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In general, in a group across the periodic table, the more basic the ion (the higher the pK a of the conjugate acid) the more reactive it is as a nucleophile. Within a series of nucleophiles with the same attacking element (e.g. oxygen), the order of nucleophilicity will follow basicity.
Also, because the intermediate is partially bonded to the nucleophile and leaving group, there is no time for the substrate to rearrange itself: the nucleophile will bond to the same carbon that the leaving group was attached to. A final factor that affects reaction rate is nucleophilicity; the nucleophile must attack an atom other than a hydrogen.
The reason lies in the higher acidity of the heavier hydrohalic acids as well as the higher nucleophilicity of the respective conjugate base. Fluoride is not nucleophilic enough to allow for usage of hydrofluoric acid to cleave ethers in protic media. Regardless of which hydrohalic acid is used, the rate of reaction is comparably low, so that ...
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.
Conjugate addition is the vinylogous counterpart of direct nucleophilic addition. A nucleophile reacts with a α,β-unsaturated carbonyl compound in the β position. The negative charge carried by the nucleophile is now delocalized in the alkoxide anion and the α carbon carbanion by resonance.
The alpha effect refers to the increased nucleophilicity of an atom due to the presence of an adjacent (alpha) atom with lone pair electrons. [2] This first atom does not necessarily exhibit increased basicity compared with a similar atom without an adjacent electron-donating atom, resulting in a deviation from the classical Brønsted-type ...
According to the New York Times, here's exactly how to play Strands: Find theme words to fill the board. Theme words stay highlighted in blue when found.
The Fukui function is named after Kenichi Fukui, who investigated the frontier orbitals described by the function, specifically the HOMO and LUMO. [3] Fukui functions are related in part to the frontier molecular orbital theory (also known as the Fukui theory of reactivity and selection, also developed by Kenichi Fukui) which discusses how nucleophiles attack the HOMO while at the same time ...