Stereoselective Synthesis of Orthogonally Protected β-Hydroxy-α-,γ-diamino Butyric Acids

A synthesis of all four stereoisomers of the unnatural amino acid β-OH Dab (α,γ-diamino butyric acid) in orthogonally protected form is described. The synthetic strategy relies on a three-step sequence comprising stereoselective dihydroxylation, sulfite formation, and regioselective sulfite opening with azide to build the densely functionalized carbon skeleton.