Reactivities of Methylenetriangulanes and Spirocyclopropanated Bicyclopropylidenes toward Bromine. Relative Stabilities of Spirocyclopropanated versus Methyl-Substituted Bromonium Ions
作者:Sergei Kozhushkov、Thomas Späth、Torsten Fiebig、Bernard Galland、Marie-Francoise Ruasse、Prince Xavier、Yitzhak Apeloig、Armin de Meijere
DOI:10.1021/jo0162686
日期:2002.6.1
rings enhances the rate of bromination and stabilizes the intermediate cyclopropyl bromonium cations against ring opening in the course of bromine addition. Calculations at the B3LYP/6-311G(d,p) level show that unsymmetrical bromoniumions are the intermediates, and that they are stabilized by the spiroannelation with cyclopropane rings. The bromoniumion derived from 1 is less stable by 6.3 kcal mol-1