Article ID Journal Published Year Pages File Type
5214436 Tetrahedron 2015 12 Pages PDF
Abstract

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.

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Physical Sciences and Engineering Chemistry Organic Chemistry
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