Stereoselective synthesis of Boc-protected l-seleno- and tellurolanthionine, l-seleno- and tellurocystine and derivatives

Optically active seleno- and telluro amino acids can be synthesized from serine via its β-lactone with selenides and tellurides under overall retention of the serine stereochemistry. Boc-protected l-selenolanthionine, l-tellurolanthionine, l-selenocystine, l-tellurocystine and l-tellurocysteine derivatives can be obtained in good yields.