Stereochemistry of Base-Promoted 1,2-Elimination from exo-2-Bicycloheptyl Tosylate and Chloride

Article abstract of DOI:10.1021/jo00001a041

Elimination reactions of exo-2-bicyclo<2.2.1>heptyl tosylate and chloride and their exo-3-deuterated analogues are studied in base-solvent systems that induce clean bimolecular 1,2-eliminations.Their relative propensities for competitive syn-exo and anti-endo-H elimination modes are assessed from nonkinetically determined deuterium isotope effects and the deuterium content in the bicyclo<2.2.1>hept-2-ene formed from the deuterated substrates.The competition between syn-exo and anti-endo-H elimination is influenced by base association, which stabilizes the synelimination transition state.Potential steric hindrance by oversized dissociated bases has no effect on the elimination stereochemistry.