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The Stereoselectivity of Intermolecular Free Radical Reactions [New Synthetic Methods (78)]
Author(s) -
Giese Bernd
Publication year - 1989
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.198909693
Subject(s) - stereoselectivity , chemistry , radical , steric effects , scavenger , intermolecular force , free radical reaction , free radical scavenger , computational chemistry , organic chemistry , molecule , catalysis , antioxidant
The regio‐ and chemoselectivities of free radical reactions are often high and largely predictable; systematic studies have now shown that the stereoselectivity of free radical reactions can also be directed. Examples involving five‐ and six‐membered cyclic radicals will be used to show how steric and stereoelectronic effects influence the diastereoselectivity of reactions of cyclic radicals with olefins. The temperature, the solvent, and the nature of the radical scavenger used also play a role, so that, if the correct reaction conditions are used, the stereoselectivity of reactions for cyclic reactants can be very high. Lower stereoselectivities are often observed for reactions between acyclic radicals and acyclic alkenes. However, preliminary experiments have indicated that under certain conditions such systems can also react in a stereoselective manner.