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The physical manifestation of leaving group ability is the rate at which a reaction takes place. Good leaving groups give fast reactions. By transition state theory, this implies that reactions involving good leaving groups have low activation barriers leading to relatively stable transition states.
A nucleophilic aromatic substitution (S N Ar) is a substitution reaction in organic chemistry in which the nucleophile displaces a good leaving group, such as a halide, on an aromatic ring. Aromatic rings are usually nucleophilic, but some aromatic compounds do undergo nucleophilic substitution.
This means that the better the leaving group, the faster the reaction rate. A general rule for what makes a good leaving group is the weaker the conjugate base, the better the leaving group. In this case, halogens are going to be the best leaving groups, while compounds such as amines, hydrogen, and alkanes are going to be quite poor leaving ...
Fluorosulfonate, in organic chemistry, is a functional group that has the chemical formula F-SO 2-R, and typically is a very good leaving group. In organic chemistry, fluorosulfonate is different than fluorosulfate. In fluorosulfonates, sulfur atom is directly bonded to a non-oxygen atom such as carbon.
Good leaving groups on the substrate lead to faster S N 2 reactions. A good leaving group must be able to stabilize the electron density that comes from breaking its bond with the carbon center. This leaving group ability trend corresponds well to the p K a of the leaving group's conjugate acid (p K aH ); the lower its p K aH value, the faster ...
For example, if the R 2 group is a methyl group and the R 1 group is a trifluoromethyl group, the resulting compound is methyl trifluoromethanesulfonate. Sulfonic esters are used as reagents in organic synthesis, chiefly because the RSO 3 − group is a good leaving group, especially when R is electron-withdrawing.
Tosyl group (blue) with a generic "R" group attached Tosylate group with a generic "R" group attached. Note the extra oxygen, compared to plain tosyl. In organic chemistry, a toluenesulfonyl group (tosyl group, abbreviated Ts or Tos [nb 1]) is a univalent functional group with the chemical formula −SO 2 −C 6 H 4 −CH 3.
The sulfonyl functional group (RS(O) 2 R') has become an important electron-withdrawing group for modern organic chemistry. α-Sulfonyl carbanions may be used as nucleophiles in alkylation reactions, Michael-type additions, and other processes. [3] After having served their synthetic purpose, sulfonyl groups are often removed.