5469-47-6Relevant articles and documents
Theoretical investigation of the reaction of dialkylzincs with α-alkoxycarbonyl radicals. Evaluation of α-bromoacrylates as radical acceptors in radical-polar crossover processes
Vibert, Fran?ois,Maury, Julien,Lingua, Hugo,Besson, Eric,Siri, Didier,Bertrand, Michèle P.,Feray, Laurence
, p. 8991 - 9002 (2015/11/02)
The evaluation of ethyl α-bromoacrylate as radical acceptor in dialkylzinc radical-polar cascades addresses the question of the parameters controlling homolytic substitution at zinc by α-alcoxycarbonyl radicals. Under non-degassed medium ethyl α-bromoacrylate reacts with diethylzinc to give a bromocyclopropane. The reaction involves successively radical addition, SH2 at zinc, conjugate addition of the resulting enolate to the electrophilic substrate and ring closure. Theoretical calculations were performed to get a better insight into the detailed mechanism. They highlight the impact of zinc(II) chelation on the formal SH2 step. Additional experiments performed in the presence of other electrophiles-aldehydes and acylsilanes-are discussed.
