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Many reactions studied are solvolysis reactions where a solvent molecule (often an alcohol) is the nucleophile. While still a second order reaction mechanistically, the reaction is kinetically first order as the concentration of the nucleophile–the solvent molecule, is effectively constant during the reaction.
As nucleophiles, organolithium reagents undergo carbolithiation reactions, whereby the carbon-lithium bond adds across a carbon–carbon double or triple bond, forming new organolithium species. [32] This reaction is the most widely employed reaction of organolithium compounds.
The two main mechanisms were the S N 1 reaction and the S N 2 reaction, where S stands for substitution, N stands for nucleophilic, and the number represents the kinetic order of the reaction. [4] In the S N 2 reaction, the addition of the nucleophile and the elimination of leaving group take place simultaneously (i.e. a concerted 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.
This reaction differs from a common S N 2 reaction, because it happens at a trigonal carbon atom (sp 2 hybridization). The mechanism of S N 2 reaction does not occur due to steric hindrance of the benzene ring. In order to attack the C atom, the nucleophile must approach in line with the C-LG (leaving group) bond from the back, where the ...
The (3+2)-cycloaddition of azides to double or triple bonds is one of the most utilised cycloadditions in organic chemistry and affords triazolines (e.g. 17) or triazoles, respectively. [40] [41] [42] The uncatalysed reaction is a concerted pericyclic process, in which the configuration of the alkene component is transferred to the triazoline ...
The transition states for SN1 reactions that showcases tertiary carbons have the lowest transition state energy level in SN1 reactions. A tertiary carbocation will maximize the rate of reaction for an SN1 reaction by producing a stable carbocation. This happens because the rate determining step of a SN1 reaction is the formation of the carbocation.
The case for S N 2 reactions is quite different, as the lack of solvation on the nucleophile increases the rate of an S N 2 reaction. In either case (S N 1 or S N 2), the ability to either stabilize the transition state (S N 1) or destabilize the reactant starting material (S N 2) acts to decrease the ΔG ‡ activation and thereby increase the ...