Synthesis and Stereochemistry of Chiral Selenoxides and Telluroxides

Optically pure selenoxides stabilized by bulky substituents and/or intramolecular coordination with amino group were isolated by optical resolution of a diastereomeric mixture of selenoxide and chromatographic separation of a racemic mixture of selenoxide using an optically active column. Optically pure telluroxides stabilized by similar techniques were also isolated by chromatographic resolution. The absolute configurations were determined by X-ray crystallographic analysis and circular dichroism spectra. Kinetic studies on the racemization of these chiral chalcogen oxides were examined, and a mechanism for the racemization via achiral hydrate was proposed based on the H2 18O tracer studies.