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Homolytic Cyclizations of N ‐Chloroalkenylamines
Author(s) -
Stella Lucien
Publication year - 1983
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.198303373
Subject(s) - homolysis , radical , chemistry , intramolecular force , protonation , stereoselectivity , reactivity (psychology) , chlorine , radical cyclization , stereochemistry , medicinal chemistry , photochemistry , organic chemistry , catalysis , medicine , ion , alternative medicine , pathology
Many N ‐chloroalkylamines with double bond(s) dissociate homolytically to give chlorine atoms and aminyl radicals which undergo intramolecular cyclization reactions. Here, the nature of the aminyl radicals (neutral, protonated, or complexed to metal salts) appears to be important. The reactivity varies strongly from one species to another, and their selectivities can be different towards addition, substitution, abstraction, or dimerization reactions. A good synthetic tool appears to be the “complexed radical”, which is generated under mild conditions. A variety of β‐functionalized, substituted, fused, or bridged azaheterocycles with alkaloid part structures thus become easily accessible in high yields, in a regio‐ and, possibly, stereoselective manner. Many examples are discussed illustrating the synthetic possibilities, limitations, and mechanistic features of this cyclization process.