Otf chemistry

With an accout for my. Triflateotf chemistry, more formally known as trifluoromethanesulfonateis a functional group with the formula CF 3 SO 3. Otf chemistry triflate group is often represented by -OTf, as opposed to -Tf. It is defined as a super acid, because it is more acidic than pure sulfuric acid.

A triflate group is an excellent leaving group used in certain organic reactions such as nucleophilic substitution , Suzuki couplings and Heck reactions. Since alkyl triflates are extremely reactive in S N 2 reactions , they must be stored in conditions free of nucleophiles such as water. The anion owes its stability to resonance stabilization which causes the negative charge to be spread symmetrically over the three oxygen atoms. An additional stabilization is achieved by the trifluoromethyl group, which acts as a strong electron-withdrawing group using the sulfur atom as a bridge. Triflates have also been applied as ligands for group 11 and 13 metals along with lanthanides.

Otf chemistry

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Thank you for visiting nature. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser or turn off compatibility mode in Internet Explorer. In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript. Covalent organic frameworks, cross-linked crystalline polymers constructed from rigid organic precursors connected by covalent interactions, have emerged as a promising class of nanoporous materials owing to their highly desirable combination of attributes, including facile chemical tunability, structural diversity, and excellent stability. Despite the distinct advantages offered by three-dimensional covalent organic frameworks, research efforts have predominantly focused on the more synthetically-accessible, two-dimensional variants. Here we present an overview of synthetic approaches to yield three-dimensional covalent organic frameworks, identify synthetic obstacles that have hindered progress in the field and recently-employed methods to address them, and propose alternative techniques to circumvent these synthetic challenges.

Otf chemistry

The main problem is that the hydroxyl group is a strong base, and thus a poor leaving group. There are two main problems. First of all, on certain secondary alcohols the reaction proceeds through an S N 1 pathway, which can lead to rearrangements. Secondly, in so doing, we can end up scrambling any stereocenters that are present. For instance if we start with one enantiomer in the reaction below, we end up with some racemization of the final product. We all know that hydroxide HO- is a strong base. But have we seen any examples of weak bases with a negative charge on the oxygen? This is due to two key factors — first of all, delocalization of charge on the other oxygens through resonance, and secondly, the inductive effect of those oxygens helping to redistribute the charge. The problem is that many nucleophiles are quite basic remember — the conjugate base is a better nucleophile and the OSO 3 H still has a very acidic proton that OH group has a pK a of about 2, making it a stronger acid than acetic acid.

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ISBN Inorganic Syntheses. They can be obtained directly from triflic acid and the metal hydroxide or metal carbonate in water. Tools Tools. Download as PDF Printable version. A triflate group is an excellent leaving group used in certain organic reactions such as nucleophilic substitution , Suzuki couplings and Heck reactions. Toggle limited content width. Cookies deactivated. To use all functions of this page, please activate cookies in your browser. DE please activate JavaScript. To use all the functions on Chemie. Lithium triflates are used in some lithium ion batteries as a component of the electrolyte. PMID

Reaction Map: Reactions of Organometallics. There has been a trend in recent years towards including transition metal catalyzed reactions in the introductory organic chemistry curriculum. The reactions most common covered are palladium catalyzed coupling reactions Suzuki and Heck reactions in particular and olefin metathesis.

Cookies deactivated. Article Talk. Another popular catalyst scandium triflate is used in such reactions as aldol reactions and Diels-Alder reactions. An additional stabilization is achieved by the trifluoromethyl group as a strong electron-withdrawing group. Especially useful are the lanthanide triflates of the type Ln OTf 3 where Ln is a lanthanoid. Keep logged in. Your browser is not current. To top. Lawrance, Peter A. Microsoft Internet Explorer 6. Since alkyl triflates are extremely reactive in S N 2 reactions , they must be stored in conditions free of nucleophiles such as water. Hidden categories: Articles with short description Short description is different from Wikidata Commons category link is locally defined. My watch list My saved searches My saved topics My newsletter Register free of charge.