Stereospecific SN2′ reactions of exo-4-substituted 3-halogenobicylo[3.2.1]oct-2-enes
Abstract
Stereochemically pure samples of exo-bicyclno[3.2.1]octan-2-ol are obtained from hydrolysis followed by hydrogenation–hydrogenolysis of exo-3,4-dihalogenobicyclo[3.2.1]oct-2-enes. Attempted tosylation of the intermediate hydroxy-halides in these reactions by the Tipson procedure gave only exo-4-chloro-3-halogenobicyclo[3.2.1]oct-2-enes. No inversion of configuration was detected in the reactions of exo-3,4-dihalogenobicyclo[3,2,1]oct-2-enes with sodiun halides in aprotic dipolar solvents. These results lead to the conclusion that the SN2′ reaction in this system occurs upon covalent substrates with relative configuration but inversion of absolute configuration.