Synthesis and Stereochemistry of Optically Active Organic Selenium and Tellurium Compounds

Abstract

Some optically active tricoordinate selenium and tellurium compounds, such as selenonium ylide, telluronium ylide, selenonium imide, selenonium salt, telluronium salt, and telluroxide, were isolated by means of optical resolution of corresponding diastereomeric mixtures or asymmetric syntheses. Absolute configurations of the optically active isomers obtained were determined by their X-ray crystallographic analyses, specific rotations, and circular dichroism spectra. Racemization of the isomers by pyramidal inversion or via achiral hydrate were also examined, and activation energies for the pyramidal inversion were estimated based on ab initio MO calculations.