Synlett 1991; 1991(6): 423-425
DOI: 10.1055/s-1991-20750
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Reversal of Diastereoselectivity in Reactions of Acyclic and Cyclic Radicals

Michel Bulliard* , Heinz-Georg Zeitz, Bernd Giese
  • *Institut für Organische Chemie der Universität Basel, St. Johanns-Ring 19, CH-4056 Basel, Switzerland
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Publication History

Publication Date:
07 March 2002 (online)

Radical addition reactions to acyclic alkenes 5 (diethyl citraconate) and 9 (methyl 3-hydroxy-2-methylenebutanoate) yield mainly threo product 7 (diethyl 2-tert-butyl-3-methylbutanedioate) and erythro product 11 [methyl 2-(tert-butylmethyl)-3-hydroxy-butanoate], respectively. Related cyclic alkenes 6 (citraconic anhydride) and 13 (2-cyclohexyl-6-methyl-5-methylene-1,3-dioxan-4-one) also react with high but opposite diastereoselectivity. This reversal of stereoselectivity reflects changes in the conformation of the intermediate radicals.

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