INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
capítulos de libros
Título:
The SRN1 reactions
Autor/es:
VICTORIA VAILLARD, JAVIER I. BARDAGÍ, ROBERTO A. ROSSI
Libro:
Encyclopedia of Radicals in Chemistry, Biology & Materials
Editorial:
WILEY
Referencias:
Año: 2011;
Resumen:
p { margin-bottom: 0.21cm; }
Since
its discovery, the radical nucleophilic substitution, or SRN1
reaction, has been widely used to achieve new C-C or C-heteroatom
bonds. The mechanism involves a chain propagation cycle with radicals
and radical anions as intermediates. The initiation step is an
electron transfer to a substrate to form its radical anion, which
fragments to afford a radical and the anion of the leaving group. The
radical thus formed couples with a nucleophile to give a new radical
anion which, in the next propagation step, transfers its extra
electron to the substrate, closing the cycle.
Here we discuss SRN1
reactions of aromatic substrates with carbanions and heteroaromatic
nucleophiles as well as ring closure reactions to obtain heterocycles
by different approaches.
SRN1
reactions of vinylic halides with nucleophiles and the competing
mechanisms are also examined. Reactions of aliphatic substrates that
do not react or are poorly reactive toward polar nucleophilic
substitutions (cycloalkyl, bridgehead, neopentyl and perfluoroalkyl
halides) are discussed in terms of mechanistic requirements to follow
a SRN1
process. In addition the reactions of alkyl substrates with electron
withdrawing groups also are presented.
In every year, new
synthetic strategies and mechanistic studies involving SRN1
reactions are reported, which constitute a useful tool in the field
of organic chemistry.