethers Formation Commonly silylation of alcohols requires a silyl chloride and an amine base. One reliable and rapid procedure is the Corey protocol in which the alcohol is reacted with a silyl chlori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilyl
A trimethylsilyl group (abbreviated TMS) is a functional group in organic chemistry. This group consists of three methyl groups bonded to a silicon atom minus;Si(CH3)3 which is in turn bonded to the rest of a molecule. This structural group is characterized by chemical inertness and a large molecular volume, which makes it useful in a number of applications. A trimethylsilyl group bonded to a methyl group forms tetramethylsilane, which is abbreviated as TMS as well. Compounds with trimethylsilyl groups are not normally found in nature. Chemists sometimes use a trimethylsilylating reagent to derivatize rather non-volatile compounds such as certain alcohols, phenols, or carboxylic acids by substituting a trimethylsilyl group for a hydrogen in the hydroxyl groups on the compounds. This way trimethylsiloxy groups minus;O-Si(CH3)3are formed on the molecule. A couple of examples of trimethylsilylating agents include trimethylsilyl chloride and bis(trimethylsilyl)acetamide. Trime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Fluoride
Sodium fluoride (NaF) is an inorganic compound with the formula . It is used in trace amounts in the fluoridation of drinking water, in toothpaste, in metallurgy, and as a flux. It is a colorless or white solid that is readily soluble in water. It is a common source of fluoride in the production of pharmaceuticals and is used to prevent dental cavities. In 2020, it was the 265th most commonly prescribed medication in the United States, with more than 1million prescriptions. Uses Dental caries Fluoride salts are often added to municipal drinking water (as well as to certain food products in some countries) for the purpose of maintaining dental health. The fluoride enhances the strength of teeth by the formation of fluorapatite, a naturally occurring component of tooth enamel. Although sodium fluoride is used to fluoridate water and is the standard by which other water-fluoridation compounds are gauged, hexafluorosilicic acid (H2SiF6) and its salt sodium hexafluorosilica ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trimethylsilyl Chloride
Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound ( silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3SiCl or TMSCl. It is a colourless volatile liquid that is stable in the absence of water. It is widely used in organic chemistry. Preparation TMSCl is prepared on a large scale by the '' direct process'', the reaction of methyl chloride with a silicon-copper alloy. The principal target of this process is dimethyldichlorosilane, but substantial amounts of the trimethyl and monomethyl products are also obtained. The relevant reactions are (Me = CH3): : x MeCl + Si → Me3SiCl, Me2SiCl2, MeSiCl3, other products Typically about 2–4% of the product stream is the monochloride, which forms an azeotrope with MeSiCl3. Reactions and uses TMSCl is reactive toward nucleophiles, resulting in the replacement of the chloride. In a characteristic reaction of TMSCl, the nucleophile is water, resulting in hydrolysis to give the hexamethy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bis(trimethylsilyl)acetamide
Bis(trimethylsilyl)acetamide (BSA) is an organosilicon compound with the formula Me3SiNC(OSiMe3)Me (Me = CH3). It is a colorless liquid that is soluble in diverse organic solvents, but reacts rapidly with compounds, including solvents and moisture, containing OH and NH functional groups. It is used in analytical chemistry for the derivatisation of compounds in analysis to increase their volatility, e.g. for gas chromatography. It is also used to introduce the trimethylsilyl protecting group in organic synthesis.Harry Heaney, Jian Cui, “N,O-Bis(trimethylsilyl)acetamide” Encyclopedia of Reagents for Organic Synthesis Copyright © 2007 John Wiley & Sons. . A related reagent is N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA). Synthesis and reactions BSA is prepared by treating acetamide with trimethylsilyl chloride Trimethylsilyl chloride, also known as chlorotrimethylsilane is an organosilicon compound (silyl halide), with the formula (CH3)3SiCl, often abbreviated Me3S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salt Metathesis Reaction
A salt metathesis reaction, sometimes called a double displacement reaction, is a chemical process involving the exchange of bonds between two reacting chemical species which results in the creation of products with similar or identical bonding affiliations. This reaction is represented by the general scheme: :AB + CD -> AD + CB The bond between the reacting species can be either ionic or covalent. Classically, these reactions result in the precipitation of one product. In older literature, the term double decomposition is frequently encountered. The term double decomposition is more specifically used when at least one of the substances does not dissolve in the solvent, as the ligand or ion exchange takes place in the solid state of the reactant. For example: :AX(aq) + BY(s) → AY(aq) + BX(s). Types of reactions Counterion exchange Salt metathesis is a common technique for exchanging counterions. The choice of reactants is guided by a solubility chart or lattice energy. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silyl Chloride
Chlorosilanes are a group of reactive, chlorine-containing chemical compounds, related to silane and used in many chemical processes. Each such chemical has at least one silicon-chlorine bond. Trichlorosilane is produced on the largest scale. The parent chlorosilane is silicon tetrachloride ().. Synthesis Hydrochlorosilanes They are prepared by the Müller-Rochow process, which involves treating silicon with hydrogen chloride at elevated temperatures in the presence of a copper catalyst. The idealized equation is :2 Si + 6 HCl → 2 HSiCl3 + 2 H2, Trichlorosilane (HSiCl3) is the main product; dichlorosilane (H2SiCl2) and silicon tetrachloride (SiCl4) are obtained as byproducts. The process was independently discovered by Eugene G. Rochow and Richard Müller in 1940. Methylchlorosilanes Methyltrichlorosilane (CH3SiCl3), dimethyldichlorosilane ((CH3)2SiCl2), and trimethylsilyl chloride ((CH3)3SiCl) are produced by the direct process. They are key reagents in organosilicon chemistr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
acetamide.svg "Click for more on -> Silylation")
