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A carbanion is one of several reactive intermediates in organic chemistry. In organic synthesis, organolithium reagents and Grignard reagents are commonly treated and referred to as "carbanions." This is a convenient approximation, although these species are generally clusters or complexes containing highly polar, but still covalent bonds metal ...
Structure of methylenetriphenylphosphorane. Phosphonium ylides are used in the Wittig reaction, a method used to convert ketones and especially aldehydes to alkenes. The positive charge in these Wittig reagents is carried by a phosphorus atom with three phenyl substituents and a bond to a carbanion. Ylides can be 'stabilised' or 'non-stabilised'.
The benzyl cation or phenylcarbenium ion is the carbocation with formula C 6 H 5 CH + 2; the benzyl anion or phenylmethanide ion is the carbanion with the formula C 6 H 5 CH − 2. None of these species can be formed in significant amounts in the solution phase under normal conditions, but they are useful referents for discussion of reaction ...
Structure of the 2-norbornyl cation based on X-ray crystallography. All other C-C bond lengths are normal (ca. 1.5 Å). [1] In chemistry, a carbonium ion is a cation that has a pentacoordinated carbon atom. [2] They are a type of carbocation. In older literature, the name "carbonium ion" was used for what is today called carbenium.
The use of 11 C can be used to study the formation of the carbanion as well as study its lifetime which can not only show that the reaction is a two-step E1cB mechanism (as opposed to the concerted E2 mechanism), but it can also address the lifetime and stability of the transition state structure which can further distinguish between the three ...
The anionic charge is delocalized over the oxygen and the two carbon sites. Thus they have the character of both an alkoxide and a carbanion. [5] Although they are often drawn as being simple salts, in fact they adopt complicated structures often featuring aggregates. [6] Structure of the lithium enolate PhC(OLi)=CMe 2 (tmeda) dimer. H atoms ...
Structure of the 2-norbornyl non-classical carbenium ion. All other C-C bond lengths are normal (ca. 1.5 Å). [7] Carbonium ions can be thought of as protonated or alkylated alkanes, bearing the general formula CR 5 + (R = alkyl or H). A typical example is the methanium ion, CH 5 +, which is formed by protonation of methane using a superacid ...
The postulated transition state possesses a five-membered, envelope-like structure. [5] The group attached to the carbanion (G) can occupy either a pseudoequatorial or pseudoaxial position, although the former is usually preferred. Large substituents on the other side of the ether oxygen prefer to occupy the exo position (R E) to avoid A 1,3 ...