Optical resolution and racemization mechanism of a tellurinic acid.

[reaction: see text] Optically active tellurinic acid was obtained for the first time by chromatographic resolution of racemic 2,4,6-triisopropylbenzenetellurinic acid (1) using a chiral column. Optically active tellurinic acid (+)-1 was stable toward racemization in hexane, although racemization occurred in hexane/2-propanol. The kinetic studies for the racemization, oxygen exchange reaction using H(2)(18)O, and theoretical studies clarified that the racemization of the optically active tellurinic acid in solution proceeds via a hypervalent tellurane formed by addition of water remaining in solvent.