Tin-free radical alkoxyamine addition and isomerization reactions by using the persistent radical effect: variation of the alkoxyamine structure

Autor:	Christian Wetter, Armido Studer, Kian Molawi, Tobias L. Schulte, Kai Oliver Siegenthaler
Rok vydání:	2005
Předmět:	Steric effects Addition reaction Nitroxide mediated radical polymerization Cobalt-mediated radical polymerization Chemistry Radical Organic Chemistry General Chemistry Photochemistry Isomerization Radical cyclization Catalysis Homolysis
Zdroj:	Chemistry (Weinheim an der Bergstrasse, Germany). 11(8)
ISSN:	0947-6539
Popis:	Various C-centered radicals can efficiently be generated through thermal C-O-bond homolysis of alkoxyamines. This method is used to perform environmentally benign radical cyclization and intermolecular addition reactions. These alkoxyamine isomerizations and intermolecular carboaminoxylations are mediated by the persistent radical effect (PRE). In the paper, the effect of the variation of the alkoxyamine structure--in particular steric effects in the nitroxide moiety--on the outcome of the PRE mediated radical reactions will be discussed. Fourteen different nitroxides were used in the studies. It will be shown that reaction times can be shortened about 100 times upon careful tuning of the alkoxyamine structure. Activation energies for the C-O-bond homolysis of the various alkoxyamines are provided. The kinetic data are used to explain the reaction outcome of the PRE-mediated processes.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_dedup___::43cf5b8ee36ab4bfe31a300a3f7207d0 https://pubmed.ncbi.nlm.nih.gov/15696581 Zobrazit plný text záznamu Plný text