Reactivity of (R)-2-tert-Butyldihydrooxazole Derivatives Prepared from Serine and Threonine: Novel, Versatile Chiral Building Blocks^†

The unsaturated cyclic N,O-acetals 1 and 2 are promising starting materials for the synthesis of further valuable chiral intermediates. They were prepared from serine and threonine, respectively, by electrochemical decarboxylation. Acylation and addition reactions as well as catalytic hydrogenation were used to convert 1 and 2 into the mono-, bi-, and tricyclic compounds of type 3, in a regio- and stereoselective fashion.