Premium
Substitution Reactions Which Proceed via Radical Anion Intermediates
Author(s) -
Kornblum Nathan
Publication year - 1975
Publication title -
angewandte chemie international edition in english
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 0570-0833
DOI - 10.1002/anie.197507341
Subject(s) - chemistry , steric effects , radical , radical substitution , azide , sulfone , ether , carbon atom , radical ion , ion , photochemistry , aryl radical , molecule , nitro , sulfur , radical disproportionation , stereochemistry , organic chemistry , aryl , ring (chemistry) , catalysis , alkyl , disproportionation
A new type of substition process at a saturated carbon atom is described. These reactions, which proceed via a chain sequence in which radical anions and free radicals are intermediates, are noteworthy for providing novel and powerful means of synthesis: they occur readily under mild conditions, they give excellent yields of pure products, and, in contrast to S N 2 displacements, they are rather insensitive to steric hindrance. As a consequence, radical anion processes are especially valuable for the preparation of highly branched structures. Many inorganic and organic anions readily enter into these displacements and, indeed, amines are also effective. Systems which undergo substitutions via this electron transfer mechanism include benzylic, cumylic, strictly aliphatic, and heterocyclic molecules. It is of interest that a number of groups which do not behave as leaving groups in S N 2 displacements are readily displaced at room temperature from a satureted carbon atom via the radical anion‐free radical pathway, e.g. , nitro, azide, sulfone, and ether groups.