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Formally, a carbanion is the conjugate base of a carbon acid: R 3 CH + B − → R 3 C − + HB. where B stands for the base. The carbanions formed from deprotonation of alkanes (at an sp 3 carbon), alkenes (at an sp 2 carbon), arenes (at an sp 2 carbon), and alkynes (at an sp carbon) are known as alkyl, alkenyl , aryl, and alkynyl anions ...
Overall, decarboxylation depends upon stability of the carbanion synthon R − , [ 1 ] [ 2 ] although the anion may not be a true chemical intermediate . [ 3 ] [ 4 ] Typically, carboxylic acids decarboxylate slowly, but carboxylic acids with an α electron-withdrawing group (e.g. β‑ keto acids , β‑nitriles, α‑ nitro acids, or ...
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 trend of carbocation stability. Note the stabilization effects from adjacent carbons that donate electrons to the positive charge. The opposite trend is seen in carbanion stability. In isotopes, a tertiary bound hydrogen is more likely to be lost because the resulting carbocation is the most stable species. Radical reactions that cleave C ...
The study conducted by Wang et. al. demonstrates how Bent's rule can be used to predict the route of a synthesis and the stability of products. [14] Showing a similar application, Dubois et. al were able to justify some of their findings using Bent's rule when they found a reaction to be irreversible. [30]
In chemistry, pyramidal inversion (also umbrella inversion) is a fluxional process in compounds with a pyramidal molecule, such as ammonia (NH 3) "turns inside out". [1] [2] It is a rapid oscillation of the atom and substituents, the molecule or ion passing through a planar transition state. [3]
The generated carbanion is then protonated by the H-B species to form the product. In the case where the base used is consumed in the reaction (i.e. Butyllithium), then the carbanion can act as a base to deprotonate further starting material to generate the final product. The Brook rearrangement reaction mechanism
A species' ability to serve as a leaving group depends on its ability to stabilize the additional electron density that results from bond heterolysis. Common anionic leaving groups are halides such as Cl − , Br − and I − , and sulfonate esters such as tosylate ( TsO − ), while water ( H 2 O ), alcohols ( R−OH ), and amines ( R 3 N ...