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In chemistry, transferability is the assumption that a chemical property that is associated with an atom or a functional group in a molecule will have a similar (but not identical) value in a variety of different circumstances. [1] Examples of transferable properties include: Electronegativity; Nucleophilicity; Chemical shifts in NMR spectroscopy
In organic chemistry, a group transfer reaction is a class of the pericyclic reaction where one or more groups of atoms is transferred from one molecule to another. Group transfer reactions can sometimes be difficult to identify when separate reactant molecules combine into a single product molecule (like in the ene reaction).
In the context of electron transfer, these groups enhance the oxidizing power tendency of the attached species. For example, Tetracyanoethylene serves as an oxidant due to its attachment to four cyano substituents, which are electron-withdrawing groups. [5] Oxidants with EWGs are stronger than the parent compound.
E (from the German entgegen) means "opposed" in the sense of "opposite". That is, Z has the higher-priority groups cis to each other and E has the higher-priority groups trans to each other. Whether a molecular configuration is designated E or Z is determined by the CIP rules; higher atomic numbers are given higher priority. For each of the two ...
In chemistry, a leaving group is defined by the IUPAC as an atom or group of atoms that detaches from the main or residual part of a substrate during a reaction or elementary step of a reaction. [1] However, in common usage, the term is often limited to a fragment that departs with a pair of electrons in heterolytic bond cleavage. [2]
An electron withdrawing group (EWG) will have the opposite effect on the nucleophilicity of the ring. The EWG removes electron density from a π system, making it less reactive in this type of reaction, [ 2 ] [ 3 ] and therefore called deactivating groups .
The Cram's rule of asymmetric induction named after Donald J. Cram states In certain non-catalytic reactions that diastereomer will predominate, which could be formed by the approach of the entering group from the least hindered side when the rotational conformation of the C-C bond is such that the double bond is flanked by the two least bulky groups attached to the adjacent asymmetric center. [3]
Heterogeneous reactions where reactants are in different phases are also candidates for diffusion control. One classical test for diffusion control of a heterogeneous reaction is to observe whether the rate of reaction is affected by stirring or agitation; if so then the reaction is almost certainly diffusion controlled under those conditions.