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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]
Enantioselective synthesis, also called asymmetric synthesis, [1] is a form of chemical synthesis.It is defined by IUPAC as "a chemical reaction (or reaction sequence) in which one or more new elements of chirality are formed in a substrate molecule and which produces the stereoisomeric (enantiomeric or diastereomeric) products in unequal amounts."
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 organic chemistry, neighbouring group participation (NGP, also known as anchimeric assistance) has been defined by the International Union of Pure and Applied Chemistry (IUPAC) as the interaction of a reaction centre with a lone pair of electrons in an atom or the electrons present in a sigma or pi bond contained within the parent molecule but not conjugated with the reaction centre.
Asymmetric hydrogenation is a chemical reaction that adds two atoms of hydrogen to a target (substrate) molecule with three-dimensional spatial selectivity.Critically, this selectivity does not come from the target molecule itself, but from other reagents or catalysts present in the reaction.
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, umpolung (German: [ˈʔʊmˌpoːlʊŋ]) or polarity inversion is the chemical modification of a functional group with the aim of the reversal of polarity of that group. [ 1 ] [ 2 ] This modification allows secondary reactions of this functional group that would otherwise not be possible. [ 3 ]
Diffusion control is more likely in solution where diffusion of reactants is slower due to the greater number of collisions with solvent molecules. Reactions where the activated complex forms easily and the products form rapidly are most likely to be limited by diffusion control. Examples are those involving catalysis and enzymatic reactions.