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The electrophilic Br-Br molecule interacts with electron-rich alkene molecule to form a π-complex 1. Forming of a three-membered bromonium ion The alkene is working as an electron donor and bromine as an electrophile. The three-membered bromonium ion 2 consisted of two carbon atoms and a bromine atom forms with a release of Br −.
In planning the synthesis of phenylacetic acid, two synthons are identified: a nucleophilic "COOH −" group, and an electrophilic "PhCH 2 +" group.Of course, both synthons do not exist by themselves; synthetic equivalents corresponding to the synthons are reacted to produce the desired reactant.
Directed ortho metalation (DoM) is an adaptation of electrophilic aromatic substitution in which electrophiles attach themselves exclusively to the ortho-position of a direct metalation group or DMG through the intermediary of an aryllithium compound. [1] The DMG interacts with lithium through a hetero atom.
The partial rate factor of electrophilic aromatic substitution on fluorobenzene is often larger than one at the para position, making it an activating group. [11] Conversely, it is moderately deactivated at the ortho and meta positions, due to the proximity of these positions to the electronegative fluoro substituent.
Synthesis of nucleosides involves the coupling of a nucleophilic, heterocyclic base with an electrophilic sugar. The silyl-Hilbert-Johnson (or Vorbrüggen) reaction, which employs silylated heterocyclic bases and electrophilic sugar derivatives in the presence of a Lewis acid, is the most common method for forming nucleosides in this manner.
Numerous quinones are significant roles in biology. Vitamin K, which is involved in coagulation of blood, is a quinone. Ubiquinone-10 is a naturally occurring 1,4-benzoquinone involved in respiration apparatus. Plastoquinone is a redox relay involved in photosynthesis. Pyrroloquinoline quinone is another biological redox cofactor.
Other mechanistic possibilities not involving direct C–H bond cleavage by the metal include (i) generation of arylmetal species by electrophilic aromatic substitution mechanism (common for electrophilic Pd, Pt, Au, Hg species), (ii) cleavage of the C–H bond via hydrogen atom abstraction by an O- or N-centered radical, which may then go on ...
When necessary, the position of the hydroxyl group is indicated by a number between the alkane name and the -ol: propan-1-ol for CH 3 CH 2 CH 2 OH, propan-2-ol for CH 3 CH(OH)CH 3. If a higher priority group is present (such as an aldehyde, ketone, or carboxylic acid), then the prefix hydroxy-is used, [19] e.g., as in 1-hydroxy-2-propanone (CH ...