The resulting carbanion is stabilized by the structure of the carbanion itself via resonance charge distribution and by the presence of a charged ion prosthetic group.
32.
The resulting carbanion is stabilized by the structure of the carbanion itself via resonance charge distribution and by the presence of a charged ion prosthetic group.
33.
The carbanion forms by proton abstraction of the acidic ?-proton by pyridine ( now serving a double role ) akin to the Knoevenagel condensation.
34.
Added base forms a carbanion which displaces the tosylate group in a nucleophilic displacement to an azirine and added water subsequently hydrolyses it to the aminoketone.
35.
"' Azomethine ylides "'are nitrogen-based 1, 3-dipoles, consisting of an iminium ion next to a carbanion.
36.
The donor substrate is then decarboxylated, forming a carbanion internmediate, which will attack C1 of the primer substrate, and create the elongated acyl chain.
37.
If an " E "-product is desired, another alternative is the Julia olefination, which uses the carbanion generated from a phenyl sulfone.
38.
In 1984 Olmstead presented the lithium crown ether salt of the triphenylmethyl carbanion from triphenylmethane, n-butyllithium and 12-crown-4 at low temperatures:
39.
In order to convert the atom from sp 3 to sp 2, a carbocation, carbanion, or carbon p " K " a of 16.
40.
These distortions, coupled with the hydrogen bonding between Arg221 and the C3 hydroxyl, induces the C3 hydroxyl group to ketonize and increases the carbanion character of C4.
